Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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

DIY Walsh Driver
DIY Walsh Driver
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 20th June 2015, 04:15 AM   #41
jerryrigged is offline jerryrigged  United States
diyAudio Member
 
jerryrigged's Avatar
 
Join Date: Jul 2014
Location: Asheville, NC
If you've followed a link to this page, you might visit a thread on this subject that is considerably more active and recent...

http://www.diyaudio.com/forums/plana...isited-31.html

Yours truly is actively pursuing diy Walsh drivers. Anyone interested is quite welcome to chime in or merely watch the pursuit.
  Reply With Quote
Old 1st September 2019, 07:19 AM   #42
jerryrigged is offline jerryrigged  United States
diyAudio Member
 
jerryrigged's Avatar
 
Join Date: Jul 2014
Location: Asheville, NC
...still @ it, BTW....
__________________
"I'm trippin' over time...I'm a Ghost in the City...." (Crystal Method; song of the same name)
  Reply With Quote
Old 14th September 2019, 05:32 AM   #43
cochleus is offline cochleus  United States
diyAudio Member
 
cochleus's Avatar
 
Join Date: Oct 2009
Location: S.E. Michigan
Hey J and Glorocks and all

The L. Walsh patent is ingenious.
I've cobbled together many prototypes and, they all sounded good.
The design is omni by nature and, any problems with that could be overcome I believe.
Lincoln Walsh never mentioned to term 'bending wave' in his patent. Although that is a correct descriptor I guess he assumed the reader understood transverse waves on a conical diaphram.
The wave velocity on the diaphram must be supersonic for all intended frequencies. The propagation velocity drops linearly with frequency.
Since wave velocity on a cone depends on bending stiffness a thin pliable cone might not even attain mach 1 even at high frequencies. Just wanted to clear that up. So, for wide band useage one would need an very stiff cone.

G (c)

Last edited by cochleus; 14th September 2019 at 05:39 AM.
  Reply With Quote
Old 15th September 2019, 01:30 PM   #44
cochleus is offline cochleus  United States
diyAudio Member
 
cochleus's Avatar
 
Join Date: Oct 2009
Location: S.E. Michigan
A Walsh driver is just a regular speaker where you are hearing the back wave sound instead of the front. The sound is not beamed at you the same way as the conventional configuration. It appears to be less efficient because it is radiated 360 deg. You would need a very strong motor and a very light cone to achieve high efficiency. That is not too hard to do but, at lower freq the wave propagation becomes evanescent. To overcome that you would need an extremely high bending modulus cone to start with. Graphene aerogel...? 3D printed
  Reply With Quote
Old 15th September 2019, 01:48 PM   #45
cochleus is offline cochleus  United States
diyAudio Member
 
cochleus's Avatar
 
Join Date: Oct 2009
Location: S.E. Michigan
At some point the cone will be probably become evanescent and that's where the enclosure takes over. Some form of mode control would be called for here, which is not a problem w low freq. High freq is no prob either w proper damping.
  Reply With Quote
Old 15th September 2019, 02:01 PM   #46
cochleus is offline cochleus  United States
diyAudio Member
 
cochleus's Avatar
 
Join Date: Oct 2009
Location: S.E. Michigan
It's mid telephonic freq which will be a prob but, a proper enclosure could remedy that I propose.

Last edited by cochleus; 15th September 2019 at 02:09 PM.
  Reply With Quote
Old 16th September 2019, 04:40 AM   #47
jerryrigged is offline jerryrigged  United States
diyAudio Member
 
jerryrigged's Avatar
 
Join Date: Jul 2014
Location: Asheville, NC
Default ...the Ghost wanders in...

Hi C(G), Glo, 'n all the other fans of All This. *S*

'Bending wave'....I'm not a fan of the term since what the cone does is recreate the 'ripples' into the gas environment we like to 'air'. My take is we're wandering about in a low-drag pool of substance. 'Bw' could be applied to a frequency pulse traveling down cone; but, again, it's a ripple...

