A Thread for those interested in PPSL enclosures

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Rudy81, it sounds like you didnt change the plenum itself in your further trials, am i right? You just added some spacers under one of the woofers? If so, your result is no surprise. The driver spacing alone will not change much. The plenum size and shape will dominte the response. If you dont change the plenum geometry itself, there will of course be no significant change.
 
hi.
first escuse me for my english and greeting from france.
i have some eminence kilomax pro18a in stock and i'm looking for a loud design for them.
do you think two of them fits good in a T-QPPSL as show in post 21 :
FYI:

A T-QPPSL to be played at lower input powers:
221851d1304698298-thread-ppsl-enclosures-2xb-c21sw152_t-qppsl_closed-ppsl-jpg
 
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I am designing my first complete speaker system using 4 10" woofers, 2 3" full range and 2 2.5" full range for each side of stereo. Should I use PPSL for the woofers if I cross at 500 hz or just PP without the narrow slot? The woofers are a wide range that do well up to 500 but only have 4 mm xmax so are not subwoofers.
*Impedance: 8 ohms*Frequency range: 34-3,000 Hz *Fs: 33 Hz *SPL: 93.15 dB 1W/1m *Qts: 0.47 I would appreciate any help.
 
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I am designing my first complete speaker system using 4 10" woofers, 2 3" full range and 2 2.5" full range for each side of stereo. Should I use PPSL for the woofers if I cross at 500 hz or just PP without the narrow slot? The woofers are a wide range that do well up to 500 but only have 4 mm xmax so are not subwoofers.
*Impedance: 8 ohms*Frequency range: 34-3,000 Hz *Fs: 33 Hz *SPL: 93.15 dB 1W/1m *Qts: 0.47 I would appreciate any help.

No, please do not use ppsl up to 500Hz. PPSL is best used for bass.
 
I think I have found a solution for my 18's. If I run PPSL... slot width is no issue, is what I gathered?

There will be an increase in upper bass caused by the plenum (slot), followed by a drop in response, a deep cancellation that won't respond well to EQ, limiting the upper response, not an "issue" unless you plan to cross over in that range.

See #823 for a bit more info.
 
Are you modelling this in horn resp? How?
Post #823 was an actual measurement, though it can be modeled in Hornresp. Posts 779 and later have posted sim input screens and discussion in this thread.

The model is of a bass/reflex and horn, the "horn" being the slot/plenum.
Using ATC and separate horn sections, even the cross sectional volumes the drivers occupy (or don't) in the plenum can be accounted for.
 
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HERE IS THE SECRET TO HOW WIDE THE WIDTH (from djk, r.i.p)

The slot width needs to be as wide as 1/4 length of the first harmonic above where you want to run.

So, say you want to go up to 150hz.
The slot should be 1/4 wavelength of 300hz, or almost a foot wide.

You don't want to not run the slot too large either, there will be a resonance from parallel walls.
I had a standing wave in my 4x12" push pull slot (top to bottom), maybe 250hz.

I should have run 2 boxes of ppsl 12's.
 

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