Thanks to all for the thoughtful discussion. I’ve been enjoying the MN/Vanska reading of the 2nd and will look for more of this pairing.
With regard to the brightness issue: I do have an update.
One of my suspicions was that my system was suffering from microphonic distortion on the peaks. The other was that my amp was clipping. I appears to be the former. I borrowed some Nordost Sort Kones to audition and the harshness during peaks is essentially gone. I’ll be auditioning other solutions to see if this can be further improved. I now recognize the significant importance of resonance control. My audio cabinet is really furniture (we’d rather look at a nice cabinet than at audio gear). I should have been paying more attention here.
The uniquely large dynamic swings of Mahler brought this to the fore.
Best to all,