Canuck Audio Mart Hifi and Audio ForumCanuck Audio Mart Hifi and Audio Forum
It is currently Wed Dec 13, 2017 8:23 pm

All times are UTC - 8 hours




Post new topic Reply to topic  [ 27 posts ]  Go to page 1, 2  Next
Author Message
PostPosted: Sun Mar 12, 2017 1:53 pm 
Offline

Joined: Sun Jan 02, 2005 10:15 am
Posts: 108
Location: Toronto, ON, CA
Picked up a pair of these from a friend who just upgraded.

There are a few pairs of these in the community so I thought I'd put this out there for both owners and future owners.
They have a well earned reputation for being a tad bright, even on my Classe DR2 DR4 system!, but otherwise a fine sounding speaker.
Don't spend a bunch of money changing electronics. I'm pretty sure the manufacturer voiced them this way to either sell sub woofers or justify the price of the Nautilus models. :-/
Here's my $2 fix.
Attachment:
WP_20170312_16_54_43_Pro.jpg
WP_20170312_16_54_43_Pro.jpg [ 170.82 KiB | Viewed 1392 times ]


Top
 Profile  
Reply with quote  
PostPosted: Sun Mar 12, 2017 2:57 pm 
Offline
User avatar

Joined: Fri Mar 11, 2005 9:30 am
Posts: 1094
Location: Sainte-Marguerite-du-Lac-Masson, QC, CA
Is it working?

_________________
I gave up everything for you, 'Cept the Blues.
Joe Bonamassa, 2014


Top
 Profile  
Reply with quote  
PostPosted: Sun Mar 12, 2017 3:17 pm 
Offline

Joined: Sun Jan 02, 2005 10:15 am
Posts: 108
Location: Toronto, ON, CA
Yes!
But after a couple hours of listening I think there is more to do.
Pulling the tweeter and mid-range back equally gives the speaker better perceived bass, but to my ears, the tweeter still draws too much attention to itself. (never liked metal dome).
The metal grill adds a nasty fizz, but are easily removed. Just a friction fit with help from the tweeter's magnet.
Be careful when you wiggle the grill off. The magnetic attraction could cause you to touch the metal dome as you remove the grill.

TLEGRES wrote:
Is it working?


Attachments:
WP_20170312_18_17_11_Pro.jpg
WP_20170312_18_17_11_Pro.jpg [ 235.29 KiB | Viewed 1347 times ]
Top
 Profile  
Reply with quote  
PostPosted: Sun Mar 12, 2017 5:19 pm 
Offline
User avatar

Joined: Thu Nov 25, 2004 4:52 pm
Posts: 1005
Location: Montreal, QC, CA
"They have a well earned reputation for being a tad bright"
Thats putting it diplomatically :lol:

I experimented with that tweak using different values of wirewound resistors on CDM7nt, 9nt and N804s with varying degrees of success but ultimately, it would take some modification in the pass band and high pass filters to get things right.
Have fun!


Top
 Profile  
Reply with quote  
PostPosted: Mon Mar 13, 2017 7:40 am 
Offline

Joined: Sun Jan 02, 2005 10:15 am
Posts: 108
Location: Toronto, ON, CA
No need to redesign the crossovers Michael, the turnovers are fine were they are. Just need to adjust the output a little.
...now getting rid of the sizzle that metal dome has will be the real challenge! I hate metal domes.

Removing the grill helped a lot, I do put them back on when not listening though. There is also some kind of tuned chamber behind the tweeter. I slid that out and plan to put a little pillow stuffing in the cavity behind the tweeter but even without the fill, some more of the spittyness of the tweeter went away.

Michael F wrote:
"They have a well earned reputation for being a tad bright"
Thats putting it diplomatically :lol:

I experimented with that tweak using different values of wirewound resistors on CDM7nt, 9nt and N804s with varying degrees of success but ultimately, it would take some modification in the pass band and high pass filters to get things right.
Have fun!


Attachments:
WP_20170313_11_14_22_Pro.jpg
WP_20170313_11_14_22_Pro.jpg [ 79.47 KiB | Viewed 1245 times ]
WP_20170312_22_30_53_Pro.jpg
WP_20170312_22_30_53_Pro.jpg [ 229.29 KiB | Viewed 1245 times ]
Top
 Profile  
Reply with quote  
PostPosted: Mon Mar 13, 2017 9:33 am 
Offline
User avatar

Joined: Thu Nov 25, 2004 4:52 pm
Posts: 1005
Location: Montreal, QC, CA
It`s the individual drive levels to the mid and tweeters that require altercation, a notch filter in the HPF would not be a bad idea either but that was not a modification I was willing to make while the speakers were still under warranty.

