Fuzzy sound -- any ideas?

WarpedWoof

Hi! I'm looking for some ideas. I recently bought a pair of old Monitor 7A's with the Peerless tweeters. One mid driver was locked so I went ahead and got a pair of replacements from Polk, so I have new mid drivers on both speakers. I'm driving these with a Denon DRA-835 amp, but I've tried using another amp with similar results. Basically, not all the time, but a good amount of the time the sound is muffled, heavy on the low mids with recessed vocals. At first I thought this was a source problem, but it seems like this is not the case. The same source material can sound beautifully clear or poor. So far I've tried changing speaker placement, different cable and a different amp. Changing the placement did help somewhat, but didn't fix the problem altogether. Could this be due to crossover problems?

Any suggestions welcome!

drumminman

Do you have output from your tweeter(s) when the sound is bad - I would check that first.

Move onto the simple things - do you have good connections between speaker wire and binding posts?

Also, if you have fuses I'd go ahead and replace them. Sometimes they can cause this sort of thing even if they appear to be good - and they're cheap.

other possibilites include a cold/broken solder joint. You'll need to get inside the speakers and have a little knowledge of circuit boards/crossovers to check this. Visually inspect everything. If you know how to use a multimeter now is the time.

Sometimes you can find cracks in joints that appear good if you slightly flex the circuit board under a strong light.

Good luck and post what you find.

WarpedWoof

Great feedback! Much appreciated.
I hadn't thought about the fuses. I have noticed that sometimes if I simply pick up a speaker and move it around then set it down, the sound improves! I will try the fuses first, then get out the multimeter and have a go at the crossover board.

Thanks!

WarpedWoof

Changing the fuses made a huge difference -- I don't think the speakers have sounded this clear since I've had them. Thanks so much!

drumminman

:cool:

skrol

You could have a bad connection internally. It could be a wire to the tweeter, a component on the crossover or even a cracked crossover printed circuit board. I found a bad solder joint on one of my crossovers and a joint that was not even soldered where two caps were paralleled. The lead of one was wrapped around the other but not soldered.
Stan

WarpedWoof

Yeah, the joy has been short-lived -- fuzzy sound is back.
I tested the resistors (there are two in my version of the M7 crossover) and one is out of spec. I tried to test the caps, but I guess I can't do that accurately without removing them, and if I'm going to go to that much trouble, I may as well upgrade them. Hopefully, any cracks in the PCB will be evident at that point

soundfreak1

May be worth doing the xovers than.also ck the fuse holders, they can get loose over age as well as the contacts to them inside.