Acoustic Engineering Workflow
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- Опубликовано: 31 май 2024
- In this video, I demonstrate one of several design workflows that an acoustic engineer may use for product design. All the showcased software is either free or open source:
OpenSCAD: openscad.org/
FreeCAD: www.freecad.org/
(Calc) Libre Office: www.libreoffice.org/
REW: www.roomeqwizard.com/
DesignSpark Mechanical: www.rs-online.com/
Blender: www.blender.org/
Car Audio Subwoofer Enclosure Design: adcaraudio.com/store/enclosur...
Home Audio & Advanced Systems Design: hexibase.com/contact/
00:00 - Preface
00:12 - Enclosure Design Request
00:46 - Listening Space Profiles
01:40 - Input
02:00 - Output(s)
02:29 - The Driver
02:54 - Enclosure Models
03:20 - Analysis: Sealed Model
04:01 - Boundary-Specific Transform Functions
04:27 - Equal Loudness Target
05:25 - Analysis: Transmission Line Model
05:56 - Exercising the Constraints
07:13 - Analysis: Bass-Reflex, Quasi-Cylindrical Model
08:29 - The "One Note Wonder" Scenario
09:09 - Analysis: Ducted Reflex Model
09:54 - Analysis: Dual-Stage Bass-Reflex Model
10:31 - "What's It Tuned To?"
11:32 - Practical Fb Scenario
12:38 - Analysis: 3rd Order Bandpass Model
13:00 - Analysis: 4rd Order Bandpass Model
13:17 - Let The Driver's Behavior Decide
13:44 - Analysis: 5th Order Series-Tuned Bandpass Model
13:50 - Analysis: 5th Order Parallel-Tuned Bandpass Model
14:11 - Analysis: 6th Order Parallel-Tuned Bandpass Model
14:25 - Upper Acoustic Order Threshold
14:46 - Air Flow Analysis
15:34 - Fabrication Strategies & Effects
16:31 - FEM: When to Brace or Double-Stack
17:11 - Final Design
17:27 - "Will It Scale?"
18:09 - Wrong Sub
18:22 - Wrong Car
18:53 - In Closing 
Наука
Hi Pete. I did serious, high-end car audio design and build in the early 90’s, and with an engineering and computer programming background, I wrote many of my own tools based upon the original T/S papers and measured drivers using techniques that were only just barely starting to factor in listening space. I stumbled upon this video, and am absolutely blown away by how detailed and thorough your engineering process has become. I am HIGHLY impressed!
my dad did DJ magic mikes set up and im trying to figure it out too
You lost me right after, "My name is Pete..." 🤣
AI would probably do all the technical work for us instantly. Then all you'd have to do is print the enclosure. Future is looking good
That feeling when you're 18 minutes into a brain-melting demonstration of enclosure design and you've been wondering the whole time how this would work in your 1990 CRX and he nonchalantly drops the set-up into a 1991 CRX... 😆🤯
This video is jaw dropping. It really makes the price of that enclosure design seem like a completely reasonable investment.
Most of the performance in any engineered assembly will be design driven. Simply by buying a commodity loudspeaker, you're paying for a lot of design work.
As a student studying acoustics, I am deeply thankful for this video. you are a huge inspiration to me. As a fellow bass enthusiast, a 3D designer, and a 3D printer enthusiast. Thank you so much.
beautiful analysis. I think we all remember the days of grabbing some swap-meet subs and throwing together a box with some leftover plywood and a jigsaw and tossing it in the hatchback, mathematics be damned 😀
Ok I'm done ,half way through and I'm exhausted 😂
This is so cool. Every time I think I know enough about sub design to get by on my own there’s just sooo much more knowledge to gain and improve. Thank you for sharing
That is some advanced modelling skills at work. This video inspires me to upskill myself to make decisions more accurately. Great work Pete, Thank you for sharing your time and expertise with me.
Hey Deepak. Fancy seeing you here 👋
@@Elliott-Designs Hi Elliott, Nice to see you again. How are you?
