Home » Sponsored » Pi Speakers » De-ringing my Pi Seven cabinets
De-ringing my Pi Seven cabinets [message #51252] Mon, 09 July 2007 14:53 Go to next message
Tim Barnes is currently offline  Tim Barnes
Messages: 46
Registered: May 2009
Baron
Hi Wayne:

I'm finally making progress with my Pi Sevens - the mid-horn cabinets are mostly done. I've been taking pictures, and I'll post some when I find the time...

I do think the panels seem quite resonant (at least they are pretty loud when I knock them with a knuckle). I'm wondering if there's space inside for me to glue on some sound-absorbing panel material (1/2" thick, comes in 48x96 sheets)? Or is there a better way to make the structure really dead? The cabinets are being built out of 3/4" MDF.

I expect to have the same question with the bass cabinets - how much can I reduce the internal volume with braces, sound deadening materials etc.?

For the bass I imagine the goal is to push the resonances above the range that will be excited by the woofer, but I'm not sure, so any advice will be appreciated.

Thanks for all your help,
tim



Midhorn bracing [message #51254 is a reply to message #51252] Mon, 09 July 2007 21:19 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 17869
Registered: January 2001
Illuminati (33rd Degree)

Brace each panel with a wedge shaped brace. The top and bottom braces are the same shape, and the side braces are the same as each other. Brace each flare panel against the side wall of the external cabinet that surrounds the midhorn. Also, preload the back panel with a rubber ball as shown below. The back panel will vibrate and make the midhorn sound resonant without it.

Re: Midhorn bracing [message #51255 is a reply to message #51254] Mon, 09 July 2007 23:37 Go to previous messageGo to next message
Tim Barnes is currently offline  Tim Barnes
Messages: 46
Registered: May 2009
Baron
Thanks, Wayne. I have put in the braces on all four sides...I haven't stuffed it with fiberglass yet though, and I haven't mounted the back panels. I'll do as you suggest. It looks from your picture as though you stuff the angled areas around the horn pretty thoroughly?

Also, do you use some kind of strip to seal the back panel to make the entire cabinet airtight? I couldn't see anything on the picture with the ball braces.

tim

Re: Midhorn bracing [message #51256 is a reply to message #51255] Tue, 10 July 2007 10:53 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 17869
Registered: January 2001
Illuminati (33rd Degree)

Loosely pack the sides, top and bottom surrounding the flare with insulation:

http://www.pispeakers.com/misc/Rubber_Ball_Brace.jpg
Midhorn packed with insulation and rubber ball brace in place

The picture above doesn't show the gasket, but one is used to seal the access panel. A suitable material for this purpose is PVC sheet rubber, commonly used for shower pans. You can get it at most builder's supply houses and cut it to fit. Makes excellent gasket material.

http://www.pispeakers.com/Basshorn/Cutting_Gasket.jpg
PVC sheet rubber, cut to form a 12π side panel gasket
Re: Midhorn bracing [message #51257 is a reply to message #51256] Tue, 10 July 2007 21:38 Go to previous message
Tim Barnes is currently offline  Tim Barnes
Messages: 46
Registered: May 2009
Baron
PVC sheet sounds good. I'll make a trip to Home Despot.

Thanks again,

tim

Previous Topic: 12pi Basshorn , assembled
Next Topic: Two Pi towers with HiVi RT2C-A Planar transducers...?
Goto Forum:
  


Current Time: Sat Sep 19 13:31:11 CDT 2020

Sponsoring Organizations

DIY Audio Projects
DIY Audio Projects
OddWatt Audio
OddWatt Audio
Pi Speakers
Pi Speakers
Prosound Shootout
Prosound Shootout
Smith & Larson Audio
Smith & Larson Audio
Tubes For Amps
TubesForAmps.com

Lone Star Audiofest