A Thread for those interested in PPSL enclosures

[MemX]

Djim, You are right.

Fuller bass can be distortion.

I swapped out double 15 for 4 x 12" ppsl and some slam went away (crossing 24db@150hz).
Plenty of couch shaking, just less impactful slam.

I also have a buddy at work when his friends were doing car audio, they missed the seeming slam that went away when trying ppsl (same area box, amp, car, etc.).

I sometimes miss the fake bass......

LOL.... I think some times the same.
I think it comes from when i attend live music ( whicch is a lot) the spl level is much higher and we feel it more. The plumped up sound gives us some of that feel maybe?

lol

I'm glad I'm not alone in this

I loooooove my PPSL, it sounds so clean but with real warmth, and it really excels on classical music especially, but sometimes I just want an off-the-hook, OTT bassfest lol


I think I just need to get it EQ'd properly and do some tweaking, as well as get some bigger mains!

 

[Scott L]

lol

I'm glad I'm not alone in this

I loooooove my PPSL, it sounds so clean but with real warmth, and it really excels on classical music especially, but sometimes I just want an off-the-hook, OTT bassfest lol


I think I just need to get it EQ'd properly and do some tweaking, as well as get some bigger mains!

I can most definitely recommend using EQ to get your ppsl as flat as possible.
I just went through this myself, and what was once considered pretty darn good, is now SUPERB.

 

[djk]

One key point:

The crossover to the mid/HF must be within a 1/4dB otherwise is will seem to go out-of-focus and lack slam.

Never use a crossover for tone or loudness compensation.

 

[chrapladm]

Pick up a couple of SI HT18 for $159 each before they disappear forever?

Big Stereo Integrity News - AVS Forum | Home Theater Discussions And Reviews

I would then you towards my build thread lol

That would be great if they didnt cost me more than a pair of 18TBW100's. I like the SI lineup but with currency exchange plus shipping they get costly. End up being about 400 each for me.

So I will have to wait. I wont be able to get the 18's right away anyways. I need to do my 3 way first. Then I will buy a pair of 18's maybe. Might just buy another 21".

For me its a hard sell which drivers to use. I want to build a BC218 style cabinet. If I could get the SPL numbers that DSL get with a dual 18" FLH then I am building that. BUT I would try a PPSL before I built that monster with the same 18's.

SO while experimenting with designs I will keep using the same drivers. That could be 21's or 18's. I can get anywhere near the SPL of DSL and their BC218 so I looked at 21's for mine. BUT I am bigger than the BC. SO I am still drawing new designs and learning.

 

[arcgotic]

Hello all,
I know that Eminence Beta 15 is not the best driver for PPSL. But for home listening level, not going past Xmax, could it be used successfully? I am interested in lower distortion of course
I want to cross at 130-150. Should i follow the dimensions for the 15" drivers that were earlier (a few years ago) mentioned in this thread?

At the moment i have them in H frame. As i want to integrate the PPSL with front loaded horns using Beyma 12MI100, i am considering a PPSL build at this moment.

Thanks in advance!

 

[djk]

As I see it you have two real choices; sealed with EQ, or open baffle.

I tend to use drivers with a Qts around 0.312, optimum for a 6th order vented system (with a high Q filter).

Of course the basic idea lends itself to sealed, vented, 6th order vented, horns, open baffle, etc.

 

[arcgotic]

So if i go for sealed, should i do something like this, first picture
http://i817.photobucket.com/albums/zz95/LegisActio/PPSL_zps7f693d86.png

or like this?
http://hometheaterhifi.com/volume_7...00-speakers-push-pull-view-of-outside-s1c.jpg

?

 

[djk]

The closed one in the second photo.

The first photo will only cancel distortion in the lowest octave.

 

[arcgotic]

Thanks djk, are you sure you don't mean the first photo, the one with the plenum?

 

[djk]

The one that has a slot, not the M&K one.

