Even though Blackbird sounds more like road-kill, don't be put off by the initial demonstration. If you can get past the introduction, there is quite a lot of accurate, well-presented information here. I wager most of these negative comments were made after hearing only the first 2 minutes of this 1 hour presentation, so those interested in learning something should keep watching.
I couldn't agree more. However, I would be concerned about the building skills of a highly skilled player. Each vocation requires a lifetime of study and practice, so it follows that a master builder cannot and need not be a master guitarist. After all, I thought I knew a little about how guitars worked until I listened to the rest of this presentation, so in the reverse situation, I would have made a real fool of myself. Even so, he'd have done himself a favor to have someone else play the intro!
Yes, I take your point. He excels in both disciplines. Perhaps I am over-generalizing with regard to the playing ability of luthiers. Even so, maybe we would agree that Henderson represents the exception rather than the rule.
the average luthier probably starts off learning to play then discover they love building guitars a lot more and put their minds to that. Id bet most luthiers arent very good players. And very few great players could build a decent guitar
Wonderful lecture- full of information and presented in a concise and easily understood style. You cleared up many points for me about guitar construction and performance, especially the critical importance of the bridge. Thanks for posting.
As others have pointed-out, the guitar playing at the beginning is excruciating - is the guitar even in tune? However, apart from that, it is an excellent and very informative video. Dominic is clearly a real enthusiast and really seems to know his stuff. He also puts it across well in a clear no-nonsense way. There's a lot of hype out there about guitar 'tone', but this video helps debunk or explain a lot of the myths. Thanks for posting - keep up the good work :-)
i think he was deliberately playing without any care for accuracy, his later little bits sounded like he knows what he's doing, it was just because the talk was about sound, rather than playing. it wasn't clear that he was making fun, but i think that was the intention.
Thank You, for a quick response ! The lesson at Sherry-Brener included the hanging of the various types of exotic woods on a thread and hitting it with a physicians 'reflex' hammer and either comparing it with a tuning fork during the in-process construction and later with an electrical or digital instrument, etc.
This guy was really informative and got a lot of flak for his playing and tuning . These instruments probably came directly from the atmosphere of his home; through all kinds of weather to the classroom. He explained that tuning would be off , but few of the critics here seemed to listen. As for his playing; he is a physics teacher/hobby builder. If Tommy Emanuel was playing -- the instrument would have been better displayed ; however this was not so much a performance but a physics class . Most critics here fail to realize this either . I did get a chuckle when he played the intro to Smoke on the Water on that old Aoud ( hope the spelling was right). Showing a 12th century Arabic rock group coming up with this would be a good sketch for SNL .
As one who spent a lifetime in physics and recently developed a love for guitars I really appreciated this presentation He did a great job bridging the gap between the art world and technology of guitar construction. I am not an expert in guitar construction but have a deep interest and Dominic Howman explained guitar construction using well established physical principals.
The life of a Luthier is certainly fascinating but I don't think I have the patience. I would much rather spend my time playing. Thank you to the talented people who make these wonderful instruments.
It has always fascinated me when things are taken down to sheer fundamental building blocks. I loved the wood bashings. :D Seen a lot of guitars but never saw an inside of one.
very professional presentation, well done ... ...I have to point out however that you got your Florentines and your Venetians mixed up ... the Florentine cutaway (as seen in the video) is the pointy one ...the Venetian cutaway is the one with the smooth rounded curves,
I wish to commend you--this has been the most comprehensive lecture on acoustic guitar making that I have seen--I am also a guitar builder and I have found this to be the most informative lecture yet---great job! I own Logan Elite Guitars--coming soon! At the moment you cannot purchase any of my guitars I am building a collection! You Sir are amazing! I wish I had the Public relations that you do to speak to the public! Thank You so much for this video!
Hello thank you for the wonderful information,i was wondering if you have videos where you go through the process of making an acoustic guitar? thanks again great info!
Hi Rockin Pip, sorry but I don’t have any videos on the process of making a guitar. Given the popularity of this video, I have been contemplating expanding the content. Construction methods would be inseparable from theory. - Dominic
Terrific lecture! It was well organized and quite comprehensive. It was a great idea to get a luthier who is really on his game to present this to science-minded folks. It brought out interesting points. Thanks.
19:49 He clearly mixed up between Venetian and Florentine cutaway... The Venetian is actually easier to make these days because machines can bend the sides through the use of a mould. Florentine requires a bit more handy work as the sharp curve is joined by two pieces of timber and a triangular supporting block at the location of the cutaway to help stabilising the cut it requires longer sides material to join otherwise you end up with weird grain pattern. That's why only high end custom built acoustic guitars have Florentine Cutaways as a standard e.g. Ervin Somogyi, Michael Greenfield, Matt McPherson...etc
Great talk, scallop remark also very interesting learning the origins, as I have two on the go, one with a very deep cross brace profile, and yes scallops,.... Both are similar volumes, but different materials, body and necks so looking forward to the finish and how well they are. Your talks about wood initially is extremely valuable (to a lay person and surprisingly misunderstood by many) as were your description of tonal modes and the top's behavior. Shame on anyone giving you a negative wave. Thank you for sharing your experience.
thank you for the talk it was so informative I really have been wanting to find more media like this about types of woods used in guitars awesome video, people remember he is not a professional guitar player he is just teaching about the properties of the woods
Yes every critiquing playing i feel they missed, how valuable this class is to aspiring luthier's he scientifically laid out an artform that many see a mystic, i can't express in words the value i have gained from this vid not even finished it and i know i will rewatch again & again. and use this info to teach my musician friends the science & woodwork that create, tone and resonance in acoustic stringed instruments. Info is even valuable for wood percussion.
Negative comments are like people (making fun of and discrediting) einstein for the way he holds his pencil and writes his 4's . How cares he just have us laws to better understand our universe. This is the final piece i needed to control what the guitar sounds like anyone can make one look like a great guitar their value is audible and i feel i can now start to control that. There is no amount of money that is too much to get this info and we get it FREE. BLESS EVERYONE WHO THIS GIVES A RICHER UNDERSTANDING OF THE ACOUSTICS OF WOOD. im off to practice and collect wood i will be back when i have invented all my dream instruments.
This was a really enjoyable, informative video. I think i'm almost ready to tackle my first acoustic guitar build (almost...), so this has been really helpful. Thank you for taking the time to share your expertise with the world.
i have ten guitars at the moment and i've owned about thirty in the last few years, my pride and joy being a '66 gibson J45, what you said about vibration going through the back to the player, and sound holes that are cut into the sides makes sense, i also have a martin OOOX1, spruce top but HPL back and sides, basically laminate, i think it's the best guitar i've ever touched, the sound is clean, the bass growls and the trebles ring, but what makes it a complete experience is that the back passes the vibration to the player, so you get to feel the guitar as well as hear it (i play fingerstyle pretty exclusively). i've been looking at (not playing) composite and carbon fiber guitars and i think the same might be true of them, mcpherson and composite acoustics guitars sound a whole lot better than some solid wood.
Despite the lack luster playing at the beginning of the video, the video is an excellent discussion of the fundamental physics behind the making of steel string guitars and how the physics is addressed in the selection of materials and construction techniques used to build a guitar. Very informative.
That was excellent! I saw this after several guitar factory tour vids and now much better get the points they were making! Especially the Godin acoustic tour.
