t-line box?

[rosrock 10+ year member]

(pictured is my current setup)I stopped over at the local shop today to discuss my concerns with a quality box builder. My concerns are I'm trying to get my sub to hit the higher bass notes which I'm sure it can and a smoother transition/timing from note to note. And of course no one wants to sacrifice that low end output.....

So I explained all of this to him and he recommended a t-line box. I was explained that basically it will turn the output of my 1 sub into 2 and have a flatter response and hit all the bass notes with quality. Basically the best of both worlds of which a sealed and ported can do combined if not better loudness wise since I'm sure 2 subs for 1 is about as good as it can get.... I heard a little 10" ct v1(not tc, I did not mispell) CT Sounds Tropo 2.0 10 sounds t-line he has in his midsized hatchback off 300 watts and GOD was I shocked what 1 10 low quality(compared to mine) off 300 watts can do..... this sucker got louder on lower notes than my 3hp ported off 800-1000(its close), it was rather embarrassing really. I'm strongly considering it. I'm looking for input/knowledge/experiences on the t-line box. Ty

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[LosIsATool 5,000+ posts]

T lines are very large. If you got the room go for it.

 

[rosrock 10+ year member]

o yea and he also said it would be good for ANY "quality" 12 ( I emphasize quality because he said if it's a sub that cant push much air it won't work) I might decide to switch to as nothing is based off the speaker specs/tsps, the only thing the port is based off is the size of the cone. Seems cool to me if its legit/true. Someone confirm.

 

[Immacomputer 10+ year member]

I am a strong supporter of transmission line enclosures and they do not have to be huge. People think you have to do SD= port area and Fs=line length but that's garbage. I've been running them for about 8-9 years now and will never look back. Smooth output, great transient response, they can dig deep while still remaining flat up high as well. Properly designed, they are the only choice for SQL as people say. I run a self loading tline with a compression chamber with two 8" TBS sub's on about 100rms each and it was louder, lower, and cleaner than two Boston 12s in 4 cubes at 34hz with 300rms each in a ford focus hatch (i have a trunk 240sx) haha. The guy couldn't wrap his mind around it. If this guy knows what he's doing, I would say give him a shot. I'm happy to hear there are shops tampering with tlines. Hope he's not an fs SD Nazi though.

 

[timhof13 10+ year member]

He's not a FS Sd Nazi, I was talking with him yesterday. Very knowledgeable and will to work with the line to make the box a manageable size, go for it. Im going to try my tantric MD 10 in a line for sh*ts and giggles.

 

[Immacomputer 10+ year member]

If he's familiar with Martin J Kings work and not fs SD Nazi, I support him haha. I've enjoyed every tline ever ever built and designed. My box for 2 8s fit what I wanted on the first try and I've had that box in for 5 years now. Plays flat from 24hz to 100hz if I didn't have it crossed over. Even with the low power, they still can make your eyes tingle.

 

[Jroo 10+ year member]

maybe Immacomputer can chime in, but I want to understand the compression chamber better. I see a few run them with their T lines and swear by them, but how do you figure out size? I also had a design a few years back that was a bandpass T line. That was a easier to figure out. Basically a sealed box for the sub that get .7 and then design the line as regular around the sealed section. When are the times that you benefit from a compression chamber vs just going to the standard line?

 

[Roland 10+ year member]

That sounds like the guy who built my T-line box near me in Marrieta Ga.

I run a sealed and a T-line in my mini van. The 12" T line can get earth shaking loud for sure. The main reason I got it is i can keep a stock electrical system with no power issues.

I'm a SQ guy for the most part, and if I had to choose between the two subs for my minivan, I'd have to keep the sealed SI BM mk IV sub, but id really miss the T-line.

Edit; if i had better bass in my doors or a smaller car i probably go with the T line.

