What are these pads for? - diyAudio
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 3rd May 2011, 05:15 PM   #1
diyAudio Member
 
Rullknufs's Avatar
 
Join Date: Mar 2010
Location: Sweden
Send a message via Skype™ to Rullknufs
Default What are these pads for?

Click the image to open in full size.

I found this B&W DM1 (according to the seller) on a swedish market-site.
I see there are like foam pads on the largest driver, what are these for?
  Reply With Quote
Old 3rd May 2011, 05:21 PM   #2
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
The oval driver is essentially a FR (brand escapes me at the moment). On the other side of the cone from the inner dark part is an aluminum subcone. I expect the pads are to restict or control its top-end.

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 3rd May 2011, 05:23 PM   #3
diyAudio Member
 
Rullknufs's Avatar
 
Join Date: Mar 2010
Location: Sweden
Send a message via Skype™ to Rullknufs
Interesting. So it acts like an LP-filter?
Why is there an aluminium subcone? Shouldn't the mms of that driver be pretty high?
  Reply With Quote
Old 3rd May 2011, 06:15 PM   #4
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally Posted by Rullknufs View Post
Interesting. So it acts like an LP-filter?
I would guess

Quote:
Why is there an aluminium subcone?
Similar in function to a whizzer cone.

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 3rd May 2011, 06:59 PM   #5
diyAudio Member
 
Rullknufs's Avatar
 
Join Date: Mar 2010
Location: Sweden
Send a message via Skype™ to Rullknufs
Quote:
Originally Posted by planet10 View Post
I would guess



Similar in function to a whizzer cone.

dave
Ah, cool
  Reply With Quote
Old 3rd May 2011, 08:01 PM   #6
diyAudio Member
 
Join Date: Jun 2004
Location: central Pennsylvania, USA
I think the elliptical cone driver is an EMI - a very fine driver. The foam pads are probably placed so as to damp cone breakup modes. As mentioned earlier, this is a full range driver, quite usable all by itself.

The dark (1 1/4 inch) dome driver is a Celestion HF1300, commonly used on as a mid-tweeter on top of the line British loudspeakers in the day.

The small (3/4 inch) dome is probably a Coles 4001G super tweeter.

These two domes were also used in the Spendor BC-1, one of the top British designs in its day.

Most of these designs had fairly complex crossovers, and were pretty inefficient (78-84 db/w/m).

Regards,

Bob
  Reply With Quote
Old 3rd May 2011, 08:07 PM   #7
diyAudio Member
 
Rullknufs's Avatar
 
Join Date: Mar 2010
Location: Sweden
Send a message via Skype™ to Rullknufs
Interesting. Was this a good speaker back in the days or was it just rubbish?
It's being sold at the moment paired with a Fisher CA-77 amplifier (what about this, rubbish too?) for 1200SEK which is around $195. Not thinking of buying it but vintage hi-fi is interesting
  Reply With Quote
Old 3rd May 2011, 08:14 PM   #8
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
[QUOTE=AstroSonic;2560374]I think the elliptical cone driver is an EMI - a very fine driver. [QUOTE]

Yes, that is it.

Quote:
These two domes were also used in the Spendor BC-1, one of the top British designs in its day.
And i a zillion other British commercial & diy speakers. Sometimes a Celstion HF2000 was subbed in for the Coles.

Coles 4001 - Loudspeakers & Drive Units

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 3rd May 2011, 10:14 PM   #9
diyAudio Member
 
Join Date: Jun 2004
Location: central Pennsylvania, USA
"paired with a Fisher CA-77 amplifier "

The Fisher CA-77 is best forgotten (unless you are into solid state grunge). :-(

The B&W DM-1's are collectable vintage if in near mint condition. The cab looks a little rough, and the associated CA-77 'could' have been run into severe clipping which might have blown one or more domes. Neither of them (the Coles or Celestion) had much power handling capacity. If the price is right, they could be worth purchasing just to get a pair of the EMI full range drivers.

Bob
  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
Insulating Pads. castlesteve Chip Amps 28 29th October 2004 02:35 AM
L-pads????? plasmodium Multi-Way 15 13th May 2004 05:21 PM
pads rulezzz Chip Amps 1 11th January 2004 02:35 PM
Isolation pads Devil_H@ck Parts 9 7th January 2004 05:25 PM
insulation pads Matttcattt Parts 0 11th June 2003 09:46 PM


New To Site? Need Help?

All times are GMT. The time now is 09:59 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