As an engineer and a solid body hobby builder, I found this exactly the kind of information I wanted. The whys of instrument making have always fascinated me. Obviously the epitome of guitar building is the acoustic. Never tried one because of the precision required and the tools needed to get it right. Yet I now have a better understanding of the physics of the build. This is something that takes extreme patience, like learning to play, which is why I'm not much of a player. Would be nice to see a follow-on for the solid body and ways to optimize it and the various sounds you get from different woods. Thanks and remember Leo Fender was an engineer and allegedly didn't play guitar.
@@cdreid99999 electric has none of this if you have a str8 fretboard & saddle + pickup. A shoe could sound great. acoustics takes more wood skill, acoustic/resonance/sound knowledge, . Mount strings pickup and action you got a great electric. Its gr8 to start learning fundamentals. This is a skill/craft/art. Like comparing riding the bike to the Tour de France
To anyone wanting to approach guitar design with a physics mind I would recommend understanding several topics which were not included in this lecture, such as -Specific modulus -Helmholtz Frequency -Neutral Axis (and 'moment') -String Exit Angles
The 'sound hole' is actually an air hole, used to prevent any standing waves that would be self-interfering by letting air escape. People that record guitars for a living know this, and do not mic the guitar at the hole, but some where else. Almost all of the sound is produced by the vibrating top, so the materials and construction of the top is essential for a specific or pleasing sound. Thanks for the video; I liked it.
Thanks very much, Dominic, for sharing your extensive knowledge. Very helpful for me, thinking about my next build. I have a question about vibrations of the table: I got the impression that the monopole mode pumps air in and out of the sound hole, whereas the cross- and long dipoles merely move it within the guitar body (because one side of the soundboard goes up while the other goes down, suggesting cancellation). So, as I understand, the dipoles only make sound from the soundboard, not through the soundhole and, even that from the board would cancel to some extent for the listener in front. Leaves me wondering why the fanstrutting of classic guitars is designed to increase the cross-diapole (as I understood you to say). Surely it wastes sound energy and makes them quieter? Big problem in a concert hall.
The info is extremely good for luthiers :) The reason the intro sounds so bad is is because it's only partly picked up by his lapel mic. If he was playing into a proper mic, it would have been more even. As far as tuning, that could be an artifact of video speed, etc. Way to many influences to cancel out in an inexpensively made video in a glossy classroom setting. Do it all over in a sound studio correctly mic'd, and most folks would not have the gripes ...
Was this an example of a bad sounding guitar at the beginning? I’m still watching the video so I’m not sure if he is going to touch on that but I thought it sounded bad
FYI at around 20:00 when you are holding your guitar and talking about the cutaways you have it backwards. the one you are holding is a florentine cutaway and the smooth curved style is a venetian cutaway.
Sir, your effort is to be praised. Are you familiar with soundboard crown? Tension on the topside and compression on the underside, with specific downbearing at the saddle by the strings. These are physics on pianos as well as guitars. this is a finely balanced equilibrium at different sections on the bridges to achieve desired resulting tonal projection ( usually more down pressure in the high treble section to achieve a balanced volume at the loss of sustain but a 2-inch long, thin wire needs to be as loud as the 7-foot bass string. less downbearing equals more sustain, but you give up dynamics. hope my 2 cents helps ps. the 70 kgs is lateral tension. not to be confused with downbearing. on an average piano lateral tension is about 20 tons, while downbearing is about 6 lbs. per string. ( about 225 strings per piano )
Great lecture. Obviously, this guy doesn't take himself (or his playing) too seriously. I'd enjoy a few hours of conversation (with a few pints) with this guy. Good stuff, Dom!
Most people take PLAYING music far to seriously. The forget its PLAYING egos destroy fun and the ability to learn and grow. Ive been around far to many of those. I would join you guys for beers but NO playing or fun conversation this is music and building instruments.
Great video Dominic. You should ignore the Trolls. Lots of useful information in a short presentation. What are you using for the finish on these guitars?
Interesting talk, and entertaining too.....Just a few extra phyics bits if interested: the bridge can be in the mid of the lower bout, as in 12 fret guitars. The only reason the wee guitars are tinny is due to the area of the guitar not the bridge position. Low tension can give nice bass sounding guitars, as in classical. Small scales on large guitar bodies are possible, and sound great. The only reason we don't see many is that blokes have large hands. We may see more choice in the future catering to smaller hands, and end up with small scale 12 fret dreads. Certainly a gap in the market there for would be makers! The saddle can be low, if the bridge is stiff. A heavy bridge has a lower response, as it takes more ooomph to shift it. My very thin bridge with a low saddle produces amazing sustain and loudness. The latest guitar makers know this. Of course you can use the 'Martin' way of making, and follow the recipe, but it is not the only way of building a guitar. The back can be considered as the speaker case, and should detract the least from the top.
Fair enough, the playing at the beginning is a shocker but the rest of the video is really interesting if you want to know about the internal construction of an acoustic and why it's made like it's made. A really good place to stat if you are thinking about making one yourself.
You say that the whole guitar vibrates and then say that the energy is transferred via the bridge only. In my reading of the events there is also a significant transference and modulation via the fret and finger. The integrity of the neck is hugely important to the tone.
periurban Tone quality is highly subjective and as a result it is hard to create an accurate science , also great music does not always have great tone instruments so it becomes even more difficult to assess just how important tone is in any song to a broad audience. Add to all this the importance of tone from the player not the instrument , if we had given this instrument to Tommy Emmanual I am sure most people would have been more convinced of Tone .
+periurban Not necessarily a contradiction. There will be an energy loss through the neck, as opposed to the bridge being directly part of the resonator, so its energy contribution must be much lower. It is also to be considered what happens when neck fails: the main part of a string instrument is a tensioned string, and it's the neck that upholds the tension. The higher the string tension, the more energy a string vibrating at a given amplitude stores. So in case of neck weakening, the contribution of loss of tension is much larger than the contribution of reduced sonic conductance.
He played White swan swimming in the pond today... So sweet. But I love the idea of rethinking guitar design. Compare it to finite set strength calculations, that has completely thrown over traditions, for example a hydrofoil can not be enhanced by simply trying a slightly different shape, you can't do without computers designing these, you'd make an average one, at best.
Super interesting presentation, the bracing designs and techniques are fascinating. It's really tough to take it seriously when all your guitars are so far out of tune though, there's really no excuse for not tuning a guitar and a real shame we couldn't enjoy the sound of all your hard work and plethora of styles of build. Immediately it makes someone question why such as detailed, obsessive, obviously talented creator would ignore 30 seconds to put a guitar in tune? Maybe some overlays of you playing in tune over those small parts would help. It's a tiny point but a guitar maker should care about tune more or what other small points could he be missing are the thoughts that come to mind. At least I would have expected you to mention it as not doing suggests you were not aware it was out of tune or simply didn't care. Both are odd choices.
Yeah those guitars clearly just went from a hot car to a cold room, but generally there's about 10 minutes to set up a computer and move everything into the room, so I get how easy it would be to overlook. Especially while trying to prepare yourself to speak for an hour. Still should've been mentioned though, but I guess once you start the show must go on!
great video! One of the key take aways was the physical properties of the soundboard playing a role. A particular species may be known for its qualities but those properties can be found in woods not necessarily known to be reputable. so the take away was, go with the properties of the piece you have. That being said, how could one do a quick specific gravity or modulus of elasticity calculation when you have a wood selection in front of you?
