Horn-loading Ribbon Tweeter?

[Paul W]

LineSource,
I've been interested in ribbons for a long time but, generally, very little interest in horns.

You seem to have very specific ideas about the application of waveguides to true ribbons. What is your definition of a "shallow" horn (in terms of wavelength)? What is a "wide radius"...conical, exponential, other???

Which Geddes paper do you recommend? I'm interested enough to buy one...just one for now.
Thanks,
Paul

[kelticwizard]

I am having some troouble with my Hotmail Email box, the one diyAudio uses. It tends to fill up and cut off incoming Emails.

I have received a couple of requests already for Merhaut's Horn Loaded Electrostatic Loudspeaker article. For those who might have sent a request and had my email service reject it, please comment here in this thread and I will try to contact you.

[mac]

These look interesting.



http://www.e-speakers.com/products/lcy-components.html

[rcavictim]

Mac,

Yes those do look interesting I wonder why they put a horn of radial symmetry on a rectangular source however. There has to be some mismatch here. I would have expected a smooth transition section. A "morphing transition"! That's my new patented name guys!

[mefistofelez]

As I am reading your suggestions, I realized that my subject line was purely worded. What I am after is pattern control, and not so much increased efficiency from horn loading.

So, here are the two questions I should have asked:

1. can one "force" the sound to follow the horn countour without undue disturbance of the sound wave; and

2. what ribbon tweeter could be used given the (as I understand) high pressure in the throat?

Thank you,

M

[bear]

Originally posted by mefistofelez
As I am reading your suggestions, I realized that my subject line was purely worded. What I am after is pattern control, and not so much increased efficiency from horn loading.

So, here are the two questions I should have asked:

1. can one "force" the sound to follow the horn countour without undue disturbance of the sound wave; and

Not exactly... what ur interested in is more the wave launch from the horn with respect to frequency... again as you go higher in freq the horn has less of an effect and the driver tends to "not see" a horn and act like a direct radiator...

Thus the advanced "wave guide" designs like Dr. Geddes which are intended to control that aspect over the loading and efficiency aspects...

2. what ribbon tweeter could be used given the (as I understand) high pressure in the throat?

imho, none.

All the ribbon tweeters that I have seen loaded into horns are "loosely" loaded... not tightly coupled at all... so the pressure in the throat is limited quite a bit compared to the compression driver set up... nothing wrong with this. So you can use any ribbon you like, pretty much.[/quote]

Thank you,

M

_-_-bear

[bear]

Originally posted by mac
These look interesting.



http://www.e-speakers.com/products/lcy-components.html

To my eye these look really bad, with a sharp hard transistion from what appears to be a short parallel wall area between the ribbon and the "horn". Major diffraction going on here.

Also, the ribbon design itself appears to be a copy of a recently patented (sic) ribbon that uses this slit down the center of the ribbon itself. This design was discussed in the thread here in the ESL/Ribbon area quite recently... wonder if it is a rip-off or if it is licensed?

who knows, maybe these are just great...

_-_-bear

[mefistofelez]

Dear Bear,

I have an impression that we are miscommunicationg, arguably due to my inability to express myself.

Not exactly... what ur interested in is more the wave launch from the horn with respect to frequency... again as you go higher in freq the horn has less of an effect and the driver tends to "not see" a horn and act like a direct radiator...

Are you referring to the fact that the driver's dispersion pattern changes (narrows) with increasing frequency?

I am aware of that, but at a certain point, the driver's dispersion pattern will be equal to or greater than the angle of the horn/waveguide attached at that frequency. What will happen?

If the above is misinterpretation of your thoughts, please correct me.

All the ribbon tweeters that I have seen loaded into horns are "loosely" loaded... not tightly coupled at all... so the pressure in the throat is limited quite a bit compared to the compression driver set up... nothing wrong with this. So you can use any ribbon you like, pretty much

Correct me if I am wrong, but it is my understanding that the horn expansion controls the compression (loading). As such, one should be able to adjust the amount of loading by the (inital) shape of the horn, correct? If so, how?

Thus the advanced "wave guide" designs like Dr. Geddes which are intended to control that aspect over the loading and efficiency aspects...

Well, I have read his papers. And although he appears to be concerned with the matching of the diriver's characteristics to the waveguide, in my final analysis, he gives essentially "one formula fits all" interface between the driver and the oblate spheroid horn contour, and I am unable to discren, how he "control[s] that aspect over the loading and efficiency aspects." Could you point me to the right equation/direction?

Thank you,

M