First of all you need air transfer through the rack to carry heat out. That means air inlets to match the outlets. It's not particularly critical if the fans are all on the inlet side or outlet side or both as long as air is made to move through. Given that you might as well go with the flow and exhaust at the top and draw cool air from the bottom. Secondary fans to circulate air inside around the bigger sources of heat may be helpful.

Most PA amps have fans that blow through. If you have a rack of amps make sure they all blow the same direction so the exhaust of one isn't drawn into the one above.

Very helpful! Thanks for your reply :)

There is also the issue of how much dirt you are also now going to be circulating through. This can deposit a heck of a lot of gunk into plenty of pieces of equipment that don't really care for gunk all that much. So you might want to also consider some low restriction air filtering devices. Besides they are always a good indicator when they need to be changed. It gives you a little extra boost to make good little regular inspections. Remember, the filter goes on the intake side. Though you might need some medications to help with your own personal exhaust?

Chili dogs anyone?
Mx. Remy Ann David

Interesting..I wouldn't have thought of this, but will certainly try to incorporate it.

Thanks so much!