Distortion on RD0194-1

decato

Hi everyone,
I have just completed restoring (and modifying) a beautiful pair of Monitor 7Cs in black with the original stands. I ordered a pair of RD0194-1 tweeters to replace the SL2000s. Oddly, one of them sounded "off". The distortion became evident when playing music with a keyboard, in particular a Rhodes Phaser. Instead of a clean spacey sound, it had a buzz on certain notes and chords. I heard the same distortion once before on my Monitor 5 Series 2 speakers that I purchased new in 1992, and the dealer installed a replacement SL2500.

This time I was more inquisitive, so I removed the front plate, which includes the dome and voice coil assembly. The problem was obvious -- a few tiny metal shavings (like finely ground peppercorn) had made their way into the voice coil gap. It required some work to get them out, but afterwards everything sounded great. I am glad the solution was easy and I wanted to share it with you in case you experience the same problem.

Regards,
Brian

xschop

QC is lacking nowadays. Glad you got them rectified. Never seen 7Cs in factory black myself.

decato

xschop wrote: »

Never seen 7Cs in factory black myself.

Here's a picture.

xschop

Thanks for sharing. Those would be the 7s I'd mod up. Is there a factory brace front to back on those?

decato

xschop wrote: »

Is there a factory brace front to back on those?

There's no bracing. Ideally, there should be one from front to back between the driver and passive radiator. The problem is the crossover is mounted higher up in this series, right where the brace should go. You can install two braces instead, one on each side of the crossover.

xschop

Ok. That's the same obstacle I encountered on the 5B's crossover position. One mod I still want to do on RD0's is stuff the chambers between pole-piece and magnet IDs with lamb's wool and see if that smooths them out as well.