Details for bi-amping

JeffreyBehr, I think he means that he wants to use a pair of monoblock solid state amps for the lows, and a pair of monoblock tube amps for the mids/highs.

You are of course making a good point that what needs to be matched is gains, not sensitivities. More likely than not the solid state amps, presumably being more powerful, will have higher gain, and therefore their inputs will probably be the ones having to be attenuated.

I second the comments about biamping being more complex an undertaking than is often anticipated, with there being a substantial possibility of disappointing results.

One of the most common misconceptions about passive biamping (i.e., biamping without an active line-level crossover) is that it makes sense to use a powerful solid state amp on the bottom, and a much less powerful tube amp on top. In addition to the possibility of that resulting in a sonic mismatch, what is commonly not realized is that much of the power capability of the solid state amp will not be utilizable, because how much of its power capability can be utilized will be limited by the clipping point of the lower powered amp. In a passive biamp arrangement, the mid/hi amp(s) have to output just as large a voltage swing as the bass amp(s).

Regards,
-- Al

Agreed, Jeffrey. The thoughts we have expressed are not inconsistent, as what I was referring to was the use of a "MUCH less powerful tube amp on top" (emphasis added), resulting in "much of the power capability of the solid state amp" not being utilizable, due to the voltage swing limitations of the lower powered amp.

Regards,
-- Al

Excellent points, Magfan. To further clarify my point about power, though, what I was basically saying is that for passive biamping voltage swing capability needs to be considered as well as power capability, particularly if there is a large disparity in the power capability of the two amps.

Using your extreme hypothetical example of a 10kHz crossover, the amount of power that would have to be provided by the high frequency amp is extremely small. However, if say a 50W amp were used for the highs and a 500W amp were used for the lows, the 500W amp would in effect be no more powerful than, for example, perhaps 75 or 100W. Asking it to provide more power than that would cause the OTHER amp to clip, resulting in lots of extraneous non-musical high frequency energy going into the tweeter.

Good point about latency, aka propagation delay. You're right, that never seems to be addressed. Not sure how it would play out quantitatively under typical circumstances.

Best regards,
-- Al