1st Glad you reinforced what I thought of in regards to scaloping bracing. 2nd the placement of the bridge, is that THE exact center or from the end of the fretboard (top of the sound hole) to the end of the guitar? Lastly I appreciate this video it helps greatly
Wonderful video thanks for sharing. I have a question if you would be so kind. Can you do a video on voicing the sound board and share your techniques? I noted the tapping and the music box. I use a tuning fork to get an idea but only have one fork in "A". From a physics perspective would you recommend all 8 notes to get a feel for resonance or is that a little over the top? I have only built a few guitars and I am now exploring voicing from a scientific perspective and would love your input. Also have you given any thought to chambering the body or know of anyone who has? What I am thinking is Dr. Bose's approach to speakers. But anyway this was really really thoughtful and provocative talk on the subject thank you from the bottom of my heart.
Excellent video. Question: What is the reason for the angle of the tone braces in the lower bout. Jean Larrivee, I'm pretty sure, aligns his tone braces perpendicular to center ('symmetrical bracing'), and the Larrivee guitars I've heard and played have superb, bright tone and projection. Thanks, B.J.
You can't compare the domed structure of guitars and violins because the bridge on the violin presses down on the top as the strings are like bowstrings, trying to shoot the bridge like an arrow through the top. A guitar bridge is pulled towards the neck and rocked towards the neck. Doming is mostly a fad on guitars, but it deals with clients who won't take care of their guitar moisture wise, reduces splitting; it may ad some structure to the bridge rock load path; And it both makes some guitars easier, or harder to build. On tone, it isn't critical, though it sorta loads the top in the wrong direction which should marginally kill tone, but doesn't seem noticeable. You are essentially forcing the sound board into tension on the bridge side, and compression on the inside, and those effects are uneven relative to grain direction.
Very enjoyable and informative lecture. I marvel at the skill of modernday builders, knowing full well that some of the tonewoods available to them today cannot hold a candle to most of the tonewoods available to luthiers in the late 19th and early 20th centuries; notably Adirondack spruce as a top.
I don't think the guitar is bad. I think he's more of a hobbyist player, and more interested in building guitars. If he hired someone to demonstrate for him or tuned it (although it wasn't as out of tune as you think, he was just hitting the wrong strings a bunch of times) I think it would have sounded really good.
For Everyone its a hobby just some people get big heads when they hear 1 person play worse than them. Great contribution can tell how much you guys learned from all this info.
A good acoustic instrument teacher will instruct to never mute the instrument (allowing shirt sleeves or other to contact). This applies mostly to the top, but also the back of the instrument can resonate as well. Humidity is a major factor - drier resonates better than humid.
It's actually very common for instrument builders (Luthiers) to not be very good at actually playing the instruments. I was surprised when I first learned this but this was how it was explained to me. In any given month they could build a guitar a violin a ukulele and a banjo. All these instruments are pretty different, and it's hard to build any real proficiency when you're learning them all at the same time. It's much more efficient to master 1 or 2 of them, then learn how to translate the skills.
Mastery takes time only so many hrs they play more instruments instead of focusing on just playing one. Most guitarist cant build one, it may look right nut would sound shitty.
I did not build my own guitar yet, but I did convert a Spanish guitar. Now it is a flat body Spanish guitar, and it has three strat clone pickups and one piëzo pickup. My tip: buy a cheap nylon string guitar, steam the glue and open the top. Yourself. Then you have some options, you can CHANGE your guitar. A. Find cedar or spruce or any wood you like, you can replace the plywood top by solid wood. That top you can plane, make it thin at spots where that is possible. Find out yourself how that works. This is a great project, you need to rebuild a lot of guitar, bracing included. B. Move the bridge! Watch out, the frets are calculated for this scale. If you want to keep things simple, you move the bridge, and you remove the fretboard, moving it according to the bridge. You can make a longer neck, getting the bridge next to the sound hole, or you shorten the neck because bridge goes to the neck strap button. Why? Position of the bridge makes the top resonate differently, the guitar will sound totally different. And it looks funny. Though, it is a lot of work, changing the neck. A and B are seperate projects. You can combine them. Thanks for reminding me of my cigar boxes, it is time to build a cedar top. And maybe on a 12 string (nylon) guitar, maybe 8 string nylon tuned like a 4 string bass, only double strings. We'll see.
You forgot to mention that there is a "sound pole" under the bridge going to the back of a violin to help transfer the vibrations and strengthen the top under the bridge.
I enjoyed your video. It was well presented. I have a few questions: Does the species of wood (sitka spruce, western red cedar, red spruce, etc.), used for the bracing on the soundboard, have an effect on the sound of the guitar? What species of wood do you prefer, for the soundboard bracing, and why? Does the style of kerfing (traditional kerfing vs. reverse kerfing) have an effect on the tone of the guitar? Can you provide more information on the vibration tool used to "break in" a new guitar? Thanks in advance.
Hi +Chad Redding, the species of wood used to brace the soundboard (and back) of a guitar is not as relevant as the stiffness of the wood used. Wood has such great variations in its mechanical properties that it is possible to make braces from two different species of wood that have identical mechanical properties. On the other hand it is possible to use the same species of wood from two different trees to make a brace and they have wildly different mechanical properties. So it is wrong to think “Martin used red spruce for their pre-war guitars so I must use red spruce to get a good sound from my guitar”. I use Sitka spruce for my bracing only because it is readily available to me. I weed out any brace stock with runout and skewed grain. What I do, and anyone serious about making guitars should do, is to consider the stiffness of the brace stock. There are many ways to measure stiffness. I prefer the old fashioned one of checking the grain count and flexing the brace with my hands. I don’t build with any pre-determined stiffness for individual braces, but find the stiffest wood and use that for the main X braces and the transverse braces on the lower bout. The skill in guitar making is not in what species of wood you use for bracing but how you carve the braces to control their stiffness. Using the stiffest wood allows you to make a brace with less mass. I haven’t explored the effect of different styles of kerfing - I use a traditional style. I have found that basswood is an excellent material to use. I was told by Bob Hoover during a tour of his Santa Cruz workshop that he liked the way basswood decouples vibrations from the top to the sides and the back to the sides. I was lucky enough to play some Santa Cruz guitars after the tour and have been a believer ever since. I handcut all my kerfing and have to say it’s my least favourite part of guitar making by a long shot. The best tool for breaking in a new guitar is your hands. I do have a Tonerite which is really just an expensive fish tank pump. Does it work? Yes it does take a brand new guitar and “settles” it down or “breaks it in”. It won’t change the fundamental tone of a guitar. Only someone who has strung up a guitar for the first time understands how much the sound changes in the first few weeks of stringing it up. Initially you might love the sound of a newly birthed guitar. Later that night you play it and it sounds awful. The next day it sounds heavenly etc. Once the tension soaks into the wood and it has been played (or Tonerited) for a few weeks, it’s essentially broken in. I sometimes get to play a friends guitar that gigs 3 or 4 nights a week, 3 hours at a time. That guitar sounds so wonderful and deep because the wood constantly gets a real workout. I think perhaps that is more what a Tonerite was designed to achieve. - Dominic
19:49+ Don't mean to be rude, as I very much appreciate the lecture, but you're mixing up Venetian and Florentine cutaways. Venetian is the rounded cutaway. Florentine is sharp. Gibson pretty much coined the terms starting back with their fancy florentine style mandolins with sharp cutaways way back. Then before WWII, they started making archtop guitars with rounded cutaways that they originally marketed as "premier." Later they began referring to the design as "Venetian." There were plenty of other companies who offered cutaways of course, but Gibson supposedly is credited for coining the terms that everybody uses today. Thanks for your lecture, Got to learn a few cool things I didn't know before!
You talk about a dipole. The most efficient transfer of energy for the back would be straight out of the neck pocket. If you solely look a the back of the guitar, the back would be like a Yagi antenna. The same argument could be made for the top. I understand sound board resonance to make the sound out of the hole, but to make the back more efficient, the back of the guitar may need to be modified. Maybe Ovation did that. Never sawed one apart.
