When I placed four 120mm cooling fans atop my Denon AVP-A1HDCI and Denon x3100, the speaker channel levels (volume) are about 6dB lower than if I only have 1 fan or no fans at all.
Yes, that's a 6dB volume difference!
Because of this, I removed all fans atop my AVP-A1HDCI and used only 1 fan atop my X3100.
I have verified 3 different times using a SPL meter. Each time, the ATI amps, AVP-A1HDCI, and X3100 have been on for 1 hour.
So the only thing that changes is the number of fans atop the AVP-A1HDCi and X3100.
Why does this happen?
Do Pre-pros/AVRs have lower volume output when they are "too cold"?
Is this the reason why some people say that amps sound better when they are "warm" and why some people even leave your amps and preamps on 24 hrs a day?
I won't be recommending to people to place more than one fan atop their amps and preamps anymore, unless it's a class-A amp or an Onkyo.