Jean Michel on LeCleac'h horns

[Jmmlc]

Hello Angelo,

You asked a lot of questions and I prefer to reply one after the other.

The large horn system on homepage of the Melaudia association :
http://www.melaudia.net/zimage/pavFD-533x400.jpg doesn't belong to me but to a friend. I still have not listened to this horn but shall during the weekend of March 28th and 29th because Melaudia organize a public demonstration of that system (well the bass reflex will be different, the Onken W enclosure will be used).

Best regards from Paris, France

Jean-Michel Le Cléac'h

Originally posted by angeloitacare
does it make sense to use such a big horn as the last pictures shown of melaudia homepage, with the Radian 950pb, if its Fs is 500hz ? have you heard this system ?

[sqlkev]

Originally posted by Jmmlc
Hello sqlkev,

That's probably due to the thrill in my spine when I listen to such good drivers as Onken, Goto, Western Electric... I never experienced such with cone drivers mounted on horns, even if some of them were very good sounding compared to 90% of the commercial stuff

The resonance frequency (mounted on the horn it may differ than the one mesured on planar wave tube) plays a role for sure in the sound. Generally I try to avoid the resonance frequency to be in the middle of the useful bandwith of the horn

The Goto and the WE possess low resonance frequency, may be that's one of the reasons why I liked them so much.

Best regards from Paris, France

Jean-Michel Le Cléac'h

Jean-Michel,
I guess i've been looking at the wrong places when it comes to compression drivers then.

Those highend drivers you've mentioned are out of reach for me, so i'll have to go with cone drivers for the lowend instead.


How do you feel about loading a dome midrange for a midrange unit? The fs should be around 400hz right where i want it.

do i model it the same as a compression unit using the measured T/S from a regular baffle?

thanks again for your contribution

Kev

[Jmmlc]

Hello sqlkev,

Low mid compression drivers are rare and expensive at the moment.

Most 2inches compression drivers from JBL, TAD, etc... don't give good results when loaded by a low-mid horn. If you want to use a compression driver that you can use in the low-mid (at the exepense of a lowered max power), you have to choose one with the diaphragm using a non metallic suspension (with the exception of exotic suspension as in the JA6681B). Friends of mine obtained good results with Radian compression drivers (or even with JBL 2inches drivers and a Radian diaphragm).

If you want to initiate yourself to low-mid compression drivers on horns there is a very cheap solution (but the results are surprisingly good for the price!), try this:

http://www.skytronic.co.uk/product/index.php?s=952.207

I am not very familiar with dome midrange even if 15 years ago I used to play with a Dynaudio loudspeaker which was excellent.

If you limit its use to above 1kHz this loudspeaker recommanded by Helmuth seems promising (very good waterfall).

http://www.diyaudio.com/forums/showt...95#post1774395

Yes you can use T&S parameters of your loudspeaker to simulate the horn (in Hornresp, Akabak, J Horn...) .

Best regards from Paris, France

Jean-Michel Le Cléac'h

Originally posted by sqlkev

Jean-Michel,
I guess i've been looking at the wrong places when it comes to compression drivers then.

Those highend drivers you've mentioned are out of reach for me, so i'll have to go with cone drivers for the lowend instead.


How do you feel about loading a dome midrange for a midrange unit? The fs should be around 400hz right where i want it.

do i model it the same as a compression unit using the measured T/S from a regular baffle?

thanks again for your contribution

Kev

[Wayne Parham]

A few posts back, you were talking about the power factor or reactivity/resistance ratio of horns. We had a lot of discussions about that on AudioRoundTable.com a few years back, mostly about how it appeared in truncated horns like basshorns but also how it appeared in every horn to a greater or lesser extent, depending on acoustic size, flare features and boundary conditions.

In the post below, there are a couple dozen links to references around the internet with very useful information, which I think you'll find germane to this discussion and also to acoustic waveguide discussions. Pipe mode and Helmholtz resonance, directivity, evanescent modes and wavefront propogation are referenced there.

• Pipes, tapered pipes and Helmholtz resonators

[j.michael droke]

Hi there tinitus: Out of sight, cool audio set-up with the below the stage horn. Could you comment on your preception of the sound and provide some details for this horn?

[Pano]

Originally posted by Jmmlc
... a very cheap solution (but the results are surprisingly good for the price!), try this:http://www.skytronic.co.uk/product/index.php?s=952.207

Funny! I often see these type of drivers in US catalogs, usually with a 70V transformer. None of them are as pretty as the Skytronic, tho. Have always wondered how they sound.

[Jmmlc]

Hello Wayne,

Thanks for the pointed list of links, it is interesting to have such compilations.

I used to read few disscussions on your website but not that one.

Bass horns are good examples to illustrate the "tuned pipe" effect of truncated horns. I am aware of that and that's why I recommand bass horns as in the attached file.

These are few examples:

http://img383.imageshack.us/my.php?i...280x768ac0.jpg

http://www.diyaudio.com/forums/attac...amp=1236807427

(The best bass I could listen to was delivered by that "Le Cleac'h" bass horn built by my friend Frédéric Lebas)

Those 2 examples will still show some diffraction due to the upper edge of the mouth but that one

http://ndaviden.club.fr/pavillon/exemples/front.jpg
will have less due to its height quasi equal to the height of the room.

One advantage of using the total width of a room for building such horns is that the quasi cylindrical wavefronts can develop gently very far from the throat (see attached graph). The amount of reflected energy as I could see on pulse measurement of the second horn is low.

Best regards from Paris, France

Jean-Michel Le Cléac'h

Originally posted by Wayne Parham
A few posts back, you were talking about the power factor or reactivity/resistance ratio of horns. We had a lot of discussions about that on AudioRoundTable.com a few years back, mostly about how it appeared in truncated horns like basshorns but also how it appeared in every horn to a greater or lesser extent, depending on acoustic size, flare features and boundary conditions.

In the post below, there are a couple dozen links to references around the internet with very useful information, which I think you'll find germane to this discussion and also to acoustic waveguide discussions. Pipe mode and Helmholtz resonance, directivity, evanescent modes and wavefront propogation are referenced there.

• Pipes, tapered pipes and Helmholtz resonators

[Pano]

Speaking of impedance in horns, here is a graph just for fun. My measurement of the same 1" compression driver with 3 different loads.

Magenta line is the driver unloaded (no horn)
Green line is a homemade roound Tractrix horn. Mouth diameter ~10"
Blue line is the same driver on an Altec 811b horn. Note the midband ripple.

I couldn't seem to find it, but I did have a measurement of the 811 horn with a roll-over added to the mouth. It was smoother.

[Wayne Parham]

I did not mention before to scan through the other posts in the thread on ART for more links, but do. In particular, see the ones about the Acoustical Klein-Gordon Equation, Benade's papers on musical instrument acoustics and the original "Basshorn or Transmission Line" post that compares a basshorn with a tuned pipe. It shows (resistive/reactive) impedance and amplitude response using a Hornresp simulation of a typical basshorn.

[soongsc]

Originally posted by Jmmlc
.
...
http://ndaviden.club.fr/pavillon/exemples/front.jpg
will have less due to its height quasi equal to the height of the room.

...
Best regards from Paris, France

Jean-Michel Le Cléac'h

This configuration looks particularly interesting. The spreadsheet would probably need modification to do this calculation.