Higher frequency cut out at higher volumes

[Ronniejay356]

Just installed a jl audio g4500 4 channel amp, only using first 2 channels to power kicker coaxial. At higher volumes past around 43 on a pioneer radio the speakers die down and sound muffled, almost as if it takes away all higher notes, could this be a bad amp?

[CrackFactory]

You might have the gain up too high. 

I had this problem with an Alpine KTP445U.

[Ronniejay356]

Gains are set with multimeter, I thought the same at first but I set them based off an 80 rms formula instead of 100 rms which is what my coaxials are rated at, so 20 watts less, not overpowering them at all

[CrackFactory]

Use a headphone to RCA cable to plug your phone or mp3 player into the amp. See if you have the same problem. 

Make sure you do not swap RCAs while the radio is powered on.