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Bi-Amp success story

Hello all-

This is a follow-up to many threads I have posted already (using my e-mail address - joelm@charter.net before I signed up officially) Rather than tack this on at the end of any one of them I wanted to start a new thread summing up my experience. In doing so I will cover what I did and what worked and what didn't work for me.

My Gear (that matters to this discussion)

Yamaha CX-1000 pre-amp (I also use this for my d/a)
Yamaha MX-1000 power amp (330 wpc into my 4 ohm speakers)
and another MX-1000 power amp for bi-amping (effective 660 wpc?)
Paradigm X-30 line-level active crossover
Infinity Kappa 9 speakers.
Phoenix Gold ZEROpoint Reference II Inner Space reference speaker cable (2 10 gauge conductors) for the low end and Phoneix Gold 12 gauge for the highs.

(1) I tried bi-wiring and that produced no noticable effects for me. (using 1 MX-1000 amp) Maybe with better wire there might be a difference.

(2) I tried bi-amping using no active crossover, and while the soundstage was a bit better the amps were working hard for just a bit of extra volume and in my opinion without an active crossover before the amps it is just a glorified bi-wire.

(3) My final arrangement was very satisfying. My Kappa 9 speakers each have 2 12" drivers that cross-over at a low 80hz. I used the Paradigm x-30 with the 80 hz high pass (a choice of 50,80,120 hz) after the pre-amp and ran it to the right side of each MX-1000. Then I ran the sub-out for each side to the left side of each MX-1000. So one MX for the left speaker, one for the right. I chose this rather than the lows to one amp and the highs to another for a few reasons. (1) elimination of cross-talk (2) decrease in overall demand on each amp during segements with high bass or high highs.

The results were great! I have a much clearer soundstage, and I get a louder, clearer sound than I have ever had before. If I had the gear I would try putting a specialized amp on the lows/highs. One suited best for each purpose. But before I would go to that level I would upgrade everything I have except for the speakers. If I can scrape together the cash I want to try a Sunfire Classic Tube pre-amp and a Sunfire Signature Stereo amp in a non-biwired configuration too. If I like it better (as I am sure I will) I might liquidate my Yamaha gear. However I run my pre-amp "source direct" by-passing all tone controls. Since my Kappa 9's have a strong high-end it is nice to be able to compensate for that just by adjusting the level of the amp or the crossover.

Anyway thanks for all the advice that has gotten me this far!

Regards,

Joel
a71spud

Showing 4 responses by garfish

garfish
1,840 posts
 
Hi Joel; Thanks for sharing your experience(s) with bi-amping. The subject is quite interesting to me as I am planning a "passive" bi-amp set-up myself in the next month or so. I have Vandersteen 3As, and Vand. Audio highly recommends passive vertical bi-amping. Based on your experience, it sounds like you weren't too impressed with passive though. I guess I'll find out.

I'm no expert but I think your "active" bi-amp may have worked well mainly because you were able to set your active X-over at the same HZ that your speakers crossed over, ie 80 HZ. As to power rating, do your Yamaha amps actually produce 330 wpc into 4 Ohms? If so it should say so in your owners manual (ie, you can't just double 115 wpc and assume they are putting out 330 wpc into 4 Ohms unless they are designed to do so). And too, I don't think you can add 330 + 330 and claim 660 watts, because amp power is conventionally expressed in watts per channel. Also, if your amps are stereo amps (as opposed to dual mono), the bass side would likely be drawing much more power than the mid/treble side.

One of the main reasons to have powerful amps is that they can better handle the "transient spikes" in music that require much more power and occur especially in dynamic music with strong bass. Speaker impedence and sensitivity are important too. And of course the other reason is just simply to play louder. A speaker with nominal 4 Ohm impedence would likely have a range of something like 3 Ohms to 16 Ohms over their whole frequency range.

About "loudness"; it takes double the power to get a 3 dB increase in actual loudness. So if your amps were actually drawing 200 wpc (and at this point I think they would be very hot), it would take 400 wpc to get a 3 dB increase in SPL. But OTOH if they were drawing 10 watts at a given SPL level, then 20 watts would produce a 3 dB increase in SPL-- this would be a much more likely scenario unless you're running your system at absolute max.

