Chris, which one have you heard?
I don't get this impression, in fact, the opposite, but not in a harsh or bright/shrill way. The words I most use to describe Jadis are romantic, sweet, and musical (probably more of these three than it should be), they're also pretty upfront and engaging. But, as with anything else, with the right tubes, ancillaries, and room, I don't doubt your assertion that things sound dark.
I don't get this impression, in fact, the opposite, but not in a harsh or bright/shrill way. The words I most use to describe Jadis are romantic, sweet, and musical (probably more of these three than it should be), they're also pretty upfront and engaging. But, as with anything else, with the right tubes, ancillaries, and room, I don't doubt your assertion that things sound dark.