The answer is that the engineers in the early days of stereo had yet to discover with two track, the phantom middle channel. Most, if not all, of the early jazz recordings suffered from this hard left, hard right/dual mono effect. From what I've been told, the first jazz LP to discover that phantom middle channel - and essentially by accident - was the Contemporary recording Art Pepper +11. Koenig/DuNann because of mixer limitations had no place to the last instrument; in the end, their solution was to mix half in the left and half in the right channel and voila the center image.
As far as the echo issue goes. I have a third gen, 15 ips copy of Midnight Blue and it's on the tape. Whether it was there initially or they got some print through because no one periodically rewound the master (upkeep of the masters is a real hit or miss operation) is anyone's guess.
As far as the echo issue goes. I have a third gen, 15 ips copy of Midnight Blue and it's on the tape. Whether it was there initially or they got some print through because no one periodically rewound the master (upkeep of the masters is a real hit or miss operation) is anyone's guess.