Hello,
Few of you may ask why I use my TAD TD2001 current driven.
First they should analyse the attached pulse response obtained at the same moment, in the very same conditions as for the pulse response of the current driven TD2001 on J321 horn. I just uses for that mesurement an amplifier with a very very low output impedance (a Bryston PP120). The level was set at 94dB at 1000Hz. Measurement is still made at 1 meter.
Attached file: pulse response of the TAD TD2001 voltage driven on Musique Concrète J321 horn (Fs = 48kHz, 16 bits)
Best regards from Paris, France
Jean-Michel Le Cléac'h
Few of you may ask why I use my TAD TD2001 current driven.
First they should analyse the attached pulse response obtained at the same moment, in the very same conditions as for the pulse response of the current driven TD2001 on J321 horn. I just uses for that mesurement an amplifier with a very very low output impedance (a Bryston PP120). The level was set at 94dB at 1000Hz. Measurement is still made at 1 meter.
Attached file: pulse response of the TAD TD2001 voltage driven on Musique Concrète J321 horn (Fs = 48kHz, 16 bits)
Best regards from Paris, France
Jean-Michel Le Cléac'h
Jmmlc said:
Hello,
The Le Cléac'h horn is not a device designed to control directivity but to insure the best resistive load to a loudspeaker within a very large interval of frequency. No equalization is needed for a good loudspeaker if used with a Le Cléac'h horn.
Many audiophile use Le Cléac'h horns having low frequency cut off as small as 160Hz, 250 or 320Hz in 2 ways system (eventually some equalization above 4000Hz may help). But if you want to retain the best resistive loading as a factor of quality (many do despite what is often said here) and if a low directivity or a controlled directivity is very important for you, you have 2 solutions:
- don't use a ( single ) Le Cléac'h horn
- use several Le Cléac'h horns (low-mid/mid + high-mid/highs...)
Attached file:
polar chart measured by me on a Le Cléac'h horn Fc = 320Hz
+ simulation under Hornresp and compared simulation for an equalized waveguide of same dimensions.
Note that below 6000Hz the Le Cléac'h 320Hz horn spreads the sound over an equal or larger angle than the OS waveguide and over 6000Hz it spreads the sound over a smaller angle than the OS waveguide (well this is using -3dB points for what it worth).
Best regards from Paris, France
Jean-Michel Le Cléac'h
The Le Cléac'h horn is not a device designed to control directivity but to insure the best resistive load to a loudspeaker within a very large interval of frequency. No equalization is needed for a good loudspeaker if used with a Le Cléac'h horn.
Many audiophile use Le Cléac'h horns having low frequency cut off as small as 160Hz, 250 or 320Hz in 2 ways system (eventually some equalization above 4000Hz may help). But if you want to retain the best resistive loading as a factor of quality (many do despite what is often said here) and if a low directivity or a controlled directivity is very important for you, you have 2 solutions:
- don't use a ( single ) Le Cléac'h horn
- use several Le Cléac'h horns (low-mid/mid + high-mid/highs...)
Attached file:
polar chart measured by me on a Le Cléac'h horn Fc = 320Hz
+ simulation under Hornresp and compared simulation for an equalized waveguide of same dimensions.
Note that below 6000Hz the Le Cléac'h 320Hz horn spreads the sound over an equal or larger angle than the OS waveguide and over 6000Hz it spreads the sound over a smaller angle than the OS waveguide (well this is using -3dB points for what it worth).
Best regards from Paris, France
Jean-Michel Le Cléac'h
JoshK said:
Attachments
Jmmlc said:
So basically any comparison between the Leclech horn and my waveguide is rather pointless because they are designed to do completely different things. One is clearly Constant directivity and the other isn't - intentionally so, as you say.
The the real discussion then should be whether constant directvity is desirable or not. I would have thought this discussion to have been resolved already.
Hello,
First you have to calculate the horn using the spreadsheet you can download here:
http://ndaviden.club.fr/outils/axial.zip
Then enter the throat diameter, cut-off frequency, the T value (generally 0.7 or 0.8)...
If you want to turn mechanically the horn or a mold then you have to use the calculated "profile".
If you want to build the horn by "petals" like a gramophone horn, you have to enter the number of "petals", the spreadsheet will then calculate the coordinates of the points to report on a planar sheet of plywood (or whatever material). Then you'll have to cut the petals and to fix one petal to the other gluing a common edge (for this you need to curve the petals acccording to the calculated profile).
Martin Seddon's website http://www.azurahorn.com/azurahorn_tradesecrets.html
can be helpful
Marc Henry and Vincent Brient's websites too:
http://www.musique-concrete.com/Emat.htm
http://vincent.brient.free.fr/round_horns.htm
Best regards from Paris, France
Jean-Michel Le Cléac'h
First you have to calculate the horn using the spreadsheet you can download here:
http://ndaviden.club.fr/outils/axial.zip
Then enter the throat diameter, cut-off frequency, the T value (generally 0.7 or 0.8)...
If you want to turn mechanically the horn or a mold then you have to use the calculated "profile".
