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 20th July 2005, 02:16 PM   #11
e-side is offline e-side  Netherlands
diyAudio Member
 
Join Date: Jun 2005
Location: The Netherlands
http://www.melhuish.org/audio/download/MLutil.zip, you could also visit http://www.melhuish.org/audio/software.html for more software

best regards
  Reply With Quote
Old 20th July 2005, 03:35 PM   #12
diyAudio Member
 
paulspencer's Avatar
 
Join Date: Sep 2003
Location: Melbourne, Australia
thanks ... in searching I found another one but it was in German!
  Reply With Quote
Old 24th July 2005, 08:52 PM   #13
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Greets!

Well, I guess it will have to do since I don't speak Dutch. Anyway, as they say, 'a picture is worth a thousand words', so now I understand (I think).

For my records, what make/model driver is this? Rest of the specs (measured?) or website?

Reactance annulling is the balancing of pressure on both sides of the diaphragm until they are ideally equal. Viewed another way, a compression driven horn optimized for max efficiency is an underdamped 4th order bandpass (BP) cab mated to a large, overdamped 'port' that nulls out each other's excess 'Q-ness'.

'Fo' = F6. The rear chamber tuning frequency is Fc, so this design is for a SQRT(35*280) = ~99 Hz horn. To calc a 35 Hz horn, Fl needs to be 3 octaves below it, or 35/2^3 = 4.375 Hz. At this frequency it takes a negative pressure rear chamber to reactance annull it, so in reality you'd be making a slightly unequal pressure balanced BLH. This assumes though that you're attaching it to a M = 0.35 horn rather than a M = 1 expo that I assume you want to use based on the attachment, which will reduce the pressure on the front side somewhat, bringing the system closer to being annulled.

Use Hornresp to find the length that makes it acoustically a half WL long, terminating into a full size mouth when all the boundaries are factored in if you want it to load smoothly all the way to 35 Hz. Use it also to find the rear chamber Vb that makes it resonate at Fc if you want it to load (protect) the driver below it.

How much BW the horn passes beyond its passband is dependent on the driver, compression ratio (CR), 'M' factor, whether or not it has a phase plug and how effective it is. If folded, then how it's done will affect it also.

Speaking of 'M' factor, the program implies that it's a design variable, but it calc'd specs for a M = 0.436 (seriously hyperbolic), not M = 1 (exponential), so apparently this is strictly for designing the horn expansion, though of course you can mate it to any lens profile to get other alignments. Bummer, it would be nice if it calc'd everything based on the 'M' factor.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 26th July 2005, 07:38 PM   #14
DorinD is offline DorinD  Romania
diyAudio Member
 
DorinD's Avatar
 
Join Date: Jan 2005
Location: Bucharest
Default Phase plug

@GM
Please, could you indicate me a link with information about using phase plug on bass-horn driver to reach a higher bandwidt? Precisely, I need a phase plug to acomodate a rectangular thoath of 140 cm2 to a 10' driver. Thanks!
  Reply With Quote
Old 27th July 2005, 01:04 PM   #15
e-side is offline e-side  Netherlands
diyAudio Member
 
Join Date: Jun 2005
Location: The Netherlands
Thank u very much GM !
  Reply With Quote
Old 27th July 2005, 01:17 PM   #16
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Greets!

I'm only aware of AES papers on the subject. There may be others also, these are just the ones I've browsed. Like these folks and the pioneers of sound reproduction though, I learned most of what I know from experimentation:

[013] Title: Phase Plug Modelling and Analysis:
Circumferential Versus Radial Types
Publication: AES-P, No. 1140, Cnv. 55 (1976-10)
Author: Clifford A. Henricksen
Abstract: Mechanical modeling of a simple phase plug
yields an electrical-mobility equivalent circuit; a
single-frequency notch filter. This applies directly
to "normal" circumferential-slit configurations. The
analysis is then applied to a radial-slit phase plug,

[014] Title: Phase Plug Modeling and Analysis: Radial
Versus Circumferential Types
Publication: AES-P, No. 1328, Cnv. 59 ( 1978-02)
Author: C. A. Henricksen
Abstract: Mechanical modeling of a simple
two-dimensional phase plug and diaphragm yields an
electrical mobility equivalent circuit; a two-pole,
low-pass filter. At higher frequencies, this analysis
becomes incomplete, and a model presented by Merhaut
(1975) is us

[015] Title: An Application of Bob Smith's Phasing
Plug
Publication: AES-P, No. 1384, Cnv. 61 (1978-11)
Author: F. M. Murray
Abstract: The war of the phasing plugs still rages
after more than 25 years. Compression driver phasing
plugs have vacillated between annular rings, salt
shakers, teardrops, and now radial slots again. When
Bob Smith provided simple design criteria for

[016] Title: The Dual Coil Inductively Coupled
Loudspeaker System Performance Optimization and the
Application of an Acoustic Phase Correction Plug
Publication: AES-P, No. 2780, Cnv. 86 ( 1989-03)
Author: Boaz Elieli
Abstract: Analysis of the dual coil inductively
coupled loudspeaker system using an electrical
equivalent circuit is presented, and some of the
practical design aspects relating to the system
optimization are discussed. The application of an
acoustic phase correct

[017] Title: Ultimate Performance of Wide-Range
High-Frequency Compression Drivers
Publication: AES-J, Vol. 24, No. 8, pp. 639 (1976)
Author: Clifford A. Henricksen
Abstract: Performance equations are developed from an
electric mobility model of a typical electromagnetic
compression driver. The analysis is independent of
impedance and relates ultimate performance to
material, air, and phase-plug variables.

[018] Title: An Investigation of the Air Chamber of
Horn Type Loudspeakers
Publication: ASA-J, Vol. 25, No. 2, Pg. 305-312,
Mar-1953
Author: Bob H. Smith
Abstract: The front air chamber design is treated as
a boundary value problem which yields a solution of
the wave equation for the general case in which the
horn throat enters the air chamber in a
circumferentially symmetrical manner.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 27th July 2005, 01:26 PM   #17
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
Originally posted by e-side
Thank u very much GM !
Apparently not since you didn't feel the need to 'pay' me what little I asked for in the way of a 'fee':

Quote:
For my records, what make/model driver is this? Rest of the specs (measured?) or website?
GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 27th July 2005, 01:36 PM   #18
diyAudio Member
 
paulspencer's Avatar
 
Join Date: Sep 2003
Location: Melbourne, Australia
I have been modelling a number of different drivers in hornresp including AV12, AV15, a beyma 18" driver, the Apex 8" and the IB15 (AE speakers IB sub driver) and have found that a BLH tends to have a similar response but with less cone excursion! I take a design that works as a FLH and then set VRC to 0.

Why would this be the case? Some of the FLHs have a very sharp peak in cone excursion which looks like a problem, but the BLHs don't have this problem, the peak excursion is at dc, not at fc, hence it is not really a problem.

If this is how they perform, why would anyone build a FLH?
  Reply With Quote
Old 27th July 2005, 02:20 PM   #19
diyAudio Member
 
slowmotion's Avatar
 
Join Date: Nov 2002
Location: Norge
Hi Paul

I get less cone excursion with a back chamber, not more.
You can make a FLH with or without a back chamber , buy the way.
If you get problems with peaks, you can try to model a larger back chamber.

cheers
__________________
- Jan -
  Reply With Quote
Old 27th July 2005, 03:19 PM   #20
diyAudio Member
 
mwmkravchenko's Avatar
 
Join Date: Jan 2002
Location: Perth Canada
Default One More plug

http://www.users.bigpond.net.au/ggoo...diy/plugs.html

Seat of the pants engineering. Most of the understanding with more of the how to.

Mark
__________________
Mark
  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
Horn segmenting questions FlipC Subwoofers 2 8th September 2008 11:09 PM
Vague horn questions bigwill Multi-Way 7 21st December 2007 07:02 PM
Horn questions slackerbob Subwoofers 11 1st August 2005 10:31 PM
A some horn questions mashaffer Multi-Way 3 19th May 2005 02:58 PM
Fostex 103 horn questions GrahamnDodder Full Range 12 2nd March 2004 06:53 AM


New To Site? Need Help?

All times are GMT. The time now is 02:43 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