Jean Michel on LeCleac'h horns - Page 51 - diyAudio
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 18th September 2009, 08:23 AM   #501
diyAudio Member
 
Join Date: Jun 2007
Quote:
Originally Posted by gedlee View Post
The fact is that if there is no mouth reflection the real part of the impedance of any device with the same throat size will be identical.
At all frequencies - I don't think so...
__________________
www.hornresp.net
  Reply With Quote
Old 18th September 2009, 09:20 AM   #502
Jmmlc is offline Jmmlc  France
R.I.P.
 
Join Date: Oct 2005
Hello David,

Anyone can be convinced of that looking at the classical graph on
fig. 2 in Bjørn Kolbrek's paper in AudioXpress.

http://www.audioxpress.com/magsdirx/...olbrek2884.pdf

and comparing the curves for the conical horn and an hyperbolic (e.g.).

This is for infinite horns therefore there is no reflexion at the mouth.

Best regards from Paris France

Jean-Michel Le Cléac'h
  Reply With Quote
Old 18th September 2009, 01:11 PM   #503
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
Quote:
Originally Posted by thend View Post
I dont know, maybe the "free air" Fs of this driver is above Fa anyway.
Above the Fa of this horn for sure! That is the interesting part to me.
Quote:
And a classical compression driver which can reproduce the 130hz without ditortions, I do not really believe.
It probably does not exist. Maybe one of the BMS coax or the old Altec 290 "Giant Voice", or something from ALE. But none are meant to work that low are they?
So it's going to be hard or impossible to match Fa & Fs if you want to play low with a compression driver. Easier for more typical horns sizes.
  Reply With Quote
Old 18th September 2009, 01:48 PM   #504
Jmmlc is offline Jmmlc  France
R.I.P.
 
Join Date: Oct 2005
Hello,

As you know I have no commercial interest in audio but I wanted to point out that my friend Marco Henry has completed a commercial version of a horn systems using 3 Le Cléac'h horns (one upper bass, one low-mid/mid and one mid-high/treble) .

Pictures of that new issue of the "Grande Castine" can be seen on Musique Concrete's website:
http://www.musique-concrete.com/MC/ENGalery.html

Below 80Hz the system is helped with a special subwoofer (not pictured) conceived by Marco Henry (from what I know it uses a large rectangular diaphragms and operates in dipole...)

The "Grande Castine" will be demonstrated soon in an Hifi shop in Paris. I'll let you know when it will be possible to listen to it and where.

The "Grande Castine" (without the subwoofer) uses 6dB/octave crossovers, it is time aligned and its efficiency is around 112 dB/1W/1m. The minimal listening distance is quite small (3 meters) and the sweet spot is large. The 3D image is fantastic. The coherence between the drivers is excellent. Marco told me that it is better to operates the "Grande Castine" inside an auditorium having minimum 50m² area.

Best regards from Paris, France

Jean-Michel Le Cléac'h

Last edited by Jmmlc; 18th September 2009 at 01:51 PM.
  Reply With Quote
Old 18th September 2009, 02:12 PM   #505
thend is offline thend  France
diyAudio Member
 
thend's Avatar
 
Join Date: May 2008
Anyway, Fs≥Fa is better than Fs<Fa for group delay, because it's the horn which introduce more distortions in time domain.
  Reply With Quote
Old 18th September 2009, 02:49 PM   #506
gedlee is offline gedlee  United States
diyAudio Member
 
Join Date: Dec 2004
Location: Novi, Michigan
Quote:
Originally Posted by David McBean View Post
At all frequencies - I don't think so...
David

Yes, of course, I should have said "above cutoff". At cutoff there is a mass load, but even this is nearly the same for all shapes with the same throat size (if they are infinite then there is no mouth size). It's the incorrect math from Webster that predicts large differences in the throat impedance for different horn shapes. I showed in the Audio Express article (the second part) how three different horn shapes with the same throat and mouth resulted in an almost idendical response (the differences were due to the different lengths required to get the same throat and mouth areas.) And I also showed how the OS when viewed through Websters approach yields the same answer(incorrect I should note) that is found for the Exponential Horn. In Websters approach it all comes down to wall angle, which is proportional to the Divergence, which is where the mass term comes from.

