How to fix my detailed, accurate but BRIGHT system

It is an expensive fix but if you use Cardas Golden reference ICs and the best Cardas or all copper speaker wire you can afford,the sound will warm up a great deal. No need to change decor. I second the liberal use of dampening stands platforms etc.It won't be as sure tonal change like the best Cardas. It brought the bass into better focus where I have used it.
According to the the numbers, I think it is in fact a very difficult load. I respect Al Marg's math but rules of audio lore are not so easily dismissed. We all know that using SS with an increasing impedance SPLs go down. Beyond the sound levels and more importantly the quality of the sound changes dramatically in real life. Tubes like a higher impedance and I proved this to myself comparing a SS Mac with a tube amp of similar wattage driving c. 1960 16 Ohm JBLs.
With the Butler, my understanding is that most of the power comes from supercharging the 300B with SS bipolars. The natural power dissipation from a 300B is 8-10 watts.

Warning what follows you may find funny or just idiotic read at your own risk.
Finally as a bit of humor take a sheet of Dynamat and carefully cut strips of it to apply to the outside of your tweeter frame only. Start with an X then add more strips as needed until almost covering the tweeterif need be. It is crucial that you use a cage to cover the cones themselves. That stuff won't come of very easily so only apply when completely sober and but frustrated at wits end. Lead tape will work as well and you can get lead sheet without adhesive. With the no adhesive sheet you can paste it up using a very small amount of green damping glue.
Or-Keep the rig exactly as it is but try the trendy Victorian bordello look. It should be dank dark reek with coal candle and cigar smoke (cuban please,) You will have to use a crystal chandleer but be carful and try to get one the scaters sound up. The room must be repleat with thick maroon colored velvet drapes, thick wool plush cut carpets to match and scatter some deer and moose heads on the walls for diffraction. A few heavily gilded ornately framed portraits of well known patrons in real cracked oil paint help as well. You can always find authentic large gilded framed 19th century oil paintings at garage sales and such.

Al,

I cross-posted with you, so I hadn't read your post, before I posted.

Are you saying that an erratic electrical speaker impedance curve doesn't actually present a more difficult load to the amplifier in this case, because it's still within the acceptable limits of the amplifiers current delivering ability, and there won't be a problem with a frequency db imbalance, unless the curve dips far enough below the amplifiers minimal impedance, lets say 2 ohms?

Rich

Hi Rich,

That is sort of what I am saying, but I would put it a little differently. As long as the output impedance of the amplifier is small compared to the impedance of the speaker at the lowest point of its impedance vs. frequency curve, and as long as the amplifier is not called upon to deliver more current than it is capable of delivering, then a tonal imbalance will not result.

The fact that an amplifier can double its output power into 4 ohms, compared to 8 ohms, is an indication that it has good output current capability. In this case, the fact that the amplifier can put 250W into 8 ohms but only 400W into 4 ohms, is an indication that its output is being limited into 4 ohms by its output current capability, and therefore the peak volume levels it can produce accurately into a speaker which dips to 4 ohms will be less than for a more benign speaker load (everything else being equal). But as long as the output current capability of the amplifier is not exceeded (and keep in mind that we are presumably talking here about tonal balance at moderate volumes), and as long as the output impedance of the amplifier is low, no frequency response imbalance will result.

A notable exception to all of this would be amplifiers which have tube output stages and are output-transformerless, such as the Atmasphere's, which may have an output impedance in the vicinity of 4 ohms or more. That would definitely result in a tonal imbalance working into a speaker that is basically 4 ohms in the bass and 8 ohms in the treble (see Stereophile's impedance measurements on the Aerial 7B). I recall Tvad once mentioning that he had an Atmasphere at one point, and perhaps that is what prompted his comment.

Regards,
-- Al

I'm in total agreement with BlindJim. Often enough, it's not the gear but how it's setup.