I got a new Onkyo Cs-525 with Onkyo speakers a month back. My vendor said that it will take 300 hours of playback before my speakers completely burn and start giving the the best possible output. Now I hear a mild crackling sound in the output when I playback and the sound cracks on musical instruments like saxaphone , flute etc which was not the case when i bought it. I followed my vendor's instruction and always kept my volume below 30 and would go higher after the speakers burn completely. I read the system hand book to troubleshoot this and removed my cell phones away from the speakers and had the speakers wires hang separate . By the way my system is kept on a shelf and I have a landline phone , a modem for internet usage and a TV below. Please give me a solution.