Just looked it up. Koenig's sleeve notes say that he wanted "to experiment with more interesting, alive and natural sounds", so the job was done in the gymnasium-auditorium of the Los Angeles Police Academy.
I must say, the sound of the album has never made any specfic impression on me. The Hawes album I DO think has a funny sound is "High in the sky", which has a cover photo of the trio playing in some lounge overlooking an airport, but was recorded in the Vault studios. You couldn't be thinking of this, could you?
MG
I'm probably just misremembering something from Ted Gioia's book West Coast Jazz--anyone have a copy handy? I remember it had a few comments on the circumstances of recording.