results of enlosure shape research - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 24th July 2002, 02:00 PM   #1
diyAudio Member
 
Join Date: Mar 2002
Location: Atlanta, GA
Send a message via AIM to Austin
Default results of enlosure shape research

I finished the report for my Acoustics class that discusses the effects of enclosure shape on speaker response. I am hesitant to post it to the forum because the bibliography is not up to par. Basically, I found that in terms of diffraction, the sphere is best in terms of shape. Using felt however, is just as good or better when used on a flat baffle. So, by rounding the edges of the baffle and using felt would be the best bet (*Flush mounting drivers is very very important too*). For internal resonances, all the evidence pointed to an enclosure that did not have parallel walls. Tapering the walls seemed to be very good, whether done like the B&W Nautilus or the Sonus Faber Amatis. As far as materials go, wood is the best. MDF or hardwoods of significant thickness will prevent enough transmission through the walls of the cabinet into the listening area to keep the desired sound unaffected. I originally thought that a more rigid material like marble would be the best, but in the case of marble, almost all transmission through the walls is prevented and a buildup of energy on the inside will almost definitely make its way back out through the cone (very bad). I didn't see any designs using this technique, but a cabinet with wood on the inside and marble on the outside, might take advantage of the benefits of both materials. Of course, some internal dampening is required to achieve the best results, although the amount is drastically decreased when you use a modified shape. The paper addresses time-alignment of the drivers, which did not seem to be a big problem in loudspeakers, unless you are far from the speakers. The best results are achieved by staying relatively close to the speakers. Slanting of the front baffle didn't seem like a good solution because it pointed the speakers at the ceiling. Separate enclosures staggered the proper distances worked best for time-alignment, but could add more problems diffraction-wise. kingdaddy's SST8's look like they would do a relatively good job in taking care of both time-alignment and diffraction. Those are the only factors I took into account for the paper, I would be happy to research other factors if anyone is interested. I can email a copy of the paper to anyone who is interested also. Hope some of the information is helpful.

Austin
  Reply With Quote
Old 24th July 2002, 02:01 PM   #2
BrianGT is offline BrianGT  United States
diyAudio Moderator Emeritus
 
BrianGT's Avatar
 
Join Date: Jan 2002
Location: near Atlanta, GA
Send a message via AIM to BrianGT
can you send me a copy

gte619j

--
Brian
  Reply With Quote
Old 24th July 2002, 02:46 PM   #3
Thomas is offline Thomas  Denmark
diyAudio Member
 
Thomas's Avatar
 
Join Date: May 2001
Location: Right here
I would appreciate a copy too.

E-mail is: kobbertraad@hotmail.com
  Reply With Quote
Old 24th July 2002, 08:33 PM   #4
diyAudio Member
 
kingdaddy's Avatar
 
Join Date: Mar 2002
Location: Fort Worth, Texas
Well done, my results mirrored yours, but as you probably know everything is a compromise, my enclosures probably suffer from some form of edge diffraction and I have tried oval foam rings around the tweeters and some other porous foams of different shapes but I can't get any positive improvement so far, and since I don't dislike anything in particular about the sound I'm not inclined to try any further. I would also like a copy of your paper if you have the time.

Thanks
mkeith@ftav.com
  Reply With Quote
Old 24th July 2002, 09:12 PM   #5
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
me too...tlinespeakers@mac.com

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 24th July 2002, 09:20 PM   #6
diyAudio Member
 
Join Date: Jan 2002
Location: Bucks County, Pa
Me too!

bcwwkg@comcast.net

Thanks,
Pete
  Reply With Quote
Old 24th July 2002, 09:32 PM   #7
CHRIS8 is offline CHRIS8  United States
Account Disabled
 
Join Date: Dec 2001
Location: VA, USA
You may of course send a copy to me, and I would be grateful.

chris8@mail.com

"Using felt however, is just as good or better when used on a flat baffle. "

This is only taking into consideration one aspect. Certainly, you will suppress the reradiatied diffractive energy in the band that the damping material is effective, but in this you are only concerning on axis response. Power response is just as important IME, and you will reduce off axis linearity to a very small degree in the process when compared to a damped flat baffle vs. a non damped flat baffle. Their is no comparison to a sphere though, or very large radiuses, as the linear power response provided at higher mid and treble frequencies is superior and provides for a much more linear dispersion field of acoustical energy. Of course, this assumes your intent to design for ideal power response in the first place. The specific importance of power response, though, is not my point to discuss in this thread. I am just pointing out that it will be affected significantly with different approaches.

-Chris
  Reply With Quote
Old 24th July 2002, 10:30 PM   #8
JoeBob is offline JoeBob  Canada
diyAudio Member
 
JoeBob's Avatar
 
Join Date: Nov 2001
Location: Montreal, Canada
I wouldn't mind a copy either joebob@videotron.ca
  Reply With Quote
Old 24th July 2002, 11:46 PM   #9
Beggar is offline Beggar  United Kingdom
diyAudio Member
 
Beggar's Avatar
 
Join Date: Aug 2001
Location: South East, UK
hey dude, would really appreciate a copy too

nik@whatisthis.com

thanks !
  Reply With Quote
Old 25th July 2002, 01:36 AM   #10
diyAudio Member
 
sianturi's Avatar
 
Join Date: Apr 2002
Location: Fontenay-le-Fleury, France
count me in, dude!

sianturi@link.net.id

Thanks,
__________________
The Great Saiyaman
Siapa bertelinga hendaklah ia mendengar... (Mat 13:9)
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
CNC shape cabinet? Audist Multi-Way 20 19th January 2006 10:12 PM
DIY Enlosure for Power Amp r!sc! Solid State 11 17th July 2005 08:26 AM
Box shape alex_g Multi-Way 7 21st February 2004 04:43 AM
Box Shape? r_s_dhar Multi-Way 13 2nd January 2003 09:51 AM
Which stuffing material to increase "perceived" enlosure size? Two Moons Multi-Way 4 6th January 2002 05:27 PM


New To Site? Need Help?

All times are GMT. The time now is 07:37 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2