@@EngineeringEssentials I'm good thanks. This video from hexibase has inspired me to go and learn some of the open source software he's shown. I already do acoustic simulations, etc like the ones shown. But if I learn this free stuff then I might actually be able to make tutorials on it, unlike the research/education stuff I currently use like ansys and comsol. How are you?
damn this really opened my eyes when it comes to enclosure design and the difference between SPL n SQ
Meanwhile I just designed my box in SketchUp by only having the max size limit of my trunk to go after, and basic knowledge of sub boxes.
Smacked that shit together and prayed it would work. And it did!
Could it be designed a lot better? Definitely, but for the last six years I've lived in ignorant bliss as my 10" Digital Designs chuff along in their tiny enclosures.
Pretty inspiring what you do, I wish to have this knowledge.
This is super fascinating. I didn't know I was so interested in acoustics and sound engineering until this video. Thank you so much
Talk about a knowledge dump! Waaaayyyy more information here than I'll ever be able to comprehend
I learned something from you today. Me at 50, technology has advanced by leaps and bounds indeed.
I recently bought a 2015 MX-5, and have been looking at my options for getting a decent sounding system in it. Thanks to this video, I now have a LOT of work ahead of me, tearing the car apart to take measurements of the area under the soft top behind the rear bulkhead so I can model an enclosure... Part of me (the part that makes spreadsheets for literally every major decision I make) is super excited. The other part (the part that has a limited number of hours in the day to screw around) is scared, lol.
Man that is a firehose of information for people not doing this daily, great stuff!
U are hands down 1 of the most intelligent and interesting people that I have ever came across on you tube.
I have no idea what you said, but as usual, I’m amazed listening to you say it! Well done.
So you use OpenSCAD to model the listening space, Freecad to build the enclosure, am I understanding that correctly? What do you use for the acoustic simulation generating FR graphs?
I undestood almost nothing but watched the whole thing
Yeah, I understood about 3% of what you said. I wish I knew how to do this for what I was planning but wow this is more complicated than I thought. You are really good at what you do man.
Super-Pete does it again! Greatest video of all time.
Watched this video 2 times. Makes me wonder how long it will take for me to get to this level. When I was a kid my idol was Zaph Audio, but times change. Great work man!
I don’t think I’ll ever make it to his level. We can try though.
Although if you’re doing half of this and you’re in the car audio space, you’re doing better than 90% of the people out there
Many years, a keen interest in the subject and the job which allows you to get to this stage.
You’re certainly on your way, man! I follow your channel as well.
Next time someone ask me to build a sub box and I say "I can build you one that will sound pretty good, but I'm no expert. You should get someone smarter than me to design it first." I'm going to send them to this video.
Good god. All of my early 2000's modeling was stone age stuff compared to now. I'm way out of the game now but I do have to say the modeling as described in this video is absolutely insane - in an awesome way. A great time to be a loudspeaker designer, for sure.
This is extremely exciting! I've been working on my own suite of software and workflow, and this indicates to me that I'm on the right track. I've been working with FreeCAD, SciLab (and similar), Ngspice, VituixCAD, etc...
Though I have no intentions of refining this much further, the practices and concepts explored here are applicable too so many different areas. I come from an electronics/RF background with a hefty helping of computer science, and all but the loudspeaker specific software is new to me.
This recent revisit of the acoustical side of my hobbies has been a boon to my knowledgebase, moreso than possibly any other facet I've explored. Systems modeling, control theory... Mmm, so good.
Thanks Pete, for the inspiration and motivation.
You have outdone yourself on this one! I understood everything about this in theory before, but now I have a more practical understanding. Thank you.
Holy shit dude. That's bonkers. Always impressed with your content.
Watching this for the third time and it makes more sense each time. I love AD subs and it's exciting to get a glimpse on what happens on the pro level.
Oh hell yea thank youuuu!!!! Ive been waiting for something like this. I have searched the internet to find a way to model frequency response using capacitive and inductive reactance because something is missing from my calculations. I hope this video has what i need
So much for just putting any beand 12s in my van 😂, you just opened (fried) my mind to a lot more senarios!! Great video and way more explanations
You are simply on another level. I did my engineering final year project on trying out a dynamically-ported speaker (port geometry changes in real time with the music chords basically) -- but I was just messing about compared to the work you do and knowledge you have. I'll pay for something like a 2-hour complete tutorial explaining each step in extreme detail, and showing how you've come to some of the intuition you have.