Hi PinprickSociety, that’s an interesting question. It is accepted that the majority of the sound from a guitar is from the top. Making the sides from Spruce would be quite a challenge to bend. I don’t know that, but knowing how stiff spruce is I could imagine it would split if bent too tightly. Making the back and top from Spruce, with say Mahogany sides would be the way to go if I went down that road. Not quite sure what you would achieve by using a Spruce back. If you think of a drum with both skins the same and tensioned the same you would have a very resonant instrument at one particular frequency. Modern drum kits typically have a thin skin on the bottom and a thicker skin on top. This mismatch provides a more complex sound from the drum. In the same way, using woods such as Rosewood, Mahogany and Maple for the guitar back (and a different bracing pattern) give the instruments tonal complexity. The back also plays a large part in the projection and sustain of the instrument. Empirical evidence is usually (not always) a good guide as to whether Spruce would work better (or differently in a good way) than using hardwoods. There is no doubt that at some stage it would have been tried in the history of stringed instrument making by more than one luthier. There may well be instruments out there constructed this way, but the softwood top and hardwood back and sides dominates in guitar making I guess for a reason. - Dominic
Dominic, Thank you for replying to my comment! I am indeed interest in building my own classical guitars, so I found your video very educational. I discovered it by searching "the physics of guitars." I don't have a background in physics or acoustics, but I tend to be autodidactic and would be very interested in learning more about the physics of guitars and sound. Maple would probably be the most available option for me to use in making the guitar's back. Thanks again for your reply, and I wish you the best success in your future videos and other endeavors. -Patrick www.reverbnation.com/pinprick#
Yes, this is an excellent presentation. I do think that the topic of an extra sound port on a guitar is much like the issue of cutaways. I personally think side soundports are great and luthiers put a lot of thought into them. The ones that I have examined have been innovative and luthiers put so much attention on beauty of whay can be seen. Your question about using spruce for back and sides as well as the top is a good one. You can do what ever you choose, but you would want to know why luthiers don't use it. it would quickly become damaged. The tone would be a lot thinner. But that shouldn't stop you doing it. At the end of the day, you are just making anninstrument. Its tone may not compete with the rich tones of some guitars, but it's still an instrument with a distinctive sound. Look at the resonator. Terrible sound but just magic for some styles. The important thing is to learn from the decisions you make.
Fusion Music Thank you for your input! Very nicely said. I recently found an old, beat up, badly damaged guitar at a thrift store for $20. I thought it would be a great starter project for me. As it turns out, it's a 1938 Recording King made by Gibson. The fretboard was mostly separated from the neck, and there are quite a lot of scratches and wear. The worst part is that there's a bunch of junk inside, so I am trying to figure out how to take it completely apart. I indeed would like to learn more, so your thoughtful comment is appreciated.
Hello, I'm in the process of converting a small (580 mm scale length steel stringed guitar) to X-brace. Do you mean it is better to remove the tops of the "hills" completely. As in the top you show braced at around 30:00, please? Thanks for the video.
This idea of side ports allowing the player to better hear the guitar themselves seems counter to the known action of the port in a Helmholtz resonator. According to the known behaviour of a Helmholtz resonator, air only flows back and forth through the port at the resonant frequency, so the only aspect of the sound that this augments for the player is the low end around the main resonant frequency of the body and top.
Sounds like the guitars were out of tune or the mic got distorted and dropped tuning in the recording process. Either way it was and awesome presentation and I learned a lot.
Very interesting as an introduction to the physics of an acoustic guitar but there should be some more aspects included. Neck stiffness and thickness, and their role of the neck in transferring vibration from the nut to the body. Torsional effects of the bridge and how they relate to top stiffness. The different ways of tying guitar strings to the bridge of further out, like old Gibson electroacoustics.
Many thanks for your lessons. It was very instructive for me. Especially your information about the bracing and how the tone arises and how to influence it. Many Thanks from Germany, Duisburg in the ruhr area.
Thought that myself, you hear that and straight away you think your tone def, tune that fkin thing before you try to say that your physics make it sound better.
Yeah a bit of a flub with Blackbird but who isn't a bit nervous in front of a group of people. My sympathy for him for that. He could have edited it out but didn't... Really interesting and informative presentation. Thanks! 🤘
He doesnt get into the soundhole design or positioning. What if you make it square? What about ovals and slanting them with regard to the centerline? What about F holes versus the sound hole? What happens if you remove it altogether and just use f holes or more randomized holes radiating from the bridge placement? What about drilling out the fibbonaci sequence in terms of holes from the location of the centerline on the saddle? Has anyone tried that!? It seems pivotal to its breathing and resonances?
Even though Blackbird sounds more like road-kill, don't be put off by the initial demonstration. If you can get past the introduction, there is quite a lot of accurate, well-presented information here. I wager most of these negative comments were made after hearing only the first 2 minutes of this 1 hour presentation, so those interested in learning something should keep watching.
I couldn't agree more. However, I would be concerned about the building skills of a highly skilled player. Each vocation requires a lifetime of study and practice, so it follows that a master builder cannot and need not be a master guitarist. After all, I thought I knew a little about how guitars worked until I listened to the rest of this presentation, so in the reverse situation, I would have made a real fool of myself. Even so, he'd have done himself a favor to have someone else play the intro!
Christopher Rude
Christopher Rude Does the name Wayne Henderson mean anything to you ?
Yes, I take your point. He excels in both disciplines. Perhaps I am over-generalizing with regard to the playing ability of luthiers. Even so, maybe we would agree that Henderson represents the exception rather than the rule.
the average luthier probably starts off learning to play then discover they love building guitars a lot more and put their minds to that. Id bet most luthiers arent very good players. And very few great players could build a decent guitar
I am a Physics teacher and found this video very useful !!! Many thanks !
Wonderful lecture- full of information and presented in a concise and easily understood style. You cleared up many points for me about guitar construction and performance, especially the critical importance of the bridge. Thanks for posting.
My god, he could at least tune it.
My same initial thought, unfortunately.
It was painful to hear. Maybe this should have been entitled: "Making guitars with a tone deaf guitar builder".
I don't think it's the guitar that was out of tune...
My sediments exactly and I do believe this guy may have a mathematical mind for building a guitar however if he can’t tune it his presentation is mute
Simply awful
As others have pointed-out, the guitar playing at the beginning is excruciating - is the guitar even in tune? However, apart from that, it is an excellent and very informative video. Dominic is clearly a real enthusiast and really seems to know his stuff. He also puts it across well in a clear no-nonsense way. There's a lot of hype out there about guitar 'tone', but this video helps debunk or explain a lot of the myths. Thanks for posting - keep up the good work :-)
i think he was deliberately playing without any care for accuracy, his later little bits sounded like he knows what he's doing, it was just because the talk was about sound, rather than playing. it wasn't clear that he was making fun, but i think that was the intention.
Thank You, for a quick response ! The lesson at Sherry-Brener included the hanging of the various types of exotic woods on a thread and hitting it with a physicians 'reflex' hammer and either comparing it with a tuning fork during the in-process construction and later with an electrical or digital instrument, etc.
This guy was really informative and got a lot of flak for his playing and tuning . These instruments probably came directly from the atmosphere of his home; through all kinds of weather to the classroom. He explained that tuning would be off , but few of the critics here seemed to listen. As for his playing; he is a physics teacher/hobby builder. If Tommy Emanuel was playing -- the instrument would have been better displayed ; however this was not so much a performance but a physics class . Most critics here fail to realize this either . I did get a chuckle when he played the intro to Smoke on the Water on that old Aoud ( hope the spelling was right). Showing a 12th century Arabic rock group coming up with this would be a good sketch for SNL .
the lecture is so amazing and not too complex for the average person be disinterested in. he really knows his craft! thanks for uploading this vid!
