DIY Ribbon speakers ?? - Page 3 - 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 25th January 2006, 09:09 AM   #21
beamnet is offline beamnet  Netherlands
diyAudio Member
 
beamnet's Avatar
 
Join Date: Jun 2004
Location: enschede
Send a message via MSN to beamnet
would be happy to be on your beta test tem micheal! I'm confident i would be the perfect null-measurement

Bas
  Reply With Quote
Old 25th January 2006, 11:22 AM   #22
diyAudio Member
 
Join Date: Jun 2005
Location: Neuss, Germany
Hello Promitheus,
have done some experimental work with metalized foils from an capacitor but that wasn't too promising: you can't corrugate very thin plastic films, so you have to stretch it and probably get a higher resonance frequency of the ribbon. Afaik traditional ribbons are made of 8 - 11 m alu.
__________________
Michael
  Reply With Quote
Old 25th January 2006, 02:03 PM   #23
diyAudio Member
 
promitheus's Avatar
 
Join Date: Jan 2001
Location: Germany
Really?
Real life ribbons are made of ALU?
wow, I thought they were some kind of special foil or something.
Do you have an idea how thick normal Alufoil from the supermarket is?

Looking at the graph from the measurements there is a dip in the middle, do you know what parameter causes that?
Is it possible to make it flat?
  Reply With Quote
Old 25th January 2006, 02:38 PM   #24
diyAudio Member
 
Join Date: Jun 2005
Location: Neuss, Germany
Standard household alu foil seem to be between 10 and 15 m thick (this is not the extra-strong variety but the cheapest you can get). So my self made ribbon should hopefully be only slightly heavier (and shurely a bit more strengthy) than a professional one.

The dip in the middle becomes deeper if you measure with a shorter distance between microphone and ribbon. With more distance measured frequency response will become flatter - exzept for room reflections and other stuff. I think that the measurement is influenced by the fact that sound is produced all along the ribbon at the same time but has to travel to the microphone (just a point in space) on ways of different length. (Other kinds of tweeters don't have such long membranes!) So at some frequency you will have interferences and a resulting dip in the response. The nearer the microphone comes to the ribbon the more different the ways and the deeper the dip. You should measure a ribbon at some two to three meters - but my basement room isn't long enough. So this seems to be a problem of measurement, not construction.
__________________
Michael
  Reply With Quote
Old 25th January 2006, 02:41 PM   #25
beamnet is offline beamnet  Netherlands
diyAudio Member
 
beamnet's Avatar
 
Join Date: Jun 2004
Location: enschede
Send a message via MSN to beamnet
Actualy, there's a big one near 1,5k too, but that doesn't show much because it is allready droping. If i look clos, there is a very small one at 3k

length is 200 mm , which results in a standing wave off about 1,7k

Might these be F1, F2 and F3?

Bas
  Reply With Quote
Old 25th January 2006, 02:51 PM   #26
diyAudio Member
 
Join Date: Jun 2005
Location: Neuss, Germany
Hi Bas,

how do you calculate 1.7 kHz? The speed of sound in alu is much faster then in air.
__________________
Michael
  Reply With Quote
Old 25th January 2006, 03:04 PM   #27
beamnet is offline beamnet  Netherlands
diyAudio Member
 
beamnet's Avatar
 
Join Date: Jun 2004
Location: enschede
Send a message via MSN to beamnet
and how does that matter?

if the air pressure waves from the center of the foil try to null out the waves from the end or something, you get a drop don't you?

just theory...
  Reply With Quote
Old 25th January 2006, 04:21 PM   #28
diyAudio Member
 
Join Date: Jun 2005
Location: Neuss, Germany
Hi Bas,

if you put your microphone at a distance of - say - 15 cm pointing to the mid of the ribbon and you have 10 cm from that midpoint to the end of the membrane (half of 20 cm ribbon length), than my Pythagoras says that the difference of the direct path from the midpoint to the microphone and the path from an endpoint of the ribbon to the microphone will be 18 cm. This makes a difference of 3 cm and that should give a dip at a frequency were 3 cm is half a wavelength. This should be at some 5700 Hz. The dip isn't very deep fore we have many points on the ribbon in between, so we have many different path lengths too and will not get perfect substraction. If you put your microphone at some new position farther away from the membrane, than the difference of the path lengths will become smaller and the dip frequency will become higher. If you could put your microphone at some point far enough from the ribbon, path difference will be so small - for a 20 cm ribbon at least - that dip frequency will be very high and out of measurement range.
__________________
Michael
  Reply With Quote
Old 7th February 2006, 07:44 AM   #29
diyAudio Member
 
Join Date: Jan 2002
Location: austin tejas
Just as a side note...

It occurred to me when re-building my ribbons that the supplier of the Kapton/Aluminum ribbon is completely happy to sell his ribbon material to the DIY community.

So....if you are hard up to build a ribbon...then there is a source for quality ribbon material with aluminum traces already manufactured. I beleive the material is in 1000 ft rolls and is 10 inches wide (meant to be trimed off), so you can buy it by the foot I assume.

For whatever its worth...

Cheers,


Ribbon Project
  Reply With Quote
Old 12th February 2006, 01:24 PM   #30
diyAudio Member
 
Join Date: Jun 2005
Location: Neuss, Germany
Default DIY Ribbon

Here comes the missing part I of my DIY Ribbon article - look at "Ribbon I" under "Lautsprecher" at http://www.michaelgaedtke.de/.
__________________
Michael
  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
does anyone recognize these ribbon speakers? cowanrg Planars & Exotics 9 15th November 2007 09:20 PM
Marantz ribbon speakers I am the Walrus Multi-Way 2 29th August 2005 07:10 PM
budget ribbon bookshelf speakers xstephanx Multi-Way 12 17th April 2005 01:15 AM
Ribbon speakers martioz Multi-Way 0 20th January 2003 12:55 AM


New To Site? Need Help?

All times are GMT. The time now is 08:47 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