Unfortunately, I think he wrote his own software, so a tutorial may not give you the skills you need to catch up. Guy is on another level. LoL
BRAVO! I'm only knowledgable enough to follow along at a high level, understanding bits and pieces throughout at varying depths, but what's abundantly clear - you're a master of your craft, and I looooved the reasoning behind the 'no on the spot enclosure recommendations' snippet towards the end.
Can you also make sub recomendations?
Seems much more efficient to have this done with the flexibility of picking a better suited driver before actually commiting to a subwoofer and make that fit as best as possible.
He can recommend from drivers he's modeled very recently, but that's just based on memory. His driver database is vast & runs over a decade and a half of models, versions, revisions etc and it takes man hours that can't be quoted on demand when you request a design. So, it's highly unlikely that you can get him to make a recommendation on drivers, it's much easier & responsible to let you dig your own foxhole & he just optimize it.
@@stevemilton3499 he must have a shortlist of what he knows works well in certain applications.
Going by that would if you don't have specific preferences for a driver make life easier for everyone involved i'd imagine.
@Baron von Limbourgh if it were me, I'd liken that to "giving financial advice" or "endorsing an exact S/N product". This, because the customer will want to hold the engineer responsible for the failure of a product, specifically after the McDonald's tech dept guy points the finger away from his company.
It blows my mind on how intelligent you are when it comes to doing these things. I'm a bit envious. It would be interesting to see what you could do if there was a fiberglass enclosure, molded to the wheel-well of the vehicle. and what kind of outcome it would produce or what it would need additionally to produce a proper conclusion. Love all your work bud! Have a great day! :)
I have a friend that did that in an audi a4 combi with a FI IB3 18 and it sounds amazing, he peaks at 15 Hz 😁
One of the best car audio videos ever viewed
i thought you would be using like winisd or vituixcad but that seems much more sophisticated. were can i get this software?🙂
Most informative video out there. From impedance curves to audio output with different drivers with given parameters. So much information in one video. AWESOME.
As always, these type of content is inspiring. Thank you so much for sharing! I have to rewatch the video to digest. ❤❤
Top tier knowledge and presentation. Thanks for all your work!
You sir are an acoustic wizard
Had a 2000 f150 single cab with two ds18 8-inch elites behind the seat in a box I built myself 2.43sf³ with a baffle and a chimney port. I did the cab measurements and tuned it for 44.7 hz and loved it now I'm running a 15" ds18 exl-xxb on 6K in a 3.5sf³ prebuilt box in my ram and while it does hit hard it doesn't have that same feel to it nor is it as loud. But hats off to you for what u do man some people don't realize what truly goes into designing an enclosure , I need to build a box for my new truck but I guess I'll get around to it if I end up getting that 18 from trinity audio
I think I know just enough of what you're saying to follow along but realize how little I know. This make my brain hurt, but in a good way. I think this could have been broken into a half dozen videos explaining all sorts of acoustic design principals. I really enjoyed this, but now need to go watch some silly cat videos. Thank you.
I had a design from you at Pwk n it was amazing Pete...
Thinking for some new project n design as well...
As always next level knowledge
Really cool that your employer was able to set you loose going over the ins and outs of enclosure design. While I always knew there were lots of intricacies to designing an enclosure, this really sets that detail in stark relief. Also makes one wonder how off-the-shelf speaker manufacturers are able to create sub enclosures for even more varied environments. The mind reels. 👍
His employer hired him because of his skill set. Pete has had multiple business from his design work. Since before 2005 for sure
Manufacturers use a one-size-fits-all approach and many are absolutely clueless how to do this kind of work TBH.
Very thorough, I have to watch your videos at least 5 times to catch everything you present! Please do a video on using multiple drivers like 4, 8 even 16 subs , I am sure the response would greatly vary compared to 1
Great channel
I would really enjoy it if you got involved in the community! Like in live video format,so we could ask questions in real time to get answers and idk get to know you better ! It would be super awesome to see one of the top acoustic engineers in my humble opinion just grace us with your presence and touch on a bunch of different topics just would be so amazing. If you were to go on Big D's 12volt talk like Aaron W did that would be sick cause thats how I fell in love with audio dynamics and you bro! Please consider it Pete??? 🙏 I know it's probably not your cup of tea but it would make the world to us fans!!!
