Bi-amping Ascents

[ted99]

I've just finished a dedicated home theater using the new Yamaha RX-Z11 in an 11.2 system. My fronts are the bi-ampable M-L Ascents and an M-L Theater as center. The RX-Z11 specs out at 140w/channel into 4 ohms, and allows bi-amping the fronts, but you lose the rear channel amps if you do so, and I don't want to lose having rear channels. I have a 2-channel Carver M-400t "magnetic field power amplifier" from a few years ago, rated at 300w/channel into 4 ohms. I can use it to bi-amp the Ascents in conjunction with the RX-Z11. The pre-amp outs of the RX-Z11 are live at all times, so I can drive an external amplifier for the fronts at the same time as the internal amp in the Z11. I am postulating that the YPAO frequency adjustment in the Z11 will be able to sort out the levels for the top and bottom of the Ascents. In doing so, I can choose to use the higher power Carver on the low freq inputs (bottom) of the Ascents, or the electrostatic inputs (top). Before I do all this wiring, I'd like other opinions on 1) At the 140w level, is bi-amping useful? 2)the basic advisability of this plan, and 3) which M-L inputs for the Carver?

 

[timm]

My experience with Yamaha & Carver... I had Paradigm mini-monitors and was running off of a Yamah RxV-1000 100 watts into 8 ohms. I added my Carver M500t to the mix - and the difference was SUBSTANTIAL and well worth it. In my opinion - I would - first try the Carver non-biamped - and let it just run the ascents and have your Yammy run the rest.... or 2)Have the Carver run the stats and your Yammy run the woofers. I just think the Carver is a better amp than what you have in the receiver - so I would put it in the place where most music is heard (the stats - or just stand have it run the ascents).

 

[ted99]

Thanks. Your suggestions make sense. Any others with opinions on this?

 

[Rich]

From experience, I will tell you that bi-amping the Ascents really improves their sound. So it is a good idea to try it. I couldn't tell you which amp would sound better on the panels and which on the bass. Your best bet there is just to experiment with each and see which you prefer.

I wouldn't assume that the receiver will be able to sort out the levels between the two. Most likely you will have a gain difference between the receiver amp and the Carver amp. The receiver may be able to adjust for this and it may not. I would do some reading in the manual before I just assumed that it would work. Otherwise, you may need an in-line attenuator for the Carver.

Ultimately, the amps in your receiver are not likely to sound as good as a decent separate amp regardless of whether they are powering the panels or the woofers. They just don't have the wattage to drive the woofers properly and probably don't have the current to drive the stat panels properly. Try it with just the Carver pushing the Ascents and see how that sounds.

 

[ted99]

That's two for the simple solution of using the Carver for both sections of the Ascents. Since I already have the speakers bi-wired, bi-amping is relatively easy. The time consuming part is running the YPAO in each setup. I'm expecting a second sub, soon; and I'll try all the configurations then, since I'll need to rerun YPAO in any event. One can do a "quick" one-position YPAO setup, rather than the 7-position setup; and I'll do that to see if the YPAO can compensate for the different levels for the amps. The Z-11 manual holds hope for being sufficiently flexible to do this. I hate to leave one of those 135w amp pairs unused, so I'm hoping that the 135w internal amps to the ascent low freq drivers and the Carver 300w to the 'stat panels setup works. I have much more confidence in the Carver's high current capabilities than the Z-11's internal amps. The YPAO assigns the front main speakers as "small" in the automated setup (possibly because I have told it I have a THX II sub), so the power requirements for the low freq drivers in the Ascents will probably be less than if they didn't have the 80Hz crossover.

 

[ted99]

Results

Have completed the prime test. Carver powering the stat panels, and internal Z-11 the cone speaker of the Ascents. YPAO correctly set the levels. Not much listening time, but there is tremendous headroom on the panels. I would say that this was a successful operation