Converting B & W DM6 To 2 Way Active

[Aug]

Following on from my previous posting for DM6 Speakers, I went with the attenuation before network, which provided the best integration with the other drive units.

I have now decided to go another step forward, hopefully, and part activate the system. I intend to run the LF of one Amp and the mid/high of another.
I intend to keep the crossover frequencies at 500hz and 5khz but using a using a 24db linkwitz filter for the 500Hz crossover.

I will be removing the high pass capacitor c3 from the band pass section of x-over and was wondering whether the midrange unit would still be in phase with the other units or would need reversing?

 

[Deano452]

Yes you should reverse the midrange if you do that at the speaker end you can easily reverse them back should you need to .

 

[Aug]

Hi Deano, tanks for your reply. That was what I was thinking as well, but then I thought that would mean mid would be out of phase with tweeter and reversing that would then mean it would be out of phase with bass, not sure how much effect this would have.

 

[Aug]

Thought I should add, I would be removing all components from Bass unit filter.

 

[Aug]

Any further comments on the possible Mid- Tweeter phase conundrum?

 

[Deano452]

I think with a Linkwitz crossover 24db filter you will find that there will be a big suckout of around -24db at the point of crossover bass to mid and then mid to tweet. It is effectively 360 degrees out , but try in then out of phase at the speaker terminals . By reversing it the mid should sound lowder.

 

[Aug]

Hi, I carried out some testing of various phase combinations. Settled on Mid Range reversed, but HF remains as is. Used a couple of different Sound Level Meters, found it's not as straightforward as I thought. Probably down to Room reflections, where I was standing, but managed to identify the dB drops when out of phase. Sounds very good as well. I thought the HF would need phase change in line with mid, but definite dB drop when phase changed.