He records a Q&A on his Patreon but it's always so few questions that it only happens quarterly 😐
So much knowledge and so much work!
This is frickin awesome! The video I've been waiting for from you! Frickin awesome! I had you design the sub enclosure for the bed of a show truck made out of aluminum. And I have always been curious about the methods you used. By the way, it hits so hard and sounds amazing!
This is one of my favorite videos yet. I did something very similar in Paradox 1.0 many years ago, with optimization for every driver in my database. It would help you pick the best solution for the available space. It was limited to sealed and ported. Great to see this with higher order and TL designs. Nice work!
This was very enlightening, and it was interesting to get a look at some of the tools available. But I think in as many words, his conclusion is "It's the back of Chevy Suburban, not Carneghie hall -you might as well just wing it"
While this may be the best video on the subject ever made, I bet at least 70% of us dont have a clue about half of the stuff you said, unfortunately or fortunately for you :)
My question is what would be the way and software for us, those 70% who would like to try to design our own enclosure, is there any procedure to follow that would make us not making big mistakes? I do understand that enclosure design if we want it to be perfect should be left to professionals, even driver choice and amps and in some cases even vehicle choice, but say we have some vehicle and some driver for which we have parameters and we roughly want it to be in specific place and have limited size available what would be the best approach to design and build enclosure which would not sound bad. For good sounding one we know who to ask and what to do, but how about some simple diy not bad sounding project which is not sensitive to millimeter precision errors which can end up more like centimeter beginner errors in build process for example?
That was awesome. Looking forward to a pt.2. Really interesting. Thank you for the work you put into the video. Your videos are awesome.
Over impressive - DEEP respect ------------------------- old git, UK
Thank you so much for this video. It is valuable knowledge to my increaing library of sound design. Another bang on video Pete😄👍
Great video! (As always)
I especially enjoyed the part showing the cabinet and output curves as you were changing the geometry with the curves following right along showing the changing results. Awesome design tool!
This is a video I have been hoping you would make for a while. You have my thanks! It will definitely take me another watch-through or two to glean everything there is to be learned from this video. The comments on tuning frequency in particular, was something I had noticed in practice, but never had a good understanding of.
Wow, this was a really interesting deep dive! Thanks! :)
First off thank you for sharing these types of videos with us. I had read in another comment that you designed and built an enclosure for someone? If so what do you charge and what info do you need?
Appreciate you sharing this.
Just WOW, learned a loooot, thanks!
Probably I could use these softwares to make my sub placement "optimal" in the livingroom, right?
cześć, pozdrowienia z Australii. Love these video's, glad I found your channel, I fill in a lot of gaps in my knowledge and get ideas from your projects, the learning is the grind but once you have the knowledge, the fun can start.
Awesome! super informative and i like the attention to modeling response in a specific tiype of car. thanks for explaining this process.
Thanks for sharing this, I'm just a car audio hobbiest but I really want to get further into audio engineering and I love the content. Keep it up
Thanks for sharing, that was very enlightening and fun to watch. I would love to see a more indepth tutorial, but seeing the overall process was great!
Fantastic video thank you Pete.
Glad your back I was worried
I would prefer to have a flat response and let the electronics handle the loudness curve. For the obvious reason loudness needs to flatten out at louder volume.
that workflow is insane! clearly not for everyone but it seems to take into consideration every aspect. And im here just doing winsid and struggling haha!
This is outstanding! I didn't know someone would really go to that much effort to simulate a loudpeaker enclosure from start to end so that the frequency response it creates in a specific environment matches a predefined curve at the listening position.
Two questions:
1) What simulation software do you use? How did you achive live-update of the simulated frequency responses while tuning the parameters in CAD? 😧
2) 04:27 - Equal Loudness Target. Why do you want to match the equal loudness curve in the first place? Producers create their music on systems that follow a rather linear frequency response and not one, that follows the shape of an equal loudness curve. So why should our subwoofer do? In my view it just adds a colouration to the low end sound.