At any rate, all this arguing about loading is simply not important to me and this IS Jean-Michel's thread so I'll go away.
  Reply With Quote
Old 18th September 2009, 04:33 PM   #507
Jmmlc is offline Jmmlc  France
R.I.P.
 
Join Date: Oct 2005
Hello,

I don't know anyone silly enough to use in the mid a Le Cleac'h horn with a angle of aperture near throat similar to any known OS waveguide. As I said previously in that case such horn should only be used for a (supert)weeter.

Inversely I'll be interested in knowing any OS waveguide having an impedance curve similar to the AH425 or my J321... this simply doesn't exist!

Best regards from Paris, France

Jean-Michel Le Cléac'h


Quote:
Originally Posted by gedlee View Post
David

Yes, of course, I should have said "above cutoff". At cutoff there is a mass load, but even this is nearly the same for all shapes with the same throat size (if they are infinite then there is no mouth size). It's the incorrect math from Webster that predicts large differences in the throat impedance for different horn shapes. I showed in the Audio Express article (the second part) how three different horn shapes with the same throat and mouth resulted in an almost idendical response (the differences were due to the different lengths required to get the same throat and mouth areas.) And I also showed how the OS when viewed through Websters approach yields the same answer(incorrect I should note) that is found for the Exponential Horn. In Websters approach it all comes down to wall angle, which is proportional to the Divergence, which is where the mass term comes from.

At any rate, all this arguing about loading is simply not important to me and this IS Jean-Michel's thread so I'll go away.
  Reply With Quote
Old 18th September 2009, 05:10 PM   #508
soongsc is offline soongsc  Taiwan
diyAudio Member
 
soongsc's Avatar
 
Join Date: Mar 2005
Location: Taiwan
Quote:
Originally Posted by Jmmlc View Post
Hello,

I don't know anyone silly enough to use in the mid a Le Cleac'h horn with a angle of aperture near throat similar to any known OS waveguide. As I said previously in that case such horn should only be used for a (supert)weeter.

...
Best regards from Paris, France

Jean-Michel Le Cléac'h
I was actually going to try some simulations with this configuration using a 3" driver.
__________________
Hear the real thing!
  Reply With Quote
Old 19th September 2009, 01:17 AM   #509
tinitus is offline tinitus  Europe
diyAudio Moderator R.I.P.
 
Join Date: Nov 2005
I wonder whether showing the flaws of this and that waveguide, is it actually scaring people not to build anything
Sorry to say, but constantly seeking perfection is a dead end
That will never happen anyway
Research is very good, and some of the sims does seem very good
They are indeed very educational and informative
But building it is even better

I dont know, but there seem to be a constant battle about something I dont understand
Would be nice to join forces instead, to encourage people to just do it

Well, pictures by Jean-Michel is a great inspiration, thanks

Personallly, I will start with a couple of cheap waveguide, just to see if theres any point in it
Maybe modify them
Surely not perfect, but at least a try, and a step on the way

Its not WHAT you do, its HOW you do it
It wont get perfect, just better
Attached Images
File Type: jpeg horn.jpeg (89.8 KB, 679 views)

Last edited by tinitus; 19th September 2009 at 01:36 AM.
  Reply With Quote
Old 19th September 2009, 08:27 AM   #510
Jmmlc is offline Jmmlc  France
R.I.P.
 
Join Date: Oct 2005
Hello Tinitus,

Your philosophical words will surely be much appreciated by a large part of the DIYers community.

I participate(d) to many group project and to join forces around a given goal is surely something I consider very positively.

IMHO many discussion threads on DIYAUDIO can be considered as a kind of group project. In a group project technical choices has to be done at a given moment and it is quite normal that different options appear and that strong opposition between the proponents arise. This should not be considered as a fight between individuals even if the character of every of use differs from the other's one...

Best regards from Paris, France

Jean-Michel Le Cléac'h



Quote:
Originally Posted by tinitus View Post
They are indeed very educational and informative
But building it is even better

Would be nice to join forces instead, to encourage people to just do it

Its not WHAT you do, its HOW you do it
It wont get perfect, just better
  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



New To Site? Need Help?

All times are GMT. The time now is 08:38 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