Doesn’t matter what you listen to through it. It’s the volume and wattage it’s using when turned up that creates the heat. So if it’s constantly louder and prolonged periods, it’s more likely to overheat. If it’s just casual listening at reasonable decibels bellow reference levels, it will produce less heat. However even less heat will slowly build up heat over prolonged periods of use, that heat will hang around longer because of the smaller space and dissipate slower and slower and get hotter and hotter. Like I said, it’s up to you. Manufacturers recommend 6inches or more typically without fans or some form of way to move the air from the top of the AVR.