So, yesterday I was hearing a weird whistling sound after recording the guitar, I record in a small kitchen but I never encountered this issue before. This started happening after I put my amplifier in the room, firstly I noticed I had the amp on, so naturally what I was recording was going to my headset and also my amp. Then I turned it off, but there was still a residual 'whistling'. Dumb question, but could a turned off amplifier somehow be reflecting the sound in a more intense way? An acoustic panel was already adviced to me here, I saw in a nearby store the LD-RF1, however how do I mount it with an akg p170? Where do I point the mic?