A Thread for those interested in PPSL enclosures

[LarryMcConville]

Hi revboden,

I'm looking at this exact shape to experiment with as a manifold design for a PPSL-IB build. Would contain one pair of 21SW152-4 drivers.

Larry

djk, ever tried a slot shaped like this

(one side cutout to show detail)

 

[revboden]

Hi revboden,

I'm looking at this exact shape to experiment with as a manifold design for a PPSL-IB build. Would contain one pair of 21SW152-4 drivers.

Larry

(retrieves jaw from floor)
That should be something...
It's hard to see but the design I posted utilizes a semi Parabolic trough.

 

[revboden]

larry,
I just finished the math.. keep the driver as close to the "back wall / reflector" as possible.

 

[revboden]

larry, you inspired me to do some more maths.

 

[tb46]

Hi,

You can also trade of width v. height in the opening:

Regards,

 

[revboden]

Hi,

You can also trade of width v. height in the opening:

Regards,

er? trade of width

 

[djk]

Tricks to reduce the rear corner volume of the plenum are to extend the midrange response, are you planning on running a pair of 21SW152-4 up into the midrange?

 

[Brian Steele]

Tricks to reduce the rear corner volume of the plenum are to extend the midrange response, are you planning on running a pair of 21SW152-4 up into the midrange?

I wonder if it's possible to treat the cavity resonance by another means? For example, extend the cavity a bit, then fill it with just enough damping material to tame the resonance? Or is that too much bother for what can be dealt with via active filtering? 🙂

 

[LarryMcConville]

djk,

Was this inquiry for me? If so, no sir; purely aesthetic in nature. If not wise to pursue, I certainly will not do so.

I have no plans to run the IB > ~100Hz; ultimately, I'll utilize quad 21SW152-4 experimenting with LPF to best compliment my mains (Danley SH50/SH69/SH50).

I have no experience with an IB install; I plan to run one pair in IB, and a second pair in 12 cubes sealed. I'll measure and listen for which alignment I prefer. Regardless of install, the drivers shall enjoy a PPSL orientation...

Tricks to reduce the rear corner volume of the plenum are to extend the midrange response, are you planning on running a pair of 21SW152-4 up into the midrange?

 

[tb46]

Post #86

Hi revboden,

Sorry I didn't make myself clearer, maybe this will help:

Regards,

 

[hawkson]

edit, save for later

 

[revboden]

Hi revboden,

Sorry I didn't make myself clearer, maybe this will help:

Regards,

Yes, that helps. I must build two of these and test to see if the back reflections /top-to-bottom, are positive or negative in-room. I suspect all energy being reflected out is better but you never know with physics...

Cheers,
rev.

 

[hawkson]

Is the PPSL design feasible with 2 LMS Ultra 5400 or is 'too much'

 

[revboden]

Is the PPSL design feasible with 2 LMS Ultra 5400 or is 'too much'

unless your room is the size of a medium sized theater... too much? yes.

 

[hawkson]

huh, approximately how big would a ppsl be with 2 LMS Ultra 5400s?

 

[hawkson]

Huh,

Well, I have 2 5400 Ultra LMS and I don't know what I should do with em. Should I only make a 1 sealed?

 

[tb46]

Hi hawkson,

Just a quick simulation:

Regards,

 

[GM]

Is the PPSL design feasible with 2 LMS Ultra 5400 or is 'too much'

'Too much' is an individual's choice. If I had a house capable of handling such output without having it collapse around/on me, a pair of DTS 'wannabes' and a few kW would be just about right for the dynamic headroom/low distortion/BW I'd want for some movies, games: AVS Forum - View Single Post - Top 5Hz-15Hz BluRey movies

GM

 

[hawkson]

Thanks TB46. The graph you posted seems underwhelming. I am not sure I am reading it right, but LMS ultra 5400 achieving only 90 dbs at 20hz, is that right? BTW< I have Lab Gruppen 14000 powering these.

GM, thats the LMS Ultra 5400 series 2? I believe I have an older version of the lms 5400...

 

[GM]

Dunno, it's whatever someone posted awhile back: ~19 Hz Fs, 0.31 Qts, 235.5 L Vas

GM

edit: hmm, they are somewhat different than Ricci's, but don't know which specs are earlier or if his are measured........