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.... 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. I heard a 10" ct v1(not tc, I did not mispell) http://ct-sounds.com/tropo-10/ in a 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 may have gotten 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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[Umbra]

Never heard of it, but I haven't been around all that long. Keeping an eye on this thread; I'd like to know about a magic design that doubles output.

 

[Jeffdachef 5,000+ posts]

@bbeljefe ;

 

[azmcrae 10+ year member]

Watch this...

 

[timhof13 10+ year member]

If you are talking with Steve he knows his ish when it comes to a tline. I think I'm gonna try my tantric MD in one.

 

[bbeljefe]

I think you probably talked to David or Steve Brondstetter? If so, you're in good hands, although I don't entirely agree with that description of a t-line. For one, if it's flat all the way across the spectrum, it can't be as loud as two subs because flat means there is no acoustical gain and thus, no increase in sound pressure over a conventional alignment. Or to put it simply, it would basically be as loud as a sealed enclosure while having a wider bandwidth... which would make it louder only where the sealed box began to fall off down low.

Also, I've yet to find a sub that doesn't do its best in a line... cheap or otherwise. To be sure, cheap subs won't do as well in a line as quality subs but that applies to any alignment so it's a moot point. So I definitely disagree with the notion that cheap subs won't work in a line. They absolutely will work and I have video showing that on my youtube channel. Other than that, I have a good deal of respect for Steve's knowledge where t-lines are concerned. He's helped me out some with the theory and from what I've seen, he has built some pretty nice t-line setups.

That said, if you're looking to get the most out of your sub and you're prepared to sacrifice some trunk space to get it, then a line is the best box you can build. They will play well above the sub bass region with ease and low end extension usually doesn't go -3dB until one full octave below tuning. So, if your box is tuned to 35Hz, you can expect good response all the way down to 18Hz. As for the dont's of t-lines, they are few but important. First... don't tune above the driver's Fs. And second... well, there isn't a second, lol.

If you have any more questions, feel free to ask away. I'm not the end all be all to lines and if you're dealing with the Brandstetter you're already dealing with experts but none the less, I'm happy to help in any way I can. Oh and, here are a few youtube links to lines I've done:

This one was built for two JL 8W3s but during testing, the surrounds crapped out so I threw in a couple of 20 year old, 75 watt woofers that came out of a pair of M&S Systems in wall home audio speakers. They're 8Ω subs wired to 2Ω and they're being hit full tilt boogie with a Ground Zero 850 watt monoblock amp:

 

[rosrock 10+ year member]

Yes, talking about steve. I'm heading back on over to get er done. What I really like is the fact that it will play the higher notes as well as not lose much dB's below tuning freq. Thx a lot for your post!

 

[hispls 5,000+ posts]

Transmission line box should play very flat and they do sound nice. You're sacrificing output and space for bandwidth.

Personally I believe that ported box is plenty capable for most modern drivers and most issues can be solved by location and orientation of box/sub(s)/port. Bear in mind your "flat" response box will still have peaks and nulls according to the acoustics of your vehicle and box placement in that vehicle.

 

[big scott]

I think you probably talked to David or Steve Brondstetter? If so, you're in good hands, although I don't entirely agree with that description of a t-line. For one, if it's flat all the way across the spectrum, it can't be as loud as two subs because flat means there is no acoustical gain and thus, no increase in sound pressure over a conventional alignment. Or to put it simply, it would basically be as loud as a sealed enclosure while having a wider bandwidth... which would make it louder only where the sealed box began to fall off down low.
Also, I've yet to find a sub that doesn't do its best in a line... cheap or otherwise. To be sure, cheap subs won't do as well in a line as quality subs but that applies to any alignment so it's a moot point. So I definitely disagree with the notion that cheap subs won't work in a line. They absolutely will work and I have video showing that on my youtube channel. Other than that, I have a good deal of respect for Steve's knowledge where t-lines are concerned. He's helped me out some with the theory and from what I've seen, he has built some pretty nice t-line setups.

That said, if you're looking to get the most out of your sub and you're prepared to sacrifice some trunk space to get it, then a line is the best box you can build. They will play well above the sub bass region with ease and low end extension usually doesn't go -3dB until one full octave below tuning. So, if your box is tuned to 35Hz, you can expect good response all the way down to 18Hz. As for the dont's of t-lines, they are few but important. First... don't tune above the driver's Fs. And second... well, there isn't a second, lol.