Glad I stuck with the video - despite the ropey start there is some very interesting information in here.
Being an engineering student, I had a design project and my topic was guitars. This video helped me a lot in an engineering sense. Thank you so much!
As one who spent a lifetime in physics and recently developed a love for guitars I really appreciated this presentation He did a great job bridging the gap between the art world and technology of guitar construction. I am not an expert in guitar construction but have a deep interest and Dominic Howman explained guitar construction using well established physical principals.
Blackbird falling down a flight of stairs
Made me snarf yo
blackbird with a broken back got thrown out of a 5th floor window in an atempt to make the thing fly.....
Hé tried at least
The guitar sounds horrible. Maybe the guy is tone deaf? Also the strings are rattling on the frets.
I'm crying laughing with my family now bahaha
This is the second time I've watched this, and keep learning more each time. Thanks again.
You're welcome Mike! We're glad to help :) - Brooklyn
The life of a Luthier is certainly fascinating but I don't think I have the patience. I would much rather spend my time playing. Thank you to the talented people who make these wonderful instruments.
It has always fascinated me when things are taken down to sheer fundamental building blocks. I loved the wood bashings. :D Seen a lot of guitars but never saw an inside of one.
very professional presentation, well done ... ...I have to point out however that you got your Florentines and your Venetians mixed up ... the Florentine cutaway (as seen in the video) is the pointy one ...the Venetian cutaway is the one with the smooth rounded curves,
Please edit the blackbird butchery out of this video... it's embarrassing.
***** Oh well.
it killed me aswell hahaha
Xalan yeah no doubt... that guitar sounds terrible
man - NO KIDDING !! didn't he edit this at all ??!! pretty embarrassing...
should just played each open string from lowest to highest and saved the embarrassment !!
I wish to commend you--this has been the most comprehensive lecture on acoustic guitar making that I have seen--I am also a guitar builder and I have found this to be the most informative lecture yet---great job! I own Logan Elite Guitars--coming soon! At the moment you cannot purchase any of my guitars I am building a collection! You Sir are amazing! I wish I had the Public relations that you do to speak to the public! Thank You so much for this video!
Hello thank you for the wonderful information,i was wondering if you have videos where you go through the process of making an acoustic guitar? thanks again great info!
Hi Rockin Pip, sorry but I don’t have any videos on the process of making a guitar. Given the popularity of this video, I have been contemplating expanding the content. Construction methods would be inseparable from theory. - Dominic
Curtin University
thank you Dominic, i appreciate your reply
@@curtinuniversity You should have tuned your guitar though. If was painfully out of tune.
Terrific lecture! It was well organized and quite comprehensive. It was a great idea to get a luthier who is really on his game to present this to science-minded folks. It brought out interesting points. Thanks.
19:49 He clearly mixed up between Venetian and Florentine cutaway... The Venetian is actually easier to make these days because machines can bend the sides through the use of a mould. Florentine requires a bit more handy work as the sharp curve is joined by two pieces of timber and a triangular supporting block at the location of the cutaway to help stabilising the cut it requires longer sides material to join otherwise you end up with weird grain pattern. That's why only high end custom built acoustic guitars have Florentine Cutaways as a standard e.g. Ervin Somogyi, Michael Greenfield, Matt McPherson...etc
Great talk, scallop remark also very interesting learning the origins, as I have two on the go, one with a very deep cross brace profile, and yes scallops,.... Both are similar volumes, but different materials, body and necks so looking forward to the finish and how well they are. Your talks about wood initially is extremely valuable (to a lay person and surprisingly misunderstood by many) as were your description of tonal modes and the top's behavior. Shame on anyone giving you a negative wave. Thank you for sharing your experience.
thank you for the talk it was so informative I really have been wanting to find more media like this about types of woods used in guitars awesome video, people remember he is not a professional guitar player he is just teaching about the properties of the woods
Yes every critiquing playing i feel they missed, how valuable this class is to aspiring luthier's he scientifically laid out an artform that many see a mystic, i can't express in words the value i have gained from this vid not even finished it and i know i will rewatch again & again. and use this info to teach my musician friends the science & woodwork that create, tone and resonance in acoustic stringed instruments. Info is even valuable for wood percussion.
Negative comments are like people (making fun of and discrediting) einstein for the way he holds his pencil and writes his 4's . How cares he just have us laws to better understand our universe. This is the final piece i needed to control what the guitar sounds like anyone can make one look like a great guitar their value is audible and i feel i can now start to control that. There is no amount of money that is too much to get this info and we get it FREE. BLESS EVERYONE WHO THIS GIVES A RICHER UNDERSTANDING OF THE ACOUSTICS OF WOOD. im off to practice and collect wood i will be back when i have invented all my dream instruments.
This was a really enjoyable, informative video. I think i'm almost ready to tackle my first acoustic guitar build (almost...), so this has been really helpful. Thank you for taking the time to share your expertise with the world.
i have ten guitars at the moment and i've owned about thirty in the last few years, my pride and joy being a '66 gibson J45, what you said about vibration going through the back to the player, and sound holes that are cut into the sides makes sense, i also have a martin OOOX1, spruce top but HPL back and sides, basically laminate, i think it's the best guitar i've ever touched, the sound is clean, the bass growls and the trebles ring, but what makes it a complete experience is that the back passes the vibration to the player, so you get to feel the guitar as well as hear it (i play fingerstyle pretty exclusively). i've been looking at (not playing) composite and carbon fiber guitars and i think the same might be true of them, mcpherson and composite acoustics guitars sound a whole lot better than some solid wood.
Despite the lack luster playing at the beginning of the video, the video is an excellent discussion of the fundamental physics behind the making of steel string guitars and how the physics is addressed in the selection of materials and construction techniques used to build a guitar. Very informative.
That was excellent! I saw this after several guitar factory tour vids and now much better get the points they were making! Especially the Godin acoustic tour.
As an engineer and a solid body hobby builder, I found this exactly the kind of information I wanted. The whys of instrument making have always fascinated me. Obviously the epitome of guitar building is the acoustic. Never tried one because of the precision required and the tools needed to get it right. Yet I now have a better understanding of the physics of the build. This is something that takes extreme patience, like learning to play, which is why I'm not much of a player. Would be nice to see a follow-on for the solid body and ways to optimize it and the various sounds you get from different woods. Thanks and remember Leo Fender was an engineer and allegedly didn't play guitar.
ill build electrics all day long and have zero doubt i can make a brilliant electric. i wouldnt even attempt an acoustic
@@cdreid99999 electric has none of this if you have a str8 fretboard & saddle + pickup. A shoe could sound great. acoustics takes more wood skill, acoustic/resonance/sound knowledge, . Mount strings pickup and action you got a great electric. Its gr8 to start learning fundamentals. This is a skill/craft/art. Like comparing riding the bike to the Tour de France
An excellent presentation! I am just learning about the construction of guitars and this has been a wealth of information for me. Thank you Dominic!
To anyone wanting to approach guitar design with a physics mind I would recommend understanding several topics which were not included in this lecture, such as
-Specific modulus
-Helmholtz Frequency
-Neutral Axis (and 'moment')
-String Exit Angles
The 'sound hole' is actually an air hole, used to prevent any standing waves that would be self-interfering by letting air escape. People that record guitars for a living know this, and do not mic the guitar at the hole, but some where else. Almost all of the sound is produced by the vibrating top, so the materials and construction of the top is essential for a specific or pleasing sound. Thanks for the video; I liked it.
