My first encounter with K2 Mastering

Bombaywalla - I found that it is K2HD. Do you know what they do different from regular 24/192 mastering. I can understand better dynamics since they most likely use less compression for "high definition" CDs but purity of sound and air especially at higher pitch string sounds is astounding.

I wonder if magic of K2 HD lies in better mastering-downsampling or it is whole recording-mastering-downsampling process. Such recordings like Kind of Blue cannot be re-recoded.

Bombaywalla, Thank you for the links - very interesting. Many people assume that 16/44.1 has to be perfect because Nyquist says so. Nyquist criteria requires no signal above half of the sampling frequency or signal would fold (alias) to 0Hz and up. That is impossible to do perfectly and any close to brick wall filter introduces non-linear phase (uneven group delays) screwing up summing of harmonics. Also Nyquist criteria applies to continuous waves only. Reconstruction of signal becomes difficult with short duration time and high frequency (cymbals), since SINC functions (that suppose to correct limited frequency response caused by limited time/duration) sum very limited number of terms introducing interpolation error. That's where people hear more natural sound from Vinyl or SACD. On the other hand Master tapes have less of a problem being recorded at 192kHz, more than 9.6x upper limit of 20kHz compare to 2.2x in redbook CD. All this suggest that downsampling process is extremely important to CD sound quality. I already enjoy standard redbook CD the way it is (perhaps have less than golden ears) but quality of this K2 mastering, while still in 16/44.1 format, make me ecstatic.