What am I overseeing?
Yes and no. There are different problems at the same time when mixing music. Yes, you could compensate in the production or mixing stage of your music BUT: the lower the note the bigger the wave and less space in the mix. So when compensating for equal loudness you'd have to limit different notes differently or you overdrive very low notes, so you only do this in a very rough way eg. octave jumps
I agree using the Equal loudness contour diagrams in this way does seem odd. I've only ever used it for comparing differences at two different volumes and compensating for that so that the content sounds the same at a volume louder or quieter than the reference. I can't quite see why he would try to trace the contour in this way. I'd like to hear his thoughts on this.
Used software was linked in the videos description, but I am interested in the live updates as well.
1) This is really interesting to me too... I'm pretty sure he's taken advantage of OpenSource CAD editors so he can easily write and run a script (possibly written in Python) from whatever operating system he's using (in this case, Windows). The script periodically extracts data from the CAD file and parses it into another text file, which the Sheets editor can then read in real time. This can be achieved using plugins or macros. Afterward, it calculates and prints data and frequency responde charts using macros within the same spreadsheet file.
Incredibly detailed. Amazing work as always!
Id love to see a future video in which you elaborate on the workbench calculations you used to yield the frequency response of the system.
The fun part is putting everything together to calculate a response curve, and then it morphs over time, when even a single tone builds in amplitude as the multiple dissipating waves bounce throughout the cabin. See that on a XYZ ∆P graph, real time....that is some cool ish. That's what he wrote over a decade ago. I can imagine what he's modified it to today.
Pete, Have you considered making a design for Barevids competition he is running? He is using a 2" driver and a cabin as a scaled cabin volume with viewers submitting 3d printable box designs that he will be testing in a head to head setup. I would be very interersted if you would go through the design process of such an enclosure, as well as going through the science of how well the setup mimics the behavior of a single 12" in a scaled cabin, of course once you scale the frequency response by a factor of 6 as well as the cabin volume. Maybe you could even collaborate on the video.
Also looking forward to this!
Me too
Hats off, amazing work!! I just worry the model of cabin is way off from reality _garbage in garbage out_
Could there be a better way to model the space?
The video is a bare-bones visual representation (for the viewers, unused by him). It gives Layman's explanation with crayons compared to what he's really looking at when modeling. He mentions it quickly, but 99.x% of watchers won't catch it.
@@stevemilton3499 Pretty sure he's modifying a basic parametric model in openscad, 0:51 "all my models". He just mentioned opening the file in a 3D viewer for us to see, but it's not strictly necessary.
So he's working off a realllly basic estimation that's probably nowhere near real world.
There has to be a better way, maybe using something like a bunch of data collected with 'REW' in conjunction with the basic model, or even better a 3D scan or actual model from OEM
Ill be coming back to this video many, many times😄
The software used at 6:15 is incredibly! Seeing how the enclosure affects the response live is amazing. Is that a software that is available somewhere?
Right now I am looking for ways to simulate enclosures and room acoustics at specific positions and something like that would be awesome!
Haven't watched that far, but have you checked the video description? It says all used software is free or open source and has a list of used programs with links.
@@raw_000 None of the programs there seem to be capable of those acoustic simulations by themselves. There are programs that are open source and free that can be used for simulation though. Including one that can be integrated into FreeCAD.
openscad
exactly what I was looking for more information on.
I think he has actually written everything in Libre office calc. It is just a spreadsheet with things color coded to make it look like a GUI, with buttons have macros assigned to them. I think the simulation is being done numerically in the spreadsheet, which is certainly possible although the math behind there must be crazy. It's also possible that the macros are launching something else to perform the simulation.
Brilliant Pete. Your software is extremely impressive. Nicely done that man xx
He shows about 10% of useful software. The rest is just visualizations made specifically for the viewer; he doesn't use visual things like you see there. It's 90% cartoon for the layman. The information is in the dialog, though. Listen again with your eyes shut.
Ah fair one, I'm no computer expert. I did like the 3d modes study software. It does run on a number of heavy assumptions pertaining to the damping factor of the surfaces though. Xx
Oh god... i was afraid of something like this. You do your calculations with an excel spreadsheet. Jesus. I guess you build that yourself? So there's no way for me to model something with your accuracy without building such a calculator myself?
