"I believe modest reduction in 2nd order distortion does not achieve the benefits claimed by PPSL proponents, I believe they like the effect of the cavity resonance."
Art Welter measured as much as 30dB reduction in 2nd harmonic, and 20dB reduction in 4th harmonic at high power using LAB 12 drivers in a co-planar mounted pair.
I guess a 1000:1 reduction is modest?
"Please , help me before you go to get me clearly fixed ... "
I don't think you can be helped.
Just completed a new experiment Push-Pull double 15" subwoofer. This is the best sounding subwoofer that I've ever heard after building sub cabinets for 33 yrs. Love it. Les Hudson
TAD cinema PP woofers.
KEF 107
Audio Pro
Electro-Voice MTS-1
Art Welter measured as much as 30dB reduction in 2nd harmonic, and 20dB reduction in 4th harmonic at high power using LAB 12 drivers in a co-planar mounted pair.
I guess a 1000:1 reduction is modest?
"Please , help me before you go to get me clearly fixed ... "
I don't think you can be helped.
An externally hosted image should be here but it was not working when we last tested it.
Just completed a new experiment Push-Pull double 15" subwoofer. This is the best sounding subwoofer that I've ever heard after building sub cabinets for 33 yrs. Love it. Les Hudson
TAD cinema PP woofers.
KEF 107
An externally hosted image should be here but it was not working when we last tested it.
Audio Pro
An externally hosted image should be here but it was not working when we last tested it.
Electro-Voice MTS-1
EAW
An externally hosted image should be here but it was not working when we last tested it.
More EAW
https://www.soundbroker.com/dynImage/?listingPicid=67193&cacheBreaker=1392640083
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Ace Bass (Audio Pro)
Linkwitz (of the Linkwitz-Riley crossover fame)
An externally hosted image should be here but it was not working when we last tested it.
Another shot of the KEF 107 showing the slot.
An M&K subwoofer (tipped sideways showing the woofer slot on the bottom of the cabinet)
Another Linkwitz loudspeaker
An externally hosted image should be here but it was not working when we last tested it.
Danley TH212
Quad 12's
Another M&K product.
Djk's 52 litre 'mini cavity' looks nothing compared to the +500 litre 😱 gigantic planer wave 'cavity' of the V28 PWH from Dynacord.
It's a dual 18" ported system in Push-Pull with a huge Planar Wave Horn and it is based on the XL-36 Bin, from Stage Accompany (below)
And Dynacord is friendly enough to provide uncensored plots... 🙂
It's a dual 18" ported system in Push-Pull with a huge Planar Wave Horn and it is based on the XL-36 Bin, from Stage Accompany (below)
And Dynacord is friendly enough to provide uncensored plots... 🙂
And let's not forget the Muse 18 subwoofer (ppsl 2 x 10” with 250wrms amp).
Taken from stereophile's review (and later re-reviews).
"Muse 18 subwoofer 2"-wide slot that runs down the unit's width. The slot provides the acoustic outlet for the dual 10" woofers.... The low-pass filter incorporates sixth-order equalization, damping control, a delay line, and a level control.... The low-frequency cutoff is adjusted by the damping control, varying the –3dB point between 18Hz and 25Hz.... The Model 18 uses a sixth-order alignment, with a tuning frequency of 18Hz.... The Model 18 uses a sixth-order alignment, with a tuning frequency of 18Hz……….”
and most importantly........
“The Velodyne F-1500 moved a great deal of air, with ample slam and punch. It was faster in the deep bass than the Muse when connected to the Quad ESL-63s. On the other hand, the Muse 18 produced cleaner deep-bass notes, had better pitch definition, and provided the best resolution of detail in the deepest bass.”
Remember the velodyne has the expensive special servo drive (distortion reducing circuitry).
Ppsl costs nothing but a bit more box and it provides some protection from driver damage.
Taken from stereophile's review (and later re-reviews).
"Muse 18 subwoofer 2"-wide slot that runs down the unit's width. The slot provides the acoustic outlet for the dual 10" woofers.... The low-pass filter incorporates sixth-order equalization, damping control, a delay line, and a level control.... The low-frequency cutoff is adjusted by the damping control, varying the –3dB point between 18Hz and 25Hz.... The Model 18 uses a sixth-order alignment, with a tuning frequency of 18Hz.... The Model 18 uses a sixth-order alignment, with a tuning frequency of 18Hz……….”
and most importantly........
“The Velodyne F-1500 moved a great deal of air, with ample slam and punch. It was faster in the deep bass than the Muse when connected to the Quad ESL-63s. On the other hand, the Muse 18 produced cleaner deep-bass notes, had better pitch definition, and provided the best resolution of detail in the deepest bass.”
Remember the velodyne has the expensive special servo drive (distortion reducing circuitry).
Ppsl costs nothing but a bit more box and it provides some protection from driver damage.
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"Your first picture looks a bit like half an Electro Voice MTL4"
Hmmm, except the MTL4 is not push-pull, and is a quad 18 design.
Actually, I was setting out to build something that would have that kind of output, but could be moved without a forklift. The original prototype PPSL were exactly the footprint of the MTL4, just half-height. With a custom large x-max 15 they had the same volume displacement capability as the EV 18.
I worked for a KEF dealer, and had seen the Ace Bass units many years before. The Linear Bass Vent was also popular with the car stereo crowd at the time. The original test pair had one with both drivers facing the slot (similar to the Linear), one pair mounted push-pull (similar to the KEF).
The one like the Linear had a peak of about 6dB or so around 160hz (it also had a deeper plenum than the current itteration) or so (not unlike the MTL4), the push-pull one did not have the peak (it was also not a BP4 like the KEF, but rather a 6th order vented like the MTL4).
All this original work was done between 1985 and 1988 and discussed with people at the trade shows (like NAMM) with people like Tom Danley (who gave my brother a set of plans for some Servodrive models in a RFQ, my brother being a cabinet maker, building many of my prototype designs as well).
I also talked with Tom Gallagher of EV (he later moved to Klipsch). Tom G. was sending people to me (at that show) that wanted plans for the MTL2 after talking to me, he seemed quite excited by my PPSL. EV came out with their version shortly after, I have no idea if my input played any role in their design, I originally intended it to be a one-box system (the size of an Altec A7) with a horn-loaded 12 and a 1" CD. I later decided this would be too big and heavy for portable use.
Hmmm, except the MTL4 is not push-pull, and is a quad 18 design.
Actually, I was setting out to build something that would have that kind of output, but could be moved without a forklift. The original prototype PPSL were exactly the footprint of the MTL4, just half-height. With a custom large x-max 15 they had the same volume displacement capability as the EV 18.
I worked for a KEF dealer, and had seen the Ace Bass units many years before. The Linear Bass Vent was also popular with the car stereo crowd at the time. The original test pair had one with both drivers facing the slot (similar to the Linear), one pair mounted push-pull (similar to the KEF).
The one like the Linear had a peak of about 6dB or so around 160hz (it also had a deeper plenum than the current itteration) or so (not unlike the MTL4), the push-pull one did not have the peak (it was also not a BP4 like the KEF, but rather a 6th order vented like the MTL4).
All this original work was done between 1985 and 1988 and discussed with people at the trade shows (like NAMM) with people like Tom Danley (who gave my brother a set of plans for some Servodrive models in a RFQ, my brother being a cabinet maker, building many of my prototype designs as well).
