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Am I nuts? Biamping question...

Hi,
I'm new here and a bottom feeder in the world of high end audio (read as "poor musician") I am upgrading my studio. I have PMC FB1's (150W) I just purchased thru Audiogon. When I pulled my 1979 Roland spa-240 amp out of storage (I've been using active monitors: Event Tria) and hooked up the FB1's they sounded superb. Two days later one channel of the amp fried - I'm guessing deteriorated caps. So I started shopping. I am considering a pair of Hafler P7000's to set up a biamped system, but those amps are WAY overkill power-wise. Am I nuts to use such amps with these speakers?

The other option I am considering is using something more reasonable like P3000's in a vertical (pseudo) biamp setup. Do the differences between "true*" and "pseudo" biamping justify the use of the P7000's? I have never done "true" biamping before, only pseudo. The P3000's and the P7000's are the same price.

I know I'll need to make custom crossover cards for the P7000's - no biggie. The FB1's crossover is at 3k. I intend to set the low pass at about 3.5k for the woofers, and the high pass at about 2k for the tweeters.

I am trying my hand at budget mastering aimed at indie musicians. Any help is appreciated.
-jim
http://www.fixthatmix.com

* I know that "true" biamping involves removing the speaker crossovers - not something I'm interested in at this point. I believe my plan will yield the benefits of true biamping without screwing with the speaker design. Please tell me if I am wrong.
jimbo_9er
kr4's avatar
kr4
3,686 posts
 
If you are cascading the effects of an external custom crossover on top of the built-in speaker crossover, the results are unpredictable and will likely be inferior to using either one or the other. You will not be getting the benefits of true biamping; you will be screwing up the speakers performance.

Either do it for real by removing the built-in crossovers or fake it by not bothering with an external crossover.

Kal
jimbo_9er OP
3 posts
 
Hi Kal,
Thanks for the feedback. The x/o's in the P7000 are before the power amp section. I don't think that removing freqs below 2k in the signal to the tweeter (and its x/o) would have a negative effect, but that is why I posted here. The speaker x/o is at 3k, and there are separate x/o's for each driver. Thanks again for commenting.

BTW - My reasons for wanting to do this include: avoiding burning up all that low freq energy in the tweeter x/o, and cutting distortion in the amps. I am not arrogant (enough ;) to think I can set up a true biamp and improve on PMC speaker design.

-jim
kr4's avatar
kr4
3,686 posts
 
Still the same. Cascading two crossovers creates phase and level problems. Use one or the other.

Kal
butsy
23 posts
 
I believe the improvement of bi-amping in a speaker like yours would be minimal. Try it with one amp first and if it sounds great ,,leave it alone (for now)!
horseface's avatar
horseface
222 posts
 

I had a Yamaha pro setup for a while with JBL 18" bass cabs, 15" JBL mid cabs and a set of Klipsch LaScala's. I was running one of the big pro Yamaha amps (350 wpc), a smaller Yamaha amp for mids and a Peavey CS-1000 for bass. I had the 18" subs (2245H) wired in parallel and the CS-1000 running mono. I bought an three way Ashley crossover.

To make a long story short ... It sounded like crud. No matter how I tried to dial it in ... when I dumped the Ashley and ran the built in passive crossover's it got a lot better.

For what it's worth - I think Kal's got a point. I do like the idea of bi-amping however. I'm running a small and large Mark Levinson amp in my 2 channel room and have the jumpers removed on my Aerials. I like the passive crossovers.

Pretty fantastic ...
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