Different speaker request

Hi,

I'm designing a system, where i need an ultrasonic speaker, range 30Khz - 80Khz. I have tried some piezo elements, but found they have horrible ringing which makes them unsuitable.

I just noticed that there are som audio speakers with spec up to 80KHz. Does anyone know a source of cheap tweeters (or an alternative) that we can use in that range?

Forgive me for posting off-topic, but in all honesty, who knows this things better than the audio people?

Thanks in advance,
Mike
 
Hi,

Such an audio driver is essentially pointless which is why they don't exist.

Why do you need 30KHz to 80KHz ? What on earth for ?

If there was a practical application for such devices they would exist.

rgds, sreten.

Plasma tweeters are probably you best line of research.
Generation of ozone seemed to be the main problem.
 
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I have been able to measure my little ESL's up to the 30Khz to 50Khz.

I have used them to get the next door nieghbors Dogs attention when they decide to bark all day long !!!!
It worked too!!! :)

I think that they will go higher than that, but my measurement mic's don't go very much higher making it difficult to detect the signal even with my scope.
Also the Frequency Response of my driving amp had a lot to do with it as well.

FWIW

jer :)
 
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Hi,

Such an audio driver is essentially pointless which is why they don't exist.

Why do you need 30KHz to 80KHz ? What on earth for ?

If there was a practical application for such devices they would exist.

rgds, sreten.

Plasma tweeters are probably you best line of research.
Generation of ozone seemed to be the main problem.

A 3D motion sensor, in essence. I've looked at plasma tweeters, but that is too expensive.


Thanks for the link, a bit pricy for our purposes though.

Plasma speaker is a suitable and reliable solution, the other is a SuperTweeter from Pioneer TAD or a Fostex T500 or T90a alnico one.

Thanks, interesting that they could build alnico with that wide range.

Can we get an ESL response up to 80KHz?

I imagine the main issue is the transformer, but with direct drive and a very small diaphragm this might be possible.

I'm sure that would work, but very expensive.

I ended up ordering a pair of NeoCD 3 (Products_Fountek Electronics Co.,Ltd). They claim a pretty straight response up to 40KHz, remains to see what happens higher up.
 
For our prototype board (which is a daughter board on a fpga board) i designed this power amp for driving each ribbon tweeter. We only have a single 12V rail, so i needed something that can drive almost rail to rail with low distortion up to 2MHz (-1dB). I came up with this after some experimentation. Over 4Ω, THD @ 9Vp-p is 0.02% and @ 10Vp-p about 0.2%, which should be ok. Biased at about 20mA.

Any constructive criticism of the design is most welcome, in particular simplifications.
 

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I have been able to measure my little ESL's up to the 30Khz to 50Khz.

I have used them to get the next door nieghbors Dogs attention when they decide to bark all day long !!!!
It worked too!!! :)

I think that they will go higher than that, but my measurement mic's don't go very much higher making it difficult to detect the signal even with my scope.
Also the Frequency Response of my driving amp had a lot to do with it as well.

FWIW

jer :)

Hahaha, thanks for the idea about the neighbours dogs! Where i live it's a problem. I will try to get their attention too :D
 
A small ESL driver can be made for just a few bucks.
And an amp for just a few bucks too using a dual opamp and a pair (or two) of HV FET's.

Here is a design that I used at 180V to drive a piezo driver when I made it, It was intended to drive my ESL's but I didn't have them running at the time.

The First Two pictures in the post were my working versions and the rest were some variations I was working on in Circuitmaker2000.

The third I may or may not have built, I think that I did adopt the triple stacked FET configuration into the frist schematic and it worked as well.

http://www.diyaudio.com/forums/head...discrete-class-headphone-amp.html#post2596223

The schematic worked with every FET that I had laying around with just a simple adjustment to center the output voltage at V/2.

I haven't got around to working on it some more since I had burned up my pair of load resistors at the time.
Since then I have learned how to replace them with FET's as current sources as shown in the rest of the pictures.

Basically it is like the Neil S. McKean's ESL Amplifier, Stax uses this same configuration for thier Solid State ESL headphone amp design.

Do It Yourself - Electrostatic Speakers - Project: ESL H.V. Amp by Neil S. Mckean

The Stax Design is here,

http://www.diyaudio.com/forums/plan...trostatic-headphone-driver-2.html#post3371857

Very simple and inexpensvie to build with great results.

Depending on how loud you want the thing, it will depend on how much bias you can achieve on your driver considering a 200v to 1000v peak to peak driving signal.

In the ultrasonic range I am sure that it will be quite a high db SPL!

Cheers !!!

jer :)

P.S. Edited, Becuase I forgot a link. :)
 
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Here is an example of my Micro ESL that I made out of some PCB boards and a couple of Credit cards,

http://www.diyaudio.com/forums/planars-exotics/158115-material-esl-2.html#post2076459

http://www.diyaudio.com/forums/planars-exotics/158115-material-esl-2.html#post2074212

This post has a slight description of it,

http://www.diyaudio.com/forums/plan...ectrostatic-headphone-driver.html#post3364252

Although I never did test it with more than 500v of bias, it was insulated enough to go higher.

I ended up tearing it apart the make the photos instead and I never did put it back together, it is still around here somewhere. ;)

As a Headphone driver it did sound great!!

jer :)
 
A small ESL driver can be made for just a few bucks.
And an amp for just a few bucks too using a dual opamp and a pair (or two) of HV FET's.

Here is a design that I used at 180V to drive a piezo driver when I made it, It was intended to drive my ESL's but I didn't have them running at the time.

The First Two pictures in the post were my working versions and the rest were some variations I was working on in Circuitmaker2000.

The third I may or may not have built, I think that I did adopt the triple stacked FET configuration into the frist schematic and it worked as well.

http://www.diyaudio.com/forums/head...discrete-class-headphone-amp.html#post2596223

The schematic worked with every FET that I had laying around with just a simple adjustment to center the output voltage at V/2.

I haven't got around to working on it some more since I had burned up my pair of load resistors at the time.
Since then I have learned how to replace them with FET's as current sources as shown in the rest of the pictures.

Basically it is like the Neil S. McKean's ESL Amplifier, Stax uses this same configuration for thier Solid State ESL headphone amp design.

Do It Yourself - Electrostatic Speakers - Project: ESL H.V. Amp by Neil S. Mckean

The Stax Design is here,

http://www.diyaudio.com/forums/plan...trostatic-headphone-driver-2.html#post3371857

Very simple and inexpensvie to build with great results.

Depending on how loud you want the thing, it will depend on how much bias you can achieve on your driver considering a 200v to 1000v peak to peak driving signal.

In the ultrasonic range I am sure that it will be quite a high db SPL!

Cheers !!!

jer :)

P.S. Edited, Becuase I forgot a link. :)

Hee gerald are these headphone amps capable of driving a small transformer like say 1:40 ?