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 23rd October 2009, 06:43 PM   #1
diyAudio Member
 
Join Date: Nov 2007
Location: Dallas
Default Styrofoam Smith Horn

Just screwing around with polystyrene... Seems to work!
But not yet tested with crossovers and rest of the system.

But the wood driver plate drifted off-center as the glue
was drying... I put a peg in the throat to try and fix the
center of dispersion (also seems to work).

I wonder most Smith horns I see built with overhanging lips??
This expansion is conical, not exponential, after the septums.
But why??? A conical expansion theoretically adds no loading,
and can't mitigate any HF sectoral beaming already created
by the exponential throats...

Future experiment will modify the top cover with sectoral
K slots (like JBL Aquarius). That begin an exponential slot
leakage about where the exponential throat area ends...
Attached Images
File Type: jpg smith1.jpg (110.0 KB, 1314 views)
File Type: jpg smith2.jpg (119.2 KB, 1229 views)
  Reply With Quote
Old 23rd October 2009, 09:58 PM   #2
fwater is offline fwater  United States
diyAudio Member
 
fwater's Avatar
 
Join Date: Nov 2007
Just screwing around? Looks like a reasonably serious attempt to me.

I am not familiar at all with this type of horn, so here's a barrage of questions...

What is the range? Coverage? Is this a design intended for a particular driver, or can they be "rolled" through? Claimed advantages / disadvantages?

I must admit, my curiousity is mainly do to the quite serious and sleek look (i'm a believer that a speaker should look good as well as sound good), and of course, my curiousity of all things audio. I am becoming more attracted to the idea of high sensitivety two-ways to go with my unkown vintage / brand name / power output tube amp.
  Reply With Quote
Old 23rd October 2009, 10:18 PM   #3
pos is offline pos  Europe
diyAudio Member
 
pos's Avatar
 
Join Date: Feb 2008
Location: Paris
Nice!
But your horn seems to be missing two half fins of the sides (and these actually make the expansion non conical)

If you do a search on the audioheritage.org forum you will find plans and spreadsheets for various versions of that horn.
  Reply With Quote
Old 23rd October 2009, 10:53 PM   #4
diyAudio Member
 
Join Date: Nov 2007
Location: Dallas
Quote:
Originally Posted by fwater View Post
I am not familiar at all with this type of horn, so here's a barrage of questions...
You can read Bob Smith's 1951 Audio Engineering article here:
http://audioheritage.csdco.com/vbull...ead.php?t=9148
  Reply With Quote
Old 23rd October 2009, 11:04 PM   #5
freddi is offline freddi  United States
diyAudio Member
 
freddi's Avatar
 
Join Date: Aug 2005
in mono it has a holographic sound with good subjective vertical dispersion - can't remember if I've run stereo but probably with 416 in K15 - there's my rock n roll bass
Click the image to open in full size.
  Reply With Quote
Old 23rd October 2009, 11:17 PM   #6
defect9 is offline defect9  Ireland
diyAudio Member
 
defect9's Avatar
 
Join Date: Sep 2007
Location: Carson City, NV
hmmm... based on the shadow characteristics, that picture looks like the fins extend to the edge of the horn

*edit* Nice "Rock n roll" guitar

Last edited by defect9; 23rd October 2009 at 11:19 PM.
  Reply With Quote
Old 24th October 2009, 02:40 AM   #7
diyAudio Member
 
Join Date: Nov 2007
Location: Dallas
OK.. Here's a sketchup of the basic idea...

Slots: acting both as plate lens for horizontal dispersion of sector beams.
And as Karlsons for continued exponential expansion of the horn mouths...

Or can just K the top plate only, sorta like JBL Aquarius...

These curves might be rounded the "wrong way" for a dispersion lens.
But artistically correct for a Karlson... Could split the diff and just cut
these notches triangularly? Somebody would surely poke an eye out...
Attached Images
File Type: jpg SmithKLens.jpg (88.2 KB, 674 views)

Last edited by kenpeter; 24th October 2009 at 02:44 AM.
  Reply With Quote
Old 24th October 2009, 03:29 AM   #8
diyAudio Member
 
Join Date: Nov 2007
Location: Dallas
Quote:
Originally Posted by pos View Post
Nice!
But your horn seems to be missing two half fins of the sides (and these actually make the expansion non conical)
Not missing. I simply cut an exponential throat in half. Sidewall is the middle.
You migh notice the mouths of those outside sectors are only half as wide.
My latest sketchup does show half fins as you describe. But either way works...

The conical part of concern is the perimeter. After exponential throats have
terminated "too early", and before reaching the edge.

Last edited by kenpeter; 24th October 2009 at 03:34 AM.
  Reply With Quote
Old 24th October 2009, 03:35 AM   #9
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
Crazy looking horn! Would love to know how it sounds.

Isn't there often someone selling wooden ones on eBay?
  Reply With Quote
Old 24th October 2009, 03:45 AM   #10
freddi is offline freddi  United States
diyAudio Member
 
freddi's Avatar
 
Join Date: Aug 2005
IIRC there were two versions on ebay
Click the image to open in full size.
  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
Styrofoam DIY Turntable Kit kilowattski Analogue Source 0 22nd July 2009 04:08 AM
Vintage Wharfedale 12" styrofoam-cone woofer GordonW Swap Meet 1 25th August 2007 09:38 PM
Tapering a transmission line...with styrofoam? Would it work? Spasticteapot Multi-Way 4 1st November 2006 07:21 PM
JBL 2397 Smith horn macka Swap Meet 3 8th November 2003 07:35 PM


New To Site? Need Help?

All times are GMT. The time now is 12:16 PM.


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