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HPM Tweeter from Pioneer HPM-100?

post #1 of 8
9/17/11 at 9:39pm
Thread Starter 

I read that this tweeter has no voice coil or moving parts or anything. Then how does it make sound without moving??? confused.gif

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post #2 of 8
9/17/11 at 10:50pm

The diaphragm (semi circle arch under the mesh screen) is both the voice coil and the driver material combined. It's like a hybrid of a ribbon type and planar magnetic IIRC. It's a cool design but it's only used at the upper end of the freq range ( likely from 4-6Khz and up) much like a super tweeter. The HPM 100 has a conventional cone tweeter as well as the "super tweeter". It's a 4 way speaker from what I can recall.

 

Peete.


Edited by Pricklely Peete - 9/17/11 at 10:51pm
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post #3 of 8
9/17/11 at 11:09pm
Thread Starter 

Thanks for the info, Peete. Now, does this diaphragm move? If not, how is it possible for it to make sound? Wikipedia says it doesn't move at all on the HPM-100 page.

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post #4 of 8
9/17/11 at 11:30pm
Quote:
Originally Posted by jtaylor991 View Post

Thanks for the info, Peete. Now, does this diaphragm move? If not, how is it possible for it to make sound? Wikipedia says it doesn't move at all on the HPM-100 page.



It likely moves a very small amount....the magnet assembly is part of the driver housing but I'm unsure of it's edge mounted horizontally or vertically. Of course I could be totally wrong ....at any rate to recreate high freq sounds there is very little movement of the driver that can be observed (if any at all). I have a set of ET LFT VIIIb's  which have a large super tweeter crossed over at 10Khz (extending to 45 Khz) and it does not move at all even at high volumes.

 

If you want to check something out that is really cool look up plasma tweeters on you tube.

 

Peete.


Edited by Pricklely Peete - 9/17/11 at 11:32pm
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post #5 of 8
9/18/11 at 12:02pm
Thread Starter 

I didn't mean visibly moving, just moving at all, seen or not. I don't think one should be able to ever see a tweeter move anyway if it is playing the correct frequencies a tweeter should be playing. But I hope you now see what I mean. It doesn't scientifically possible for the thing to make sound without moving at all, visibly or not, and I wanted to first know if it actually does move or not, and if not, how does it make sound.
 

Quote:
Originally Posted by Pricklely Peete View Post





It likely moves a very small amount....the magnet assembly is part of the driver housing but I'm unsure of it's edge mounted horizontally or vertically. Of course I could be totally wrong ....at any rate to recreate high freq sounds there is very little movement of the driver that can be observed (if any at all). I have a set of ET LFT VIIIb's  which have a large super tweeter crossed over at 10Khz (extending to 45 Khz) and it does not move at all even at high volumes.

 

If you want to check something out that is really cool look up plasma tweeters on you tube.

 

Peete.



 

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post #6 of 8
9/20/11 at 12:36pm

A ribbon driver consists of magnets and a metal film membrane that also acts as a voice coil since it is conductive.

As an electrical signal is sent through the ribbon it turns magnetic and will then move relative to the magnets.

With a true ribbon drivers the ribbon is suspended by the short ends between two rows of magnets making a push/pull arrangement.

True ribbons usually require a transformer and tends to have problems with directionality, but are ideal high frequency drivers.

Planar magnetic drivers the metal membrane is suspended by all sides and has magnets in front of and behind the membrane, also making a push/pull system.

The membrane in planars will be deformed as the driver plays sound, this is the main downside to this tech.

It seems the HPM tweeter only has magnets on the back side of the membrane making a push system, I could be wrong.

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post #7 of 8
9/20/11 at 1:01pm

Here is a nudie of a VLD-12 true ribbon AlNiCo tweeter, it does 2400-40000Hz.

It's a little beat up it's 36 years old but works without a hitch.

 

AUT_1501.JPG


Edited by Adda - 9/20/11 at 1:03pm
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post #8 of 8
9/24/11 at 7:16am
Thread Starter 

Thanks for the pic! Looks very cool!

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