 

[fizzylime]

Any problem using servo subs for PPSL? Rythmik DS1200s specifically.

I was thinking being able to play with the damping of the woofer might allow me to really dial in performance

Sub use only (below 80hz) Hi-fi

 

[rew432]

Hi. I want to build PPSL 2 speakers ciare 12.00 sw. I have two questions . :
1. Do I have to do the plenum maximum small?
2. Is it possible to hang the subwoofer frequency up to 250 Hz ? Then I can exclude from midbass mini PA system.

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

 

[slackweather]

Slowly getting very curious on PPSL in tapped horn (stereo, home use) for bass, say 10 inch drivers for 30hz-120hz. Are there any designs available (best of course drawimgs). Thanks!

 

[tb46]

Hi slackweather,

Take a look @ epa's double 15" TH that can be used both ways, drivers in regular arrangement, or as PPSL:

http://www.diyaudio.com/forums/subwoofers/231339-double-15-th-18-sound-15-nlw9401-4r.html

Regards,

 

[denito]

Notch loaded push pull?

Apologies if this has already been asked but what would be the effect of partially dropping away two sides so that the slot hole exposes 180° of the speaker as opposed to 90°? In other words a "notch" rather than a slot?

It's a but hard to describe with words hopefully the 3D models make it clear. I realized that making my speaker have an "emerald cut" shape would solve some geometric/economy of materials problems with their design. Extending the concept around all sides leads to having a choice between making 2 walls of the slot very thin or simply cutting out the thinnest parts to turn the slot into a notch.

Will this actually improve the sound? Ruin it? No effect? If no effect then it's still worth it to me for aesthetic and structural reasons.

 

[MemX]

I may well be wrong... but I believe that by reducing the sides of the slot, you will also reduce the bandpass effect created by a slot. This should therefore mean that the peak created at the top end of the response curve is lower or removed.

How high are you intending to cross it over? If under something like 200Hz(?), I think the bandpass effect would be outside of the operating frequencies, so it shouldn't make that much difference whether the slot is a proper slot or not.

You should still see a reduction in even-order harmonics, though, due to the PP design.

 

[hum4god]

Hi

i am very interested in building a reflex ppsl . as i understand , because of the slot loading it would be 6th order .
unfortunately i cannot sim a 6th order box so i hope someone could help and sim
four drivers in one cabinet

Dayton Audio RSS265HF-4 10" Reference HF Subwoofer 4 Ohm
and
Dayton Audio RSS265HO-4 Reference HF Subwoofer 4 Ohm

are the candidates .

i assume the qts for the HO is better suited .
i am trying to cover 25-150hz . lower is better but 25hz or a bit more should be sufficient .
i have an old sub box i might be able to reuse that is approx. 6.8 cuft . gross.

any help is much appreciated

 

[norman bates]

I'll take a stab.

6th order is where you put a driver in a ported box, tune to the f9, then run a high pass filter with a q of 2 at the tuning frequency. The filter does 2 things, it gives a 6db boost at tuning and acts as a subsonic filter below that. A qts around .32, you can tune to fs and box area smaller than a typical 4th order with qts .4 (usualy equal to vas).

Djk explains it better

https://www.audioasylum.com/messages/hug/127065/low-qts

 

[Zero D]

@ norman bates

I think you meant, tune to the f3

 

[norman bates]

Nope. Low qts ported makes high output (higher spl with 1 watt) but less low bass. Running the numbers, low qts drivers in typical 4th order boxes usualy have f3's mid 40 to 50hz, not quite subwoofer to me. Even f9 of 27hz ported is good, but f3 of 27hz ported is way better.

You tune to the f9 then add 6db so you are now only 3db down near 30hz. You have a smaller box than qts drivers around .4, and deep strong output, but it takes 6db of power boost.

Drivers with Qts .312, makes the ported tuning at Fs which is the f9.

There is a jbl article for 6th order maybe back in the 80's, a way to get bass for their low qts 18".