Coil-driven planar - diyAudio
Go Back   Home > Forums > Loudspeakers > Planars & Exotics

Planars & Exotics ESL's, planars, and alternative technologies

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 27th November 2009, 08:14 PM   #1
bentl is offline bentl  Norway
diyAudio Member
 
Join Date: Apr 2009
Location: Norway
Default Coil-driven planar

Hi,

I have been playing with the idea of building a "planar" speaker with a flat esl-type diapraghm tensioned in a frame...and moved by a voice-coil/magnet.

I was thinking of using 6my Hostapan left over from a ESL project

As I see it; i remove the problems of coating, stator openness, spacer distance and transformer and powersupply setup.

The diaphragm obviously will be driven from the center, not a disperced force like a esl.

Has this been tested before? I think i can recall having seen something like this done in a magazine 20 years ago..


Regards

Bent
  Reply With Quote
Old 27th November 2009, 09:23 PM   #2
Illusus is offline Illusus  Canada
diyAudio Member
 
Illusus's Avatar
 
Join Date: Sep 2002
Location: Prairie Wasteland, Canada
Parts-Express.com:*Surface Transducer Turns Virtually Anything Into A Speaker | CYBER09 stick on speaker exciter tactile transducers sound transducers nxt sonic impact 5029 5029 sound pads hidden speakers daex25 Marcato DIY projects fbr1 gift2009
__________________
Fighting the program since 1976.
  Reply With Quote
Old 28th November 2009, 06:39 AM   #3
Calvin is offline Calvin  Germany
diyAudio Member
 
Calvin's Avatar
 
Join Date: Nov 2004
Location: close to Basel
Hi,

oh of course it has been tested.....billions by billions. It´s called dynamic speaker *lol*
Driving force is applied to the ESL membrane over its complete area by an homogenous electrical field. Since each and every point of the membrane is driven the same, there´s no need for mechanical stiffness. That´s the reason why we can use a soft thin membrane material in first place. As soon as the driving force is distributed unevenly over the membrane (as a ring -->voicecoil) we either need a very stiff membrane that ideally should move in a pistonic fashion, or we need a very soft membrane without any mechanical tension within but lots of damping (bending wave transducer, Manger). As we know, no material is so stiff that it works in a pistonic fashion over its complete bandwidth. From a certain frequency range on the membrane behaves as if it were soft, leading to breakups. With a soft thin stretched film there´s hardly any stiffness, so the membrane works in breakup-mode over its complete bandwidth. On the other hand it doesn´t behave like a bending wave transducer, because of the stretching forces within the membrane.
In short, the membrane behaviour is rather chaotic.....not at all what we want, eyhh?

jauu
Calvin
  Reply With Quote
Old 28th November 2009, 08:08 AM   #4
andyr is offline andyr  Australia
diyAudio Member
 
Join Date: Nov 2003
Location: Melbourne (Oz, not Florida!)
Quote:
Originally Posted by bentl View Post
Hi,

I have been playing with the idea of building a "planar" speaker with a flat esl-type diapraghm tensioned in a frame...and moved by a voice-coil/magnet.

I was thinking of using 6my Hostapan left over from a ESL project

As I see it; i remove the problems of coating, stator openness, spacer distance and transformer and powersupply setup.

The diaphragm obviously will be driven from the center, not a disperced force like a esl.

Has this been tested before? I think i can recall having seen something like this done in a magazine 20 years ago..


Regards

Bent
Haven't you come across Maggies? They've only been going for over 35 years ... see here:
Stereo Speakers, Home Theater Speakers, High Fidelity Audio - Magnepan, Inc.

Regards,

Andy
  Reply With Quote
Old 28th November 2009, 10:16 AM   #5
diyAudio Member
 
Join Date: Mar 2008
Hi bent,

be carefull, you will most likely end up in the bending
wave loudspeaker thread then ...

What can be expected is that your system will be a bending
wave loudspeaker with soft membrane and a high coincidence
frequency (possibly located above the audio range).

A corresponding transducer already patented and commercially
available is the Manger transducer.

Manger Schallwandler

So the good news is, that a quality transducer based on that principle
is possible.

Another good news is that one can spend his whole lifetime without
problems in developing and optimiting those constructs.

Best regards
__________________
Oliver, RFZ believer (?)
www.dipol-audio.de

Last edited by LineArray; 28th November 2009 at 10:21 AM.
  Reply With Quote
Old 28th November 2009, 10:51 PM   #6
Ron E is offline Ron E  United States
diyAudio Member
 
Ron E's Avatar
 
Join Date: Jun 2002
Location: USA, MN
Google Museatex or Melior, and look for posts on diyaudio by moray james.
__________________
Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan
Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. —Aldous Huxley
  Reply With Quote
Old 9th December 2009, 09:47 PM   #7
diyAudio Member
 
reverber's Avatar
 
Join Date: Nov 2002
Location: Lawrence, Kansas, USA
I immediately thought of BES loudspeakers from the 80s(?) when I read your post. A little digging shows that Sonance now owns what was BES.
IIRC, they used a molded styrofoam panel as the driver, which was excited by a standard magnet/voicecoil motor assembly or two.

Picture

Cody
  Reply With Quote
Old 17th December 2009, 03:16 AM   #9
godfrey is offline godfrey  South Africa
diyAudio Member
 
Join Date: Nov 2009
Location: Cape Town
Quote:
Originally Posted by bentl View Post
I have been playing with the idea of building a "planar" speaker with a flat esl-type diapraghm tensioned in a frame...and moved by a voice-coil/magnet.
[snip]
Has this been tested before? I think i can recall having seen something like this done in a magazine 20 years ago..
I remember that too. The reviewer was surprised to find it actually produced good bass. The drive was asymmetric, though. i.e. The voice-coil needs to be off-center somewhere to break up the resonance modes.
  Reply With Quote
Old 17th December 2009, 04:54 AM   #10
amp_guy is offline amp_guy  United States
diyAudio Member
 
Join Date: Oct 2004
Location: utah
Another one from the past was polyplanar, they consisted of a block of styrofoam with a roll suspension and a voice coil attached, they made sound I wouldn't call it good sound though.
Also more recent is the NXT design, which I don't much care for either.
Something with less mass might have potential though, what about woven silk with a Dammar coating?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
G2-driven 6BM8 wfmali Tubes / Valves 34 13th February 2008 05:47 PM
g2 driven tubes gianis Tubes / Valves 10 24th January 2008 04:30 PM
Single Voice Coil Vs Double Voice Coil Subwoofer Workhorse Car Audio 6 12th April 2007 06:36 AM
Tubes driven by BJT's drago Tubes / Valves 12 12th April 2006 08:35 PM
sub not being driven enough? dlagace Subwoofers 3 25th November 2003 11:26 PM


New To Site? Need Help?

All times are GMT. The time now is 08:36 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2