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Old 24th January 2013, 09:04 PM   #11
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I don't quite get the plenum (slot loaded) area. Can this be thought of as a single driver mount? In other words, is everything that's "behind" the two drivers all one big shared space?

To simplify, if I assume a sealed enclosed with a push-pull (cones pointed to each other to reduce plenum size) then the following would work if the floating structure was sealed to the front "baffle" with a cut-out around the plenum.

And further, if that's true, then the model would be as for a single driver but twice the enclosure volume.

(Excuse the lame drawing as I never fully understood sketchup, either.)
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Old 24th January 2013, 10:29 PM   #12
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Quote:
Originally Posted by stevemac00 View Post
I don't quite get the plenum (slot loaded) area. Can this be thought of as a single driver mount? In other words, is everything that's "behind" the two drivers all one big shared space?

To simplify, if I assume a sealed enclosed with a push-pull (cones pointed to each other to reduce plenum size) then the following would work if the floating structure was sealed to the front "baffle" with a cut-out around the plenum.
"Push Push" cones are pointed towards each other, "push pull" drivers have one cone pointing at the other driver's magnet.

The plenum should be modeled as two drivers in an offset horn.
The cabinet can be shared or dual, sealed or BR.
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Old 24th January 2013, 11:47 PM   #13
banaca is offline banaca  Canada
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The opposite of your Idea is in the Totem Mani-2 ;-)
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Old 25th January 2013, 12:24 AM   #14
sreten is offline sreten  United Kingdom
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Hi,

Slot loading subs is a very dumb idea born out of very poor physics.

rgds, sreten.
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Old 25th January 2013, 07:12 AM   #15
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?
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Old 25th January 2013, 12:21 PM   #16
epa is offline epa  Netherlands
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Quote:
Originally Posted by sreten View Post
Hi,

Slot loading subs is a very dumb idea born out of very poor physics.

rgds, sreten.
care to elaborate?
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Old 25th January 2013, 12:59 PM   #17
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I am interested in hearing more from #13 as there were failures in the PPSL thread from lack of design knowledge and I fear that as well. Can someone with experience confirm that it's safe to think of the plenum edge mounting as a single driver? In other words, seal around the rectangular edge to the baffle.

I used face-to-face which would be wired out of phase so that it would still be push-pull. The reason for this is to reduce the plenum area due to my small box constraints as recommended by #10.
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Old 25th January 2013, 01:47 PM   #18
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Quote:
Originally Posted by stevemac00 View Post
I am interested in hearing more from #13 as there were failures in the PPSL thread from lack of design knowledge and I fear that as well. Can someone with experience confirm that it's safe to think of the plenum edge mounting as a single driver? In other words, seal around the rectangular edge to the baffle.

I used face-to-face which would be wired out of phase so that it would still be push-pull. The reason for this is to reduce the plenum area due to my small box constraints as recommended by #10.
Not following you, the plenum exit contains the output of both drivers.
Both drivers, if facing each other, should be wired in polarity.
If they are "push pull" (which cancels even order harmonic distortion, leaving the non-musical odd order distortion) the reversed cone should be reversed in polarity.

Regarding post # 13, my isobaric PP TQWP Totem sub is quite different .
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Old 25th January 2013, 06:37 PM   #19
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Quote:
Originally Posted by weltersys View Post
If they are "push pull" (which cancels even order harmonic distortion, leaving the non-musical odd order distortion)
It's that a problem of the push-pull isobarics? Can you link to some notes or paper on that issue (isobaric distortions types). Regards.
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Old 25th January 2013, 06:48 PM   #20
sreten is offline sreten  United Kingdom
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Quote:
Originally Posted by epa View Post
care to elaborate?
Hi,

Show me a design where whatever volume you use
for the slot is not best used internally, or any good
sub design where a slot would have any useful effect.

rgds, sreten.
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Last edited by sreten; 25th January 2013 at 06:51 PM.
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