B&W Matrix 805 Problem

Hi everyone,

I need help in finding out what's wrong with my speaker. I have been using the 805 as surround speakers in my HT setup. Recently, when I tried to calibrate the channel volume, I noticed that one of the speaker would play a much lower volume than the other.

If I tried to increase/push that particular speaker by increasing the output gain from my Pre/Pro, then I would hear some kind of crackling/hissing sound at the higher level.

The strange thing is, sometimes, the volume of the speaker would gradually rise up to reference level if I play the pink noise for a while without adjusting the gain from the pre/pro. When this happened, I didn't hear the crackling sound. Other times, if I leave it one for a while (not playing any sound through that channel), and then play the pink noise, it would play fine at reference level. The fluctuation varies over 10 dB (i.e., not a small difference) between when it doesn't works to when it works.

I have swapped cables etc and I am pretty sure it is the one speaker that is problematic.

My question is: Does it sound like it is the Kevlar driver or the internal crossover that needs replacement?

Thanks in advance for reading and your advice.
If the speaker was defective it is hard to see how it could repair itself so of the two the crossover would seem more likely. Are you using their equalizing network? Mine is currently not working properly. I assume that you have switched the speakers and it is not channel dependent.
Thanks for your posting. I am not using their Bass Alignment Unit if that's what you mean.

The oddest part for me was the level would fluctuate over time. Sometimes, once it reaches the normal level, it would stay at that level. I don't have any actual data, but my impression is that if I play that channel at high/reference volume for a while (i.e., when I calibrate), it tends to get better. As a surround channel, the speaker normally would not get that much work, but it feel as if, it needs to "warm-up" by playing at higher volume before it stabilizes.

I have indeed switched the channel output from the amp end and the same speaker remained problematic. I guess I have not officially ruled out the speaker cable but that really seems unlike.

I forgot to mention the reason I haven't taken the speaker apart and looked inside is because they were mounted high up on the wall and not easily accessible. So I am hoping to have some idea what might be wrong before I proceed further.