I also talked with Tom Gallagher of EV (he later moved to Klipsch). Tom G. was sending people to me (at that show) that wanted plans for the MTL2 after talking to me, he seemed quite excited by my PPSL. EV came out with their version shortly after, I have no idea if my input played any role in their design, I originally intended it to be a one-box system (the size of an Altec A7) with a horn-loaded 12 and a 1" CD. I later decided this would be too big and heavy for portable use.
not a subwoofer but Allison Acoustics AL120
"Details for this set are as follows: - Black Cabinet - Push-pull Dual 6" Woofers Acoustically in phase, - Electronically/Magnetically out of phase - Allison Convex Diaphragm 1" Tweeter with Ferrofluid Cooling/Damping Material - Crossover Frequencies: 100Hz, 2000Hz - Impedance: 6 Ohms - Sensitivity,SPL: 90dB - Amplifier Power: 15-200 Watts - Dimensions: 23"H x 11"Wx 11"D @ 33 lbs each - Includes Manual/User Guide and Speaker Wires"
sold on audioasylum for around $250 maybe a year ago.
"Details for this set are as follows: - Black Cabinet - Push-pull Dual 6" Woofers Acoustically in phase, - Electronically/Magnetically out of phase - Allison Convex Diaphragm 1" Tweeter with Ferrofluid Cooling/Damping Material - Crossover Frequencies: 100Hz, 2000Hz - Impedance: 6 Ohms - Sensitivity,SPL: 90dB - Amplifier Power: 15-200 Watts - Dimensions: 23"H x 11"Wx 11"D @ 33 lbs each - Includes Manual/User Guide and Speaker Wires"
sold on audioasylum for around $250 maybe a year ago.
Allison Acoustics IC 20 VERY RARE Photo #650742 - Canuck Audio Mart
Allison claimed a 10dB reduction in distortion, more would have been possible mounted in a plenum.
http://www.classicspeakerpages.net/library/allison/allison_ic20/allison_ic20_brochure/allison_ic20_brochure_pg3.html
At $5K per pair years ago, not many are around today.
Allison claimed a 10dB reduction in distortion, more would have been possible mounted in a plenum.
http://www.classicspeakerpages.net/library/allison/allison_ic20/allison_ic20_brochure/allison_ic20_brochure_pg3.html
At $5K per pair years ago, not many are around today.
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Sorry to resurrect an old thread, but the discussion of push/pull designs has my interest piqued. Would it be considered "old" design tech now? I ask because you say you were designing them in the 80's but they don't seem too popular these days. Now days all the new, popular, designs I see seem to be tapped horns, for instance the Cubo, and TH15.
Are the tapped horns just a "fad," or are they actually a superior design? I'm asking because I don't care about "fads." I want the better design.
Are the tapped horns just a "fad," or are they actually a superior design? I'm asking because I don't care about "fads." I want the better design.
Tapped horns have more efficiency, and can be designed to sound darn good. Push pull is just a driver arrangement, you can (I am) use drivers in a push pull arrangement in a TH. Plus then you get the best of both designs...
Someone correct me if I'm way off.
"I ask because you say you were designing them in the 80's but they don't seem too popular these days. Now days all the new, popular, designs I see seem to be tapped horns"
Danley has four tapped horn models that are push-pull.
There is a YouTube video that plays the dual 12 PP TH vs the single 18 TH and you can hear it has less distortion.
Danley has four tapped horn models that are push-pull.
There is a YouTube video that plays the dual 12 PP TH vs the single 18 TH and you can hear it has less distortion.
DJK
Those. Allison's are cool!
AS well know..His premise is that the wall affects influence the speaker up to 300-400hz. A slot load would have to take that into account.
I'm debating a dual 12 with the Dayton classics or single 18 with the Dayton 465S 18". Both 6th order with 25hz high pass to 150hz.
Do you think the 12s could take a Crest V1500 a few hours a week?
Any other 90db 12" woofer recommendations?
What do you use for the high pass\eq?
Thanks!!
Scott
Those. Allison's are cool!
AS well know..His premise is that the wall affects influence the speaker up to 300-400hz. A slot load would have to take that into account.
I'm debating a dual 12 with the Dayton classics or single 18 with the Dayton 465S 18". Both 6th order with 25hz high pass to 150hz.
Do you think the 12s could take a Crest V1500 a few hours a week?
Any other 90db 12" woofer recommendations?
What do you use for the high pass\eq?
Thanks!!
Scott
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