Yes, this is a fifty year old mono recording, but the sound quality is very good, it is spatial. The remastering onto CD has enhanced the clarity of sound. The conducting is amazing, as one would expect, and the orchestra are of the highest quality. But it is Flagstad who is the revelation. Having heard the Bohm/Nilsson DG set and thinking it couldn't be better, I recently bought this one, realising straight away this is one of the finest recordings of an opera ever produced. Furtwangler takes the work at the correct speed, unlike Bohm's over paced conducting. Flagstad is the selling point though. She has both power and vulnerability. Once you have heard this performance you will find all other recordings stand in it's shadow. Do yourself a favour and buy it, you won't be disppointed.