A Thread for those interested in PPSL enclosures

[weltersys]

Originally Posted by Scott L

I'm using a 12 inch driver; the approx SD is about 90 square inches and my plenum exit is also 90 sq inches, so is that a 2:1 ? (or does the volume of said plenum come into play somehow?)

DJK's examples compare SD to plenum exit area.

If you are using "a 12 inch driver" the ratio is 1/1 .
If your two drivers total 180 SD, and the plenum exit is 90, the ratio is 2/1.

[jdubs]

Guys, can anyone help me out with a PPSL design for the PE 295-120? djk recommended it to me as a good home-system driver with a -3db @ 27hz in the PPSL design with a ~5 cu ft. cabinet. I need to cross it at 300hz and djk indicated this would be no problem. Specs are as follows:

Dayton Audio ST305-8 12" Series II Woofer 295-120

• Power handling: 275 watts RMS/380 watts max • VCdia: 2-1/2" • Le: 3.07 mH • Impedance: 8 ohms • Re: 6 ohms • Frequency response: 25-2,000 Hz • Magnet weight: 56 oz. • Fs: 30 Hz • SPL: 92 dB 1W/1m • Vas: 4.52 cu. ft. • Qms: 10.55 • Qes: 0.36 • Qts: 0.35 • Xmax: 8 mm • Dimensions: Overall diameter: 12", Cutout diameter: 11", Depth: 6", Magnet diameter: 6-1/8", Magnet height: 1-7/8".

I've been trying to get through to djk, but to avail. Anyone that can help, I would very much appreciate it.

Thanks,
Jim

[djk]

Driver Properties
Name: 295-120
Type: Standard one-way driver
Company: Dayton Loudspeaker Co.
Comment: Nov 2011 (New)
No. of Drivers = 2
Mounting = Standard
Wiring = Parallel
Fs = 29.6 Hz
Qms = 10.55
Vas = 128.1 liters
Cms = 0.351 mm/N
Mms = 82.29 g
Rms = 1.451 kg/s
Xmax = 8 mm
Xmech = 12 mm
P-Dia = 254 mm
Sd = 506.7 sq.cm
P-Vd = 0.405 liters
Qes = 0.36
Re = 6 ohms
Le = 3.07 mH
Z = 8 ohms
BL = 15.97 Tm
Pe = 275 watts
Qts = 0.348
no = 0.89 %
1-W SPL = 91.64 dB
2.83-V SPL = 92.89 dB
-----------------------------------------
Box Properties
Name:
Type: Vented Box w/ Active HP Filter
Shape: Prism, square
Vb = 4.502 cu.ft
Fb = 27 Hz
QL = 6.24
F3 = 27.1 Hz
Fill = minimal
No. of Vents = 2
Vent shape = rectangle
Vent ends = two flush
Hv = 10 in
Wv = 2 in
Lv = 29.49 in
-----------------------------------------
Active 12 dB/oct. HP Filter
Fx = 27 Hz
Qx = 2

[jdubs]

djk! Thanks!! Hugely helpful. Now, just one more favor (not just for me, but the community at large!) Can you do a cut list for a vertically oriented cabinet following these design parameters? Similar to what you did for the PA cabinet, here, but higher than wide (better for most home setups):

A Thread for those interested in PPSL enclosures

Seriously, you would then have provided detailed plans for both PA and home system cabinets. This would be great for LOTS of people!

Thank you again.

Jim

[anubisgrau]

anything came out of jdubs plea? interested in the same thing, vertical cab for a 12" like the above dayton.

[Scott L]

To my fellow diy'ers: please bear in mind this thread contains a wealth of information. A lot of questions have been asked, answered and then asked again. The most amazing aspect of this thread is, it went off topic by the 3rd post and never agained returned. Even I, as in myself, missed this the first 2 times i read everything on here, in it's entirety. It wasn't until (by coincidence) that I came up with the idea of using a ppsl "motor" as a compression chamber for a mid-bass horn, that i went back (again) and read the beginning, only to see that's what "jamikl" had in mind, in the first place.

Please allow me to re-iterate. This ppsl concept is not as complicated as some would make it out to be. For me, my adaptation of the ppsl principle has given me the exact: accurate, full, punchy and dynamic system I had been seeking for a long time. For my application, it's mid-bass, and the most twisted hybrid style never seen before, but I also plan on doing a conventional in box ppsl woofer system for a 3 way in another project.
My hat's off to djk.

[anubisgrau]

wow, the most right pic looks most interesting - PPSL coupled with mid horn, EV's big whale and TPL-150. is this your system scott?

what do you expect to get attaching a front horn there (except maybe to harmonize the crossing and smooth the sound characters from sub/bass and mid-horn)?

[Scott L]

Originally Posted by anubisgrau

wow, the most right pic looks most interesting - PPSL coupled with mid horn, EV's big whale and TPL-150. is this your system scott?

what do you expect to get attaching a front horn there (except maybe to harmonize the crossing and smooth the sound characters from sub/bass and mid-horn)?

Yes, this is my system aka "the beast". The ribbon tweeter is the Stage Accompany SA 8535. I listend to the ppsl motor sans the horn for a while,
but when I added it, the directivity factor increased, as well as the dynamic impact. So, yes, you are correct. This is the best system I have ever had.
Only took 39.5 years of building, and trying different things. Tube amps and horns for me. Having said that, I realize they're not for everybody. For me, this approach allows me to emotionally connect to the peformance.

Not visable in any of the above pics, is the sub-bass system. Mono because of space restrictions/ room layout. 8x AE IB15's in an infinite baffle.50Hz and down to about 17, but I am considering changing up to 60 Hz.

Throw Thiel/Small out the windown when dealing with this type of ppsl. There is strong response down to the mid 30's. I can't expalin why, it just is.
Of special note: the fs of the Eminence Definimax4012HO is 46, but when coupled in the ppsl with the partnering driver, the fs dropped to 40. Then, after I added the sealed back-wave enclosures (which are of differing volumes to compensate for the fact one driver is "flipped") the system resonance (Fc as oppossed to Fs) was @ 57Hz with a Qtc of about .6 if memory serves correct. Stunning, articulate, and dynamic bass with no hint of a "box" sound at all. Highly reccomended.

[anubisgrau]

thanx for explaining, though not sure if your approach - ppsl plus extra subs - would be as appealing as ppsl alone - the reason why i'm attracted to this is a promise you can get have a reasonably (!) sized sub/midbass (say 30-300hz) solution. not everyone can afford too much real estate for this hobby...

[TMHutson]

I am also curious if using a common enclosure instead of a divided enclosure effects the sound in a positive way on your horn...

I have a question... Most of the people on here have been dealing with large diameter woofers... Does this design work with smaller woofers, such as a 10" in a home/music setting? I also have some 8" subs laying around. I suppose I could just do it with some freebies I have laying around and measure when I can get some equipment to do so. I have seen OB PPSL enclosures that used smaller woofers, but it had at least 6 of them or more due to the low SPL with OB in the lower frequencies...