A Meyer CP10 parametric proved to be a more practical and less invasive solution but even then it cannot change the characteristics of a metal dome. In the end, only a Fedex truck solved the problem completely in all 3 cases :lol:


Top
 Profile  
Reply with quote  
PostPosted: Mon Mar 13, 2017 10:13 am 
Offline

Joined: Wed Sep 14, 2005 11:47 am
Posts: 3834
Location: Ottawa, ON, CA
Ended up doing the same thing with my N804's.

Except, suggest trying a Mills power resistor.
I've found those commercial grade power resistors sound harsh.

The resistor value I used between the posts on the N804's was 15 ohms.


Something to investigate.
It seems one major change from the N804's to the Signature 804's
was the inductors, for the LH drivers, have a lower R value.

To add, B&W manuals can be obtained on line.
So if you want to check the cross over schematic, it will be here
http://bwgroupsupport.com/manuals/bw-service

.


Top
 Profile  
Reply with quote  
PostPosted: Mon Mar 13, 2017 10:50 am 
Offline

Joined: Sun Jan 02, 2005 10:15 am
Posts: 108
Location: Toronto, ON, CA
15 ohms seems a lot. I used 1/10th that much.
I do have the service manual. Went looking for it even befor I picked up the speakers.
The tweeter/midrange balance is ok. It's just that they are too loud with respect to the woofers AND the tweeter has a nasty character that needs to be dealt with.
I haven't ruled out replacing it with a silk dome ...if I can find one that fits. I'm not going to do anything that is not easily reversed.

Uunderhill wrote:
Ended up doing the same thing with my N804's.

Except, suggest trying a Mills power resistor.
I've found those commercial grade power resistors sound harsh.

The resistor value I used between the posts on the N804's was 15 ohms.


Something to investigate.
It seems one major change from the N804's to the Signature 804's
was the inductors, for the LH drivers, have a lower R value.

To add, B&W manuals can be obtained on line.
So if you want to check the cross over schematic, it will be here
http://bwgroupsupport.com/manuals/bw-service

.


Attachments:
WP_20170312_22_28_42_Pro.jpg
WP_20170312_22_28_42_Pro.jpg [ 80.74 KiB | Viewed 1184 times ]
WP_20170313_14_20_16_Pro.jpg
WP_20170313_14_20_16_Pro.jpg [ 60.83 KiB | Viewed 1184 times ]
Top
 Profile  
Reply with quote  
PostPosted: Mon Mar 13, 2017 1:06 pm 
Offline

Joined: Wed Sep 14, 2005 11:47 am
Posts: 3834
Location: Ottawa, ON, CA
Bill wrote:
15 ohms seems a lot. I used 1/10th that much.
I do have the service manual. Went looking for it even befor I picked up the speakers.
The tweeter/midrange balance is ok. It's just that they are too loud with respect to the woofers AND the tweeter has a nasty character that needs to be dealt with.
I haven't ruled out replacing it with a silk dome ...if I can find one that fits. I'm not going to do anything that is not easily reversed.


Bill,

I wouldn't replace the tweeter - you'll lower the value of the speakers.

It seems the problem in this era, was that B&W had highly accurate tweeters
but used lower grade crossover components - which were labeled "Bennic"
The subsequent use of higher grade crossover components, used in the Signature and Diamond series,
is almost an admission of this.

In the Diamond series, B&W used Mundorf Silver/Gold Oil Caps in series with the tweeter.
These are underneath the person's arm in the picture.
The white caps in the picture are basic Mundorf MKP's, which were used in non strategic locations.
The power resistors they used, look to be Caddock - but I can't confirm this.
http://www.caddock.com/Online_catalog/p ... wAodPcMEPA

I replaced the "Bennic" resistors in my 603 s2, with Mills and it made a dramatic improvement.



Image


Top
 Profile  
Reply with quote  
PostPosted: Mon Mar 13, 2017 2:15 pm 
Offline

Joined: Sun Jan 02, 2005 10:15 am
Posts: 108
Location: Toronto, ON, CA
Like I said, anything I do will be easily reversed. I won't be butchering the speaker in any way. Replacing the tweeter is not my fist step to improving the sound, although it is most likely the best way, buying "boutique" parts is even further down the list.