LF control can be controlled, as you point out, by the enclosure. You're inferring that you've been looking at an approach. Kewl...*G* I'm still looking @ acoustic suspension with an eye on minding a resonance. If I can 'park' it where it'll help vs. hinder, bingo....

3d print aerogel. A worthy target, but I suspect the $ for the prototype would induce mental implosion; dups wouldn't be distinctly less. I got a reply from a German firm that indicated a 2mil Al or Ti might be possible.
I just haven't had the time to reply with a 3d file for further discussion, but it's in the ToDo to follow up on it....

Went to PE to register for the Open/Unlimited contest, but their roster is already filled and closed. 5 entrants, 2 hrs. boils down to 10~15 of performance time after set-ups.

Asked to sign up for '21.

Still going to go in '20, if only to scope it out. Bringing earplugs, you bet.

Meanwhile, because it was quick 'n dirty to do, took the Utah pair of woof 'n horn and set it up with the woof in a proper OhmCo configuration. The woofer could use a proper enclosure; can 'IT' be tubular vs. rectilinear? This combination shows promise of a sort. Either way, it's entertaining to FW. *G*

(Brazen ploy, to keep C/G in endless contact with the keys of his calculator...*L*)

...anyway....YouTube test pattern...*s* Back to the Shadows again....*poof*
__________________
"I'm trippin' over time...I'm a Ghost in the City...." (Crystal Method; song of the same name)

Last edited by jerryrigged; 16th September 2019 at 04:44 AM.
  Reply With Quote
Old 18th September 2019, 01:03 AM   #48
cochleus is offline cochleus  United States
diyAudio Member
 
cochleus's Avatar
 
Join Date: Oct 2009
Location: S.E. Michigan
Thanks J. I was beginning to think I was a thread killer.

I don't like the term bending wave because to me it implies flexibility and compliance. Both of which counter wave propagation velocity which the Walsh patent depends on.

For the patent to work there needs to be supersonic wave propagation speed on the cone itself. With current technology this won't be possible with the lowest frequencies because transverse waves are dispersive. I once did a thumb nail figure for cone velocity and I got mach 30 something for the highest frequencies. At that modulus low frequencies would still be supersonic and thus coherent for the intended purpose. Full range operation is suggested for this invention. For that to happen IMO one would need a 3D printed cone structure of ultra high modulus material in some type of matrix form.

Some type of enclosure would still be needed to counter phase interference (w transmission line/waveguide).

G(c)

Last edited by cochleus; 18th September 2019 at 01:30 AM.
  Reply With Quote
Old 18th September 2019, 01:21 AM   #49
cochleus is offline cochleus  United States
diyAudio Member
 
cochleus's Avatar
 
Join Date: Oct 2009
Location: S.E. Michigan
In addition: I will say that the need for wave coherency will drop as frequency drops due to the wavelength increase. But, I think a starting point would around 700 Hz for the coincidence frequency. This 'crossover freq' would be within the region of information importance and of the enclosures ability to mode control low freq resonance.

Last edited by cochleus; 18th September 2019 at 01:42 AM.
  Reply With Quote
Old 18th September 2019, 02:24 AM   #50
cochleus is offline cochleus  United States
diyAudio Member
 
cochleus's Avatar
 
Join Date: Oct 2009
Location: S.E. Michigan
I think that one reason Ohm used paper as the last segment of the cone despite the lower modulus is that thickness made up for it and then some and, it absorbed higher freqs...


G(c)

Last edited by cochleus; 18th September 2019 at 02:38 AM.
  Reply With Quote

Reply


DIY Walsh DriverHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Ohm Walsh 2 - can i cut these pool strainers off? ark Multi-Way 21 26th September 2019 03:16 AM
OHM Acoustics "Walsh F" Speaker remakes microwalsh8504 Multi-Way 165 30th December 2018 05:48 PM
The Pencil: inspired by Ohm Micro Walsh Tall Juspur Multi-Way 117 21st March 2018 03:07 AM
I need replacement tweeter suggestions for OHM Walsh 4XO speaker Jack Torrance Full Range 1 13th March 2008 07:30 PM


New To Site? Need Help?

All times are GMT. The time now is 04:34 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki