A Thread for those interested in PPSL enclosures - Page 45 - diyAudio
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Old 17th February 2013, 06:54 PM   #441
tinitus is offline tinitus  Europe
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Quote:
Originally Posted by kees52 View Post
Is it not better use a speaker with a lower vas?
maybe
but higher Qts and higher Vas together really pulls up the box size
would work better for IB designs

for smaller boxes in general, I think you need a max Qts of around 0.33 and a max Vas of about 100
one reason why many sub drivers have high Qts is that its easy to make them go very deep
high Qts also means less control, so it presents certain compromises ... looks good on paper, but ...
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Old 17th February 2013, 08:21 PM   #442
kees52 is offline kees52  Netherlands
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Quote:
Originally Posted by tinitus View Post
maybe
but higher Qts and higher Vas together really pulls up the box size
would work better for IB designs

for smaller boxes in general, I think you need a max Qts of around 0.33 and a max Vas of about 100
one reason why many sub drivers have high Qts is that its easy to make them go very deep
high Qts also means less control, so it presents certain compromises ... looks good on paper, but ...
And so a tapped horn is the only one to get deep with small speakers who have a low qts/strong motor.

the visatons have qts 0.34 but also high vas of 220 liters, only in compound I get the volume low with two drivers or if one driver then -3 db gets in 28 hz with 110 liters but ppsl have two speakers for canceling and more spl watt.

I have them in a linkwitch dipole and she play very deep here, it can let the doors rattle.

Last edited by kees52; 17th February 2013 at 08:25 PM.
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Old 17th February 2013, 09:01 PM   #443
tinitus is offline tinitus  Europe
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Quote:
Originally Posted by kees52 View Post
And so a tapped horn is the only one to get deep with small speakers who have a low qts/strong motor.
dont know..6th order bandpass ought to work ok with low Qts woofer ?

Quote:
Originally Posted by kees52 View Post
.... but ppsl have two speakers for canceling and more spl watt.
yeah, I thought it could be nice for bass guitar, but then...two woofers in one box means big and heavy, so...

but I am thinking about a single woofer SL 6th order bandpass front port may be calculated such that it ends with just a hole, or a slot.......I dare not mention Carlson ...

my plan is to use detachable baffle to try different slot openings
but thats OT, sorry ....cheers

and good luck with your projects
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Old 18th February 2013, 01:09 PM   #444
kees52 is offline kees52  Netherlands
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These woofers are maybe good for OB, like a ripole, 4 15 inch of them each channel will give enough spl

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Old 19th February 2013, 05:28 PM   #445
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Possible to do a PPSL with 4 drivers?
How would you orient and wire them up?

Last edited by EternaLightWith; 19th February 2013 at 05:39 PM.
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Old 19th February 2013, 06:16 PM   #446
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Originally Posted by EternaLightWith View Post
Possible to do a PPSL with 4 drivers?
How would you orient and wire them up?
PPSL could be done with any even amount of drivers, just make the plenum taller.

Positive voltage applied should move all the cones toward the plenum.

They could be wired series, parallel, or series parallel, as long as the reversed cones are wired in reverse polarity.
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Old 19th February 2013, 08:12 PM   #447
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I have built quad 12s in this fashion.

Click the image to open in full size.

A friend is building quad 8s in this fashion to bolt up to the horn throat of his 15" bass horns.
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Last edited by djk; 19th February 2013 at 08:17 PM.
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Old 19th February 2013, 08:19 PM   #448
tinitus is offline tinitus  Europe
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or ?
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Old 19th February 2013, 08:36 PM   #449
kees52 is offline kees52  Netherlands
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Why not face the conus to each other like in a ripole, it lowers the Fs and ups the qts, but like a ripole, who has on front as on back of the woofers a small plenum, the ppsl has a big box on outside the plenum. my test with a small plenum without a box did not lower the Fs but I think this is because of the faul measuring, I need a small amp with limp, and i did use only the ouput of the soundcard headphone output.
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Old 19th February 2013, 10:08 PM   #450
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Originally Posted by tinitus View Post
or ?
Post #448 shows a plenum loaded "clamshell" isobaric loading, not push pull.
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