You know it Mark, I've made a 8th order or Triple Reflex Bandpass. Very difficult indeed. Any chance of putting the T Line in the jeep for a test bump when it's finished?
My passion for building enclosures using mathematics is the only reason why I graduated college. My classmates always griped about how “boring” math is, but when they came to me to build an enclosure, they finally understood a real-world application that affected them directly.
Great video! As a ham radio operator, the concept of a transmission line box for audio really resonates with me. Thank you for making it easy to understand!
This is a very simple TL box. The woofer is at one end meaning the peaks and dips are pretty big. Moving the sub down the line can help smooth the response quite a bit. You can also taper the line(bigger at one end) and also play with damping at various points in the line. This is a good explanation but there are many more variables that can be tuned in a TL.
I had already known much of this because I have been studying this subject since the 90's. But this was the best simplified explanation of TLine vs ported boxes I have heard to date. Well done.
Question, I’m working with a 12 inch speaker that’s 6 inch’s in depth, do I have to make my air passage way more than 6 inch’s or can I stay at 6 inch’s where the speaker would touch the back of the board for the t line build. Looking at dimensions 15” x 38” x20”
The first time i ever saw the bose wave radio ad in a magazine showing the port layout inside ive been wondering how it would work in a vehicle. thank you so much for making this video and explaining the pros and cons. Much appreciated man!
I've built two T-Lines designed by a guy on the East Coast. One for two 12's (Pretty basic layout) and another for a single 15 (Tapered with a 180 degree kerfed wall). There is nothing like a properly designed T-Line! Also, both of these enclosures were very compact and broke a lot of the "rules" around T-Lines. I got out of car audio for awhile, but I'm hoping to build one again soon! Nice video!
Hey Mark i have a JL Audio 8W7AE subwoofer...i would like to build a T-Line for it. Can you prove the data sheet for it with all dimensions to build it?
I'm keen on this build for a number of reasons, not least because the 6.5" Skar subwoofer I got for a specific application, and planned on a bass reflex enclosure based on an email in which they claimed a "tuning frequency" of 40Hz (which I thought meant resonant frequency) turned out to have a resonant frequency of 64Hz. I am definitely looking for FLAT frequency response (I'm 62 years old and have never been a fan of BOOM BOOM!), and if this takes me down to 32Hz (using you half-below-twice-above-Fs rule of thumb) before things fall off, I think I can live with that. If you're wondering why I'm using a 6.5" sub, the space I'm working with (package shelf of a first series Miata) is very limited in height. While there's not much total volume either, given the SD of 17.52in2, and the relatively high Fs (which, if my calculations are correct, makes for a port length of less than 4.5 feet), I think it's doable. What scares me is the "...once we build the box, we're going to need to do some [testing and] fine tuning". Besides adding stuffing, it's hard to imagine how to fine tune something that is a glued together wooden box. And apart from using my ear, I don't know about testing (I'll be searching this site for videos about that, but if you wanted to shoot me some links, that would be most helpful).
Question for you Mark: I noticed in your calculations as well as a few of my own T-Lines trying with different speakers, the mounting depth is larger than the 'W' calculation. Now correct me if I'm wrong, but wouldn't this put the speaker through the first wall? Or did i misunderstand the orientation of the 'width'? I also noticed you didn't touch too much on Md in your Thiele Parameters video, which i could also have misunderstood. Thanks -From, a fellow engineer.
I've been trying to figure out a good box for my 2006 r50 mini cooper. Running a 10" alpine hdz-w10. I'm going to utilize the spare tire space but not much room. Running the skar 10 ported box but def to small. Wish me luck. Definitely checking out your website. Thanks for all the info. I've been researching for a few weeks now.
In some more advanced TL theory is stated that the speed of sound is slowed when passing through fibrous material such as poly-fill. This reduction in speed is dependant upon the sound frequency in question. It involves some extra math. However with proper stuffing it is possible to build a much smaller (read shorter line) TL subwoofer cabinet.
Mark, this is honestly one of the best explanations of the basics of enclosure design that I've ever seen. If you just add the qualities of different types of enclosures so people learn what the do to the frequency response (maybe more with the dogfood if Hz doesn't mind ;-) ) there would be a lot of people that would finally understand what's going on in their sub box. Heck, I think even some experienced people would gain by watching this, nailing down some basic concepts that are often overlooked.
1) there will be a 180° phase change when the sound wave reflects off a hard surface. 2) there should also be a 180° phase change when it transitions from the box to the cabin of the vehicle. 3) this box design tunes the system at the Fs of the driver, what happens when you tune the system for the resonant frequency of the vehicle, say 60hz? What gap does it fill in or does it provide a boosted response at that frequency, assuming the driver Fs is much lower?
