New tweeter from fostex - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 29th May 2007, 08:41 PM   #1
badman is offline badman  United States
diyAudio Member
 
badman's Avatar
 
Join Date: Sep 2003
Location: Sunny Tustin, SoCal
Default New tweeter from fostex

New fostex tweeter

Gimmick? Or the real deal? Knowing fostex, I'm thinking there's something to this.... the Le looks nice and low, Fs is reasonably low, there's something to be said for oversized magnets, and poly/resin chassis are usually pretty good when done right.

But more than the unusual magnet structure and dome material and chassis/waveguide (yeah yeah, shallow I know), the UDR surround is interesting here. A tweeter would seem to be the ideal place for such a deal.

Sort of a 'what's your take'/FYI thread I suppose. Maybe we can con(vince) John Krutke into aquiring a couple samples for testing, mmmm?
__________________
I write for www.enjoythemusic.com in the DIY section. You may find yourself getting a preview of a project in-progress. Be warned!
  Reply With Quote
Old 29th May 2007, 10:51 PM   #2
diyAudio Member
 
Join Date: Aug 2006
My router threatens to quit if I even think of using that tweeter.
  Reply With Quote
Old 29th May 2007, 10:53 PM   #3
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Must be tested soon indeed. Any idea of its price?
  Reply With Quote
Old 30th May 2007, 12:00 AM   #4
badman is offline badman  United States
diyAudio Member
 
badman's Avatar
 
Join Date: Sep 2003
Location: Sunny Tustin, SoCal
Madisound Catalog Page

Catalog page from madisound. $263 ain't exactly cheap, but it does look like a hell of a tweeter- all that copper pays off in the astonishingly low Le-- the impedance only rises from 8 to 12 ohms at 100kHz (!)
__________________
I write for www.enjoythemusic.com in the DIY section. You may find yourself getting a preview of a project in-progress. Be warned!
  Reply With Quote
Old 30th May 2007, 12:09 AM   #5
diyAudio Member
 
Timn8ter's Avatar
 
Join Date: Jul 2003
Location: Seattle, WA
Quote:
Originally posted by Willitwork
My router threatens to quit if I even think of using that tweeter.
That faceplate is intended to be surface-mounted, similar to the FT207D.
Pretty exclusive company in that price range; Scan-Speak 2904, Seas Crescendo, Accuton C25......
  Reply With Quote
Old 30th May 2007, 12:59 AM   #6
Tenson is offline Tenson  United Kingdom
diyAudio Member
 
Join Date: Feb 2006
Location: Kent
Most interesting is the quoted Xover of 1.5KHz with a second order filter - that is pretty damn low for a super-tweeter!

I don't think you can really tell a lot about it until you see real measurements though, as the PDF doesn't say a lot. Disto and CSD will tell the tale.
  Reply With Quote
Old 30th May 2007, 09:20 AM   #7
diyAudio Member
 
Join Date: Nov 2003
Location: Brisbane, QLD
Hmmm....

No obvious resonant peaks in the >15kHz range.

The huge magnet and high sensitivity combination doesn't make sense to me.

With DC electric motors, if you increase the magnet strength the torque increases but RPM decreases. Likewise, a large magnet on a speaker implies a low Qes together with low sensitivity. 90dB/W isn't that low, which could be explained by the low inductance, but then the question is: why bother having a low inductance anyway?
__________________
Lech
  Reply With Quote
Old 31st May 2007, 01:04 AM   #8
badman is offline badman  United States
diyAudio Member
 
badman's Avatar
 
Join Date: Sep 2003
Location: Sunny Tustin, SoCal
Quote:
Originally posted by CeramicMan
Hmmm....

No obvious resonant peaks in the >15kHz range.

The huge magnet and high sensitivity combination doesn't make sense to me.

With DC electric motors, if you increase the magnet strength the torque increases but RPM decreases. Likewise, a large magnet on a speaker implies a low Qes together with low sensitivity. 90dB/W isn't that low, which could be explained by the low inductance, but then the question is: why bother having a low inductance anyway?
I'm not really following you- you're saying a bigger magnet means weaker? That's not my understanding, can you elaborate? Note that low sensitivity speakers have magnet sizes ranging all over the place, but high sens usually are pretty big....
__________________
I write for www.enjoythemusic.com in the DIY section. You may find yourself getting a preview of a project in-progress. Be warned!
  Reply With Quote
Old 31st May 2007, 03:04 AM   #9
diyAudio Member
 
Join Date: Nov 2003
Location: Brisbane, QLD
Quote:
Originally posted by badman


you're saying a bigger magnet means weaker?
It's do with motor theory (most of which I've forgotten ). Basically a strong magnet x small gap height x large Le, produces a relatively high torque (low Qes), but low RPM (SPL) due to the efficient build-up of back-EMF which opposites the applied force.

It also explains why ribbon tweeters tend to have very high sensitivity despite (or rather because of) the magnet gap height being very large.

Edit:

For example, try comparing Visaton's AL130 M and AL 130 bass mid.

The only difference is that the bass midrange has a longer voice coil, which gives it a lower Qes (and Qts) and lower sensitivity.
__________________
Lech
  Reply With Quote
Old 31st May 2007, 01:17 PM   #10
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Quote:
Originally posted by CeramicMan

Edit:

For example, try comparing Visaton's AL130 M and AL 130 bass mid.

The only difference is that the bass midrange has a longer voice coil, which gives it a lower Qes (and Qts) and lower sensitivity.
Hi,

Those two are not directly comparable.
The lower Qts is due to the lower Fs.

Generally if you make the coil longer Qts
increases, sensitivity drops, and vice versa.

/sreten.
  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 PM2 Tweeter repair kammhron Multi-Way 2 14th July 2013 05:42 PM
Recommendations for a tweeter for Fostex fe-126e? boidos Full Range 11 1st July 2009 05:45 AM
Using Fostex with a helper tweeter, should I cut off the whizzer? cotdt Full Range 17 27th October 2008 11:14 PM
Unknown tweeter, (fostex?) help? Cobra2 Multi-Way 8 16th April 2008 02:50 PM
Fostex 166e BLH Tweeter cantskienuf Full Range 11 18th May 2005 02:34 AM


New To Site? Need Help?

All times are GMT. The time now is 01:11 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