Great discussion.

For some of this, I am going to have to reference my Yamaha sound bible.

To make sure I understand correctly. The important element is the amplifier.

I understand the power to speaker sensitivity aspect.

If we look at the two graphs Altec provided...
the tube signal after 10khz, it flattens out. As compared to the SS after 10khz, there are a lot more peaks (distortion peaks?). In regards to the tube signal, would this account for the "liquid highs" characteristics of tubes? Tubes are often characterized as having sparkle? How would that show when analyzing the graph?

And with the distortion of the solid state after 10khz, would it be safe to say this is the "brightness" aspects of SS?

My next question concerns hybrid systems. What defines hybrid? One component SS and the other tube? Or one component that uses both transistor and tubes? If I remember correctly, my dad made the transition to solid state in the mid 80's, when (correct me if I am wrong) tubes were still not effecient. He bought a Audio Research SP-10 preamp that if my memory serves me correctly (please cut me some slack for a conversation over 20 years ago) was a hybrid component, both SS and tube. But I am saying this without researching the component.

If you have one component SS and one tube...I am assuming ideally you want the pre amp to be SS and the amp to be tube. Yes? This is especially relevant regarding HT, since there doesn't seem to be a plutheria of tube HT processors.

However, maybe the tube relevancy is only when considering 2 channel audio. I find that I do not have any sonic quality issues with the 990. In this realm, with multi-channel decoding the signal processing seems to be more important. There is a lot more information for the processor to decypher.

What has more effect on the sound quality, pre/pro or the amp? I would assume it is the amp, even the preamp is processing the signal to analog considering Altec's reference to the output stage.

At this point, I may need a little sound 101 before I thoroughly confuse myself.

This may not be making BQ's decision any easier (chuckle).

AK