I have no experience on 4400 but I have a BM3000 which can't be that much different. Usually the switches on the front panel get oxidized and cause one channel to mute or go down in volume. In my BM3000 I found especially the MONO L / R, LOW / HIGH FILTER and LOUDNESS switches to cause lost channels. Does the 4400 have a TEST -switch at the rear panel? That have caused me troubles as well. 

Season greetings from not-so-far-away 🤒

I agree on the switches. Especially the ones that are only rarely used. Work them all a bit.
Swap the speakers first to make sure that the problem is not with one of them.

Martin

Many thanks for your replies 🙂

Hmm, I tried going through the switches a bit, but I couldn't really notice anything this time - also moving to the second speaker outputs sounded pretty identical to me (first time by the way) 😮 But yes, swapping the left and right channels does make a difference - it sounds more balanced and better having them reversed 😎

I've got to admit that I might be a bit confused by myself now as well, but shouldn't that mean one of the channels is getting more power than the other one? Would I be able to measure the output with a multimeter just to be sure?

My current speaker placement isn't too optimal - that's why I'm scared if there used to be a slight problem with the other channel which just got normalized again, but I'm thinking it the wrong way now as I might already got used to it before 😛

Regards, Jouni

A signal generator and a power (watt-)meter would be nice.
I use B&O TG7 and RWM4 but others will work just as well.
A multimeter on AC volts put across the speaker output and a steady and continous
test signal of f.e. 1KHz sinewave on an input will surely be adequate
to at least give you an idea.

Martin

Oh yes!

The multimeter test showed 0.044V for the left channel and 0.054V for the right channel playing a 1kHz sine wave MP3 with volume at 1, balance at 0 and loudness on. I used an old 2-3m speaker cable to meter though, but of course that shouldn't have any effect when I just move the connector between the channels.

I've got to set the balance slider to around -1,1 or -1,2 to get them both at 0.044V - hmm.. Let me try with different frequencies and a bit higher volume as well 😂

Edit: Well most interestingly noticed that pushing down the mono switch makes the difference like half smaller - otherwise different frequencies and volumes were acting quite much as you could supposed, as well as loudness and linear switches (loudness seemd to have a very minor effect on the lower frequency balance though, but nothing more than that apart from the normal level boost).