On the tweeter approach. A quick search brought up a couple possibilities. Both Vifa and SEAS make this style of tweeter. The SEAS actually makes the same tweeter in both a fabric and metal dome. I doubt B&W made the drivers, although they could have specified the mount.


Attachments:
h1396-1.jpg
h1396-1.jpg [ 113.46 KiB | Viewed 1128 times ]
264-1018_ALT_0.jpg
264-1018_ALT_0.jpg [ 167.77 KiB | Viewed 1128 times ]
Top
 Profile  
Reply with quote  
PostPosted: Mon Mar 13, 2017 4:04 pm 
Offline

Joined: Sun Jan 02, 2005 10:15 am
Posts: 108
Location: Toronto, ON, CA
Added 50 ohms across each tweeter just now. Likely gonna have to drop that to 30 ohms.


Attachments:
WP_20170313_19_43_35_Pro.jpg
WP_20170313_19_43_35_Pro.jpg [ 87.85 KiB | Viewed 1111 times ]
WP_20170313_19_36_24_Pro.jpg
WP_20170313_19_36_24_Pro.jpg [ 85.32 KiB | Viewed 1111 times ]
Top
 Profile  
Reply with quote  
PostPosted: Tue Mar 14, 2017 8:06 am 
Offline

Joined: Wed Sep 14, 2005 11:47 am
Posts: 3834
Location: Ottawa, ON, CA
Michael F wrote:
I experimented with that tweak using different values of wirewound resistors on CDM7nt, 9nt and N804s with varying degrees of success but ultimately, it would take some modification in the pass band and high pass filters to get things right.


I think part of the issue is that the impedance of the LF drivers drops down to a low value.

Looking at the schematic, there are 2 inductors in series with these LH drivers.
The R of these inductors is significant compared the Z of the LH drivers.

In the Signature series, they increased the wire guage of these inductors.

So basically one issue is that much of the power intended for the twin woofers
is being dissipated by the R in the inductors.

Replacing the larger inductor with one outside the cabinet may be a solution.

Bi Amping - one amp for the LH / MF drivers and another amp for the LF drivers may be another solution.


Also, with B&W's - absolutely make sure they are well anchored to the floor
with floor spikes - this makes a noticeable improvement.


Top
 Profile  
Reply with quote  
PostPosted: Tue Mar 14, 2017 8:57 am 
Offline
User avatar

Joined: Thu Nov 25, 2004 4:52 pm
Posts: 1005
Location: Montreal, QC, CA
Uunderhill,
I had some S804s with a similar driver compliment in the same room and system a few years later and found them to be completely different in character, so much more listenable in stock form.
It would be interesting to compare the two passive networks.


Top
 Profile  
Reply with quote  
PostPosted: Tue Mar 14, 2017 10:46 am 
Offline

Joined: Sun Jan 02, 2005 10:15 am
Posts: 108
Location: Toronto, ON, CA
Found a review of the speaker were they did spectral measurements, now a days a review is personal opinion coupled to literary masturbation. Anyway, the graph showed a rise in output, at and above human voice. The mid driver handles all of that so i'll look into the notch filter Michael suggested but for the mid, not the tweeter. Just happen to have the right value coils in my used parts drawer. :-)

Here's a link to that review.
http://www.audio-ideas.com/reviews/loud ... dm9nt.html

The bass isn't lean on these speakers it's just being drowned out by the mid. My $2 fix takes care of that. No need to spend large on 12 gauge coils that won't be enough on their own.


Attachments:
WP_20170314_14_34_09_Pro.jpg
WP_20170314_14_34_09_Pro.jpg [ 110.02 KiB | Viewed 983 times ]
Top
 Profile  
Reply with quote  
PostPosted: Tue Mar 14, 2017 11:20 am 
Offline

Joined: Wed Sep 14, 2005 11:47 am
Posts: 3834
Location: Ottawa, ON, CA
From this magazine review it says:
These are very fine measurements, especially at frequency extremes, and are typical of B&W.
However, the fairly broad midrange hump from 400 to 2 kHz is what defines the sound of the CDM9NT,
the new FST midrange seeming B&W CDM9 NT Impedence to be just a little more prominent than its siblings


If I'm reading this curve correctly - it says the FST mid range could be attenuated by about 3 dB's.

Looking at the impedance curve, Z drops down to about 3.1 ohms @ 100 Hz
which can present a difficult load for many amps.


Image


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 27 posts ]  Go to page 1, 2  Next

All times are UTC - 8 hours


Who is online

Users browsing this forum: msommers and 6 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group