If you want to build the horn by "petals" like a gramophone horn, you have to enter the number of "petals", the spreadsheet will then calculate the coordinates of the points to report on a planar sheet of plywood (or whatever material). Then you'll have to cut the petals and to fix one petal to the other gluing a common edge (for this you need to curve the petals acccording to the calculated profile).
Martin Seddon's website http://www.azurahorn.com/azurahorn_tradesecrets.html
can be helpful
Marc Henry and Vincent Brient's websites too:
http://www.musique-concrete.com/Emat.htm
http://vincent.brient.free.fr/round_horns.htm
Best regards from Paris, France
Jean-Michel Le Cléac'h
tinitus said:
Hello Earl,
Constant directivty should be desirable if we could maintain it over a very large interval of frequency.
For the moment, according to your own words, practically, waveguides cannot be used for that below 800Hz.
IMHO it should be most interesting to do it over 200Hz... (May be Bessel loudspeakers arrays can do it...)
Best regards from Paris, France
Jean-Michel Le Cléac'h
Constant directivty should be desirable if we could maintain it over a very large interval of frequency.
For the moment, according to your own words, practically, waveguides cannot be used for that below 800Hz.
IMHO it should be most interesting to do it over 200Hz... (May be Bessel loudspeakers arrays can do it...)
Best regards from Paris, France
Jean-Michel Le Cléac'h
gedlee said:
"Do the Le Cléac'h horns beam? Do you have any polar response charts anywhere?"
From the posted DI plots yes they do. You can't get flat on axis response using a compression drivers without EQ. You can use electrical EQ or use the DI from the horn. To me electrcal is the way to go with a CD type horn/waveguide. That way you get good power response and a much larger and more consistant listening widow. Less than 30 degrees for -6db points is tight. That is one small widow.
Rob 🙂
From the posted DI plots yes they do. You can't get flat on axis response using a compression drivers without EQ. You can use electrical EQ or use the DI from the horn. To me electrcal is the way to go with a CD type horn/waveguide. That way you get good power response and a much larger and more consistant listening widow. Less than 30 degrees for -6db points is tight. That is one small widow.
Rob 🙂
Jmmlc said:
You are misquoting me. I said that I didn't see any point in controling directivity in a waveguide below 800 Hz, so I don't. I never said that it couldn't be done, because it can.
Clearly your device doesn't have constant directivity for any interval of frequency. Mine works great within the frequency range that it was designed to work.
Can you show the phase with that gate setting?jzagaja said:
What software do you use to generate these plots?
Huh!!?
I figured out three ways to make an OS waveguide and I'm a mechanical ignoramus. 😀
OS waveguides are public domain.
If you look through the last dozen pages of the Geddes on Waveguides thread you can certainly see how to make one.
There's no mystery. 😉
Making a really good one might be difficult.
I figured out three ways to make an OS waveguide and I'm a mechanical ignoramus. 😀
OS waveguides are public domain.
If you look through the last dozen pages of the Geddes on Waveguides thread you can certainly see how to make one.
There's no mystery. 😉
Making a really good one might be difficult.
Jmmlc said:
Yes. I've done this and works pretty well. A lot of work, tho! But maybe less than wood or plaster.
I made a pair of Tractrix horns from cotton - 100%. (Well, almost)
The material was papier-maché from hi quality French watercolor paper. Arches brand. Very heavy, very stiff. 100% cotton rag.
Wall paper paste (wheat paste) was used to hold it all together.
They are very, very ugly, but it was my 1st try. 😛 Sure sound good. I may try a Le Cléac'h horn next. The tractrix do beam a bit, Jean-Michel's horn looks better.
I think the discusson is getting a bit out of context.
I mean there are plenty of PA cd horns that measure nice and have a great power response but they are not for hifi use for a lot of reasons Earl and Jean-Michel have discussed andf I refer to this as the JBL mentality of marketing CD horns.
Power response does not have to be a perfect curve but a smooth and constant response over a defined listening window in horizontal and vertical planes.
People do not way enough attention to the vertical axis imho. It is much more difficult to design a good crossover transition if the vertical and horizontal off axis response is not smooth at least 1 octave either side of the crossover point.
And dont expect a single horn to do the entire range.
I think broad listening position windows are a bit of a myth and thas has more to do with loudspeaker positioning and the recording techniques then anything else
Perhaps more important are early reflections, low distortion and a controlled coverage for internal domestic use and low Homs as Earl points out.
I am sure either Earl's or Jean-Michel's designs work well if correctly implemented for diy use.
I mean there are plenty of PA cd horns that measure nice and have a great power response but they are not for hifi use for a lot of reasons Earl and Jean-Michel have discussed andf I refer to this as the JBL mentality of marketing CD horns.
Power response does not have to be a perfect curve but a smooth and constant response over a defined listening window in horizontal and vertical planes.
People do not way enough attention to the vertical axis imho. It is much more difficult to design a good crossover transition if the vertical and horizontal off axis response is not smooth at least 1 octave either side of the crossover point.
And dont expect a single horn to do the entire range.
I think broad listening position windows are a bit of a myth and thas has more to do with loudspeaker positioning and the recording techniques then anything else
Perhaps more important are early reflections, low distortion and a controlled coverage for internal domestic use and low Homs as Earl points out.
I am sure either Earl's or Jean-Michel's designs work well if correctly implemented for diy use.
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