Thanks very much, Dominic, for sharing your extensive knowledge. Very helpful for me, thinking about my next build. I have a question about vibrations of the table: I got the impression that the monopole mode pumps air in and out of the sound hole, whereas the cross- and long dipoles merely move it within the guitar body (because one side of the soundboard goes up while the other goes down, suggesting cancellation). So, as I understand, the dipoles only make sound from the soundboard, not through the soundhole and, even that from the board would cancel to some extent for the listener in front. Leaves me wondering why the fanstrutting of classic guitars is designed to increase the cross-diapole (as I understood you to say). Surely it wastes sound energy and makes them quieter? Big problem in a concert hall.
Aaaaaaaaah. I recently bought a 3/4 size classical. I instantly noted how loud of a treble sound it produced. Glad he was able to explain that.
The info is extremely good for luthiers :)
The reason the intro sounds so bad is is because it's only partly picked up by his lapel mic. If he was playing into a proper mic, it would have been more even. As far as tuning, that could be an artifact of video speed, etc. Way to many influences to cancel out in an inexpensively made video in a glossy classroom setting. Do it all over in a sound studio correctly mic'd, and most folks would not have the gripes ...
Nope.
@@ed-rb4bs was going to ask if you learned anything from this awesome lecture but you already answered my question
It definitely was out of tune lol, it happens though
So interesting explanations with practically demonstrations....Love the way you teach them up...Thank you ...
Was this an example of a bad sounding guitar at the beginning? I’m still watching the video so I’m not sure if he is going to touch on that but I thought it sounded bad
FYI at around 20:00 when you are holding your guitar and talking about the cutaways you have it backwards. the one you are holding is a florentine cutaway and the smooth curved style is a venetian cutaway.
Glad I found your comment .... avoided a duplicate. Yep, got the folrentine and venetian backwards.
Fantastic lecture. Maximum information, zero bullshit. Great stuff
Thank you for sharing your knowledge!! Very informative...
Sir, your effort is to be praised. Are you familiar with soundboard crown? Tension on the topside and compression on the underside, with specific downbearing at the saddle by the strings. These are physics on pianos as well as guitars. this is a finely balanced equilibrium at different sections on the bridges to achieve desired resulting tonal projection ( usually more down pressure in the high treble section to achieve a balanced volume at the loss of sustain but a 2-inch long, thin wire needs to be as loud as the 7-foot bass string. less downbearing equals more sustain, but you give up dynamics. hope my 2 cents helps ps. the 70 kgs is lateral tension. not to be confused with downbearing. on an average piano lateral tension is about 20 tons, while downbearing is about 6 lbs. per string. ( about 225 strings per piano )
I enjoyed this presentation very much. Thank you.
Top stuff Dom. Sam told me to come check this out, and I'm damn glad I did.
So many questions answered! Great lecture! thanks you
You're welcome Michael, we're glad we can help - Brooklyn
Great lecture. Obviously, this guy doesn't take himself (or his playing) too seriously. I'd enjoy a few hours of conversation (with a few pints) with this guy. Good stuff, Dom!
Most people take PLAYING music far to seriously. The forget its PLAYING egos destroy fun and the ability to learn and grow. Ive been around far to many of those. I would join you guys for beers but NO playing or fun conversation this is music and building instruments.
what a fascinating lecture. Beautiful presentation.
Glad you enjoyed it!
Man, I really, really, ABSOLUTELY enjoyed watching and learning. I wish I could have a beer with ya and talk about this stuff for hours!
i don't even play guitar but this was one of the most interesting presentations ive ever seen
Great video Dominic. You should ignore the Trolls. Lots of useful information in a short presentation. What are you using for the finish on these guitars?
Interesting talk, and entertaining too.....Just a few extra phyics bits if interested: the bridge can be in the mid of the lower bout, as in 12 fret guitars. The only reason the wee guitars are tinny is due to the area of the guitar not the bridge position. Low tension can give nice bass sounding guitars, as in classical. Small scales on large guitar bodies are possible, and sound great. The only reason we don't see many is that blokes have large hands. We may see more choice in the future catering to smaller hands, and end up with small scale 12 fret dreads. Certainly a gap in the market there for would be makers! The saddle can be low, if the bridge is stiff. A heavy bridge has a lower response, as it takes more ooomph to shift it. My very thin bridge with a low saddle produces amazing sustain and loudness. The latest guitar makers know this. Of course you can use the 'Martin' way of making, and follow the recipe, but it is not the only way of building a guitar. The back can be considered as the speaker case, and should detract the least from the top.
Fair enough, the playing at the beginning is a shocker but the rest of the video is really interesting if you want to know about the internal construction of an acoustic and why it's made like it's made. A really good place to stat if you are thinking about making one yourself.
You say that the whole guitar vibrates and then say that the energy is transferred via the bridge only. In my reading of the events there is also a significant transference and modulation via the fret and finger. The integrity of the neck is hugely important to the tone.
periurban Tone quality is highly subjective and as a result it is hard to create an accurate science , also great music does not always have great tone instruments so it becomes even more difficult to assess just how important tone is in any song to a broad audience. Add to all this the importance of tone from the player not the instrument , if we had given this instrument to Tommy Emmanual I am sure most people would have been more convinced of Tone .
+periurban Not necessarily a contradiction. There will be an energy loss through the neck, as opposed to the bridge being directly part of the resonator, so its energy contribution must be much lower. It is also to be considered what happens when neck fails: the main part of a string instrument is a tensioned string, and it's the neck that upholds the tension. The higher the string tension, the more energy a string vibrating at a given amplitude stores. So in case of neck weakening, the contribution of loss of tension is much larger than the contribution of reduced sonic conductance.
song title at the begging is "how to kill a blackbird" by Dominic Howman
He played White swan swimming in the pond today... So sweet. But I love the idea of rethinking guitar design. Compare it to finite set strength calculations, that has completely thrown over traditions, for example a hydrofoil can not be enhanced by simply trying a slightly different shape, you can't do without computers designing these, you'd make an average one, at best.
Super interesting presentation, the bracing designs and techniques are fascinating. It's really tough to take it seriously when all your guitars are so far out of tune though, there's really no excuse for not tuning a guitar and a real shame we couldn't enjoy the sound of all your hard work and plethora of styles of build. Immediately it makes someone question why such as detailed, obsessive, obviously talented creator would ignore 30 seconds to put a guitar in tune?
Maybe some overlays of you playing in tune over those small parts would help. It's a tiny point but a guitar maker should care about tune more or what other small points could he be missing are the thoughts that come to mind. At least I would have expected you to mention it as not doing suggests you were not aware it was out of tune or simply didn't care.
Both are odd choices.
Yeah those guitars clearly just went from a hot car to a cold room, but generally there's about 10 minutes to set up a computer and move everything into the room, so I get how easy it would be to overlook. Especially while trying to prepare yourself to speak for an hour.
Still should've been mentioned though, but I guess once you start the show must go on!
great video! One of the key take aways was the physical properties of the soundboard playing a role. A particular species may be known for its qualities but those properties can be found in woods not necessarily known to be reputable. so the take away was, go with the properties of the piece you have. That being said, how could one do a quick specific gravity or modulus of elasticity calculation when you have a wood selection in front of you?
really nice explanations. Thanks!
Excellent and very informative! Thanks?
