liquid sound

That's one of those things that is difficult to convey in words, but when you hear it, you'll know.

Smooth, flowing, and without grain. Liquid would also be organic, and very unclinical. The detail never interrupts the flow of music.

One might say that liquid could also be a component of PRaT. Pace - Rhythm - and - Timing.

Basically, the relief your dry, sore throat feels after a Luden's Cough Drop takes effect, heheh.

I suppose liquid sound "flows".

Gunbei did a great job-- smooth, flowing, and without grain. I'd emphsize "without grain" and would add "easy to listen to."