Transmission Line Subwoofer
Options
unc2701
Posts: 3,587
The woman was out of town, so a friend of mine & i decided to throw together a sub subwoofer with the lowest possible WAF, cost and -3db limit. The cost and the ability to put it together stinking drunk were the true limits.
He had a spare Polk 10" DB series driver, and I just picked up the crown amp from hoosier, and there was plenty of scrap plywood in the garage from another project. For a crossover, I used a variable psuedo active FMOD... mid 50's to 60's seemed to blend well with the LSi 9's, but even going up to 89 didn't get too boomy.
So, 2 hours and $30 later (that includes the beer) we had this:
He had a spare Polk 10" DB series driver, and I just picked up the crown amp from hoosier, and there was plenty of scrap plywood in the garage from another project. For a crossover, I used a variable psuedo active FMOD... mid 50's to 60's seemed to blend well with the LSi 9's, but even going up to 89 didn't get too boomy.
So, 2 hours and $30 later (that includes the beer) we had this:
Gallo Ref 3.1 : Bryston 4b SST : Musical fidelity CD Pre : VPI HW-19
Gallo Ref AV, Frankengallo Ref 3, LC60i : Bryston 9b SST : Meridian 565
Jordan JX92s : MF X-T100 : Xray v8
Backburner:Krell KAV-300i
Gallo Ref AV, Frankengallo Ref 3, LC60i : Bryston 9b SST : Meridian 565
Jordan JX92s : MF X-T100 : Xray v8
Backburner:Krell KAV-300i
Post edited by unc2701 on
Comments
-
:eek: :eek:
-
So how did it sound?Dodd - Battery Preamp
Monarchy Audio SE100 Delux - mono power amps
Sony DVP-NS999ES - SACD player
ADS 1230 - Polk SDA 2B
DIY Stereo Subwoofer towers w/(4) 12 drivers each
Crown K1 - Subwoofer amp
Outlaw ICBM - crossover
Beringher BFD - sub eq
Where is the remote? Where is the $%#$% remote!
"I've always been mad, I know I've been mad, like the most of us have...very hard to explain why you're mad, even if you're not mad..." -
The sub fires upwards in to an 8' X 12" diameter concrete form tube. The tube could stand to be a hair shorter to match the Fs of the driver, but for our purposes it didn't matter that much. The idea is that the tube is 1/4 the Fs for the driver, so the backwave comes out of the tube in phase with the bottom end, extending your response. You also get some of the tight punchiness of a sealed enclosure since the length allows for a good bit of pressure to build up at the driver end of the tube. The only real drawback is that it's one ugly ****. Oh, and if your driver's Fs is more like 20 hz, you need a 14 foot tube...
How did it do? for a driver with a Fs of about 40 hz, it was hitting things that it never should have been able to reach- well into the mid 20's I'd say. We were too drunk to, say, run test tones, but it had no trouble digging all the way down to the lowest notes (we had to break out some Chemical brothers & Outkast go past the low E).
So if you've got some free time it's a fun project to try out. Oh, and needless to say, the tube is going out with tomorrow's trash... (the woman didn't think it went with the rest of the decor...)Gallo Ref 3.1 : Bryston 4b SST : Musical fidelity CD Pre : VPI HW-19
Gallo Ref AV, Frankengallo Ref 3, LC60i : Bryston 9b SST : Meridian 565
Jordan JX92s : MF X-T100 : Xray v8
Backburner:Krell KAV-300i -
I'm confused... how is this a transmission line?
A transmission line is something like this...- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit. -
Sid - I seen a T line sub that some of the guys were playing around with in Home Theater magazine about a year ago. It was something like 16 foot in length. They to, just wanted to see what it would sound like, from the article it was said that a T line sub is any cabinet design where the sub driver is mounted on one side of the tube...Wait a minute............
O.k. googled the H.T magazine description...here it goes
"Transmission Line: A (sub)woofer cabinet design where the driver is mounted at one end of a tube with the same diameter as the radiating area of the driver and a length of 1/4 wavelength of the 3dB down frequency. This "tube" may or may not be round and may be folded to decrease the size of the cabinet."
scott
not as large, but looks nice
http://www.teresaudio.com/haven/subs/subs.html#cabinets -
Vr3MxStyler2k3 wrote:I'm confused... how is this a transmission line?
A transmission line is something like this...
unc2701's is a straight transmission line, I believe yours is a folded style. If you want it more esthetically pleasing and you think the wife will not notice a slight bump in the wall you can try...
http://www.t-linespeakers.org/projects/peter/index.html
heh...
regards
DaveTime is the best teacher. Unfortunately it kills all its students. -
Yep, it's just a straight T-line... you could fold it like that picture, but that'd take time, money and sobriety. I will admit that the sonotube was vibrating some, but I doubt that PVC would be much better. Since the pressure is distributed equally, the cardboard is plenty thick (it's like trying to crush an egg by squeezing it...)Gallo Ref 3.1 : Bryston 4b SST : Musical fidelity CD Pre : VPI HW-19
Gallo Ref AV, Frankengallo Ref 3, LC60i : Bryston 9b SST : Meridian 565
Jordan JX92s : MF X-T100 : Xray v8
Backburner:Krell KAV-300i -
Gotcha
Cool- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit. -
Very cool project.
For those that have never seen this link before. Here is Nelson Pass' El Pipo T-Line sub.
Sony KDL-40V2500 HDTV, Rotel RSX-1067 Receiver, Sony BDP-S550 Blu-ray, Slim Devices Squeezebox, Polk RTi6, CSi3 & R15, DIY sub with Atlas 15