1st Glad you reinforced what I thought of in regards to scaloping bracing. 2nd the placement of the bridge, is that THE exact center or from the end of the fretboard (top of the sound hole) to the end of the guitar? Lastly I appreciate this video it helps greatly
Very informative, thank you for the upload.
You're welcome Christopher :) We are glad you like it - Brooklyn
Wonderful video thanks for sharing. I have a question if you would be so kind. Can you do a video on voicing the sound board and share your techniques? I noted the tapping and the music box. I use a tuning fork to get an idea but only have one fork in "A". From a physics perspective would you recommend all 8 notes to get a feel for resonance or is that a little over the top? I have only built a few guitars and I am now exploring voicing from a scientific perspective and would love your input.
Also have you given any thought to chambering the body or know of anyone who has? What I am thinking is Dr. Bose's approach to speakers.
But anyway this was really really thoughtful and provocative talk on the subject thank you from the bottom of my heart.
Excellent video. Question: What is the reason for the angle of the tone braces in the lower bout. Jean Larrivee, I'm pretty sure, aligns his tone braces perpendicular to center ('symmetrical bracing'), and the Larrivee guitars I've heard and played have superb, bright tone and projection. Thanks, B.J.
You can't compare the domed structure of guitars and violins because the bridge on the violin presses down on the top as the strings are like bowstrings, trying to shoot the bridge like an arrow through the top. A guitar bridge is pulled towards the neck and rocked towards the neck. Doming is mostly a fad on guitars, but it deals with clients who won't take care of their guitar moisture wise, reduces splitting; it may ad some structure to the bridge rock load path; And it both makes some guitars easier, or harder to build. On tone, it isn't critical, though it sorta loads the top in the wrong direction which should marginally kill tone, but doesn't seem noticeable. You are essentially forcing the sound board into tension on the bridge side, and compression on the inside, and those effects are uneven relative to grain direction.
Very enjoyable and informative lecture. I marvel at the skill of modernday builders, knowing full well that some of the tonewoods available to them today cannot hold a candle to most of the tonewoods available to luthiers in the late 19th and early 20th centuries; notably Adirondack spruce as a top.
absolutely amazing video. you explain things very well.
I would love to know what you think of Taylor's new V Bracing. I will consider this in my upcoming build
This guy must have some balls to start off a guitar related presentation by sucking to this extent on a simple tune. Respect.
I don't think the guitar is bad. I think he's more of a hobbyist player, and more interested in building guitars. If he hired someone to demonstrate for him or tuned it (although it wasn't as out of tune as you think, he was just hitting the wrong strings a bunch of times) I think it would have sounded really good.
You can clearly hear it's awfully out of tune as well.
He's a professional luthier... he knows how to tune and set up a guitar.. but he didnt bother.......
For Everyone its a hobby just some people get big heads when they hear 1 person play worse than them. Great contribution can tell how much you guys learned from all this info.
53:16 did you mean the string angle into the bridge ?
Sharper angle the higher the force without having to raise the saddle.
A good acoustic instrument teacher will instruct to never mute the instrument (allowing shirt sleeves or other to contact). This applies mostly to the top, but also the back of the instrument can resonate as well.
Humidity is a major factor - drier resonates better than humid.
It's actually very common for instrument builders (Luthiers) to not be very good at actually playing the instruments. I was surprised when I first learned this but this was how it was explained to me. In any given month they could build a guitar a violin a ukulele and a banjo. All these instruments are pretty different, and it's hard to build any real proficiency when you're learning them all at the same time. It's much more efficient to master 1 or 2 of them, then learn how to translate the skills.
Mastery takes time only so many hrs they play more instruments instead of focusing on just playing one. Most guitarist cant build one, it may look right nut would sound shitty.
26:00 I had never thought of the bridge as a brace. Thats fascinating that it is made to tie together the x brace on the inside.
I did not build my own guitar yet, but I did convert a Spanish guitar. Now it is a flat body Spanish guitar, and it has three strat clone pickups and one piëzo pickup.
My tip: buy a cheap nylon string guitar, steam the glue and open the top. Yourself. Then you have some options, you can CHANGE your guitar.
A. Find cedar or spruce or any wood you like, you can replace the plywood top by solid wood. That top you can plane, make it thin at spots where that is possible. Find out yourself how that works. This is a great project, you need to rebuild a lot of guitar, bracing included.
B. Move the bridge! Watch out, the frets are calculated for this scale. If you want to keep things simple, you move the bridge, and you remove the fretboard, moving it according to the bridge. You can make a longer neck, getting the bridge next to the sound hole, or you shorten the neck because bridge goes to the neck strap button. Why? Position of the bridge makes the top resonate differently, the guitar will sound totally different. And it looks funny. Though, it is a lot of work, changing the neck.
A and B are seperate projects. You can combine them. Thanks for reminding me of my cigar boxes, it is time to build a cedar top. And maybe on a 12 string (nylon) guitar, maybe 8 string nylon tuned like a 4 string bass, only double strings. We'll see.
You forgot to mention that there is a "sound pole" under the bridge going to the back of a violin to help transfer the vibrations and strengthen the top under the bridge.
I just learned about those earlier arent they free floating
Very interesting stuff, very helpful- thanks
Thanks very much to Mr. Howman. This explains a lot and is very interesting and useful to me.
I enjoyed your video. It was well presented. I have a few questions: Does the species of wood (sitka spruce, western red cedar, red spruce, etc.), used for the bracing on the soundboard, have an effect on the sound of the guitar? What species of wood do you prefer, for the soundboard bracing, and why? Does the style of kerfing (traditional kerfing vs. reverse kerfing) have an effect on the tone of the guitar? Can you provide more information on the vibration tool used to "break in" a new guitar? Thanks in advance.
Hi +Chad Redding, the species of wood used to brace the soundboard (and back) of a guitar is not as relevant as the stiffness of the wood used. Wood has such great variations in its mechanical properties that it is possible to make braces from two different species of wood that have identical mechanical properties. On the other hand it is possible to use the same species of wood from two different trees to make a brace and they have wildly different mechanical properties. So it is wrong to think “Martin used red spruce for their pre-war guitars so I must use red spruce to get a good sound from my guitar”. I use Sitka spruce for my bracing only because it is readily available to me. I weed out any brace stock with runout and skewed grain.
What I do, and anyone serious about making guitars should do, is to consider the stiffness of the brace stock. There are many ways to measure stiffness. I prefer the old fashioned one of checking the grain count and flexing the brace with my hands. I don’t build with any pre-determined stiffness for individual braces, but find the stiffest wood and use that for the main X braces and the transverse braces on the lower bout. The skill in guitar making is not in what species of wood you use for bracing but how you carve the braces to control their stiffness. Using the stiffest wood allows you to make a brace with less mass.
I haven’t explored the effect of different styles of kerfing - I use a traditional style. I have found that basswood is an excellent material to use. I was told by Bob Hoover during a tour of his Santa Cruz workshop that he liked the way basswood decouples vibrations from the top to the sides and the back to the sides. I was lucky enough to play some Santa Cruz guitars after the tour and have been a believer ever since. I handcut all my kerfing and have to say it’s my least favourite part of guitar making by a long shot.
