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

Wooden Cone
Wooden Cone
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 24th January 2011, 08:45 PM   #31
markaudio is offline markaudio  Hong Kong
diyAudio Member
 
markaudio's Avatar
 
Join Date: Nov 2008
Quote:
Originally Posted by fatbattery View Post
We can all be all knowing in our own bedrooms. I still like the nanobots idea. I cant understand why polly Kevlar and those composites never where as good as most thought they should of been. Where back to organic things again. Cellulose has promise. I think nxt drivers seem like good way of playing around with weird speaker materials. Why they spent so much time investing in wood cones can only be a fashion. Flat panels are the future or spheres. I am so over this thread. Dont insult me I wont be around to read. I have horns (real speakers) to talk about. Come into my horn threads if you want to finish insulting me. Good luck
Hi Guys,
You might find my new thread on cone development useful:

http://www.diyaudio.com/forums/marka...aper-cone.html

Flatbattery may have a point. There is "fashion" in some of the audio industry that sometime overrides sensible acoustic principles and good engineering practices.

I'm starting to cover some basics on cone design. Designing and making cones is very complex. I've lost track of the number of hours I've spent on this part of driver making process.

I'm happy to talk more about cones should DIY members like me to do this.

Cheers

Mark.

Last edited by markaudio; 24th January 2011 at 08:53 PM. Reason: typo fix
  Reply With Quote
Old 24th January 2011, 09:32 PM   #32
LineArray is offline LineArray  Germany
diyAudio Member
 
Join Date: Mar 2008
Quote:
Originally Posted by markaudio View Post
Hi LineaArray.
"The propagation of bending waves........."
"The fibers should be orientated....."

1 - Exactly how did you come to these conclusions?
2 - You've done specific experimentation, testing, data that supports your statements?
3 - How many cone types and designs do you make?

Thanks

Mark.

Hi Mark,

1. Wood is anisotropic, having higher stiffness
in parallel direction to the fibres, thus wavelength
of bending waves is always larger in parallel to the
fibres compared to orthogonal direction, when the
structure is excited with a frequency high enough
to excite bending waves.

2. Indeed. But that is also basic knowledge of materials
and structure born sound and does not necessarily
call for "experiments".

3. I am designing bending wave speakers. I am
not interested in development of cone type speakers.

Nevertheless every speaker is a bending
wave speaker when driven in the modal frequency
range.


Kind Regards
__________________
Oliver, RFZ believer (?)
www.dipol-audio.de

Last edited by LineArray; 24th January 2011 at 09:41 PM.
  Reply With Quote
Old 24th January 2011, 10:34 PM   #33
markaudio is offline markaudio  Hong Kong
diyAudio Member
 
markaudio's Avatar
 
Join Date: Nov 2008
Hello Oliver,
I only wish it were so simple to design and make audio drivers, especially full range units.

In the case of Parc Audio's 5cm, 8cm and 10cm wood coned drivers, these cones will likely have been processed to control their resonance patterns and afford stability under oscillation and static loads. On such small diameter cones, I very much doubt the direction of the wood grain has an audible effect. If it does (be interesting to see the anechoic measurements), there could be a modest wide field dispersion advantage to setting driver in position as shown in Parc audio's box image. Given that these driver's cones are relatively deep, the design relying on a phase plug, positioning the grain direction horizontally maybe a performance feature.

I know the cone maker and Parc audio. It's a Japanese audio speaker company with an excellent reputation. Unlike many in the speaker industry, they do their research before going to production. I was in Japan for much of last September and November. I've personally heard Parc's DCU-F071W driver in the enclosure illustrated during studio listening tests in Tokyo. It performed quite well with no major perceptible inconsistencies.

Personally, as a driver designer with a mechanical and production engineering heritage, wood isn't a material I prefer using to make cones. It likely presents density and structural variations beyond tolerances I'd be willing to accept. All the same I commend those driver designers and makers who are willing to try to perfect this art.

Your assumptions on the properties of wood and related resonance in relation to cone design and production is overly simplistic. You have too little working knowledge on cone/driver design to offer specific and authoritative conclusions.

Cheers

Mark.

Last edited by markaudio; 24th January 2011 at 10:50 PM. Reason: typo fix - additional
  Reply With Quote
Old 25th January 2011, 08:07 PM   #34
LineArray is offline LineArray  Germany
diyAudio Member
 
Join Date: Mar 2008
Quote:
Originally Posted by markaudio View Post

...

