biamping with different output amps

[bleeding ears]

Hi guys, I would imagine that when bi amping one should ideally use 2 amps of equal output.

So my question is, what effects would occurr if using 2 amps of different output eg say 250 watt amp for bass drivers and
say 125 watt amp for tweeter/mids

Would or could this be a problem ?

Anyone ?

[Kal Rubinson]

No. The problem is that the amps need to have the identical voltage sensitivity (or you need to add level controls) or the resulting sound will be significantly unbalanced. That applies even if the amps have the same nominal output rating.

Kal

[Karma]

No. The problem is that the amps need to have the identical voltage sensitivity (or you need to add level controls) or the resulting sound will be significantly unbalanced. That applies even if the amps have the same nominal output rating.

Kal

HI,
Yes, Kal is exactly right. Another way of saying the same thing is both amps must have exactly the same voltage gain. Sensitivity and gain are equivalent but there is no standardization in the use of the terms between different manufacturers or even between different models from the same manufacturer. The difficulty is that although identical gain and sensitivity resuts in the same output value, the two terms are stated differently. Gain is expresssed in dB and sensitivity is expressed in input volts to output volts.

If you know how to convert the terms you can make valid decisions. Just be careful.

Sparky

[whoaru99]

Aside from the gain and sensitivity issue, is it not prudent to use amps of very nearly equal power when (I assume) passive bi-amping because the voltage swing issue?

Since (again assuming passive biamp) both amps are producing the same full range output voltage swing, don't they need to have the same capability or the lower powered amp will "run out of gas" and clip much before the other?

[Karma]

HI who,
Defintely prudent but not essential as long as the lower powered amp has sufficient headroom. As you imply, identical amps would be best but that's not the question that was asked.

Sparky

[whoaru99]

Hmmm. I think the point did contribute to answering the question of how amps interact in a passive bi-amp scenario.

1. The sensitivity and or gain must match, or be matched somehow, else the bass and mid/high balance will be altered.

2. The amps should be closely matched in output power or one could actually go backwards (IMO) as the system clipping point cannot be any higher than the voltage swing of the least powerful amp. So, in effect, the 3dBw advantage of the 250wpc amp on the bass is essentially nullified by the clipping point of the 125wpc amp on the mid/high.

At least that's my understanding, anyway.

[Karma]

HI who,
Sure, the hypothetical system would be theoretically limited by the lower powered amp. We are saying the same thing, I think. However, it's entirely possible that 120W would be sufficient to drive the speaker (tweeter in this case) into distortion in which case, the amps would be adequate even if unequal in power. I think you understand that.

It really depends on the sensitivity of the hypothetical speakers. We really can't be more specific unless the parameters of the speakers are known. So, the next logical question would involve compatable speakers. But that question has not yet been asked.

Based upon the question, there is no actual reason why the stated amp combo won't work just fine as long as the gains are matched and the speakers sensitivity is in the proper ballpark. For example, horns would work fine.

Sparky

[bleeding ears]

Thanks for the replies, as usual there seems to be a bit more to it than what meets the eye.

Without being able to ask questions here one could get things very wrong and as was said, actually go backwards in sound quality. (and bank account)

I guess if one was to continually look for improvement and has taken a system to the point of bi amping etc etc then it would seem prudent to do it in the correct manner otherwise it may be fruitless.

I may have to forget about using two different amps for the time being.

It does give me something more to look forward to trying down the track though.


thanks