Bi-amping question

Just theoretical at this point. If I had a pair of speakers that could be bi-amped, would it sound "right" with a tubed amp going to the upper section (highs, mids, bass to around 125Hz or so) and a solid state for the lower bass drivers? Part of me thinks it might be a good combination, but another part thinks that because they are two different amplification styles, they may not mesh properly. (IOW, the transistor amp might be "faster"...for lack of a better term.)

 

Rood, I don't know the first thing about this but from what little I've read, it sounds like an interesting combination. You'd get the sweeter midrange of tubes and the bass slam of SS. Sounds good, at least on paper.

 

If you have the right amps, this can work very well. For the woofers, I would use a Bryston solid state amp, and for the upper range, I would use a McIntosh tube amp.

 

Steve--is that for the reason I was getting at? (The amps being too dissimilar to "mesh" properly.) It would make more sense with a separate subwoofer, but having a pair of woofers on the same plane as the mids/highs, I was thinking there might be some kind of time distortion there.

 

I have only one amp in my bedroom, the amp into my HT receiver. If I want it loud, I just use volume controls.

 

Are we talking about an active speaker Rudy?

 

I was looking at a line of speakers that is a bit power-hungry, and it got me to thinking about amplification needs if I were to buy or build a similar system. Owners of the line I looked at were saying the speakers needed a good hefty amplifier to get the most out of the speaker, or even bi-amping to make the speaker sound "full" in the bass. (In other words, powering it from a typical home theater receiver wasn't working well--the sound was "thinner" in the bass with inadequate amplification.) For bi-amping, most of them are using the same brand of amplifier, same series, but a different wattage for the high and low sides. In this case, too, the crossover in the speaker is still used. (Without bi-amping, the pair of terminals are connected together.) They aren't running an outboard electronic EQ before the amps, in other words. The low-end section crosses over around 120Hz so it is like having a subwoofer, but it's built into the same cabinet as the main drivers.

For this question, no...but I see what you're getting at. One speaker line I looked at had its own active subwoofer section. But it seemed a bit strange to have a 100 watt powered subwoofer section if I were powering the rest of it with a more powerful amp.

 

with due respect steve, my understanding is that the objective of bi-amping is not volume, but sonic quality. to do it right, the amps have to be perfectly matched. if they are, then you shouldn't notice the "join".

of course, as in anything like this, the results are in the eye(and ear) of the beholder.

 

Rudy, some people bi-amp in the way you described. They like the tube warmth for the treble and midrange and the solid-state "power" for the bass. I can see the desire to do this based on the different qualities of tubes and solid-state, but I don't know if it works in practice. If the two amps are not gain-matched, as I suspect a tube amp and a solid-state likely will not be, then one could have problems making it work.

 

Absolutely. I have my Totem Arro speakers passively bi-amped with an NAD C 370 integrated and NAD C 270 power amp, and I am very happy with the results. I used the C 370 alone for a year before adding the C 270, and the addition of the power amp made a significant difference soundwise. I use the integrated for the tweeters and the power amp for the drivers, and the sound is more layered and open than with the integrated alone.

I've never heard of anyone claiming to bi-amp for increased volume (perhaps some do, though). People do it for better sound quality. Now, one could use two amps in a bridge mode for increased power. I don't know how well that works, as I've never tried it. I could do it with my NAD set-up, but I don't need more power.

 

A few points about my bi-amping questions:

1) The crossover inside the speaker would be used. The crossover was designed specifically for those drivers and the specific cabinet size. An outboard electronic EQ would not only be redundant, it would screw things up sonically. It would throw the balance off. In other words, a speaker crossover with 12dB/octave and an outboard EQ at 18dB/octave would be quite nasty sounding IMHO. Too severe of a slope. (Just using these values as an example--I have no idea what electronic crossovers would be set for.)

2) My argument is that the amps should be exactly the same in terms of brand and series, like Keith does with his NAD electronics. The speed and other specs of the amps are similar enough that the sound should be more coherent than going with dissimilar amplification. However, I was somewhat tempted by the idea of having the most musical portion of the signal running through a good tube amp, while having a powerful solid state amplifier for the subwoofer. Which was my reason for asking, BTW.

3) One possible problem with bi-amping: if I have two amps sending the signal to the speaker, the full frequency range is being sent to each set of terminals. If I had, say, a 100w amplifier feeding the highs/mids/bass and a 300w powering the bass, wouldn't the 100w amplifier overload first? I believe it would. The speaker is doing the filtering via the crossover, vs. having some kind of filter on the amp side. Whether the lack of a subwoofer in the circuit has anything to do with this, I don't know. (No current draw...since there's no driver in the system.) If that's the case, would it be better to go with, say, a single 400w amp and forget the bi-amping? (I'm just picking some arbitrary values here.)

4. Tube vs. solid state? Unless there were a good 200w tube amp within my price range (if they're even available), I'm pretty much stuck to using solid state. (I do like to "crank it" once in a blue moon, but there are a few pieces of music I can play at moderate volume that clip even a 200w amp.) I can always go tubes in a separate system, which I'm considering for when I renovate one of my unused bedrooms. Probably would be something I could tinker with, like a Dynaco PAS3X and a pair of Mk IIIs, provided they're not too wildly expensive. (Unless ST70s could be bridged to mono...?)

But amping isn't my issue right now--I'm just kicking around the plusses and minuses of bi-amping...or not.