Your assumptions on the properties of wood and related resonance in relation to cone design and production is overly simplistic. You have too little working knowledge on cone/driver design to offer specific and authoritative conclusions.

Cheers

Mark.

Hello Mark,

you are right on that. My scepticism was too
quick and too severe.

Nevertheless i would be interested in comparing
polar response with fibre orientation vertically vs.
horizontally as shown in the picture.

Effect of anisotropic material on modal shapes
is not too far away from having an oval driver.

Mounting it with fibres horizontally corresponds
to mounting an oval driver with its shorter
axis in horizontal orientation, which is what we
would intuitively do.

Comparing the polar responses would surely
tell us something.

Kind Regards
__________________
Oliver, RFZ believer (?)
www.dipol-audio.de

Last edited by LineArray; 25th January 2011 at 08:26 PM.
  Reply With Quote
Old 25th January 2011, 09:35 PM   #35
markaudio is offline markaudio  Hong Kong
diyAudio Member
 
markaudio's Avatar
 
Join Date: Nov 2008
Hello Oliver,
I've only experimented with wood for short time. That was around 4 years back. The biggest challenge I found with this material was cone stability. The grain of wood affected rigidity. This variation in rigidity meant the cone flexed unevenly. The cone profile couldn't be maintained, effectively its shape changed significantly while under load. I had 2 samples that were so severe the coil moved out of gap alignment under heavier loads. Bear in mind that I needed very thin wood, reducing mass to minimise resonance losses across the cone profile.

At the time I was looking into wood, the cone making guys in question had managed to make cones to a size of around 90-mm diameter for small woofs and mid range drivers. There was a limit on how thin they could go with wood. It was tough to get those cones to emit a wide range of frequencies. From what I've seen, they have moved the making process forward although its interesting to note the reliance on phase plugs. This maybe an indicator of the emittance limitation for wood.

Coming back to stability, I'm fairly certain the wood cone maker has to stiffen the wood with either a cellulose or polymer based agent. If this is the case, the rigidity of the cone maybe more uniform and variations in emittance due to wood grain may be reduced. This effect is likely dependent upon cone size. I suspect you point about the frequency variation on grain direction may have a measurable effect if the maker could produce larger diameter cones. Agreed, it would be interesting to test wood coned drivers to see if the grain has an effect on emittance.

There are many challenges when making Full-range cones. My own experiences found wood to be the challenging of all the materials. I never succeeded in getting a wood cone to full range without the use of a whizzer or phase plug.

Hope this helps.

Cheers

Mark.

Last edited by markaudio; 25th January 2011 at 09:44 PM. Reason: typo fix
  Reply With Quote
Old 26th January 2011, 07:36 AM   #36
LineArray is offline LineArray  Germany
diyAudio Member
 
Join Date: Mar 2008
Hello Mark,

as i said before, cones are not in my focus.

That rigidity problem is not a problem in itself
for a pure bending wave transducer - independently
from the material used - unless you aim for using
the "whole body motion" or Mode 0,0 .

Using wood for making rigid cones without using some
"conditioning" coats/drenches and/or carrier material
seems fairly impossible.

Wood can only bring some interesting acoustical
features into play, like anisotropy and - yes - it's
typical 'defects' and tolerances due to being
a naturally grown material.

Those properties may be valuable acoustically but
cause large effort in manufacturing, when aiming
for a low tolerance end product.

Strategies have to be found to deal with those
properties.


Kind Regards
__________________
Oliver, RFZ believer (?)
www.dipol-audio.de
  Reply With Quote
Old 26th January 2011, 07:55 AM   #37
markaudio is offline markaudio  Hong Kong
diyAudio Member
 
markaudio's Avatar
 
Join Date: Nov 2008
Hello Oliver,
I am curious. I looked at your website link and noticed your speaker system design. I used Google Translate so not 100% sure of its accuracy.

So....Are you going to make a transducer specifically to the "bending wave concept"?

I'm curious and also welcome DIYers who join the small manufacturing members here on DIYaudio forum.

Cheers
Mark.
  Reply With Quote
Old 26th January 2011, 07:25 PM   #38
kach22i is offline kach22i  United States
diyAudio Member
 
kach22i's Avatar
 
Join Date: Oct 2009
Location: Michigan
Quote:
Originally Posted by markaudio View Post
So....Are you going to make a transducer specifically to the "bending wave concept"?.
Good question.

