Doc Severinsen is one of the big trumpet heroes. In the 60's he was recording on the Command label and his recordings during that period are considered to be a "Golden Era" of his output where he did a number of virtuosic renditions of various pop tunes.
Listening to them now, I hear things that weren't obvious to me as a kid. This recording of "It Ain't Necessarily So" is a good example because you can hear him doing different parts on both channels. I don't think they really did that great a job of capturing his sound. His performance is so incredible it shines through but it sounds kind of stuffy, buzzy and distorted. I gather they close-mic'd him. I have no idea what mic was used.
https://www.youtube.com/watch?v=G8J3U5AHQxo
The technology had long existed to do a stellar job of capturing the sound of a trumpet. Contrast to this earlier (1962) recording of Al Hirt on "Memories Of You", how sparkling every aspect of the recording is.
https://www.youtube.com/watch?v=QvQ4acZw1a8
Do you think the Command recordings were just a particular sound they were aiming for or less than stellar engineering? He was the most visible trumpet artist, recording with a prominent label, I would have thought his recordings would have gotten the Cadillac treatment.