Go Back   Home > Forums > Loudspeakers > Subwoofers

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 21st February 2012, 04:25 AM   #1
arrie is offline arrie  South Africa
diyAudio Member
 
Join Date: Feb 2012
Location: South Africa
Default Ported Horn

Has anyone ever tried a reflex enclosure with a straight horn loaded at the front of the baffle board. That is, the driver and the port mounted on the same plane, at the throat of the horn (15").
I was thinking of a conical horn flare of about 1100mm long with a horn mouth of about 1400mm x 600mm. i have seen some horn designs utilizing a bass reflex port (W-Bins), but never in the throat area.
The idea here is to utilize the concept of putting the backward radiating sound waves to some r good use, other than just reflex boosting, such as the higher efficiency of horn loaded designs.
  Reply With Quote
Old 21st February 2012, 05:43 AM   #2
VaNarn is offline VaNarn  Australia
diyAudio Member
 
Join Date: Dec 2010
Location: Ivanhoe
arrie,I would refer you to the ALTEC,Voice of the Theatre speakers, typically the A7 model,where a front mounted horn boosts the O/P in the mid-range spectrum.This application has a limited freq. coverage of around two octaves,but in conjunction with a multi cellular H.F. horn gives a controlled directivity that was the design intention.In fact horns in general can only offer improved efficiency over a limited bandwidth and do so by narrowing dispersion.
  Reply With Quote
Old 21st February 2012, 06:19 AM   #3
arrie is offline arrie  South Africa
diyAudio Member
 
Join Date: Feb 2012
Location: South Africa
Default Ported Horn 2

Thanks for the referance VaNern!
the A7 is indeed a horn combined with the reflex design, but the reflex port is seperate from the horn. does this mean that a port in the throat of the horn is a bad idea. what if one were to load only the port of a reflex enclosure with a front horn and have the driver seperate from the horn?
  Reply With Quote
Old 21st February 2012, 09:46 AM   #4
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
"does this mean that a port in the throat of the horn is a bad idea"

Yes.

"what if one were to load only the port of a reflex enclosure with a front horn and have the driver seperate from the horn? "

Mixed results.

Most of these have small horns on the port and have a peak in the 100hz~200hz region. If you have a really big horn for the port this is called a scoop. Also see Tapped Horn, the latest and greatest idea.
__________________
Candidates for the Darwin Award should not read this author.
  Reply With Quote
Old 21st February 2012, 01:45 PM   #5
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by djk View Post
"does this mean that a port in the throat of the horn is a bad idea"

Yes.

Also see Tapped Horn, the latest and greatest idea.
A port in the throat of a horn may or may not be a good idea.
Tom Danley, inventor of the tapped horn (as we know it) has many horns that use bass reflex ports as well as speaker band pass ports at various points between the throat and the mouth.

Martin Audio's ASX, using a 30 mm Xmax 21" driver, is using bass reflex and a front horn for very high bass output, with ports virtually part of the horn exit.

Art
  Reply With Quote
Old 21st February 2012, 08:27 PM   #6
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
"with ports virtually part of the horn exit."

Good

"a port in the throat of the horn "

The opposite (bad).
__________________
Candidates for the Darwin Award should not read this author.
  Reply With Quote
Old 22nd February 2012, 01:34 AM   #7
diyAudio Member
 
paulspencer's Avatar
 
Join Date: Sep 2003
Location: Melbourne, Australia
It's an interesting idea. Simulating it could be a challenge but it would not be difficult to test with a prototype and try with and without the port.

I do wonder if it's worth it. The port output is not required if the horn is adequately sized. If it isn't adequately sized, then I'm not sure a port is going to help much.

Perhaps more interesting would be a bandpass horn. In other words, a 4th or 6th order bandpass coupled to the horn throat. This is essentially what happens with a Synergy horn. The advantage is acoustic filtering of the driver at the throat and then horn loading is applied to the acoustically filtered output of the driver.
  Reply With Quote
Old 22nd February 2012, 06:05 AM   #8
diyAudio Member
 
Top Shelf's Avatar
 
Join Date: Apr 2010
Location: Midland, Ontario
I tried this years ago on a 50 hz horn , long throw 18" car sub with (2) 4" low tuned ports all firing into the throat. Tuned it like a regular BR with the addition of the horn flare. Frequency response was fairly flat from 50-130hz ,it put out a hell of a lot of punch and even when driven with a equal voltage down to 30 hz the cone didn't unload enough to bang the backplate. Big box though!
__________________
JEREMY M_________________________________
I like it loud, BUT NOT TOO LOUD!.... Hey do you hear that high pitched ringing sound ?
  Reply With Quote
Old 22nd February 2012, 09:16 AM   #9
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
"Simulating it could be a challenge but it would not be difficult to test with a prototype and try with and without the port."

The back volume required for the driver for a regular horn and a ported horn are quite different, just porting the optimum horn won't work. The other issue is at some higher frequency the port will absorb throat pressure causing a dip in output.

BFM investigated this many years ago in Speaker Builder Magazine.

A PR driving the throat may solve the absorption problem, there is a patent on a speaker like that.

Patent US5898138 - Loudspeaker having horn loaded driver and vent - Google Patents

"In other words, a 4th or 6th order bandpass coupled to the horn throat. "

Like this drawing?

http://www.google.com/patents?id=Txa...page&q&f=false
__________________
Candidates for the Darwin Award should not read this author.

Last edited by djk; 22nd February 2012 at 09:23 AM.
  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
W4-1320 TL or Horn or Ported VEC7OR Full Range 28 5th December 2012 03:04 AM
Ported TH Zero D Subwoofers 17 18th February 2012 02:40 PM
why is a tapped horn more efficient than ported? 60ndown Subwoofers 34 1st September 2011 04:15 PM
Enclosure Change Horn/Ported/Sealed/TL-Sub, For Existing Altec Lansing 2.1 System ankithmistry Full Range 9 25th May 2011 07:42 PM
Woofer Towers, front-ported or rear-ported? Goldenboy Multi-Way 6 15th June 2004 06:44 PM


New To Site? Need Help?

All times are GMT. The time now is 10:47 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