I suppose the above sounds sort of negative, but I don't mean to be. I'm just trying to understand what you did so it might help in what I do in a month or so in my attemps at bi-amping. Again, thanks for sharing and Happy Listening. Craig
garfish
1,840 posts
 
Hi (again) Joel; Thanks for the detailed info. on your bi-amp setup. Your Yamaha amps are more powerful than I expected, especially dynamically. I don't know what order cross overs your Kappa 9 speakers use, but Vand. 3As use 1st order-- this is the steepest x-over.

An active electronic x-over cannot be used w/ Vandersteen speakers, because the signal cannot bypass the internal x-over. Because of your thread, I dug out my Vand. owners manual, and looked up specs., x-overs etc. R. Vandrsteen also says only slight to moderate improvements in sonics can be expected by passive bi-amping, and he goes on to say that a single higher quality amp will out-perform a pair of lesser quality amps-- I guess I'm about to find out about some of this, so we'll see!

Just one more Vand. "thing"-- their speakers also should not be horizontal bi-amped as mids will be "confused" (like me). I already have two high quality McCormack DNA-2DX amps(300 wpc 8 Ohms, 600 wpc 4 Ohms etc), and they are now in for upgrading at SMc Audio to Rev. A, when done, my amps should approach world class-- but still, I've got my fingers crossed that I'm going to like the "new" amps, and in a bi-amped configuration. I've enjoyed the exchange of info. Thanks. Craig
garfish
1,840 posts
 
Sean; It's late, but I've got to know-- would you feel differently if the amps were 1200 wpc mono-blocs? I can easily arrange to have my DNA2s converted to 1200 wpc monos and use them as monos rather than passive bi-amping. The mono cost is not expensive-- about $500. per pair. Thanks Craig
garfish
1,840 posts
 
Thanks for the response(s) guys. In the course of arranging to have my amps upgraded, I have had several long talks with Steve McCormack. There are four (main) options:
1. Upgrade, and use, only one amp.
2. Upgrade both amps and vertical biamp.
3. Upgrade both amps and convert to monoblocs.
4. Bi-amp with no up-grade (no matching either)-- but I consider matching very important, but shipping two 100 lb. amps is expensive just for matching.

Where two amps would be used, matching would be done as closely as possible by SMc. S. McCormack said he had a slight preference for the mono-bloc route, but that the other two methods are excellent also. Richard Vandersteen said, and I quote "only an idiot or a drunk would hook up that kind of power to Vandersteen speakers" (RV was referring to the 1200 wpc monos).

Well, decisions had to be made and in continuing discussions with Steve Mc., and the fact that I already owned two DNA2s, we decided that upgrading the amps to Rev. A, matching the amps, and then vertical bi-amping would be an excellent way to go-- and that's the route I'm taking. I emphasize that the the DNA2s are very powerful as is, ie 300/600/1200 wpc into 8, 4, 2 Ohms. These amps will even put out 2400 wpc into 1 Ohm. I also note that these amps are a true dual mono design-- they are not conventional stereo amps.

Steve, Richard V., and I all agreed that going to monos would be of little or no benefit for my purposes and would even likely be overkill. A notable benefit of identical amps for biamping is that if I don't like the biamping, I can sell one of the DNA2s Rev. A and keep one for my own use, whereas monos would have to be sold as a pair.

R. Vandersteen recommends 1. bi-wiring, 2. vertical bi-amping, and 3. short as possible speaker cables with Vandersteen speakers. BTW Sean, in the short term, at least, I'm staying with my 14 ft. spkr. cables, and 4 ft. ICs. One last point-- while my DNA2s are gone, I'm using a stock DNA.5 (I do have a Syn, Res. MC cord on the .5), and it's sounding great. Maybe all this expense and hassle with big amps is not needed-- but hey, I'm an audiophile: ).Thanks again for the interest in my "project"-- guess I should have started my own thread on it-- maybe after I get the amps back. Cheers. Craig.
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