An you just blew my mind how you took time to explain all of the math used in the builds, awesome! Please keep up the informative vids, I learn more every vid. Thank you.
Glad to see you explain the science behind it. When I was in the industry (Got out when Tweeter went belly up) I stayed away from ported as I thought they always sounded sloppy. It was also hard to explain to people how much more work it was.
I made a tapering T-line with stuffing. Some tapering enclosures expand, the one I made contracts from equal surface area to about one third. It's half wave with a 12", and my god does it pound at 20Hz. I'd be interested to see what it's like in a car though it's 8' long, this one is just for the home theatre. The idea of the stuffing is also to reduce any port type resonances as the chamber behind the sub is larger, before the stuffing it had a 50Hz resonance and had cancellation at 60-70, the stuffing absorbs the higher frequency waves to reduce cancellation and reduces the type of airflow that a port produces to eliminate that resonance. I also used thin sheet metal behind the driver and at the curve (the design is up and back) with expanding foam behind it to make a perfect curve.
Genuinely one of, if not the most useful video I have ever seen on RUclips. How did I not find this channel earlier! Always wanted to know how Bose get so much bass from a small speaker and this pretty much sums it up. Top man! 👍🏼
So if it's not built 100% mathematically correct, the nice flat frequency will be off. Good stuff. I thought a tline was just a fancy name for a extra long port. I learned something. Thanks
So I noticed when you were calculating everything out for your box, you have a port dimension of 9.75x5.5". But your sub has a mounting depth of 6". How did you make it fit without the magnet hitting the wall of the port? Im having the same issue trying to calculate a box design for a 12" sub I have.
I have a 1990 eagle talon tsi and I'm trying to use 2 p3 10" what do you believe the best lay out is that will allow it to be removable for drag race but let me keep my spare tire w/ it being accessable
I tried to calculate a t line box for my 18. Is it possible that given my mounting depth, and speaker diameter, it will simply never fit in my cross section area????
Excellent video! I've been wanting to do something with T-Line myself and your explanation is much easier to follow than some of the other stuff online lol.
what would I do if my subwoofer was deeper than the width of the port? I have a 10W7AE which has a mounting depth of 8", but with a 10.5" port height it'd only be 5.75" wide. Would I make just that section of the port wider? Would I make a small compression chamber with the port coming off it? Any help would be greatly appreciated
Really like these super technical videos. You do such a good job at explains complex concepts and techniques. Could you possibly do a video or even a demo comparing 3 boxes of equal size and volume but one is t line, 1 ported, 1 sealed and measure the response with the same woofer and amp? That would be so interesting to see and would reinforce how much difference a good enclosure can make.
I had a question. I've seen boxes similar to this but with short folds aswell as longer runs in the same box. Does this change how the port will work and overall sound?
Very interesting, I always thought of t-line as sort of a mystery I could probably figure out if I was really interested, but I 'get it' now, and it's not exceptionally difficult. I'm not sure about _tapered_ t-lines, but this is a good starting point. Thanks!
Excellent video, every time I was thinking, "but what about....(tappered, guys who think they add SPL, stuffed, multiple complex mathematical theory formulas, )" man, you had it covered. I think you really covered the basics of a T-line enclosure, with a simple formula to get someone started. 👌 Just like sealed, ported, and passive radiators, you can make full-range T-lines for home speakers. The ones I have seen are usually 6"-8" full-range drivers in a T-line.
Please tell me that would the values change if suppose you add a sealed enclosure in the front leaving the port alone?? I mean the front area of the sub in a sealed enclosure and the back in a tline would the values change as you've given??
You mentioned a "tapered" box. Does this mean that the chamber does not need to be equal all the time? Is it simply the cubic feet volume that you're concerned with? Keeping the chamber the same height and width is easier to find that volume, but could you theoretically change the dimensions as you go? I would think the corners would have some variation in them that isn't accounted for. (minimal at best) I'm not sure why you would do this, but I'm just curious about the math behind it.
Love your tutorials and have followed a few in the past with great success. Really struggling to calculate the port size, my issue is that the cut out and mounting depth to match, im using a 12" sub with a 6.22" mounting depth but the math says the port width will only come to 5.85", any help would be appreciated
Hi Mark, Thanks for the awesome video but i have a question. The begin of the line length is the bottom left of the schematic or the center of the magnet? And if so, does mounting location matter? Thanks
Brother thank you soooo very much for this video. you explain everything so well. I just built a TLine for my American Bass VFL 8 and i wish this video was around a year ago when i first decided to build it simply because i wanted it for car and home due to my new baby Boy so he can love it just as much as Daddy!!!
