Go Back   Home > Forums > Loudspeakers > Full Range

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 19th December 2007, 04:06 PM   #1
Peter17 is offline Peter17  Netherlands
diyAudio Member
 
Join Date: Dec 2007
Default Fostex F200A

Bij 4000-5000 hz gives the Fostex driver a metalic sound bij bigger volumes.
What can i doe about it?
  Reply With Quote
Old 19th December 2007, 04:37 PM   #2
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
I bet you do. Looking at Fostex's massively smoothed FR plot, there's a peak centred at 4KHz, and from experience we know that the small bump that appears on their published FE126E FR, is in reality a +8 - 10db spike, which probably explains the metallic sound you're hearing.

Not sure -phase plugs might (might) be possible, which would certainly solve the problem if they could be fitted. Damping the dust-cap with varnish etc., might be an option.

EnABL apparantly makes a big sonic improvement, and I suspect would be worth doing at some point. Only slight problem is that nobody has figured out exactly what it does in a technical sense yet. Ron's certainly established what it doesn't do, so we're in a 'we don't know what it does, but we know what it doesn't' situation at present; this will only improve in the near future though as it's further explored.
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  Reply With Quote
Old 19th December 2007, 11:22 PM   #3
ronc is offline ronc  United States
diyAudio Member
 
Join Date: Mar 2003
this will only improve in the near future though as it's further explored.


The physical actions has merit. I can see some very good applications/results ,with the current design/methods, within a limited BW.

Now to tackle the physics outside the limited BW.

I have some time now to investigate as i handed over the ultrasonic edge scanner to production(up to Rev C) and i am not going to invest time in any other work projects till after the holidays.

ron
  Reply With Quote
Old 20th December 2007, 03:48 AM   #4
el`Ol is offline el`Ol  Germany
diyAudio Member
 
Join Date: May 2005
Location: Bavarian Forest
J.Manger mentions some viscoelastic polymers you could apply to the metal dustcap.
http://www.freepatentsonline.com/4029171.html
But this is probably not up to date, since the patent is quite old.
  Reply With Quote
Old 20th December 2007, 04:38 AM   #5
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
EnABLed drivers that have been measured have not shown significant changes in FR so it is unlikely to kill that problem. Syill worthwhile doing, but it would be better to fix the problem before doing anything else.

The FF125 has what might be a similar colouration, I suspect it is from the metal dustcap. Removing the dustcap would probably fix the problem, but would also, i suspect, reduce HF extension dramatically.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 21st December 2007, 04:59 AM   #6
OzMikeH is offline OzMikeH  Australia
diyAudio Member
 
Join Date: Mar 2007
Quote:
Originally posted by planet10
EnABLed drivers that have been measured have not shown significant changes in FR so it is unlikely to kill that problem. Syill worthwhile doing, but it would be better to fix the problem before doing anything else.

The FF125 has what might be a similar colouration, I suspect it is from the metal dustcap. Removing the dustcap would probably fix the problem, but would also, i suspect, reduce HF extension dramatically.

dave

....unless that little metal dustcap is ringing like a bell.
Reduced reflections from it's edges would mean less ringing.

Off with it's head! (well, it's dustcap anyway)
  Reply With Quote
Old 23rd March 2011, 08:50 PM   #7
diyAudio Member
 
tiefbassuebertr's Avatar
 
Join Date: Jul 2005
Location: D-55629 Schwarzerden
I have heard, that the versions from currently production of this model is much more better in all respects than older versions.

Are there such observations by user's, that have tested both versions ??

P.S. By the model No FE 166 this is so in real life (especially by the frequency response graph - equalizing in the midrange aera isn't necessary by the newer versions).
  Reply With Quote
Old 23rd March 2011, 09:57 PM   #8
BHD is offline BHD  United States
diyAudio Member
 
BHD's Avatar
 
Join Date: Jun 2004
Location: Brooklyn Park, MN
Send a message via Yahoo to BHD
I know it's heresy, but the right thing to do is use a notch filter and cross the driver over to a really good supertweeter. I've heard the driver with and without one and the difference is really night and day. Even with extended break in the peak is just awful sounding. Used with a notch filter and a good (in this case ribbon) supertweeter the F200 is a world class driver.
__________________
My religion is the golden rule. The only time it's forsaken me is when I've forsaken it first.
  Reply With Quote
Old 30th April 2011, 01:16 PM   #9
brady is offline brady  Philippines
diyAudio Member
 
Join Date: Mar 2005
Location: Cebu City
hello BHD. so an LRC centered at 4khz? or would it be better to just cut it off at say 2k5hz or maybe 3khz, and then supplement with a tweet
  Reply With Quote
Old 30th April 2011, 09:20 PM   #10
diyAudio Member
 
Join Date: Feb 2009
What about a convex foam plug over that ringing dustcap, to disperse some of the HF beaming, similar to the foam plug on the Geddes waveguide. It seems even more heresy to be discussing modding a $400 driver.
__________________
It is only rarely that one can see in a little boy the promise of a man, but one can almost always see in a little girl the threat of a woman. ~Alexandre Dumas

Last edited by steviedon; 30th April 2011 at 09:27 PM.
  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
Fostex F200A For Sale ianc13 Swap Meet 2 7th November 2007 08:00 AM
Fostex F200A for sale herm Swap Meet 6 28th June 2007 02:06 PM
FS: Fostex f200a TomekZ Swap Meet 0 15th April 2006 03:26 PM
FS: NIB Fostex F200A (pair) nullspace Swap Meet 1 5th May 2005 08:26 PM
Fostex F200A Questions LageB Multi-Way 2 3rd December 2003 04:13 PM


New To Site? Need Help?

All times are GMT. The time now is 02:01 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