Hello,I have a Yamaha HTR-5280 HT Reciever that is Pre-Outed to a 2 Channel HK PA-2000 Amp and every once in awhile the right Channel/Speaker goes muffled (No high end) but when i bump the volume up kinda loud the Channel/Speaker springs back to life.Does anyone know what could be causeing this?Thanks and have a very Happy New Year,Keith.