Thank you so much for this. I used your math to build a regenerative transmission line subwoofer like I saw from wisdom audio. I used 2-3ohm 8" Tymphany woofers with a QTS of .58 and it sounds incredible. The bass hits lower then I could have ever hoped for. I do have a question though as I want to build a giant cabinet to go under the couch. My question is: Would a woofer with a lower QTS yield better results? or are there particular specs you look for when choosing a woofer?
Hey man I want to build a tline enclosure for a 10 inch sub with a mouthing depth of 6.81 inches, the port length would be 104 inches long for a tuning frequency of 32Hz and its high would be 12 inches, however I could not get any information on the effective cone area so I used 8 inches, is that too wide or do I need to go back to the drawing board?
Great video Mark....never built one of these transmission line enclosures ...but I’ll now have a better grasp of the construction and math behind one...thanks again
As always, a clear and concise explanation to a subject with lots of technical depth. I've been watching for years and just wanted to say thank you and if you offered online classes or even in person classes I'd be (one of the) first in line. Maybe even selling ~hour long instructive videos on parameters for various applications and the various theories for sound quality etc. Just a thought, I don't mean to be that guy who tells you how to run your business lol. Anyways, superb video just like all your others. Your dog is one adorable lil fella too btw.
I am making a classic /straight T-line with a 12" woofer. The cabinet/waveguide is now at 240 lenght and is around 155 liters. Someone i know say i should try to make the T-line closer to VAS of the driver(85 Liter) Should i worry about VAS when making a classic T-line? I dont se how since the line area should equal or exceed slighty the cone area of the driver used and the line length should be 1/4 wavelength tuned to the resonant frequency of the chosen speaker. Can someone help me out? Thx
You could absolutely get more output with 2 ported 10’s/12’s. But I’ve always been intrigued with how efficient a box can be with little power. I wonder how a band pass compares to a t-line like this.
Newbie question: how does one determine which frequency to use? Is there some sort of natural resonance for each speaker, or is it a personal preference, rather than based on the actual speaker? Also, I have not seen the effective bandwidth of the TL mentioned. I am a ham radio operator and use the same principles when designing antennas and transmission lines...our calculations provide solutions that can only work for about + or - 10 percent of the center frequency.
At what point dose the port start? Is it at the back of the chamber or the middle of the sub? And what if there’s more then one sub ? I’m assuming it starts at the back of the chamber. I ready to build one so your guys help would be great
Can I ask how it works when your port width is 5.5 inch but your sub mounting depth is 6 inch I'm trying to calculate my own box and have come across the same problem
This was a really good and informative video about T-line design, I understand the math so much more now that! Thanks as always, looking forward to the build video! :D
I built the tapered transmission line box and the speed of sound needed to be more accurate. You can't really get an exact because just a change in 1 degree F adjusts the speed. 1130 fps is if temp is at 72 deg. Air in a ported box after 20 min is at 100 deg and usually stays around the 100 to 110 deg area, sealed boxes get up to 130 deg give or take. All this changes each sub is different so you can't get a perfect fps speed of sound. Instead of using the standard speed I used the speed at 90 or 100 don't remember. At 72 deg speed 1130 fps at 100 deg speed 1160 fps could almost be fully out of phase. I'm not sure if that would be the case or if it would even be noticeable. Just throwing it out there.
You should do videos explaining the difference between ported, 4th order, and 6th order bandpass enclosures and also show how the work and how to build them for people trying to get into spl builds.
T-Lines (or back wave variation) will always be my go to enclosure for SQ or in home and when I can get them to fit, the vehicle environment. There are some good tricks you can employ using these.
People. If you have not experienced a 1/4 wave T-line. It is so worth the time to design and build. This isn't a throw together box. You want all cuts tight and precise. Mine was first used in a 2010 ford Taurus SHO. I loved it. it is now doing work no in a 30x50 pole barn. Still the loudest and cleanest single 10" sub I've ever heard. Put my buddies twin 12 Sony Xplodes in a Sony pre fab to total shame. In his own Explorer.
When building a T-Line enclosure, do you know if there is a difference between mounting the speaker parallel or perpendicular to the line? I don't know if I'm describing it properly, but I would describe your speaker as being mounted perpendicular to the line because there is no chamber behind the speaker, it's mounted directly in the line.
Hi. My is Shannon. I have a new 2022 ford maverick truck. I am hoping to make a box for 2 - 6.5" skar 4 ohm subs. The subs are 200 rms. The truck has very little space behind the back seat. The box has to have .25 cubic ft for a sealed box for each sub or .60 cubic ft for a ported box . I don't know if your familiar with this type of truck . But I'm wondering what you would recommend for the design if the box. Thanks for your time. Ps. Your videos are very informative.
Good day , I have 2 8'" db drive wdx8 3k 1200 w dual 4 ohm subs and a db drive wdx 3k 3000 w monoblock amp and plan on putting it in a 2014 ford escape looking for any design ideas on a box design to fit in the cargo area . Removing the spare tire can be a option but would perfer not to due to long trips n may need it lol. also how do i wire it to the lowest ohms . i have allzero gauge wire for batteries ( one battery is stock n the other is a SHURIKEN 1500watts 60 amp hrs agm rechargable power cell ) what should i boost the altenator to for amp output to power this ....any help would be appreciated . I also am woodworker and a can build any thing you send my way for designs ,, also fiber glassing is not a problem many thnx in advance , steven
Does this work with every subwoofer? Some of the subwoofers calculations don't seem to add up right. An example is with the Skar ZVX 8. Its mounting depth is 6.5" and its Sd is 29.14 in^2 and its outer diameter (not the cut out) is 8.65" so when i do 29.14/8.65 the answer is 3.36 which is less than the 6.5" mounting depth.
Sometimes you have to account for difficulties in design. It doesn't always work perfectly. Might have to inverted mount a subwoofer or space it out with spacing rings.
So by my logic if you were to simply make the box height dimension taller you could bring the port cross section width down significantly thus shrinking the giant footprint right?
I've built a T-Line enclosure for a 6,5" sub using this formula and it sounds great at low/medium volume but at higher volumes when the sub gets to move, a lot of turbulence starts to occurs at the port. Any idea of what causes this?
OH man I so miss my T line box in my old wagon... The car was painted flat black, with a coffin shaped outer layer on the box. Figured since it was so big might as well play to the "coffin" thing everyone refers these as :P
I just learned about transmission line enclosures and I'm rather interested in learning more. Is there a calculator, or program for designing this type of enclosure?
Who's ready to see the build video? Let's see if we can get this video to 1,000 likes for the next video to be released! Thanks for watching! - Mark
heck yeah!! i'd also love to see the other side of the spectrum. like maybe an aperiodic bi-chamber, or a 4th order, or something!!
You know it Mark, I've made a 8th order or Triple Reflex Bandpass.
Very difficult indeed.
Any chance of putting the T Line in the jeep for a test bump when it's finished?
CarAudioF
abrication
T/L subs are awesome!! Thanks for the quick tutorial on the math. Had them with my ESL's in my home rig.
CarAudioFabrication Of course why not!
My passion for building enclosures using mathematics is the only reason why I graduated college. My classmates always griped about how “boring” math is, but when they came to me to build an enclosure, they finally understood a real-world application that affected them directly.
I'm currently a mechanical engineering student and my car audio hobby makes most of what I'm learning pertinent.
Great video! As a ham radio operator, the concept of a transmission line box for audio really resonates with me. Thank you for making it easy to understand!
This is a very simple TL box. The woofer is at one end meaning the peaks and dips are pretty big. Moving the sub down the line can help smooth the response quite a bit. You can also taper the line(bigger at one end) and also play with damping at various points in the line.
This is a good explanation but there are many more variables that can be tuned in a TL.
Car Audio, bagging a dozen parameters … not a problem.
I had already known much of this because I have been studying this subject since the 90's. But this was the best simplified explanation of TLine vs ported boxes I have heard to date. Well done.
Question, I’m working with a 12 inch speaker that’s 6 inch’s in depth, do I have to make my air passage way more than 6 inch’s or can I stay at 6 inch’s where the speaker would touch the back of the board for the t line build. Looking at dimensions 15” x 38” x20”
The first time i ever saw the bose wave radio ad in a magazine showing the port layout inside ive been wondering how it would work in a vehicle. thank you so much for making this video and explaining the pros and cons. Much appreciated man!
I've built two T-Lines designed by a guy on the East Coast. One for two 12's (Pretty basic layout) and another for a single 15 (Tapered with a 180 degree kerfed wall). There is nothing like a properly designed T-Line! Also, both of these enclosures were very compact and broke a lot of the "rules" around T-Lines. I got out of car audio for awhile, but I'm hoping to build one again soon! Nice video!
Justin Vetter
Ehm, when you brake a lot of the "rules" for a TM build, is it still a TM? And how about frequency curves, doesn't that hurt?
Hey Mark i have a JL Audio 8W7AE subwoofer...i would like to build a T-Line for it. Can you prove the data sheet for it with all dimensions to build it?
Really good visual explanation using the dog food. Good stuff!
I wanted to have a way to visually represent it, I hope it helped! Thanks for watching.
CarAudioFabrication it did the trick
Stuart Wood I find the wet dog food yields a smoother response.
@@CarAudioFabrication Agree! What if you horn-load the sub? Does that add to the number of dog foods, due to higher efficiency?
I'm keen on this build for a number of reasons, not least because the 6.5" Skar subwoofer I got for a specific application, and planned on a bass reflex enclosure based on an email in which they claimed a "tuning frequency" of 40Hz (which I thought meant resonant frequency) turned out to have a resonant frequency of 64Hz. I am definitely looking for FLAT frequency response (I'm 62 years old and have never been a fan of BOOM BOOM!), and if this takes me down to 32Hz (using you half-below-twice-above-Fs rule of thumb) before things fall off, I think I can live with that.
If you're wondering why I'm using a 6.5" sub, the space I'm working with (package shelf of a first series Miata) is very limited in height. While there's not much total volume either, given the SD of 17.52in2, and the relatively high Fs (which, if my calculations are correct, makes for a port length of less than 4.5 feet), I think it's doable.
What scares me is the "...once we build the box, we're going to need to do some [testing and] fine tuning". Besides adding stuffing, it's hard to imagine how to fine tune something that is a glued together wooden box. And apart from using my ear, I don't know about testing (I'll be searching this site for videos about that, but if you wanted to shoot me some links, that would be most helpful).
Alan Johansson did you ever do this? I too have some spare 6.5 woofers around
Bry Ytab Not yet. Considerable life has happened since.
Alan Johansson understandable..it will be cool to see, if you ever attempt it
Usually tuning is adding wood in the "chamber" or creating a narrow "throat" to distinguish where the chamber ends and the port begins
Question for you Mark:
I noticed in your calculations as well as a few of my own T-Lines trying with different speakers, the mounting depth is larger than the 'W' calculation. Now correct me if I'm wrong, but wouldn't this put the speaker through the first wall? Or did i misunderstand the orientation of the 'width'? I also noticed you didn't touch too much on Md in your Thiele Parameters video, which i could also have misunderstood.
Thanks
-From, a fellow engineer.
I've been trying to figure out a good box for my 2006 r50 mini cooper. Running a 10" alpine hdz-w10. I'm going to utilize the spare tire space but not much room. Running the skar 10 ported box but def to small. Wish me luck. Definitely checking out your website. Thanks for all the info. I've been researching for a few weeks now.
In some more advanced TL theory is stated that the speed of sound is slowed when passing through fibrous material such as poly-fill. This reduction in speed is dependant upon the sound frequency in question. It involves some extra math. However with proper stuffing it is possible to build a much smaller (read shorter line) TL subwoofer cabinet.
I have worked with Mark in making a custom box for my 12's and everything went great.
Right now I'm having him build another for some DDX-12's
Daniel Lanning can you let me know what you come up with for yr ddxs I'd really appreciate it thanks
Mark, this is honestly one of the best explanations of the basics of enclosure design that I've ever seen. If you just add the qualities of different types of enclosures so people learn what the do to the frequency response (maybe more with the dogfood if Hz doesn't mind ;-) ) there would be a lot of people that would finally understand what's going on in their sub box. Heck, I think even some experienced people would gain by watching this, nailing down some basic concepts that are often overlooked.
1) there will be a 180° phase change when the sound wave reflects off a hard surface.
2) there should also be a 180° phase change when it transitions from the box to the cabin of the vehicle.
3) this box design tunes the system at the Fs of the driver, what happens when you tune the system for the resonant frequency of the vehicle, say 60hz? What gap does it fill in or does it provide a boosted response at that frequency, assuming the driver Fs is much lower?
An you just blew my mind how you took time to explain all of the math used in the builds, awesome! Please keep up the informative vids, I learn more every vid. Thank you.
Glad to see you explain the science behind it. When I was in the industry (Got out when Tweeter went belly up) I stayed away from ported as I thought they always sounded sloppy. It was also hard to explain to people how much more work it was.
5,5" wide port but subwoofer mounting depth is 6", how did you solve that problem?
Invert the sub that's what I had to do with my old box, didn't make any difference in sound
I made a tapering T-line with stuffing. Some tapering enclosures expand, the one I made contracts from equal surface area to about one third. It's half wave with a 12", and my god does it pound at 20Hz. I'd be interested to see what it's like in a car though it's 8' long, this one is just for the home theatre. The idea of the stuffing is also to reduce any port type resonances as the chamber behind the sub is larger, before the stuffing it had a 50Hz resonance and had cancellation at 60-70, the stuffing absorbs the higher frequency waves to reduce cancellation and reduces the type of airflow that a port produces to eliminate that resonance. I also used thin sheet metal behind the driver and at the curve (the design is up and back) with expanding foam behind it to make a perfect curve.
UniCrafter In the South, we don't use Stuffing... We make dressing on the side... Will that work? 😂
Genuinely one of, if not the most useful video I have ever seen on RUclips. How did I not find this channel earlier! Always wanted to know how Bose get so much bass from a small speaker and this pretty much sums it up. Top man! 👍🏼
So if it's not built 100% mathematically correct, the nice flat frequency will be off. Good stuff. I thought a tline was just a fancy name for a extra long port. I learned something. Thanks
Dog food demo was so on point, couldn’t explain any better great video
So I noticed when you were calculating everything out for your box, you have a port dimension of 9.75x5.5". But your sub has a mounting depth of 6". How did you make it fit without the magnet hitting the wall of the port? Im having the same issue trying to calculate a box design for a 12" sub I have.
+Pat B the thickness of the wood...
I love the dog food graphics! Amazing :D
Could an adjustable baffle be installed at the perfect location to give this woofer a sealed box option on the fly?
I have a 1990 eagle talon tsi and I'm trying to use 2 p3 10" what do you believe the best lay out is that will allow it to be removable for drag race but let me keep my spare tire w/ it being accessable
I tried to calculate a t line box for my 18. Is it possible that given my mounting depth, and speaker diameter, it will simply never fit in my cross section area????
Excellent video! I've been wanting to do something with T-Line myself and your explanation is much easier to follow than some of the other stuff online lol.
what would I do if my subwoofer was deeper than the width of the port? I have a 10W7AE which has a mounting depth of 8", but with a 10.5" port height it'd only be 5.75" wide. Would I make just that section of the port wider? Would I make a small compression chamber with the port coming off it? Any help would be greatly appreciated
How would I figure for multiple subwoofers. I plan to use 4 toro 62 (6.5inch subwoofers)
Really like these super technical videos. You do such a good job at explains complex concepts and techniques.
Could you possibly do a video or even a demo comparing 3 boxes of equal size and volume but one is t line, 1 ported, 1 sealed and measure the response with the same woofer and amp?
That would be so interesting to see and would reinforce how much difference a good enclosure can make.
Car Audio.etc i
This isn't super technical, its basic.....
I had a question. I've seen boxes similar to this but with short folds aswell as longer runs in the same box. Does this change how the port will work and overall sound?
I really wanted to design a tline but didn't know where to start. Thanks for the info bro!!
Thanks for watching!
Great advice as always.
Very interesting, I always thought of t-line as sort of a mystery I could probably figure out if I was really interested, but I 'get it' now, and it's not exceptionally difficult. I'm not sure about _tapered_ t-lines, but this is a good starting point. Thanks!
Would inverting the sub change the length of the line? Would there be any issues with having an inverted sub with this style enclosure?
Excellent video, every time I was thinking, "but what about....(tappered, guys who think they add SPL, stuffed, multiple complex mathematical theory formulas, )" man, you had it covered. I think you really covered the basics of a T-line enclosure, with a simple formula to get someone started. 👌
Just like sealed, ported, and passive radiators, you can make full-range T-lines for home speakers. The ones I have seen are usually 6"-8" full-range drivers in a T-line.
Please tell me that would the values change if suppose you add a sealed enclosure in the front leaving the port alone?? I mean the front area of the sub in a sealed enclosure and the back in a tline would the values change as you've given??
You mentioned a "tapered" box. Does this mean that the chamber does not need to be equal all the time? Is it simply the cubic feet volume that you're concerned with? Keeping the chamber the same height and width is easier to find that volume, but could you theoretically change the dimensions as you go? I would think the corners would have some variation in them that isn't accounted for. (minimal at best) I'm not sure why you would do this, but I'm just curious about the math behind it.
Love your tutorials and have followed a few in the past with great success. Really struggling to calculate the port size, my issue is that the cut out and mounting depth to match, im using a 12" sub with a 6.22" mounting depth but the math says the port width will only come to 5.85", any help would be
appreciated
Excelente una pregunta que pasa si se unen más las tablas del puerto o se le pone otra tabla cambia el. Sonido la frecuencia
Hi Mark, Thanks for the awesome video but i have a question. The begin of the line length is the bottom left of the schematic or the center of the magnet? And if so, does mounting location matter?
Thanks
I want to know where you purchased the hole guides for the router.
What would it sound like if the t line is tuned below the speakers FS, like FS is 37hz but port length tunes the enclosure down to 30 Hz ???
i know 33hz was the fs of the driver you used but does it always need to be tuned to the drivers fs frequency?
Brother thank you soooo very much for this video. you explain everything so well. I just built a TLine for my American Bass VFL 8 and i wish this video was around a year ago when i first decided to build it simply because i wanted it for car and home due to my new baby Boy so he can love it just as much as Daddy!!!
Is there no damping material in a TL box? Just plain Wood inside?
Thank you so much for this. I used your math to build a regenerative transmission line subwoofer like I saw from wisdom audio. I used 2-3ohm 8" Tymphany woofers with a QTS of .58 and it sounds incredible. The bass hits lower then I could have ever hoped for. I do have a question though as I want to build a giant cabinet to go under the couch.
My question is: Would a woofer with a lower QTS yield better results? or are there particular specs you look for when choosing a woofer?
Interesting followup, the differences between quarter wave, half wave, full wave, ect.
Is it ok to install two subwoofers side by side, or will the different port lenghts be harmful?
the dog food analogy was cool.... now add a sealed enclosure. would it produce a similar line as the T line box?
Can you use a epicenter on this type of enclosure,if so how does it sound
I need advice on one 12 orion hcca122 box for a 2014 camry se I'm trying to use the wheel well space what do you recommend
Brilliant explanation. I saw one once back in 1996 that was a single 18” in the bed of a p/u truck. Took up the entire bed.
Hey man I want to build a tline enclosure for a 10 inch sub with a mouthing depth of 6.81 inches, the port length would be 104 inches long for a tuning frequency of 32Hz and its high would be 12 inches, however I could not get any information on the effective cone area so I used 8 inches, is that too wide or do I need to go back to the drawing board?
Great video Mark....never built one of these transmission line enclosures ...but I’ll now have a better grasp of the construction and math behind one...thanks again
Hey Mark, Great intro to T-lines. Please consider doing an advanced math video for T-Lines as well.
Cheers
As always, a clear and concise explanation to a subject with lots of technical depth. I've been watching for years and just wanted to say thank you and if you offered online classes or even in person classes I'd be (one of the) first in line. Maybe even selling ~hour long instructive videos on parameters for various applications and the various theories for sound quality etc. Just a thought, I don't mean to be that guy who tells you how to run your business lol. Anyways, superb video just like all your others. Your dog is one adorable lil fella too btw.
I am making a classic /straight T-line with a 12" woofer. The cabinet/waveguide is now at 240 lenght and is around 155 liters. Someone i know say i should try to make the T-line closer to VAS of the driver(85 Liter) Should i worry about VAS when making a classic T-line? I dont se how since the line area should equal or exceed slighty the cone area of the driver used and the line length should be 1/4 wavelength tuned to the resonant frequency of the chosen speaker. Can someone help me out? Thx
How much space you need to leave behind the spk. When the depth of the spk is equal to the depth of the cross sectional area
Mark, isn't the tuning frequency supposed to be a bit below Fs, just like in ported enclosures, to smooth out the peak at driver's resonance?
You could absolutely get more output with 2 ported 10’s/12’s. But I’ve always been intrigued with how efficient a box can be with little power. I wonder how a band pass compares to a t-line like this.
Newbie question: how does one determine which frequency to use? Is there some sort of natural resonance for each speaker, or is it a personal preference, rather than based on the actual speaker? Also, I have not seen the effective bandwidth of the TL mentioned. I am a ham radio operator and use the same principles when designing antennas and transmission lines...our calculations provide solutions that can only work for about + or - 10 percent of the center frequency.
My buddy had 2 10" DC Audio xl's in a t line box, that box was huge and heavy, sounded really good tho, love these boxes
At what point dose the port start? Is it at the back of the chamber or the middle of the sub? And what if there’s more then one sub ? I’m assuming it starts at the back of the chamber. I ready to build one so your guys help would be great
Can I ask how it works when your port width is 5.5 inch but your sub mounting depth is 6 inch I'm trying to calculate my own box and have come across the same problem
Where can I purchase a box like that for 2 CT sounds STRATO- 8s...I need low bass
I was looking at the box and thinking that it would make a great home theater enclosure. I might have to build one for my home system.
Duuude, I have a question what's the difference with a positive and negative pressure subwoofer enclosure? I'm really curious
This was a really good and informative video about T-line design, I understand the math so much more now that!
Thanks as always, looking forward to the build video! :D
I built the tapered transmission line box and the speed of sound needed to be more accurate. You can't really get an exact because just a change in 1 degree F adjusts the speed. 1130 fps is if temp is at 72 deg. Air in a ported box after 20 min is at 100 deg and usually stays around the 100 to 110 deg area, sealed boxes get up to 130 deg give or take. All this changes each sub is different so you can't get a perfect fps speed of sound. Instead of using the standard speed I used the speed at 90 or 100 don't remember. At 72 deg speed 1130 fps at 100 deg speed 1160 fps could almost be fully out of phase. I'm not sure if that would be the case or if it would even be noticeable. Just throwing it out there.