You're use of deity is telling...🤪
@@scottiffanimccord1509
Oh Holey Jebus, please bless my spreadsheet and send angles to guide my hand on the router.
Seriously though, I'm a software engineer but I don't know shit about cabinet design.
If anybody wants I can write an excellent application to do this.
I've always wanted to as well, I just don't know anything about how to turn the idea into the math into the cab.
The best I've ever managed is take a pair of 6x9s where I had access to those attribute numbers drivers have and build a pair of sealed cabinets with a decent response curve.
Then I added all the electronics, gave it a lid, handles, wheels and a battery and basically made a _massive_ Bluetooth speaker.
@@MostlyPennyCat i would be able to manage to make a spreadsheet like his in the video but the amount of physical interactions between air molecules with each other and other surfaces is mind-boggling. No idea how to accurately represent everything with a formula. I'll try to find out
What software / visuals are used to create the pressure simulations, such as at 16:20? I thoroughly enjoyed this and might look into picking up model-based enclosures in the future. As of right now, most designs are just simple Bassreflex Boxes.
I would like to know as well!
Been asking since the early days 😢
I don't mind being pointed in the direction of where to go, I also don't mind paying for a similar program. Can someone (Preferably Pete) guide us please?
From what I understand he designed the whole software suite himself by programming live scripts so he could output his SPL graphs in real time...
Simply astounding level of engineering. I understand why he wouldn't want to share his intellectual property, but I would pay so much to get to use this software 😂
GOLD. THANKS!
my yamaha subwoofer has a "yst" system (yamaha active servo tech), would a system like that have a effect on the design of the enclosure?
the yst would make the ts parameters and such from the driver itself unusable? would they measure the driver with the yst system active? or arent they matched at all and could use any random 10" driver?
Hopefully you and Sam Vennard work together on bass or Bust? Definitely interested in seeking what you two could do together?
The less I understand what you're saying the more I enjoy it.
You need to start a tutorial series teaching others your wizardry..
Let me add: I watched this after drinking a decent amount of quality Kentucky style bourbon. My face now hurts very badly from straining to comprehend what the heck you are talking about.
Can you model that same subwoofer with a passive tunable radiator or even infinit baffle?
hold on a minute, let me grab a mop. My brain melted.
Pete,
Thanks for your videos. At some future date could you model the Karlson Ultra-Fidelity speaker enclosure please?
This is pretty incredible, and honestly looks more approachable than I'd expected; Do you think it'd be possible to invert this workflow in order to design a soundproof enclosure for a specific sound source?
Also, the description lists all software as being free or open source, but I'm not sure which one the actual speaker configuration and acoustic simulation program is supposed to be; It looks like it might be in-house software?
Si
Thanks for thoroughly discouraging me from progressing in the world of professional custom subwoofer design.
Please help explain:
This level is above me and have some basic questions.
I understand the bass distance is based on the hz it is played at, 28hz around 34 feet. But does certain box enclosures change the distance of the apex? Or is it just the note played? Is the apex also the completion of the frequency wave? Or the whole wave length? What would be the order of distance apex be- sealed/passive radiator/ported/4th order/horn?
Man, I could've used you in the late 90's. Now I need you for a new build lol. Orion SPLX 12 going into a S90.....
Great modelling methodology and an amazing video as per usual too! A bit baffled as to why you used the Equal Loudness Contours in this way, but nonetheless, an amazing showcase of your workflow. Thank you!
People don't like to see actual single pressure wave traces.
@@stevemilton3499 Hi, sorry, what are you referring to in this instance? The visualisations of areas of positive and negative pressure for a given frequency?
impressive video and helpful context for the detail oriented design process you undergo. i am very curious about your excel spreadsheet that you use to develop the response values.
Amazing video!
I wonder if this is the latest version of Pete’s own built modeling software he made years ago?? If so it is wild now for sure! Awesome stuff
I'd still love to know what the simulations software is. Either I blinked and missed it or he didn't tell?
Amazing!!
intensely interesting video. thank you!
Absolutely amazing.
I just face planted the learning curve