nope, no thread of my 18's (now owned by my neighbor) designed by a close friend. I feel them thumping my chest in my apartment every month or so. I'm rarely on this forum, but the ppsl thread caught my attention.
I ended up using 1 box (I used 2) crossed to a pair of 15" 3-way vega's at 100hz. Actually I blew the midranges on 2 different pairs of 3 way vegas (who's ever heard of doing that?). But I had used both sub boxes when running dual 15" per side, mid horn, piezo with active crossover points (24db LR) at 80hz, 500hz, and 5khz. Jeez that was loud. My kids said "You know when you told us not to crank it ? We didn't realize it was for our own hearing protection." lol.
Dimensions don't matter (maybe 2' x 3' x 4'). It was 16-18ft3 tuned to 27hz where the driver box was 9db down (6th order = high pass filter with a q=2 at tuning = 6db boost at tuning with subsonic filter below tuning). You are adding 6db boost at tuning, where the driver isn't moving much. Massive output from a pair of 4.6mm xmax 18's. It works well with lower qts drivers (higher spl 1w/1m), small box and deep with a squeek of boost, and inexpensive also. I'd crank it and people wouldn't believe 20hz wasn't there. It went lower without the booster box, but the volume also went down as the freq went below 60hz (27hz was 9db less than 60hz, and 20hz was there but maybe another 9db lower than 27hz).
The guy that built the box was scoffing as we brought them in. He was a car audio guy. "I don't like 18's" he said. We turned them on and he said "I've never heard 18's that quick and clean." I'd made a smaller prototype box with a pair of 12's. The 12" ported were quicker, cleaner, and punchier than his 3 x 10" sealed jl audios (qtc .707) in his pickup. There went his sealed vs ported quickness arguements.
If I was to build another sub, I'd only build a ppsl. Sealed / ported / passive radiator/ linkwitz transfer / 6th order, that's all up to you. I recommend lots of cone area. That way the driver isn't moving as far = less harmonic distortion, if you can tolerate the large box.
I don't even run a sub now. See my avatar.
Norman
I ended up using 1 box (I used 2) crossed to a pair of 15" 3-way vega's at 100hz. Actually I blew the midranges on 2 different pairs of 3 way vegas (who's ever heard of doing that?). But I had used both sub boxes when running dual 15" per side, mid horn, piezo with active crossover points (24db LR) at 80hz, 500hz, and 5khz. Jeez that was loud. My kids said "You know when you told us not to crank it ? We didn't realize it was for our own hearing protection." lol.
Dimensions don't matter (maybe 2' x 3' x 4'). It was 16-18ft3 tuned to 27hz where the driver box was 9db down (6th order = high pass filter with a q=2 at tuning = 6db boost at tuning with subsonic filter below tuning). You are adding 6db boost at tuning, where the driver isn't moving much. Massive output from a pair of 4.6mm xmax 18's. It works well with lower qts drivers (higher spl 1w/1m), small box and deep with a squeek of boost, and inexpensive also. I'd crank it and people wouldn't believe 20hz wasn't there. It went lower without the booster box, but the volume also went down as the freq went below 60hz (27hz was 9db less than 60hz, and 20hz was there but maybe another 9db lower than 27hz).
The guy that built the box was scoffing as we brought them in. He was a car audio guy. "I don't like 18's" he said. We turned them on and he said "I've never heard 18's that quick and clean." I'd made a smaller prototype box with a pair of 12's. The 12" ported were quicker, cleaner, and punchier than his 3 x 10" sealed jl audios (qtc .707) in his pickup. There went his sealed vs ported quickness arguements.
If I was to build another sub, I'd only build a ppsl. Sealed / ported / passive radiator/ linkwitz transfer / 6th order, that's all up to you. I recommend lots of cone area. That way the driver isn't moving as far = less harmonic distortion, if you can tolerate the large box.
I don't even run a sub now. See my avatar.
Norman
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The idea is actually quiet simple, take two Tham TH style folding (pathlength should be at least 3m for 38Hz) and put them together. Make sure you make up for the volume of the driver or you will loose LF. You will get some strange resonances you have to deal with and make sure you use enough bracing to keep the panel flex under control. Can’t advice this driver because it lacks definition in the kick region (I suppose this is one of the reasons why Danley changed them in his TH115). Go instead for the latest generation extended LF drivers. For dimensions and weight think of Turbosound TSW218 (so make sure you truck is loaded with a hydraulic lift 
) .
) .
"just a quick question - did you ever try building a PPSL where the vent exited through the plenum? I'm thinking a shelf port to the rear of the enclosure that vents into the back of the plenum. "
No, it doesn't seem like a good idea to me.
