A Thread for those interested in PPSL enclosures

[sunnysal]

any thoughts on this driver for PPSL application

I saw this driver and thought its shape would lend itself to a nice PPSL build based on DJK´s design. thoughts on how appropriate it would be? what key dimensions I would need to assure function? I am only interested in response below 100-150hz (getting down as low as 20hz if possible) to mate with my Klipschorn based system.
http://www.tb-speaker.com/detail/1208_03/w8q-1071f.htm

An externally hosted image should be here but it was not working when we last tested it.

 

[tb46]

Hi sunnysal,

I think that one is discontinued? (Otherwise a nice driver.)

Regards,

 

[sunnysal]

Hi sunnysal,

I think that one is discontinued? (Otherwise a nice driver.)

Regards,

maybe this one? W69-1042J, a little smaller and doesnt go quite as low (35hz free air) but...
http://www.tb-speaker.com/detail/1208_03/w69-1042j.htm

An externally hosted image should be here but it was not working when we last tested it.

 

[DizRotus]

Would it be worth trying KEF B139s in PPSL?

 

[Juhazi]

I'm joining in here too. I was just tempted to make use of a 450L cabinet and put two 15" woofers in it. Norman guided me to PPSL which principle I already knew. Here is my latest plan, drivers will be the very cheap Dayton DCS380-4 an two 220-230L closed boxes opposed to make a slot. Yes the system will be 220cm wide! (8ft)

I plan to start makin cabinets soon but I can (if I can ) buy the drivers only after Christmas

 

[norman bates]

I assume you'll have 1 magnet hanging out and the other magnet in the enclosure.

Also, have both of the drivers share the same volume.

Sealed 8ft3 (qtc .707) each for that driver making F3 = 32.4hz.
Should do fine.

It would be neat to do a shootout of sealed F3 = 30hz compared to a ported F3 = tuned = 27hz. I'd imagine one would sound cleaner and louder but the other would go deeper.

Looks like a good driver for the money.

 

[Juhazi]

Norman,
it's very difficult to make a connection between the two boxes because of the max. space available. Would a 100mm sewerpipe be enough?, I could put that in the lower corner in the slot behind elements. The backside corners should be covered/rounded anyway.

PP arrangement is easy here, only problem I see is that these drivers have a stamped steel frame that is not optimal. On the other hand it's easy to make a tight plenum.

Is it wise to make the opening of plenum 1/3 of total Sd like Nelson Pass did for his ppsl dipole?

I'm after clean and snappy (sub)bass mainly for music and I have MINIMUM 400L of cabinet volume to use. And MINIMAL budget. A tappeded horn is an option but I'm afraid of making it really well tuned. PPSL looks very promising and I'll go that way this time.

 

[norman bates]

the narrower the plenum, the higher in frequency it works. Nelson got some boost with narrow slot.

It will be cleaner.
My dual 12's push pull slot loaded 27hz tune ported was cleaner, punchier, and faster than my buddy's 3 x jl audio 10" sealed.

Too bad the drivers can't share a box.

But good luck.

 

[Juhazi]

Google Sketches of boxes, to get the idea of making the ppsl plenum

Left side with the plenum filling, chamber-connecting tube and driver magnet out.
Right side with the driver magnet in

Hey, if I some day have the money for two RSS390, I could make this to two vented boxes using the openings for pipe as throats of reflex tubes! Honestly, I am sure that the closed one satisfies my spl needs for some time

(don't pay attention to precise matching, this is a novice's quick sketch!)

 

[djk]

That looks like a good solution, the chamber-connecting tube need only carry the difference in pressure between the two boxes, should work fine.

 

[Juhazi]

Than you very much for your help, guys!

Here are a better sketches of the sub and my home theater room with a 100" screen in precise proportions. I just ordred the boards, but I'll get the drivers and amp only after Christmas. Photos will come later on and I can do nearfield and room measurements too.

Juha

 

[OscarS]

A plenum, or slot, is the space between the two speakers.
The plenum does not increase efficiency like a large horn would, but does subjectively increase "punch" and "tightness", and allows for a smaller frontal area than if the speakers were front loaded, and is easier to build than a stepped baffle for push pull as is used with speakers requiring a higher crossover point.

Hmm. how about configuring a PPSL type of setup within a tapped horn? One side (the plenum side) could fire into S2, and the opposite side could be channeled into S3 (or any other S in a multi-segment TH) perhaps?

 

[djk]

Danley has several that meet the PP criteria, minus the slot.

It would be pretty straightforward to do a quad 12 PPSL with the plenum driving a central path bifurcating and coming back down both sides.

 

[epa]

the only "problem" with that, is the difference in s4.
soon whe are going to bild a double 15 sub ,then whe try it out.

 

[tb46]

Hi epa,

When you turn one of the drivers around you get an automatic S2 correction, but now you have to play with the other side of that driver, as you say there will be a difference in S4s (it might not be a problem).

Regards,

 

[tb46]

PPSL T-TQWT

Hi Y'all,

I once drew this one up for ODougbo, it's a bjorno T-TQWT that evolved from a NEO Dan single driver design. The driver was a PE 299-114 6-1/2" factory buyout.

Regards,

 

[epa]

hi oliver
i simed both with normal and reversed driver .
that is for s2.
i left s4 the same.
well see how it go's.

 

[tb46]

Hi epa,

It'll be interesting to see how it measures.

Regards,

 

[Djim]

well see how it go's.

No need to worry Erik, you'll get there . Just keep an eye on differences in movement between the drivers around 120Hz at high levels.

 

[epa]

hi jim
it wil be crossed at 80~100hz steep.
i wil put some sort of stub in the s4 area,for the test.