A Newbie Hello, and yet another bi-amping question.

Doug Ravizza · « **on:** 4 Nov 2005, 07:28 pm »

Greetings to all.

I’ve been lurking on this board for ~2-1/2 years contemplating whether or not to get a pair of RM40’s, and three weeks ago, I finally did.

I was wondering if anyone is bi-amping their 40’s and using stepped attenuators, such as those available from Marchand or Goldpoint, for balancing the levels of the LP and HP amplifiers.

Apologies in advance if this has been discussed before.

Thanks,
Doug

woodsyi · « **Reply #1 on:** 4 Nov 2005, 07:46 pm »

Yes, when I was passively biamping them, I did use an atenuator on the mid/highs to balance. I didn't like it. The attenuation killed the mid/highs. I went with active biamping and like it much better. You do have to disconnect the coil from the woofer. I think I may even have posted pictures of it. This of course is assuming you are using tubes on top and ss on the bottom. If you are using same type amps, you may not have to use any attenuation.

Doug Ravizza · « **Reply #2 on:** 4 Nov 2005, 08:42 pm »

woodsyi,

What type of attenuator did you use, stepped/potentiometer, series/ladder?
Was it matched to the input impedence of you amp?

I am surprised at your result. Although I have no personal experience with them, stepped attenuators are supposed to be very good sonically.

woodsyi · « **Reply #3 on:** 4 Nov 2005, 09:16 pm »

Doug,

It was this one. http://www.tubeaudiostore.com/pasvolkit.html I built it using an aluminum switch box. It was no thing of beauty but was functional. I am sure it was a combination of the two amps and preamp that didn't match well for this particular set up. If you are more carefull with component matching you may do better but I have to tell you the biggest gain was in going active. Ribbons just sing without the woofers messing them up.

ZMan · « **Reply #4 on:** 8 Nov 2005, 04:23 pm »

Doug,

Take a look at Ric Schultz's design at EVS:
www.tweakaudio.com

His Attenuators fit directly onto the amp and do not degrade the signal. I've tried a few passive pre's, each has had it's pro's and con's. EVS poses much less of a compromise to the sound. It may offer an interesting alternative.

Ed

Doug Ravizza · « **Reply #5 on:** 9 Nov 2005, 03:47 pm »

Ed,

Thanks for the link. I've decided to experiment with inserting "breadboarded" voltage dividers on the inputs of the HP amp to see if attenuation at that point will help reveal the bass response of the 40's. My room is 15' X 23', vaulted ceiling, ~3500 ft.^3 and just seems to absorb most of the bass out of these guys.