The best tool for breaking in a new guitar is your hands. I do have a Tonerite which is really just an expensive fish tank pump. Does it work? Yes it does take a brand new guitar and “settles” it down or “breaks it in”. It won’t change the fundamental tone of a guitar. Only someone who has strung up a guitar for the first time understands how much the sound changes in the first few weeks of stringing it up. Initially you might love the sound of a newly birthed guitar. Later that night you play it and it sounds awful. The next day it sounds heavenly etc. Once the tension soaks into the wood and it has been played (or Tonerited) for a few weeks, it’s essentially broken in. I sometimes get to play a friends guitar that gigs 3 or 4 nights a week, 3 hours at a time. That guitar sounds so wonderful and deep because the wood constantly gets a real workout. I think perhaps that is more what a Tonerite was designed to achieve. - Dominic
19:49+ Don't mean to be rude, as I very much appreciate the lecture, but you're mixing up Venetian and Florentine cutaways. Venetian is the rounded cutaway. Florentine is sharp. Gibson pretty much coined the terms starting back with their fancy florentine style mandolins with sharp cutaways way back. Then before WWII, they started making archtop guitars with rounded cutaways that they originally marketed as "premier." Later they began referring to the design as "Venetian." There were plenty of other companies who offered cutaways of course, but Gibson supposedly is credited for coining the terms that everybody uses today. Thanks for your lecture, Got to learn a few cool things I didn't know before!
You talk about a dipole. The most efficient transfer of energy for the back would be straight out of the neck pocket. If you solely look a the back of the guitar, the back would be like a Yagi antenna. The same argument could be made for the top. I understand sound board resonance to make the sound out of the hole, but to make the back more efficient, the back of the guitar may need to be modified. Maybe Ovation did that. Never sawed one apart.
Firstly, this is an excellent video.
Would you make a guitar with sides and back also made from spruce, as well as the soundboard?
Hi PinprickSociety, that’s an interesting question. It is accepted that the majority of the sound from a guitar is from the top. Making the sides from Spruce would be quite a challenge to bend. I don’t know that, but knowing how stiff spruce is I could imagine it would split if bent too tightly. Making the back and top from Spruce, with say Mahogany sides would be the way to go if I went down that road. Not quite sure what you would achieve by using a Spruce back. If you think of a drum with both skins the same and tensioned the same you would have a very resonant instrument at one particular frequency. Modern drum kits typically have a thin skin on the bottom and a thicker skin on top. This mismatch provides a more complex sound from the drum. In the same way, using woods such as Rosewood, Mahogany and Maple for the guitar back (and a different bracing pattern) give the instruments tonal complexity. The back also plays a large part in the projection and sustain of the instrument. Empirical evidence is usually (not always) a good guide as to whether Spruce would work better (or differently in a good way) than using hardwoods. There is no doubt that at some stage it would have been tried in the history of stringed instrument making by more than one luthier. There may well be instruments out there constructed this way, but the softwood top and hardwood back and sides dominates in guitar making I guess for a reason. - Dominic
Dominic,
Thank you for replying to my comment!
I am indeed interest in building my own classical guitars, so I found your video very educational. I discovered it by searching "the physics of guitars."
I don't have a background in physics or acoustics, but I tend to be autodidactic and would be very interested in learning more about the physics of guitars and sound.
Maple would probably be the most available option for me to use in making the guitar's back.
Thanks again for your reply, and I wish you the best success in your future videos and other endeavors.
-Patrick
www.reverbnation.com/pinprick#
Yes, this is an excellent presentation. I do think that the topic of an extra sound port on a guitar is much like the issue of cutaways. I personally think side soundports are great and luthiers put a lot of thought into them. The ones that I have examined have been innovative and luthiers put so much attention on beauty of whay can be seen. Your question about using spruce for back and sides as well as the top is a good one. You can do what ever you choose, but you would want to know why luthiers don't use it. it would quickly become damaged. The tone would be a lot thinner. But that shouldn't stop you doing it. At the end of the day, you are just making anninstrument. Its tone may not compete with the rich tones of some guitars, but it's still an instrument with a distinctive sound. Look at the resonator. Terrible sound but just magic for some styles. The important thing is to learn from the decisions you make.
Fusion Music Thank you for your input! Very nicely said.
I recently found an old, beat up, badly damaged guitar at a thrift store for $20. I thought it would be a great starter project for me. As it turns out, it's a 1938 Recording King made by Gibson.
The fretboard was mostly separated from the neck, and there are quite a lot of scratches and wear. The worst part is that there's a bunch of junk inside, so I am trying to figure out how to take it completely apart.
I indeed would like to learn more, so your thoughtful comment is appreciated.
Holy. Check out 39:13
The difference it makes when you let the back resonate is insane
Hello, I'm in the process of converting a small (580 mm scale length steel stringed guitar) to X-brace. Do you mean it is better to remove the tops of the "hills" completely. As in the top you show braced at around 30:00, please?
Thanks for the video.
This idea of side ports allowing the player to better hear the guitar themselves seems counter to the known action of the port in a Helmholtz resonator. According to the known behaviour of a Helmholtz resonator, air only flows back and forth through the port at the resonant frequency, so the only aspect of the sound that this augments for the player is the low end around the main resonant frequency of the body and top.
That was fascinating and very informative.
thank you. this presentation is very detailed and informative.
Sounds like the guitars were out of tune or the mic got distorted and dropped tuning in the recording process. Either way it was and awesome presentation and I learned a lot.
Very interesting as an introduction to the physics of an acoustic guitar but there should be some more aspects included. Neck stiffness and thickness, and their role of the neck in transferring vibration from the nut to the body. Torsional effects of the bridge and how they relate to top stiffness. The different ways of tying guitar strings to the bridge of further out, like old Gibson electroacoustics.
That could be a whole other video
Excellent video, I am a physicist and enjoyed the explanations. Thanks
Glad it was helpful!
the intro cheered me up!
I've heard that tuning the instrument helps demonstrate it's design better... or did you design it for avant gard?
Thank you. This is a great and informative video for guitarists.
Good idea to give a throw away performance for the first minute. It gets rid of the Physics dunces immediately.
Very informative... a snappy salute to Dominic Howman
Many thanks for your lessons. It was very instructive for me. Especially your information about the bracing and how the tone arises and how to influence it. Many Thanks from Germany, Duisburg in the ruhr area.
You're welcome Wolfgang! I'm glad we could help - Brooklyn
very informative,I don't build but for purchasing a guitar I will now tap the back and the bridge.
The first part sounded like a 3 dollar guitar without a proper setup
+ZeGypsy lol for sure
Thought that myself, you hear that and straight away you think your tone def, tune that fkin thing before you try to say that your physics make it sound better.
I thought he was making a joke and a funny start by playing a crappy guitar and explaining why it was crappy.
I thought it sounded like a washtub with strings attached. Worst I've heard!
I really thought it was a joke too. Everything about it sounds terrible!
Brilliant. Really useful stuff. Thanks a lot!
Yeah a bit of a flub with Blackbird but who isn't a bit nervous in front of a group of people. My sympathy for him for that. He could have edited it out but didn't... Really interesting and informative presentation. Thanks! 🤘
I'm a big side sound port fan. Certainly not on a upper end or vintage instrument, but it's an old and fine idea IMHO.
I'm still waiting for the tuning a guitar lesson or the how NOT to play Blackbird lesson. YIKES, bro!
Blackbird? I though that piece was entitled: "Dying moments of a fatally wounded pigeon"
That was so informative, the physics of guitar making applies to other string instruments. Many thanks
please stop the guitar from talking. it sounds very ill
He doesnt get into the soundhole design or positioning. What if you make it square? What about ovals and slanting them with regard to the centerline? What about F holes versus the sound hole? What happens if you remove it altogether and just use f holes or more randomized holes radiating from the bridge placement? What about drilling out the fibbonaci sequence in terms of holes from the location of the centerline on the saddle? Has anyone tried that!? It seems pivotal to its breathing and resonances?