How much clearance around components in a console?

Mostly depends on how much HEAT is produced by the component.
If it produces NO heat, only the sealed case gets slightly warm, then NO SPACE is sufficient. (Such as some CD players, and DACs.)
IF the item produces a little heat, and has vents top and bottom, and you can feel warm air moving out of the case, then you need an inch or so top and bottom.
If it is a receiver, and gets HOT with plenty of open vents all around. It needs three inches all around. AND if you put THAT in a 'semi'sealed cabinet (semi sealed is a cabinet with vents, but closed doors when in use), you would need a fan in the cabinet.
The whole thing is about controlling the heat generated by the equipment.
So, If you plan on a cabinet that will serve for generations of electronics, remember that new stuff may need a lot more room to disperse heat.
A rule of thumb is 3" all around each item to be really safe. and a fan exhaust for a receiver.

It really helps too if your console has an open back.

I will probably go and err on the side of caution with 3” per side extra. How much for the top clearance? Should I have vent holes in the bottom of each shelf? I plan to have an open back, but there will be a closed front. I was planning on some side vent holes also. Thanks for the info so far.

Joe in Mobile

The more air flow the better. My center panel door has sun screen instead of wood. In hind site i wish I would have done the screen on all three doors. If you click on my system, the main page photo "From the money seat", you can see what I am talking about.