B&W tweeter replacement

[speedmadness]

I recently acquired a pair of B&W DM602s2 speakers. Like seemingly most of these, the original metal dome tweeters had been pushed in. One of them wasn't too bad and I was able to remove the diaphragm and get the dome mostly back into shape. The other was much worse and is in fact torn. Replacement diaphragms and complete tweeters are listed on the B&W site, but are no longer available. Ebay has produced nothing but a bunch of similarly damaged tweeters, mostly at exorbitant prices for something that is basically a paper weight.
For those not familiar, these speakers are generally well regarded but are sometimes considered a bit "bright" on the top end. They are an 8ohm speaker with an SPL of 90dB@1W/1M. The 7" bass driver is 8Ohm, but the tweeter is a 4Ohm, with a 3.4Ohm resistor on the crossover. The crossover is at 4k Hz.
I found a site with tested parameters of the DM60xs3 tweeter which is very similar to the s2 models.


BW Bowers Wilkins Tweeter Loudspeaker Measurements and Information


I would like to use these from Parts express as replacements. Hoping the slightly lower efficiency might resolve the slight brightness of the original tweeters and bring these back to life.


https://www.parts-express.com/pedoc...me-neodymium-tweeter-4-ohm-specifications.pdf


These are another option I found that is relatively simple for me to mount:


https://www.parts-express.com/pedocs/specs/275-053--dayton-audio-ND25FN-4-specifications.pdf


Any input would be appreciated.


Thanks,
Speedmadness

 

[Inductor]

You can test the new crossover by Rumen Suvandjiev, here
B&W Bowers Wilkins DM 601-S3 Crossover Upgrade for Better Midrange Perfoprmance
with new cap from parts express 3.3uF or 3.0uF
Dayton Audio DMPC-3.3 3.3uF 250V Polypropylene Capacitor
and/or you can use the FRD/ZMA Data Files provided for the new crossover before testing.
Dayton Audio ND25TA-4 1" Titanium Dome Neodymium Tweeter

 

[system7]

How many times have we bought a bargain old speaker only to find the tweeters are completely fried? I know I have, too often.

This one is a stinker, despite B&W's generous documentation on service manuals:
B&W Group North America Service & Support - Home

I have heard a pair of these sort of B&W 600 speakers and I heard Kevlar bass breakup and overly bright metal tweeter. Which is confirmed by Rumen Suvandjiev's excellent investigation and (very necessary) crossover upgrade:
B&W Bowers Wilkins DM 601-S3 Crossover Upgrade for Better Midrange Perfoprmance

IMO, if you are a lazy student of diyaudio, you are heading for a world of hurt here!

Couple of "fix it" threads on similar stuff:
B&W DM602 s3 crossover mod
Tweeter Replacement on B&W DM602 S3's

I really don't know how you are going to fix these, because I don't have them in front of me, but these small tweeters might fit and are of similar quality to the B&W Nautilus originals:
SB29RDNC-C000-4 / Fabric – Sbacoustics
https://www.tymphany.com/transducers/xt25sc90-04/

But for sure, some crossover adjustments and soldering, and mechanical adjustment will be necessary.

 

[speedmadness]

Steve,
You seem much more well versed on Crossover design than I. Wondered if you had some insight into the differences in the crossover changes needed for a pair of DM602s2, vs. the DM601s3 that Rutcho worked his magic on? There are differences in the original Capacitor and resistor values. For example. The DM602s2 Caps are 6.8 and 10.0 while the DM601s3 are 4.7 and 10.0 I have also chosen a replacement tweeter that is slightly less efficient for this repair, 91dB vs 92dB.




https://www.parts-express.com/pedoc...me-neodymium-tweeter-4-ohm-specifications.pdf



Thank you,
Rick

 

[system7]

Rick, if that tweeter fits, I'd give it a go!

It is very simple to adjust tweeter loudness. Every ohm in front of a tweeter filter changes level by about 1dB. Resistors cost a buck!

I do have an interest in that speaker. I bought a pair for my nephew for his wedding present.

They were highly rated at the time. Looking back on it, they were a very harsh sound. I think the Kevlar bass was the problem. He has moved on to a lovely old pair of 3 way vintage Celestion Ditton 22:

I don't know how much time or enthusiasm you have for this, but in the long run, you could do worse than look at this Michael Chua design:

Finch (Morel CAT378 + Vifa PL18W0-09-08) – AmpsLab

I can think of two 6" woofers that would work well with that:

Vifa PL18WO-09-08 Woofer

Vifa P17WJ-00-08 Woofer

You'd need to make a new wooden top baffle.

 

[fatmarley]

My advice would be to sell them for parts and buy some much superior Kef Coda 8.

 

[speedmadness]

Thanks for the replies on this. I did machine up some mounting plates and installed some titanium dome ND25TA-4 tweeters: Dayton Audio ND25TA-4 1" Titanium Dome Neodymium Tweeter. I wasn't completely happy with what I had so I also tried some Reference series silk dome: Dayton Audio RST28F-4 1-1/8" Reference Series Fabric Dome Tweeter 4 Ohm .

While both of these seemed to work fine, I was less than thrilled with what I ended up with. In side by side listening with my ancient B&W DM110s, I liked the old 110s better, and I believe it is the kevlar mid-woofer and 4k crossover that I didn't like. I am not a crossover designer and finally decided to cut my losses and part these out. Part of that decision was finding a like new pair of Klipsch RP600M for a very good price right near by. I, for one, agree with the hype. Klipsch Reference Premiere 600M, the Audiophiliac Speaker of the Year - CNET


Thanks again for the guidance on this small audio adventure.