if you've listened to the urushi, then you know something of the "koestsu sound." as you move up the ladder, the attributes of that sound increase. the onyx platinum is even more lush, yet more detailed, quiet and grainless than the urushi. i've noticed no differences among these very fine cartridges in tracking ability. bass response is wonderful on all models, tho even tighter than the rest on the onyx. IMHO, the koestu's, from the urushi upwards, are the most musical cartridges i've yet heard. they mate particularly well with graham arms and the upper range of basis tt's.