A Thread for those interested in PPSL enclosures

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#861
Not vibrations of enclosure although with opposed motion of cones, there is no net acceleration on the cabinet so mechanical vibrations from inertia are low. The harmonic distortion cancellation derives from the suspension induced non linearities being cancelled out if the cones are mounted cone to magnet. Thus, motion in cone out direction in one is opposed by cone in direction in the other and even-order distortions are cancelled by motion reversal.
 
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#863
weltersys said:
The plenum volume reduces the BR chamber volume.
In WinISD you don't include the plenum (or bass reflex port, or driver) volume in the BR chamber volume.

With Hornresp, you can model the effect the plenum has on the upper response.
Post 779 has an example of the plenum (and a "too high" Fb)...

As Norman pointed out, most of DJK's PPSL designs were for PA, where a 35Hz Fb (box tuning) was a good compromise between low frequency response and efficiency.
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How in the world did I miss THIS??? I would have MADE room for THAT!

https://www.audioasylum.com/cgi/vt.mpl?f=hug&m=190049

https://www.usaudiomart.com/details...er-jbl-driver-hsu-plate-amp-free-pickup-only/
 
#865
1st of all, I didn't know about the site.

2nd, audiophiles and PA guys would call a 72" tube a SUBwoofer. They both build 50hz bass bins and call them SUBwoofers. Aren't the Cerwin Vega FLH paths 6ft?

3rd...

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#867
BP1Fanatic said:
hey both build 50hz bass bins and call them SUBwoofers.
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Good point I guess. Sorry for being all "technical" 😀
weltersys said:
We aren't going to hold our breath 😉
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I did good by not finalizing just yet. I've been able to test the subwoofer in different acoustical environments with baffle and without baffle. Surprisingly, in my basement corner placed positioning, and low ceilings, baffle on, provided better FR., I thought that maybe I was spreading the source out, and potentially improving the FR but the opposite happened. There was more comb filtering from seemingly the ceiling reflection. Outside the measurements did the opposite, better FR without the top baffle as the ground as the bottom baffle. In the basement carpet is the bottom baffle, but I think to use wood on top and bottom baffle and fill the slot, strategically, with damping material.
 
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