Jean Michel on LeCleac'h horns

[GM]

Greets!

Wonder why I get a bit different combined response?

HR v2840.110427:

GM

 

[revintage]

I run masked, you don´t.

But all this is tricky as we can´t get Combined together with On/off-axis. Anyone have a clue?

 

[GM]

Don't know, can it be done in AkAbak?

OK, so in my haste, what am I missing this time around? All my sims that apply are 'masked' AFAIK.

GM

 

[David McBean]

OK, so in my haste, what am I missing this time around? All my sims that apply are 'masked' AFAIK.

Hi GM,

The Hornresp combined response is always calculated 'unmasked', even though the user may have the 'masked' option selected. You can check this for yourself by comparing the combined response with the 'masked' option selected against the combined response with the 'unmasked' option selected. The results will be the same. This is why the masking option is not shown on the combined response chart - it could be confusing.

Incidentally, I get the same combined response result as you do .

Kind regards,

David

 

[revintage]

GM, you ran it unmasked after all.

Changing Lrc to 15cm makes everything look good again. But how do we arrange this in a box 50cm deep?

 

[Jmmlc]

Hello Revintage,

Eventually, just for the fun, you can try the driver + attached horn unbaffled in a corner.

You'll have to use a 8 to 10 series resistor.

Hornresp record and screen copy here attached (pathlength = 50cm for combined response).

Best regards from Paris, France

Jean-Michel Le Cléac'h


Best

Also did a Hornresp sim with "Le Petite Onken"/Altec414-8A in combination with a 200Hz JMLC. Had to adjust BR area to 1/4th of the original.

The problem is that the frequency-response sims look to good to be true. Any comments on that?

 

[revintage]

Hello Jean-Michel,

What you show looks great wrt frequency response. Sensitivity isn´t good though. My idea was to have higher sensitivity on the whole system than the driver itself in a BR where, refering to Hornresp, 414 is around 100dB with Rg=2ohm. The hornreflex is well over 105dB.

 

[revintage]

I simmed the Onken/Le'Cleach-horn against a closed box of the same volume(155dm3) and that one looked even better with F-3dB at 30Hz compared to BR F-3dB at 35Hz! Lowering the closed box volume to 100dm3, still gave us a F-3dB of 35Hz.

Looks like an interesting combination, if it works IRL?

It´s hard to find drivers in the same style as 414, high VAS, low Qts and low Mms, but with the help of Jack J. we have gone through a lot of European drivers and have found a "not to expensive" one that looks interesting.

 

[Jmmlc]

Hello Revintage,

Why do you want a low Qts loudspeaker if you use a bass-reflex (for loudspeakers used in bass-reflex, optimal balues of Qts are around 0.39).

Best regards from Paris, France

Jean-Michel Le Cléac'h

I simmed the Onken/Le'Cleach-horn against a closed box of the same volume(155dm3) and that one looked even better with F-3dB at 30Hz compared to BR F-3dB at 35Hz! Lowering the closed box volume to 100dm3, still gave us a F-3dB of 35Hz.

Looks like an interesting combination, if it works IRL?

It´s hard to find drivers in the same style as 414, high VAS, low Qts and low Mms, but with the help of Jack J. we have gone through a lot of European drivers and have found a "not to expensive" one that looks interesting.

 

[revintage]

Why do you want a low Qts loudspeaker

Hello Jean-Michel,

Just because I love the sound of the "Onken" and "Petite Onken". Both 416 and 414 has the qualities I mentioned earlier. So my wishes has no scientific background.

Probably other criterias is needed here. Do you have any suggestions on driver suitable for this type of design? It would be nice to be able to use "modern" drivers.

 

[jamikl]

If it is OK with jmmlc could somebody email me the two files that were posted in messages 1018 and 1019. I missed them.
jamikl

 

[revintage]

Found this at ETF2010:

http://forums.melaudia.net/attachment.php?aid=1760

 

[revintage]

Hello,
Seems like the nice-looking sims are depending on full Le'Cleach. 90 degrees is shown in black.

 

[IslandPink]

Hmmm

This is an interesting result Lars , but it surprises me .
If I just sim a Fane studio 8M front loaded with a 120Hz LeClea'ch ( t=0.8 ) and I run the sim for full mouth ( ~ 11500cm2 ) and truncated at 3500cm2 , then I get the following two graphs ( superimposed ).
Yes there are two plots there.
The full mouth has a little less ripple, that's all .

It seems odd you'd get big differences at an even lower frequency .

 

[revintage]

Hey,

Your result is as the Fane driver doesn´t have anything at the lowend. Instead it will go quite high.

See Jean-Michels answer in the Hornresp thread earlier today about the principle.

I guess your aim is to build a 3-way system. The idea with my design is to find out if a 2-way system is possible. If we cross at let´s say 600Hz with an Iwata JMLC-350 or a JMLC-400 and a good 1" driver, it should be possible.

This a design idea. Will not build it, as I am at the moment building a compact midbass with same concept.

 

[GM]

The Hornresp combined response is always calculated 'unmasked'...........

Greets!

OK, thanks, I must have missed/forgotten this in the HELP files. Still, I can't quite duplicate this combined plot from his input parameters or even with the shortened 15 cm Lrc [attached], so still not seeing the 'forest for the trees': http://www.diyaudio.com/forums/atta...3757t-jean-michel-lecleach-horns-onkleccr.png

GM

 

[GM]

GM, you ran it unmasked after all.

Changing Lrc to 15cm makes everything look good again. But how do we arrange this in a box 50cm deep?

OK, how are you running it masked then? I mean I can't seem to get your smoothness combined with a 20 Hz dip using your posted parameters.

The cab is existing? If so, then seems like the horn has to either mount on the rear to allow a recessed blank baffle/rear cover the way HR sims it or the horn has to fit a recessed baffle from the front with any surrounding airspace filled with a suitably massive material. FWIW, I use kitty litter/oil dry as an acceptable mass/damping/weight trade-off to the more commonly used sterilized sand, Portland cement.

GM

 

[revintage]

Hey GM,

Looks good enough. But it´s more realistc with 20-50cm path. The system will not be useful above 0,8-1,0kHz anyway due to driver mass-corner.

One should see it as a very compact bass+midbass system.

Also run it Vrc=100 with Ap1=556/Lpt=2,2

 

[IslandPink]

Further

OK Lars
I understood what you were trying to do, but I had just grabbed what I had to try a quick sim .
I read Jean-Michel's post as you suggest, and so I went further with the Fane on LeCleac'h .
This is very educational . Certainly if you increase the mouth to the full extent and use bigger back-volume and some series resistance, then it's possible to extend the Fane response down to 70-80Hz.
Very interesting .
Shame I can't accommodate 11500cm^2 !!

 

[David McBean]

Hi GM,

I must have missed/forgotten this in the HELP files.

You didn't miss or forget anything - it's not documented in the Hornresp Help file . I didn't think it needed including because there is nothing that the user can do about it anyway...

Still, I can't quite duplicate this combined plot from his input parameters or even with the shortened 15 cm Lrc.

Me neither - I get the same result as you. The SPL responses posted by Lars must have been generated using values slightly different to those shown on his original Input Parameters window screenprint (changing Lrc to 15 cm is obviously only part of the story).

Kind regards,

David