segmented panels - 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 10th June 2006, 08:29 PM   #1
Lucius is offline Lucius  United States
diyAudio Member
 
Join Date: Sep 2005
Default segmented panels

Hello All

In an 8" (20cm) wide ESL would two 4" ( 10cm) segments give you better sound quality
even though the D/S spacing allows the full width? Would silicone dots in the middle of
the wide panel be the same as a segmented panel? I've read here that a single panel can sound harsh.Or does that have to do with having a different DS spacing for two panels?
I know panels with different DS is better in free range but I hope to avoid that problem
playing > 200hz.

Lucius
  Reply With Quote
Old 11th June 2006, 09:01 PM   #2
diyAudio Member
 
Join Date: Nov 2005
Location: Southern Germany
Hi Lucius,

segmenting isn't just a matter of segmenting the stator areas by additonal spacers or silicone dots, but dividing the entire stator width into electrical independent stripes of defined width.

This is to compensate for the 3dB/octave increase of level, which is inherent in planar dipol speakers.

To set the right size and appropriate frequency range of each segment will result in a flat frequency response and an improved high frequency dispersion.

Capaciti
  Reply With Quote
Old 11th June 2006, 10:35 PM   #3
Lucius is offline Lucius  United States
diyAudio Member
 
Join Date: Sep 2005
Thanks Capacity

Thats beyond what I or my 50/1 Trafos can do, at least this time around. I'll
keep it simple when I order stators this week.

Lucius
  Reply With Quote
Old 28th June 2006, 07:24 PM   #4
diyAudio Member
 
Join Date: Aug 2005
Quote:
This is to compensate for the 3dB/octave increase of level, which is inherent in planar dipol speakers.
Im curious what you are basing this on? Is it from seeing so many measurements of planars that you noticed a pattern, or are there some equations that reflect this phenomenon? If you have any links, or have read it any books I would like to see them.
BTW Im not doubting the validity of your statement Im just curious about it, I have some Neo8's that have a sloped response and I eventually want to build some tall narrow planars.
  Reply With Quote
Old 3rd July 2006, 05:22 AM   #5
diyAudio Member
 
Join Date: Nov 2005
Thumbs up Segmented esl

Hi All,
My name is Marco Petrolesi and I'm an italian employer
in my free tyme i'm writing a book (in italian) about ESL.
About 3dB compensation, this is still right because more streep
play the same frequencies with different slopes.
This make possible to compensate the for phase cancellation and
improve the dispersion range of High frequencies.
If the segmentation are calculated right this is OK.
Sorry for my english...
...Marco
  Reply With Quote
Old 3rd July 2006, 05:40 AM   #6
Bazukaz is offline Bazukaz  Lithuania
diyAudio Member
 
Bazukaz's Avatar
 
Join Date: Nov 2005
Location: Vilnius
Send a message via Skype™ to Bazukaz
Hi,
You say that it is possible to calculate segmentation.
Could you please give a short description of how it is done ? I understand that ideally , the section width must be less than wavelength it reproduces.How to calculate the frequency , from which the rise of high frequencies starts ? I assume that there must be multiple segments for the best results.
Is it possible to simulate this with any kind of software ?

Regards,
Lukas.
  Reply With Quote
Old 3rd July 2006, 08:09 AM   #7
Calvin is offline Calvin  Germany
diyAudio Member
 
Calvin's Avatar
 
Join Date: Nov 2004
Location: close to Basel
Hi,

directivity calculations depend on the size of the speaker.
Therefore the so called k-factor was introduced with k=omega/c = 2*pi*f/c.
With c=340m/s or 34.000cm/s k becomes: k=f*1.848*10^-2(1/m) or f*1.848*10^-4 (1/cm).
With a as radius of a circular speaker the cone becomes directional when ka=2
So f =2/(a*1.848*10^-x) x beeing 2 or 4 depending on units chosen for the radius a

Example: an 8"cone with a diaphragm radius of 10cm will become directional above a frequency of f=2/(10*1.848*10^-4)= 1084Hz
Since the frequency and the radius vary oppositely linear You can easily estimate that a diphragm of 5cm radius will start to direct at a frequency of ~2.1kHz and a diaphragm of 1cm radius will start to direct at a frequency of ~10.8kHz

jauu
Calvin
  Reply With Quote
Old 3rd July 2006, 10:44 AM   #8
diyAudio Member
 
Join Date: Nov 2005
hi,
it is right that say calvin.
you must consider only the width on one single cell.
to calculate the segmentation you can make a division
of esl in more strips that have the dimension wavelenght of 500hz (for start) and make more little strip at step by one octave,
until 20Khz.
the results is 7 strips but for pratice you can make only 5...
the other 2 won't sound because of their width...
bye marco!!!!!
  Reply With Quote
Old 3rd July 2006, 08:18 PM   #9
Bazukaz is offline Bazukaz  Lithuania
diyAudio Member
 
Bazukaz's Avatar
 
Join Date: Nov 2005
Location: Vilnius
Send a message via Skype™ to Bazukaz
Hi,
Say , the panel's width is ~= 11 cm.
The segments might be 6 , 3 , 1.5 , 0.75 cm.
The directivity for 6 cm section starts at ~1.7 kHz.
Lets say , it has a capacitance of 100pF. Therefore the needed resistor will be f=2*pi*f*c ~= 900 kOhms. Is it correct ?
How do i calculate the next resistor (for 3 cm section) ? By the way , i do connect the segments in series , right ?


Regards,
Lukas.
  Reply With Quote
Old 5th July 2006, 06:25 AM   #10
diyAudio Member
 
Join Date: Nov 2005
Location: Southern Germany
Hi bazukaz,

it is 3,4 Khz for 6cm width !

Forget about a 0,75cm segment. There will be no output from such a segment. 2 cm is the least width of a segment.

Yes 900K is correct - you need 450K for each half to put in serie to the segmented stator.

some people say its better to connect all segments is serie, some say connect them in parallel. The advantage of serie is that resistor value of the first segments adds to the value of the following. On the other hand, serie connection also puts the capacity of the segments in serie, probably causing phase shifts.

capaciti
  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
is there anything bad about MDF panels? jarthel Multi-Way 3 22nd June 2007 05:47 PM
angles for segmented ESL? Few Planars & Exotics 21 25th February 2005 03:30 PM


New To Site? Need Help?

All times are GMT. The time now is 07:44 PM.


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