 

[Immacomputer 10+ year member]

A standard line will have slightly lowered mechanical power handling for starters. It will also have slightly less output. Depending on the size, sometimes the compression chamber is really just part of the tline that's slightly larger making it a minutely tapered line lol. This gives minimal differences. If large enough though, it can add a Helmholtz resonance to your transmission line (ported box style). If done correctly, this can gain you increased mechanical handling and output around the combined 1/4 wave resonance and the Helmholtz resonance. If you're able to make these two values equal, interesting things can happen. For instance, I made a tline like this for an old Acoustic Elegance AV12 that matched the Fc for the sub in a sealed box of equivalent size, the Helmholtz resonance, and the 1/4 wave resonance. It took some work to get all three to equal and they all were 35hz. In my old integra hatch, it was -3dB at 17hz and 75hz with a peak at 22hz of 3dB. At 22hz, the sub wouldn't move just as if it were in a ported box tuned to 22hz but it wasn't. It was also flat within .1dB everywhere except at the end of range and at 22hz. It was also loud enough to do a small hair trick at 22hz with just the sunroof open (I guess that's kind of cheating... Still loud as **** for that low and that flat.). The compression chamber allowed me to get those three resonances to line up. Combining them gave a nice smooth response with plenty of output capabilities and not a huge enclosure though it was probably 3.5ft^3 for one 12 lol.

Size calculations for the compression chamber are based around VA's and (bl^2)/re. The bigger the compression chamber, the more boomy the response will be. The smaller, the tighter and controlled the response will be. It also varies based on your line.

 

[negolien]

How big would something like that be and can you run it with 2 subs say SQ HDS310's or HDS210's?

 

[Immacomputer 10+ year member]

Yea, you can use multiple sub's. Those subs could definitely work in a transmission line. Mid to low Q and strong motor usually makes a good candidate for one. Size depends. Sometimes they're large sometimes they're just a little bigger. It depends on how much line area and length you need. Calculations for that can be found in Dr. Matting J. King's papers on 1/4 wave theory.

This is what I use right now with two True Bass Solutions 8s: http://oi35.tinypic.com/14t96b8.jpg

It fits in a 240sx trunk so its obviously not huge but maybe a little bigger than a normal ported box for those subs.

 

[negolien]

Meh 18-3/4"D x 31-3/4"W x 15-3/4"H is the max I have to work with sounds nice though. I also like to hear the mids yet also be able to get low. Just started the install on upgrading from a 500 watt rms dual 12" MTX jh45 sub + stock monsoon set up. Laid the 0 gauge and distros last weekend and I' am doing the speaker amp and speakers this weekend leaving only the subs, box and sub amp left.

 

[Roland 10+ year member]

Yea, you can use multiple sub's. Those subs could definitely work in a transmission line. Mid to low Q and strong motor usually makes a good candidate for one. Size depends. Sometimes they're large sometimes they're just a little bigger. It depends on how much line area and length you need. Calculations for that can be found in Dr. Matting J. King's papers on 1/4 wave theory.
This is what I use right now with two True Bass Solutions 8s: http://oi35.tinypic.com/14t96b8.jpg

It fits in a 240sx trunk so its obviously not huge but maybe a little bigger than a normal ported box for those subs.

That box looks awesome. I dont have the skills to comprehend all the technical aspects of T-line designs. I'm wondering if you build or design for folks. I sent you a PM i'd like to try something a little different.

 

[Immacomputer 10+ year member]

Thanks for the compliment! It honestly sounds just as good as it looks and every day for the past 5 years I have been happy with it. So much so that I sealed up my trunk with expanding foam haha.

I used to design for people here but unfortunately, I lost all the work I did modifying Martin J King's Mathcad worksheet for transmission lines. I had added equations that I came up with over the course of about a years worth of testing and building boxes. That's more work than I have time for right now nor am I usually home long enough with nothing better to do. I'm still really sad and bummed out about losing it too as I was able to accurately predict/simulate cabin gain in my Integra and my 240sx coupe. I don't know of anybody else who has done that as most just apply some random 6dB/octave gain when that's no where near correct. It turns out, car interiors act like transmission lines. Ever heard of measuring the longest length of the interior to get your theoretical resonance or peak frequency? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Also, I noticed that every enclosure has 1/4 wave aspects to it, even sealed. That's why port area can have an acoustical difference, even if everything is the same, when in theory it should not.

 

[Jroo 10+ year member]

Yea, you can use multiple sub's. Those subs could definitely work in a transmission line. Mid to low Q and strong motor usually makes a good candidate for one. Size depends. Sometimes they're large sometimes they're just a little bigger. It depends on how much line area and length you need. Calculations for that can be found in Dr. Matting J. King's papers on 1/4 wave theory.
This is what I use right now with two True Bass Solutions 8s: http://oi35.tinypic.com/14t96b8.jpg

It fits in a 240sx trunk so its obviously not huge but maybe a little bigger than a normal ported box for those subs.

Would the box you designed for the true bass solution 8's work with Sundown SA8s?