Frugel-Horn Mk3 - Page 48 - 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 28th March 2011, 05:04 PM   #471
chrisb is offline chrisb  Canada
diyAudio Member
 
Join Date: Aug 2002
Location: victoria BC
Quote:
Originally Posted by Scottmoose View Post
Group delay in a back horn is a function of axial length and its upper corner frequency. Nobody's complained about group delay yet, so make of that what you will. FH3 when used as intended should have a lower Fhm than the A126 though. Different designs, different priorities.


FWIW, some folks are / claim to be far more sensitive to group delay in BLH than others, and would recommend (multiple) front loaded horns instead - which are not without their own complications of design / implementation in smaller domestic situations.
__________________
you don't really believe everything you think, do you?
community sites t-linespeakers.org, frugal-horn.com commercial site planet10-HiFi
  Reply With Quote
Old 28th March 2011, 05:05 PM   #472
MJK is offline MJK  United States
Account disabled at member's request
 
Join Date: Feb 2002
Location: Clifton Park, NY
Quote:
Originally Posted by chrisb View Post
by a perverse extension of that logic, an open baffle nested into a corner would be horn loaded as well?
What is your definition of horn loading?

At low frequencies, I don't think there are very many enclosures that can be classified as horn loaded. By my definition, the size of the mouth determines if an enclosure is horn loaded or a resonant (TL or TQWT) enclosure. By my definition, an expanding geometry does not automatically become the definition of a horn.

Martin
  Reply With Quote
Old 28th March 2011, 06:00 PM   #473
diyAudio Member
 
Bob Brines's Avatar
 
Join Date: Jan 2003
Location: Hot Spring Village AR
Quote:
Originally Posted by chrisb View Post
....by a perverse extension of that logic, an open baffle nested into a corner would be horn loaded as well?
I will admit that I am way out of my element, but I would think that anything stuck in a corner will get some degree of horn loading. One of the things I want to try is a corner loaded woofer in a box that simply constitutes the back chamber. In other words a front loaded horn.

Bob
  Reply With Quote
Old 28th March 2011, 06:18 PM   #474
ra7 is offline ra7  United States
diyAudio Member
 
Join Date: Feb 2009
Blog Entries: 1
Martin has a valid point. The mouth of the FH is more like a slot. It is not really expanding like a horn should.

In a strict voight pipe, there is some horn loading because the expanding profile opens into a mouth that is consistent with expansion. There is also resonant action due to the nature of the tapered tube and the location of the driver.

Last edited by ra7; 28th March 2011 at 06:38 PM.
  Reply With Quote
Old 28th March 2011, 07:05 PM   #475
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
I think Martin was speaking generally. Either way, this subject has already been discussed / commented on at the start of the thread, but to briefly repeat, FH3 is expanding exactly as it 'should.' Inserting a choke into the flarepath of a back-horn certainly has precident: I refer you to Harry Olson. Which is a fairly good precident as far as I'm concerned.

Yes, a Voigt (no 'h': P. G. A. H. Voigt you know) pipe could be described as a chamberless tapped conical horn if you do not choose to define a horn by impedance matching to Fc, but by, for e.g., the presence of 1/2 wave behaviour. Both definitions seem perfectly sensible to me, so YMMV.

FWIW, FH3 is nominally impedance matched when corner loaded (as it was strictly speaking designed to be) to ~85Hz, about 1/4 octave above Fc.

Last edited by Scottmoose; 28th March 2011 at 07:27 PM.
  Reply With Quote
Old 28th March 2011, 07:21 PM   #476
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
Quote:
Originally Posted by Bob Brines View Post
I will admit that I am way out of my element, but I would think that anything stuck in a corner will get some degree of horn loading. One of the things I want to try is a corner loaded woofer in a box that simply constitutes the back chamber. In other words a front loaded horn.

Bob
Well, if the corners & room dimensions are such as to provide the desired gain BW, you'll be in business. At the very least, baffle-step will become a non-issue.

Last edited by Scottmoose; 28th March 2011 at 07:30 PM.
  Reply With Quote
Old 28th March 2011, 07:29 PM   #477
MJK is offline MJK  United States
Account disabled at member's request
 
Join Date: Feb 2002
Location: Clifton Park, NY
I would not classify corner loading as horn loading. As you add boundaries you restrict the area that the source is radiating into (4 pi - 2 pi - 1 pi - 0.5 pi) and thus increase the resulting SPL output with each step down in pi space. Horn loading increases the efficiency of the output from a source in free space. Corner loading can be used to reduce the mouth size requirement to achieve a horn and raise the horn's SPL output even more.

Try the following exercise. Model the FH3 in your favorite software tool (MathCad is recommended), then model the FH3 without the end flare stopping at the restriction and compare the SPL responses. I have spent quite a bit of time studying the FH3 because it is such an interesting design.

The FH3 is a really elegant and simple design that is reported by many individuals to perform extremely well with several different drivers. Congrat's to the design team. But in looking at the simulations it appears to me to be a resonant mass loaded TQWT type of speaker and not what I (my definition of a horn which may not be consistent with somebody else's definition) would classify as a horn. There are a series of resonant peaks and valleys that help produce the bass output. When combined with a floor and rear wall boundary condition the bass produced matches the mid-bass and higher response, no BSC needed. Well done.

Martin
  Reply With Quote
Old 28th March 2011, 09:16 PM   #478
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
Thanks, Martin, that's quite a compliment. Glad you like it.

Scott

Last edited by Scottmoose; 28th March 2011 at 09:46 PM.
  Reply With Quote
Old 28th March 2011, 09:35 PM   #479
ra7 is offline ra7  United States
diyAudio Member
 
Join Date: Feb 2009
Blog Entries: 1
Very interesting. I might give this a try. I have several drivers lying around which might fit this design.

Was the supra baffle ever designed for the FH3? That would allow quick mounting and dismounting of different drivers.

Thanks.
  Reply With Quote
Old 28th March 2011, 09:53 PM   #480
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
No, primarily because it doesn't need one -not with the MA drivers at any rate. If the Fostex is corner loaded (should be noted strictly speaking FH3 is a corner-horn design) it should pass muster with a high output impedance amplifier & the assumption you're not expecting that combination to excel at playing Metallica.

Which isn't to say you can't try one if you wish. I believe Dave & Chris's prototype have removable / detachable baffles to allow precisely that, although they are not suprabaffles in the sense that they are not physically larger than the front baffle.

Just to stress again, FH3 is certainly not supposed to be the last word in back-horns. Far from it. It's a deliberately simple box offering that is easy to build, reasonably forgiving of different drive units, & hopefully a good footing for people new to the hobby and / or horn variations.

Scott

Last edited by Scottmoose; 28th March 2011 at 10:05 PM.
  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
The Frugel-Horn Project planet10 Full Range 1216 8th June 2014 09:02 PM
My Frugel-Horn Build italynstylion Full Range 130 22nd June 2010 12:24 AM


New To Site? Need Help?

All times are GMT. The time now is 02:13 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