This is a topic I'm very interested in.

Conventional Planar v. Bending Wave Planar Loudspeakers
Quote:
Unlike speakers aiming for pistonic membrane movement, a BWL is not a 'moving mass' loudspeaker. The membrane can be seen instead as a two-dimensional medium for bending wave propagation, allowing the radiation of frequencies even above the audio range. In fact the highest usable frequency depends mainly on the properties of the exciter. The travelling speed of bending waves, the dimensions of the membrane and damping can be optimized for a seamless and very dense distribution of vibrational modes over a wide frequency range.
Sorry about the Hi-Jack.

Back to wooden cones.................

Found this in a Google search.

Wood Cone Speakers
Quote:
JVC's unique Wood Cone Speaker Series.
Click the image to open in full size.

Wood Cone Speakers
Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.
Quote:
It happened that one of JVC's engineers visited a Japanese pub after work, and he was regularly served a dish of soft squid (a fairly common snack in such pubs). How, he wondered, was this typically hard and rather rubbery food softened? A little research led him to discover that squid is softened when it is soaked in sake, or Japanese rice wine, overnight.
Booze...............not always the answer............but it sometimes is.

.................................................. ...............................................



Fair is fair, and these are made in the USA.
Quote:
Made and Designed in MPLS, MN USA
Wood Cone - Woofers - Home Audio
Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.
__________________
Tubes and Martin Logan's

Last edited by kach22i; 26th January 2011 at 07:32 PM.
  Reply With Quote
Old 26th January 2011, 07:36 PM   #39
LineArray is offline LineArray  Germany
diyAudio Member
 
Join Date: Mar 2008
Hello Mark,

thank you for the 'salutation'.

Yes, i am making a rather large full range bending
wave transducer operating in dipole radiation mode.

Cannot reveal too much up to now. Small "pre serial"
production is in it's phase of being planned.

Prototypes of different 'flavors' worked statisfactory.

Nevertheless, starting such a project at own risc is an
adventure of its own ... the effort in each piece is
comparable to the making of a musical instrument and
you need good partners and suppliers - which is not
too different from making cone shaped drivers i guess.

Kind Regards
__________________
Oliver, RFZ believer (?)
www.dipol-audio.de

Last edited by LineArray; 26th January 2011 at 07:48 PM.
  Reply With Quote
Old 26th January 2011, 09:30 PM   #40
markaudio is offline markaudio  Hong Kong
diyAudio Member
 
markaudio's Avatar
 
Join Date: Nov 2008
Quote:
Originally Posted by LineArray View Post
Hello Mark,

thank you for the 'salutation'.
Yes, i am making a rather large full range bending
wave transducer operating in dipole radiation mode.

Cannot reveal too much up to now. Small "pre serial"
production is in it's phase of being planned.

Prototypes of different 'flavors' worked statisfactory.

Nevertheless, starting such a project at own risc is an
adventure of its own ... the effort in each piece is
comparable to the making of a musical instrument and
you need good partners and suppliers - which is not
too different from making cone shaped drivers i guess.

Kind Regards
Hello Oliver,
Good to read your post. Could be a very interesting project. Yes, it will take much effort and often allot of money, especially if CNC tooling is required.

Also carefully consider how you measure the prototypes. This is critical. Its most important to eliminate external influences when testing and have accurate outcome data from any modifications you make in the pre-production phase. I'm lucky because I have access to very large purpose built anechoic chambers. I also developed my own system for measuring micro-resonance at any point across a cone profile.

I wish you all the best for this project. If you need assistance, feel free to message me.

Cheers

Mark.
  Reply With Quote

Reply


Wooden ConeHide 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
Increase cone mass to rid cone resonance; worth it? bikinpunk Multi-Way 6 30th July 2010 05:08 PM
Repair Vifa D6.8 Plastic Speaker Cone with hole in cone excetara2 Multi-Way 0 30th August 2009 02:32 AM
Cone weight vs Cone stiffness musgofasa Full Range 9 25th July 2008 08:16 PM
Cabinet solutions to tame a wooden cone knightsound Full Range 0 25th May 2008 02:03 PM
Anyone seen the wooden cone speakers? scott wurcer Multi-Way 3 20th May 2004 04:40 AM


New To Site? Need Help?

All times are GMT. The time now is 11:37 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki