EXPERTS ONLY PLEASE Building the perfect transmission line box, many questions

[hispls 5,000+ posts]

right so why is it ok for u top tell me to run 1k to a sub but not ok for me to say 750? or 1500rms for a fu 750 when there are people running fsb 1600 to 1 or even a 3k amp on 1.. u may have seen guy just said he ran taramps 8k on 4 of them  a long time no problems.. don't tell me about rise when u are correcting me for tell people to "over power" subs because of rise

You had just better hope Kuthe or Papermaker comes back to take the heat off you at this point.  You've said some dumb **** here and you are just currently the low man on the pecking order these days.

 

[Boomin_tahoe 5,000+ posts]

I'm currently running a T-line tuned to 34Hz. Will play down to 28Hz and upwards of 90Hz. It's a very bandwidth enclosure. Sub is a DC Audio m3 8

 

[BOOMINGRANDPA 5,000+ posts]

You had just better hope Kuthe or Papermaker comes back to take the heat off you at this point.  You've said some dumb **** here and you are just currently the low man on the pecking order these days.

yeah i'm not here anoymore either there are much better places to be i just come back to answer pm's.. this site has to many Aholes that flame me for saying same thing they do.. and 1 guy designed a box that was to big for guys cheap subs for the power he had 1 blew and he blamed the subs.. i knew box was to big and pm'ed the guy and told him so.. i was right but the everyone here loves the guy that designs bad boxes and tells me idk what i'm talking about, whatever

 

[Popwarhomie 5,000+ posts]

right so why is it ok for u top tell me to run 1k to a sub but not ok for me to say 750? or 1500rms for a fu 750 when there are people running fsb 1600 to 1 or even a 3k amp on 1.. u may have seen guy just said he ran taramps 8k on 4 of them  a long time no problems.. don't tell me about rise when u are correcting me for tell people to "over power" subs because of rise

I told you you would be better off getting the FU300 because you are probably getting 300 watts with your 1k amp after rise and on stock electrical.... Yet you continue to tell everyone you are putting 900rms to your subwoofer.

I ran a f*****g Taramps T20k on two subwoofers. Did I claim they are getting 10k each? Nope not even close.

Are you going to warranty subwoofers for these companies when the people you are telling they can handle double rated power blow theirs up?

 

[Popwarhomie 5,000+ posts]

yeah i'm not here anoymore either there are much better places to be i just come back to answer pm's.. this site has to many Aholes that flame me for saying same thing they do.. and 1 guy designed a box that was to big for guys cheap subs for the power he had 1 blew and he blamed the subs.. i knew box was to big and pm'ed the guy and told him so.. i was right but the everyone here loves the guy that designs bad boxes and tells me idk what i'm talking about, whatever

Who would PM you asking for your help?

You run stock electrical.

You have never built a box

You couldn't re glue a subwoofer surround. 

You run coaxial door speakers off headunit power.

You keep giving advise to things you have ZERO experience with.

You are a stay at home mom who smokes 4 packs a day yet complains about not being able to afford anything and yet your english and grammar is still horrible.

 

[1995Tercel 10+ year member]

Do download and figure out how to use hornresp software.  EVERYBODY I have ever seen trying to build any type of horn, bin, or quarter wave box uses it. 

You can safely say you'll lose an inch from the diameter of the driver for surround, that should get you close enough.  Speaking of close enough if you're off on an end 3hz change in tuning of a box is inaudible in my experience and even 5hz is barely audible so don't drive yourself crazy there.

According to that source the unwanted high resonances that you think you want to tame with stuffing are only an issue in full range system so you should not need any batting unless you're trying to cheat a shorter line and from my experience with stuffing in general while you can change response slightly you pay for it with efficiency.

I do not believe you need a chamber for a true transmission line, that becomes more of a horn or just a ported box.  AFAIK true T-line is the woofer firing into the line which is consistent length throughout.  Having an odd size chamber puts you more into horn territory, though I suspect the hornresp software will have options where you can play with that.

Lastly I think if you want to play down to 20hz you will not be able to build this without a bend.   You are getting into a LONG wavelength, and that said I'm not sure how far below FS you can go with a t-line.   There have only been a handful of guys on this forum who have built these so if you want better, do a forum search and see who has done them, PM those guys and hope they're still active.  Good luck and please post a build log as you go.  I've heard one proper T line in person and it sounded very nice.   Almost worth the space and the wood.   Mind you, with today's EQ options and how cheap power is and how robust our woofers are there's no reason you can't get flat from 20-80hz in the same space a few different ways these days.   I'd consider T-line not something you "have to have" in order to get a particular sound but just an alternative as something to do if you like a good DIY woodworking challenge and interesting conversation piece.

Good luck and please post a build log here.

Thank you for your response. I downloaded hornresp, there is a learning curve to say the least.

The batting wont help with any of the harmonics below a certain Hz? Even thought my sub box will have a low pass filter (i think thats what it's called) won't it still produce multiples of the 39hz Fs that are problematic?

I am currently trying to find a woodworking shop (or audio shop) that will rent me their space on the weekend to work on the box, still no concrete dimentions. I'll try to document my progress once I start.

I'm currently running a T-line tuned to 34Hz. Will play down to 28Hz and upwards of 90Hz. It's a very bandwidth enclosure. Sub is a DC Audio m3 8

So would your box be a modified horn, because it has the chamber behind the sub? From my elementary understanding, doesnt the parallel wall directly behind the sub load it with air and create many resonances? Beautiful finish on that box, what kind of wood/stain/sealant/wax? What's the box underneath the subs? Mid drivers in an enclosure?

 

[hispls 5,000+ posts]

Thank you for your response. I downloaded hornresp, there is a learning curve to say the least. 

Yep.  Definitely not as simple or user friendly as WinISD or other simple box design software.  Other forums have guys that really geek out on it though so you should be able to find answers with google.

The batting wont help with any of the harmonics below a certain Hz?

It's the higher stuff that becomes an issue, but that's really only true (audibly) if you're, for example, using Fostex 7" full range (popular for various exotic horn type boxes)to try to make some bookshelfs where your total power is a 40WX2 tube am and you wind up with issues at audible levels at the higher multiples fighting with your midrange.  Safe to say with what we do in a car and a true subwoofer any of that higher stuff could be ignored.    Batting probably won't hurt but we simply don't see it used in cars.

I am currently trying to find a woodworking shop (or audio shop) that will rent me their space on the weekend

I'd think for liability reasons you won't get anybody to bite unless you're close personal friends with someone there.  Better bet might be to finalize a cut-sheet and ask a cabinet shop how much to cut those pieces.    

 

[BOOMINGRANDPA 5,000+ posts]

Who would PM you asking for your help?

You run stock electrical.

You have never built a box

You couldn't re glue a subwoofer surround. 

You run coaxial door speakers off headunit power.

You keep giving advise to things you have ZERO experience with.

You are a stay at home mom who smokes 4 packs a day yet complains about not being able to afford anything and yet your english and grammar is still horrible.

mom? i'm 51 mom died 15 yrs ago

 

[1995Tercel 10+ year member]

Yep.  Definitely not as simple or user friendly as WinISD or other simple box design software.  Other forums have guys that really geek out on it though so you should be able to find answers with google.

It's the higher stuff that becomes an issue, but that's really only true (audibly) if you're, for example, using Fostex 7" full range (popular for various exotic horn type boxes)to try to make some bookshelfs where your total power is a 40WX2 tube am and you wind up with issues at audible levels at the higher multiples fighting with your midrange.  Safe to say with what we do in a car and a true subwoofer any of that higher stuff could be ignored.    Batting probably won't hurt but we simply don't see it used in cars.

I'd think for liability reasons you won't get anybody to bite unless you're close personal friends with someone there.  Better bet might be to finalize a cut-sheet and ask a cabinet shop how much to cut those pieces.    

Yeah I definitely have to look up what all the abbreviations mean. Almost none of them match the units on the Sundown Spec sheet for the sub.

Ah makes sense. I'll try to keep this project simple.

By cabinet shop, do you literally mean kitchen cabinet place? Would I supply the wood?

 

[Boomin_tahoe 5,000+ posts]

Thank you for your response. I downloaded hornresp, there is a learning curve to say the least.

The batting wont help with any of the harmonics below a certain Hz? Even thought my sub box will have a low pass filter (i think thats what it's called) won't it still produce multiples of the 39hz Fs that are problematic?

I am currently trying to find a woodworking shop (or audio shop) that will rent me their space on the weekend to work on the box, still no concrete dimentions. I'll try to document my progress once I start.

So would your box be a modified horn, because it has the chamber behind the sub? From my elementary understanding, doesnt the parallel wall directly behind the sub load it with air and create many resonances? Beautiful finish on that box, what kind of wood/stain/sealant/wax? What's the box underneath the subs? Mid drivers in an enclosure?

No. It's still a T-line. That chamber you see is just a void area that needed to be filled to get the correct "volume" and maintain the necessary width/length for the super long port. I used a stain from Lowes called English Chestnut. Something not too light or too dark of a finish but in between. Once applied, it's the polyutherane that really brings out the shine and colorness of the stain. That "box" under my enclosure is where my amp is...

 

[Boomin_tahoe 5,000+ posts]

Who would PM you asking for your help?

You run stock electrical.

You have never built a box

You couldn't re glue a subwoofer surround. 

You run coaxial door speakers off headunit power.

You keep giving advise to things you have ZERO experience with.

You are a stay at home mom who smokes 4 packs a day yet complains about not being able to afford anything and yet your english and grammar is still horrible.

Are you on FB at times?

 

[hispls 5,000+ posts]

 By cabinet shop, do you literally mean kitchen cabinet place? Would I supply the wood?

Yes.  Any shop that builds custom cabinets for homes should be able to make perfect cuts and deal with pieces about the size of what you'll want.  They may or may not use MDF, do not use particle board unless you plan to coat it with resin (which you probably wouldn't for this project).  Any decent 3/4 ply should do the job too.

 

[Popwarhomie 5,000+ posts]

Are you on FB at times?

Yep. Always trolling facebook.