A Thread for those interested in PPSL enclosures

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
this in your car, it will blow.

Danley Sound Labs - YouTube

I did play the music here with my present dipoles and these dipoles go low and pretty loud, what it will do with two of these MTX Europe - RT12-04 each channel, I presume that I then get also 6 dB extra and can I multiply 4 x Sd for calculating max SPL.

with the small visatons I did just listen to that danly TH my doors did rattle already but I miss puch a little a tappen horn with this unity horn My Unity Horn Speakers.

Well I can then be DJ with enough high quality spl or home theatre but then nabures will complaine, with the dipoles not it do not tick room modes..
 

Attachments

  • DSCN0620.JPG
    DSCN0620.JPG
    798.4 KB · Views: 857
Last edited:
I try to scetch but it is not so easy, drawn lines don,t always work when I drawn a other panel, and how do I make holes in the panel, maybe there is a other more easy drawn program , not the windows one please.

To put an opening in a panel, such as for a round speaker cut-out, or in this case the plenum opening for the PPSL sub.

Draw the panel as you have, position and size the opening you desire, then use the push/pull feature to open the panel as you wish. Push or pull only as far as the thickness of the panel.

I agree with you on the frustration of the free version of Sketchup adding plane surfaces when you do not necessarily want them, I hope someone can chime in here and illuminate the technique for us all....

John
 
Is the pro version better?
... frustration of the free version of Sketchup ...
I sometimes have the feeling it's not worth learning drawing programs for the occasional builder.
Just a piece of paper, ballpoint and calculator is all you need and will be faster.
But if you want to build regularly, it does pay off.
Also if the box is not a simple cube but has strange corners or port(s). This is why I learned Sketchup.
 
About impulse response of a slot arrangement in Hornresponse

I have mede simulations of my subwoofer project http://www.diyaudio.com/forums/subwoofers/223960-bench-style-cabinet-subwoofer-2x15-closed.html in Hornresp and now I think that I have learned to set parameters right. I checked the Impulse response simulation and was shocked!

The plenum seems to generete "ringing" a lot. I show a graph of 800cm2 opening area/40cm deep slot simulation and standard closed box.
- Can we hear this? is it relevant at 20-100Hz (plenum resonance 180Hz)
- What is the effect of two elements in slot push-pull arrangement
- Does the profile of the slot make difference

The attached simulations use RSS390HF but the driver has no effect to this
 

Attachments

  • pp470 RSS390HF impulse.png
    pp470 RSS390HF impulse.png
    54 KB · Views: 702
  • pp470 RSS390HF system.png
    pp470 RSS390HF system.png
    49.5 KB · Views: 707
  • ppsl470 RSS390HF impulse.png
    ppsl470 RSS390HF impulse.png
    64.7 KB · Views: 719
  • ppsl470 RSS390HF system.png
    ppsl470 RSS390HF system.png
    49.4 KB · Views: 748
Pray tell, how do you get Hornresp to model the highly irregular space between the front of the one cone and the magnet of the other?

Measurements on the 1988 prototype showed a strong cavity resonance when the drivers faced each other, and that it went away when the drivers were mounted push-pull. There was an out-of-band organ-pipe resonance up around 800hz or so IIRC.
 
FAITAL PRO W18N8-1000

I'd like to give these dual 18's a try using DJK's PPSL design. Its my first time designing a box using WINISD and I'm having trouble with the small box and long port.
I'm trying for 4.5 cu ft with 40hz tuning but I don't know how small I can make the box and still allow the speakers to "breathe".
At 4.5 cu ft I used two ports 5.50" x 10.875" x 38.2" to keep the port velocity down to 17m/s with full power.

This box is too big and I'm not sure where I can scale it down. The inside end of the port is getting too close to the speaker baffles with this arrangement.
The drawing is not to scale but the panel sizes are what I've got so far.
I tried to bend the port around the back. And move the speakers to the opposite side from the port opening.
Any help would be appreciated.


An externally hosted image should be here but it was not working when we last tested it.
 
Really small reflex cabinets with high x-max drivers have problems with the ports. I've seen some 21" drivers that sim well in 4 cu ft, but the porting looks like a problem.

Passive radiators are the usual fix for hi-fi speakers, but present problems for PA. The total volume they need to displace can be on the order of 2x~3x what the main woofer is capable of doing, and its cone will be so heavy it will need to be clamped during transport.

I am looking at a dual Beyma 12LX60 design that will require an 18" PR with an x-max on the order of 20mm~25mm (one way) to work properly. The net volume of the box only need be 2.5 cu ft, and it looks like it would be flat to 40hz.

I will probably end up putting them in a PP tapped horn instead. Although it will be much larger, it should go to 30hz with no EQ (102dB/2.83V/1M).
 
Originally Posted by tb46

The basic PPSL as shown in Post #474 is not isobaric. It's a bass-reflex w/ two drivers.

Hi

Well, shiver me timbers :D As he's posted in a PPSL thread i presumed it was one ! It sure looks like it's meant to be. Otherwise what's the Open area leading up to F for ?

Plus he said this,

I'd like to give these dual 18's a try using DJK's PPSL design
 

Attachments

  • ppsl.png
    ppsl.png
    29.5 KB · Views: 264
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.