If you have any more questions, feel free to ask away. I'm not the end all be all to lines and if you're dealing with the Brandstetter you're already dealing with experts but none the less, I'm happy to help in any way I can. Oh and, here are a few youtube links to lines I've done:

This one was built for two JL 8W3s but during testing, the surrounds crapped out so I threw in a couple of 20 year old, 75 watt woofers that came out of a pair of M&S Systems in wall home audio speakers. They're 8Ω subs wired to 2Ω and they're being hit full tilt boogie with a Ground Zero 850 watt monoblock amp:

ya buddy, i see your using a tablet were did you get the cable to use a tablet ?

i have a galaxy tab 2 and for some reason never thought about using it .

and i take it has rca's on the end ?

 

[bbeljefe]

ya buddy, i see your using a tablet were did you get the cable to use a tablet ?i have a galaxy tab 2 and for some reason never thought about using it .

and i take it has rca's on the end ?

I have the cables for them in stock but I Bluetooth my tablet to the head unit. I've used cables that charge and have A/V outs and then I've used them that just have A/V out. The latter work better but obviously, you have to be sure the unit is charged ahead of time. Also, when you use the cable that does both there is often a difference in ground potential on the USB input in the tablet that causes some noise.

 

[big scott]

I have the cables for them in stock but I Bluetooth my tablet to the head unit. I've used cables that charge and have A/V outs and then I've used them that just have A/V out. The latter work better but obviously, you have to be sure the unit is charged ahead of time. Also, when you use the cable that does both there is often a difference in ground potential on the USB input in the tablet that causes some noise.

o ok, i did not think about that.

i picked up this cable..

as this will work on my radio and tablet. thanks for the info.

 

[Immacomputer 10+ year member]

I think you probably talked to David or Steve Brondstetter? If so, you're in good hands, although I don't entirely agree with that description of a t-line. For one, if it's flat all the way across the spectrum, it can't be as loud as two subs because flat means there is no acoustical gain and thus, no increase in sound pressure over a conventional alignment. Or to put it simply, it would basically be as loud as a sealed enclosure while having a wider bandwidth... which would make it louder only where the sealed box began to fall off down low.

This isn't entirely true. True that if the response is flat, you're sacrificing max spl for bandwidth but enclosure efficiency has a lot to do with output. A properly designed transmission line (one that fits the driver AND the vehicle) will be much more efficient than sealed enclosure and more efficient than a bass reflex enclosure. That means there will be acoustical gain even with a flat response curve. My tline in my old Integra was leaps and bounds louder (a good 4dB) than any of the bass reflex enclosures I had it in, louder than a ghetto 4th order BP, and louder than a DCTV box I put it in. It was also flatter and had WAY more low end extension while still being able to play very well above 60hz. And that's also ignoring the amazing transient response that was achieved vs the nasty port delay some of those boxes had (my god the DCTV was sloppy as all hell).

 

[bbeljefe]

This isn't entirely true. True that if the response is flat, you're sacrificing max spl for bandwidth but enclosure efficiency has a lot to do with output. A properly designed transmission line (one that fits the driver AND the vehicle) will be much more efficient than sealed enclosure and more efficient than a bass reflex enclosure. That means there will be acoustical gain even with a flat response curve. My tline in my old Integra was leaps and bounds louder (a good 4dB) than any of the bass reflex enclosures I had it in, louder than a ghetto 4th order BP, and louder than a DCTV box I put it in. It was also flatter and had WAY more low end extension while still being able to play very well above 60hz. And that's also ignoring the amazing transient response that was achieved vs the nasty port delay some of those boxes had (my god the DCTV was sloppy as all hell).

Perhaps I misunderstood the original comment but my use of the word flat was in the context of output. Ergo, flat being 0dB rather than consistent across a given bandwidth.

 

[Immacomputer 10+ year member]

Or maybe I did haha!

 

[eradicator006 10+ year member]

That said, if you're looking to get the most out of your sub and you're prepared to sacrifice some trunk space to get it, then a line is the best box you can build. They will play well above the sub bass region with ease and low end extension usually doesn't go -3dB until one full octave below tuning. So, if your box is tuned to 35Hz, you can expect good response all the way down to 18Hz. As for the dont's of t-lines, they are few but important. First... don't tune above the driver's Fs. And second... well, there isn't a second, lol.

I'm considering a quarter wave tline for one of my subs. The problem is most of my subs have a low FS and I don't think I have room for a low tune. Why is it bad to tune above the drivers FS?

Subs I currently possess:

15" RE XXX v2 (FS of 19hz, probably not even an option for a tline in a vehicle. Will likely become a H/T sub)

2006/2007 15" FI BL Dual 2 ohm. FS of ~30hz.

2 12" RF Power HX2. FS of 26hz.

15" Mach 5 SPL. FS is high 30's or even low 40's.