David, as much as I am enjoying my Dynavector XX-2 mk II cartridge, I don't think that it will help to hide your JM speakers brightness. The Dynavector itself is not bright, but it is not rolled off either, if used with bright gear, the brightness will come shining through. I have long been a fan of soft dome speakers, Dynaudio, Verity, ProAc, etc. I learned to avoid metal dome tweeters over 20 years ago.
If I were you, I would change speakers first. If you cannot change speakers, I would advise against getting a Dynavector cartridge. To control brightness, you would be better off with a Transfiguration, Koetsu, or wood-bodied Benz cartridge, IMHO.
If I were you, I would change speakers first. If you cannot change speakers, I would advise against getting a Dynavector cartridge. To control brightness, you would be better off with a Transfiguration, Koetsu, or wood-bodied Benz cartridge, IMHO.