Can anyone give details on some multi-channel thoughts/purpose?

5.1 is the basic minimum unless you have a large room and/or many seating positions.  In those cases, 7.1 is useful.  Beyond that are the immersive systems (Atmos, Auro-3D, DTS:X) which utilize arrays of speakers above the listener's ear plane.

OP:

Now, in 2020, anything more than stereo is almost entirely for movies/tv. Multi-channel music was attempted with SACD and DVD/Bluray but it really didn't go anywhere. I think it probably got less interest than 3D television watching.

Take a look at Kal Rubinson’s articles on Stereophile entitled "Music in the Round."

He was an early adopter of multi-channel music playback, and he has tried some pretty awesome demo systems, including the use of 3 or more stereo DACs to produce the full 6 channels (5.1).

Unfortunately for him and others that pretty much vanished, and those articles stopped a few months ago. There are of course performance DVD and Bluray disks out there.

Personally I really enjoy having a mixed-use (music and movies) setup. If you are going this route, check out Anthem products. Great room correction and auto-calibration, and sound really good.



Best,

E

Thank you for the thoughtful replies.  It seems like many things in life, it does depend on the intent/purpose. 

I've got 5.1 for SACD but don't use it much.  SACD and DVD-A do sound pretty good.  Vinyl usually wins unless I'm feeling lazy and just want to immerse myself.
For theater, it never seems like enough.  Who has a room large enough for 7.4.2 or even 11.4.2...
I did add the rear height speakers for fun but after wasting enough money I'm not ditching a fairly expensive system to go for Atmos.  I did splurge on OLED which was worth every penny for video but LG built in audio stinks.

I went with 7.1 for ht years ago and have never felt the need for more.
Its pretty darn effective for movies which was the prime aim.
I occasionally play dvd-a or sacd on it when the wife is out and they do sound good.

However my main rig in my room is pure two channel and I have no desire to ever try and build one system that does both ht and music.

I know it can be done but as they are in two totally separate rooms in my house there is no need.