I have made the plenum with ports above and below the opening for the woofers. I made a dual 18 tuned to 28hz this way, and a dual 12 tuned to about 40hz. I am designing a dual 15 tuned to about 28hz this way too.
No, it doesn't seem like a good idea to me.
I have made the plenum with ports above and below the opening for the woofers. I made a dual 18 tuned to 28hz this way, and a dual 12 tuned to about 40hz. I am designing a dual 15 tuned to about 28hz this way too.
One of my friends built a double-TH - the topology was basically identical to a PPSL with a vent through the plenum (because he used a small mouth for his design), but of course one driver wasn't reversed. It actually sounded pretty good, especially considering that it was built using 6.5" long-throw drivers....
Hi Mashaffer, the problem with the PPSL-TH is that you want equal distribution of the sound pressure throughout the whole bandpass between the 2 paths. That’s the main reason why I’m still not satisfied with the end results so far. For the combination of PPSL-TL, I would go for the plenum (cavity) idea and use just one path.
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"Hmm... the PPSLTH above makes me wonder about doing a PPSL with TL. Could do a single TL instead of the slot ports or two separate TL like he does in his TH. Interesting."
I did something like this with a pair of 8s around 1985 or so. It was kind of a cross between a TH and a TL. In retrospect the cross-section of the line was too big for the 8s, but it worked well anyway. The main box was about 12x12x48H with the drivers in opposite sides of the bottom and the cabinet spaced off the floor about 3".
"Do you have a build thread of the 18" PPSL that you built? What are the dimensions? What is the port tuned to?"
That's totally dependent on the T/S parameters of your drivers. If you look at post #56, Norman used about 8 cu ft per driver (net) tuned to 28hz.
I built some for a dance club that were a 3 foot cube tuned to 28hz. They were using a subharmonic synthesizer and ruined a few sets of drivers, there were no drivers with a large x-max at that time. I re-tuned for 40hz with our 8mm x-max drivers, removed the subharmonic synthesizer, and stopped having problems.
Another set were used for a live band, they were tuned for 38hz and were about 30Wx24Dx39H. The design was 6th order vented, and the 20hz filter in a Rane AC23 was changed to the 38hz Q=2 filter required by this design.
I did something like this with a pair of 8s around 1985 or so. It was kind of a cross between a TH and a TL. In retrospect the cross-section of the line was too big for the 8s, but it worked well anyway. The main box was about 12x12x48H with the drivers in opposite sides of the bottom and the cabinet spaced off the floor about 3".
"Do you have a build thread of the 18" PPSL that you built? What are the dimensions? What is the port tuned to?"
That's totally dependent on the T/S parameters of your drivers. If you look at post #56, Norman used about 8 cu ft per driver (net) tuned to 28hz.
I built some for a dance club that were a 3 foot cube tuned to 28hz. They were using a subharmonic synthesizer and ruined a few sets of drivers, there were no drivers with a large x-max at that time. I re-tuned for 40hz with our 8mm x-max drivers, removed the subharmonic synthesizer, and stopped having problems.
Another set were used for a live band, they were tuned for 38hz and were about 30Wx24Dx39H. The design was 6th order vented, and the 20hz filter in a Rane AC23 was changed to the 38hz Q=2 filter required by this design.
What drivers are good for PPSL designs.
I have several extra woofers sitting around
Like...
TD12S 12" woofers
TC2000 15" subwoofers.
I already have an IB array, Sealed LMS5400s and Im building JBL 2226 Mid-bass horns (XOed with the IWATA-300/BMS 4590) but I would like to plan for a PPSL build and Im hoping my unused drivers could work.
I would like to see a 40Hz to 200Hz design with the TD12S 12" woofer.
Thanks for any advice.
I have several extra woofers sitting around
Like...
TD12S 12" woofers
TC2000 15" subwoofers.
I already have an IB array, Sealed LMS5400s and Im building JBL 2226 Mid-bass horns (XOed with the IWATA-300/BMS 4590) but I would like to plan for a PPSL build and Im hoping my unused drivers could work.
I would like to see a 40Hz to 200Hz design with the TD12S 12" woofer.
Thanks for any advice.
Hi doug20,
Maybe it would help to think about PPSL more as a driver mounting method than a destinct type of enclosure. You can use the PPSL plenum mounting method with any type of enclosure.
Plug the T/S values for your drivers (e.g.: the TD12S) into Hornresp, and take a look at what you can model.
Regards,
Maybe it would help to think about PPSL more as a driver mounting method than a destinct type of enclosure. You can use the PPSL plenum mounting method with any type of enclosure.
Plug the T/S values for your drivers (e.g.: the TD12S) into Hornresp, and take a look at what you can model.
Regards,
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