Rear-loaded horns: disadvantages? - diyAudio
Go Back   Home > Forums > Loudspeakers > Full Range

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 3rd October 2007, 01:43 PM   #1
diyAudio Member
 
Taterworks's Avatar
 
Join Date: May 2007
Default Rear-loaded horns: disadvantages?

Hi, everyone. I'm considering a rear-loaded horn design for a pair of floorstanding 2-way loudspeakers. I know this is the full-range forum, and none of my drivers are running close to full range, but this is the area of the forum that seems to have the most experience with rear-loaded horn enclosures.

So, aside from build complexity, what are the disadvantages of a rear-loaded horn design?
__________________
If it works, but you don't know why it works, then you haven't done any engineering.
Taterworks Audio (nothing for sale)
  Reply With Quote
Old 3rd October 2007, 01:46 PM   #2
diyAudio Member
 
PigletsDad's Avatar
 
Join Date: Jul 2007
Location: South Worcestershire
An intrinsic problem is time smear. Sound from the backwave arrives delayed with respect to the front.

Opinions differ about the audibility and importance of this effect, but it is unavoidable.
  Reply With Quote
Old 3rd October 2007, 02:57 PM   #3
diyAudio Member
 
Join Date: Sep 2006
I read somewhere that in a BLH there is usually a dip in the response around the mid-bass region (70-90hz) because of the delay, is this true?
  Reply With Quote
Old 3rd October 2007, 03:10 PM   #4
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
I doubt it is unique but Tannoy, in their Autograph and Westminster adopted a front horn that went down to about 200Hz and used the folded rear horn to extend the response to a claimed 18Hz to 20Hz (-6db).

That system keeps the delayed rear wave to only the lower frequencies and maybe that hides some of the audible effect.

There are some threads looking at clones of these two speakers and as far as I can recall none/few builders commented on hearing time smear/delay/slowness in the bass.

Reviews of the Westminster actually major on the bass impact and reproduction of bass transients as a major advantage of the combined BLH FLH system. They say there is nothing like it from any boxed speaker.
__________________
regards Andrew T.
  Reply With Quote
Old 3rd October 2007, 05:22 PM   #5
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Greets!

Assuming a BW below ~250 Hz (though some claim as high as 400 Hz) and if you XO it below the 3rd harmonic dip, then nothing since the time delay will be minor and down in our rapidly rolling off hearing acuity BW.

WRT the dip's location, it's a function of the horn's design, so not necessarily in the 70-90 Hz BW.

Agreed, if a HE single driver is used in a relatively low impedance system, a BLH works best with a FLH to cover the acoustic XO BW between the driver's front and rear radiation since otherwise you have to either accept the broadband dip in the response or suffer the time 'smear' of a too high acoustic XO.

The way around all this though is to design using either a relatively high Qts driver or a HE driver with significant added series resistance to lower its effective Qts/mass corner/acoustic XO point or use a matching impedance amp.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  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
Info needed about Expo-Falthorn or Rutsche rear loaded horns? Norris Wilson Full Range 1 30th June 2011 04:01 PM
My 103E Rear loaded horns shporsche Full Range 17 15th July 2009 11:16 PM
8inch woofer rear loaded horns with tweeters Naudio Full Range 1 10th January 2009 09:54 AM
Need info on designing front/rear loaded bass horns jSisco Multi-Way 7 4th June 2003 12:47 AM


New To Site? Need Help?

All times are GMT. The time now is 06:34 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