How can i buld 2 15 inche woffers to fit in trunk but all the bass port air to travel in cabin of car and not the trunk
I have 2 12 inches kicker comp vr sub,would like a custom blueprint to but a sup box to fix my toyota altezza. Ported
Good day what subwoofer is that the box was design for
want to do a t-line for a 5 1/4 for home audio
have any blue prints for that
You should do videos explaining the difference between ported, 4th order, and 6th order bandpass enclosures and also show how the work and how to build them for people trying to get into spl builds.
You are the best on the line!
how do you fit the driver, which is 10,5 wide, while you calc. the port at 9,75 wide? something does not add up.
The entire driver is that wide, the cone is not.
T-Lines (or back wave variation) will always be my go to enclosure for SQ or in home and when I can get them to fit, the vehicle environment.
There are some good tricks you can employ using these.
What a clear concise video ... Thanks
Glad to hear it, enjoy the build!
@CarAudioFabrication Thanks I have to do bookshelf speakers 4" full range speakers
If i can figure it out in a 10x7x12 LxWxH Id be very happy
People. If you have not experienced a 1/4 wave T-line. It is so worth the time to design and build. This isn't a throw together box. You want all cuts tight and precise. Mine was first used in a 2010 ford Taurus SHO. I loved it. it is now doing work no in a 30x50 pole barn. Still the loudest and cleanest single 10" sub I've ever heard. Put my buddies twin 12 Sony Xplodes in a Sony pre fab to total shame. In his own Explorer.
How it performs regarding delay and phase, compare to a ported one?
When building a T-Line enclosure, do you know if there is a difference between mounting the speaker parallel or perpendicular to the line? I don't know if I'm describing it properly, but I would describe your speaker as being mounted perpendicular to the line because there is no chamber behind the speaker, it's mounted directly in the line.
Hi. My is Shannon. I have a new 2022 ford maverick truck. I am hoping to make a box for 2 - 6.5" skar 4 ohm subs. The subs are 200 rms. The truck has very little space behind the back seat. The box has to have .25 cubic ft for a sealed box for each sub or .60 cubic ft for a ported box . I don't know if your familiar with this type of truck . But I'm wondering what you would recommend for the design if the box. Thanks for your time. Ps. Your videos are very informative.
Do you have any vids or ideals or experience with old school muscle cars sub setups?..need to put one in a 69 Camaro
Good day ,
I have 2 8'" db drive wdx8 3k 1200 w dual 4 ohm subs and a db drive wdx 3k 3000 w monoblock amp and plan on putting it in a 2014 ford escape looking for any design ideas on a box design to fit in the cargo area . Removing the spare tire can be a option but would perfer not to due to long trips n may need it lol. also how do i wire it to the lowest ohms . i have allzero gauge wire for batteries ( one battery is stock n the other is a SHURIKEN 1500watts 60 amp hrs agm rechargable power cell ) what should i boost the altenator to for amp output to power this ....any help would be appreciated .
I also am woodworker and a
can build any thing you send my way for designs ,, also fiber glassing is not a problem
many thnx in advance ,
steven
Is there anything you would do differently if you were to build one for surround sound?
If dual subs, would the measurements just double and would the center line measurement for port be between the two subs?
Does this work with every subwoofer? Some of the subwoofers calculations don't seem to add up right. An example is with the Skar ZVX 8. Its mounting depth is 6.5" and its Sd is 29.14 in^2 and its outer diameter (not the cut out) is 8.65" so when i do 29.14/8.65 the answer is 3.36 which is less than the 6.5" mounting depth.
Sometimes you have to account for difficulties in design. It doesn't always work perfectly. Might have to inverted mount a subwoofer or space it out with spacing rings.
So by my logic if you were to simply make the box height dimension taller you could bring the port cross section width down significantly thus shrinking the giant footprint right?
Is an eighth wave transmission line enclosure a thing? Seems like shortening the path by half would reduce the size by quite a bit.
I've built a T-Line enclosure for a 6,5" sub using this formula and it sounds great at low/medium volume but at higher volumes when the sub gets to move, a lot of turbulence starts to occurs at the port. Any idea of what causes this?
I was wondering, how will would it sound doing a down firing t-line box.
Does a T line effect the eirp antenna?
Hola amigo en tu ecuacion por que divides 34.25 entr 4 y después por 12 saludos
Where can I find speed of sound?
OH man I so miss my T line box in my old wagon... The car was painted flat black, with a coffin shaped outer layer on the box. Figured since it was so big might as well play to the "coffin" thing everyone refers these as :P
I just learned about transmission line enclosures and I'm rather interested in learning more. Is there a calculator, or program for designing this type of enclosure?
The math is in this video...
Lol thanks.