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 26th July 2006, 09:02 AM   #1
Puggie is offline Puggie  United Kingdom
diyAudio Member
 
Join Date: Oct 2004
Default horn cut off frequency, dependant on mouth area or circumference?

I've hunted round and not really got an answer, the low end limit of a horn, does the area of the horn mouth or the circumference of the horn mouth dictate the lowest frequency the horn will support? I'm playing with horn designs for in the car, for those who don't know these are very flat and wide, and traditionally positioned under the dash using the roll up off the dash as an extension of the horn mouth. Now if the circumference is the deciding factor its not important to make the horn very high as most of the circumference is found in the width, BUT if the mouth are dictates the lower cut off, then doubleing the height of the horn should have a very pronounced effect.

I've looked around and found argument stating circumference is the deciding value, and I've found arguments stating mouth area? I know the likes of Hornresp use mouth area but they also assume an axially symetric horn which this is not.

any help or advice? (I put this in 'full range' as I guess these are more horny types in here )

thanks
  Reply With Quote
Old 26th July 2006, 09:29 AM   #2
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
First stop: www.quarter-wave.com

Martin has lots of white papers etc on horns that you can read. Pretty technical in many ways, but that's a good thing. Hifi is ultimately about science. You can implement it in an artistic way, but the laws of physics don't change.
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  Reply With Quote
Old 26th July 2006, 09:30 AM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
the circumference of the horn mouth applies to circular mouth horns only.

If you convert your mouth area to an equivalent circle of the same area, then the circumference can give a good correlation.

A second rule determines the lower bass extension. The flare rate will fix the high pass frequency of your horn.

A third rule suggests the horn length must be between a quarter wavelength and a half wavelength of your lowest frequency.

Some suggest that after you have applied these three rules you can truncate your horn by upto 40% with acceptable response ripple in the passband.

To get bass you need big mouth area, a slow flare rate and a long horn.

Below the passband the driver is effectively unloaded and "in car" amps have some pretty big powers that are liable to damage your expensive driver, especially if you try to show off the bass response of your new speaker.
__________________
regards Andrew T.
  Reply With Quote
Old 26th July 2006, 09:31 AM   #4
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
Quote:
Hifi is ultimately about science
HiFi is about accuracy. Sometimes science has to be used to achieve it.
__________________
regards Andrew T.
  Reply With Quote
Old 26th July 2006, 10:52 AM   #5
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
A true enough ultimate objective, but I was refering to the means necessary to achieve said accuracy in reproduction, as you note.
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  Reply With Quote
Old 26th July 2006, 11:19 AM   #6
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally posted by AndrewT
Hi,
HiFi is about accuracy. Sometimes science has to be used to achieve it.

I don't know of any other way than scientific to achieve it....

Jan Didden
__________________
Never explain - your friends don't need it and your enemies won't believe you anyway - E. Hubbart
Check out Linear Audio Vol 7
!
  Reply With Quote
Old 26th July 2006, 11:52 AM   #7
Puggie is offline Puggie  United Kingdom
diyAudio Member
 
Join Date: Oct 2004
thanks for the info, this is for mid and highs, not bass. My current designs are good down to 650Hz and use 1.4" throat radian compression drivers, I want to go lower and change CDs. My aim is to get 300Hz up to 20kHz, I'm looking at the new BMS 4594 compression driver.

so designing in hornresp and then 're-shaping' the conical horn into the shape I want would not be a bad way to go about it.
  Reply With Quote
Old 26th July 2006, 12:08 PM   #8
diyAudio Member
 
Join Date: Mar 2004
Location: Hobart, Tasmania
Send a message via MSN to noodle_snacks
Quote:
Originally posted by janneman



I don't know of any other way than scientific to achieve it....

Jan Didden

how about _extensive_ trial and error
  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
TH mouth area bubblersound Subwoofers 2 7th June 2009 05:57 PM
Horn Mouth Diffraction mefistofelez Multi-Way 11 14th October 2005 01:04 AM
rear horn mouth area big_kahunah Full Range 1 16th August 2005 01:35 AM
Screen in horn mouth? Stocker Multi-Way 7 9th March 2005 09:39 AM
Frequency Dependant Damping? electro samurai Solid State 4 20th May 2004 08:57 PM


New To Site? Need Help?

All times are GMT. The time now is 02:07 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