I have an old pair of B&W DM602s2 that I would like to perform a similar crossover mod to what Rutcho did on those DM601s3 a while back. B&W Bowers Wilkins DM 601-S3 Crossover Upgrade for Better Midrange Perfoprmance
Interesting mod to bring better performance to an old pair of speakers. My DM602 are the next size up in the 600 series and have a larger cabinet and Bass driver, but all of the 600 speakers in a given series use the same tweeter. These also both use a 4000Hz crossover frequency. The crossover components are of different values however. Looking for input on capacitor, Inductor and resistor values that should be used. Anyone with a better understanding of Rutcho's mods want to give some input?
Thanks in advance,
Rick
Interesting mod to bring better performance to an old pair of speakers. My DM602 are the next size up in the 600 series and have a larger cabinet and Bass driver, but all of the 600 speakers in a given series use the same tweeter. These also both use a 4000Hz crossover frequency. The crossover components are of different values however. Looking for input on capacitor, Inductor and resistor values that should be used. Anyone with a better understanding of Rutcho's mods want to give some input?
Thanks in advance,
Rick
Hello Rick. The changes include increasing the order of the filters. Removing the resistor by the inductor in the tweeter circuit makes the rolloff more steep through the stopband. The woofer has an RC circuit added, which for the most part give or take, turns this into a second order filter. OP has then chosen to swap the polarity, which understandably requires attention after this kind of change.
It also appears that a tweak of the tweeter first resistor and capacitor helped reach the goal.
Looking at the result, the original treble might have been a bit loud. It seems as though originally the treble 7-10kHz was tamed on axis by an interaction with the woofer. It would have given a more bright reverberant field. It's difficult to say if this on its own is a bad thing but there was definitely something uncertain about it and that is the general inconsistency of woofers at such higher frequencies. The polar plot looks ok but it isn't high resolution. Normally I'd suggest a tenuous nature in such an interaction.
On one hand, the new version gives the response a broad downward slope. It reduces the woofer participation through breakup. While also reducing the region of the crossover, there seems to be a limited band where phase comes together. Some would point out that this is odd, but I'm not so dismissive myself. Look at the listening impressions. It's unclear whether you could do even better yourself, but that's always possible when you diy 😉
It also appears that a tweak of the tweeter first resistor and capacitor helped reach the goal.
Looking at the result, the original treble might have been a bit loud. It seems as though originally the treble 7-10kHz was tamed on axis by an interaction with the woofer. It would have given a more bright reverberant field. It's difficult to say if this on its own is a bad thing but there was definitely something uncertain about it and that is the general inconsistency of woofers at such higher frequencies. The polar plot looks ok but it isn't high resolution. Normally I'd suggest a tenuous nature in such an interaction.
On one hand, the new version gives the response a broad downward slope. It reduces the woofer participation through breakup. While also reducing the region of the crossover, there seems to be a limited band where phase comes together. Some would point out that this is odd, but I'm not so dismissive myself. Look at the listening impressions. It's unclear whether you could do even better yourself, but that's always possible when you diy 😉
The two speakers have nothing in common, different woofers and tweeters. I bet that they share a common philosophy, and something can be improved, but without a measurement this is IMHO impossible. I had the DM602s2 a while back and sold them, with what I know and can do now if I still had them I could have tried this task.
Ralf
I had a pair of DM602s2 which I felt lacked midrange.
I've now got a pair of CM8s2 which absolutely knocks spots off them.
I've now got a pair of CM8s2 which absolutely knocks spots off them.
I see he has a 'Contact' where he welcomes questions about his projects. Why not drop him a line?