Help. Wife says Teres 340 Is too bright.

Doug,
You are right about factors, other, than just a power output, having effect on the sound of the particular speaker.
And there are an examples of that statement- 18 Wt/ch Lamm ML 2.1 SET comes to mind immediately.
But, all that said, I still feel, that the SPL, that can be achieved with a particular wattage, has very little to do with the quality of sound, reproduced by a speaker. It has more to do with a control, the power amp has over the drivers, dynamic range, such elusive characteristics, as "an ease and effortlessness of the musical presentation",
microdynamics, etc.
Speaking with Victor Khomenko of BAT about this very issue, he once mentioned driving his own Avantgarde Trios (106 dB efficiency), with TWO BAT VK-150 SEs per channel at some point, and hearing an improvement over a single 150 per channel.
My own experience confirms his position, as well.
I have yet to run into a situation, where more watts (everything else being equal), didn't make a positive change, and much less being detrimental to a sound.
Just a personal observation.

Yes, but as you say, Maril, it is more than just extra watts.

I've tried the same with my 110+ db horns. Almost to the point of having one SET channel per driver. I find I get much more presence and presentation with the Lectron. I do have another Doshi-Lectron, but they are not configured close enough to use both at this time. But keep in mind that what is happening is that there is less and less demand on the power supplies and thus more clean, clear headroom.

Kind of the same thing you're saying, but with a little more sauce.

Artemus,

Your statement that one of the differences is that you now play your system louder "because you can" raises a number of possibilities. Any comparisons made at different volume levels is almost impossible to assess. At lower levels, high frequency problems will be much less evident -- because the ear is less sensitive to high frequencies at lower levels, because the electronics are less likely to be stressed and distorting, because the room will be less likely to be suffering from excessive reverberation, and because the turntable itself will be less likely to be suffering from feedback problems.

Also, your statement suggests that you had problems with higher volume playback before making the switch that are ameliorated somewhat by the switch so that you "can" now play at a higher volume. Do you have an idea why you could not play at a higher volume before? Did you have feedback problems? Do you have similar issues (or other problems) when playing CDs or other sources? Answers to such questions will make it easier to determine where in your system you are having problems.

Doug,
Agree.

I suppose somebody could bi-monobloc (2 BAT VK-150 SE) for a total of 4 monoblocs. And if it really sounded better, I'm sure there are audiophiles who would do it. I also imagine it would introduce new problems matching gain.

The point is, if higher wattages strongly correlated with better performance for efficient to moderately efficient speakers, then more goners would be bi-monoblocing. Well, at least driving their speakers with more watts.

Seriously though, I am open to a scientific explanation as to why 150 watts should sound better with 106db efficient speakers when compared to enough watts to get the job done well.

In general, I postulate that it is more difficult to build a muscial amplfier outputting more watts rather than fewer watts. So, in a perfect market, I imagine that a goner would do better putting his or her budget into the best quality amp that puts out enough watts to do the job.