folded horns?

[stratusrt01]

Pete just sent me an awesome looking folded horn design, and I was wondering how much of a gain or loss you'd usually end up with over a folded horn over a standard ported box for a loud street beater, not tones.

[Forevrbumpn]

I love this topic. 1/4 wave enclosures, t-lines, folded horns. I have personally tested, and tested, on t-line design, folded horn is pretty much the same, but if the horn was laid out, it would be a horn where the subwoofer side is narrow, and as the horn exits, it opens up. Some people do this backwards, I never have, and dont see how it would benifit really. The best part about t-lines, and horns is the efficiency. But lacks maximum power handling. I have tested, over and over again, with about 5 box designs, and LEAP/LMS software, and have seen huge gains at low power with horns and t-lines.

Woofers Older style Kove Armegedons 2-12s

Boxes-

1-2cf sealed dual sub

1-4cf sealed dual sub

1-1.5cf ported dual sub 38hz

1- 4cf ported dual sub 38hz

1- 38hz 1/4 wave transmission line single 12"

sealed boxes with 500w @4ohms didnt see more than 132-133db

ported, smaller ported box actually seen about a .5db increase over the 4cf box ( I assume it was due to port location) 137-138db

Then the transmission line, well with 1-12" I seen up to a 3db

increase. 141db with 250 watts (ran at 8ohm) same amp, all sub tests I used a 3db gain at 40hz. But after awhile, swapping amps, I noticed the transmission line box couldnt handle the power the ported boxes, or sealed boxes coul handle, but the benifits, is higher efficiency, increased low bass output (the tline was putting out lows like a 18") the ported were more punchier, even thow all tuned the same freq, with the same subs. Tlines, and folded horns are definitly the way to go for high dbs, with low power, but box sizes are usually a little bit longer/wider, This isnt from one or 2 tests, I build t-lines for almost all my customers. Once I can sell a 10" in a t-line, tuned at 40hz, using a 40hz bass boost, and a small amp, and charge the customer an arm an leg in box design, the customers usually get mad props for the spl output.

[irupp33]

how do you figure out the box? Ive been wanting to try my hand at it but cant quite get the hang of it...

[Sonic FX]

Have you read http://melhuish.org/audio/horndesign.htm that explains a lot about horns and has most of th common formulas and a few programs to get you started.

later

Doug

[Guest MegaloManiac]

doesnt Folded horns give a flat response?

[Forevrbumpn]

T-lines I build, when useing Low Qts drivers drop to about the next octave down. I usually build 40hz t-lines, and see them drop in the 20's pretty easy, and stay strong up to 60-80hz. If you run a T-line with a eq/bass boost, it really gets the output  kickin hard. Thats why I stay around 40hz, just cuz my pioneer deck, ofcourse has the 40hz bass boost.  So, it all works out fine, and sounds flat enough for me.

[GHOPPOMAN]

ive been waiting to hear back from pete myself but it sounds like forevrbumpn has alot of knowledge too! my question to pete (and now forevrbumpn) is how is the sq of the tline compared to a small sealed enclosure? im running multible eclipse sw8102dvc each in a .9 cu enclosure hitting 144.9 on tl. the whole setup is about sq...i love the punch and responce of the sw8102s in the sealed box. 99% of the time i play rock music. i really would like to do over 150 db though without losing my sq. can it be done?

[Forevrbumpn]

Yeah, it can be done. How many of those do you have?

The SQ on tlines rivals the best Sealed boxes, but with a good 3db gain min  (seen 3db gain switching from 2- subs ported to 1 in a tline with a better response)  Yeah they can play pretty flat, if you build them based on the subs Fs, but if you build them based on a bass boost, or EQ, you are bypassing the subs FS, and get a descent gain at Boost. But still, the SQ is pretty amazing. If you do a 1/4 wave box with a 40hz boost/40hz length (only boosted about 1/4-1/3rd up) you can get some incredible output.  Infact, tonite I learned 1-$150 10" in a tline, with a 250 wrms mono block plate amp, swapped out with a $2000 15" and a 500wrms class D amp in a 4cf sealed box--- The 10" still played deeper, louder, with alot less effort, I would say the 15" lost 3db easy to the 10" in the tline  (that was home audio ofcourse)

But PM me, I have tons of tline designs I have no problem helping you with

[GHOPPOMAN]

i have 8 sw8102dvc...pushed with 2 2400d directed amps. each r in their own .9 cube sealed box. im gonna shoot u a pm later. thanks

[stratusrt01]

I guess it all depends on how they are built, my folded horn picked up over 4db at 36hz over my old ported box, however, I lost a bit of SQ, and below 30hz is kind of weak, although anything over that is awesome.