Polk Audio RMSERIES RM7500 instruction manual Here’s the real answer

Q. “WHY DOES MY SYSTEM HUM?"

A. BECAUSE IT DOESN'T KNOW THE WORDS.

This is what passes for humor in the audio business.

Here’s the real answer:

If you have any electrical (60Hz) hum in your system, you're going to hear it clearly as soon as you hook up your subwoofer. Most hum problems are caused by “ground loops.” That is, the electrical grounds of the compo- nents in your system are not at the same electrical potential. A very common ground loop source is cable TV. Disconnect the coaxi- al cable from your TV and/or VCR. If the hum goes away, the cable is the ground loop vil- lain. In that case you need a 75 ohm ground loop isolator. This device is about the size of a pen and is attached to your coaxial cable where it plugs into your VCR (or television). You can obtain this device from some audio dealers, Radio Shack stores, Zantech (1-800- 843-5465) or Channel Plus (1-800-999-5225).

Ground loops and hum can also be the result of faulty electrical wiring in your home. Consult a licensed electrician to evaluate and, if necessary, repair the AC wiring in your home. Light dimmers also tend to intro- duce noise into audio systems. Remove them.

If none of our suggestions work for you, call our customer service number.

SAFE LIMITS OF OPERATION

Your Polk Audio loudspeakers are made with the highest-quality materials, insuring years of great sounding, trouble-free performance. However, damage to loudspeakers can occur when an amplifier, regardless of its wattage, is made to play at higher listening levels that its power can clearly produce. (This is usual- ly beyond the “1 to 2 o’clock” position on the volume control.) This results in very high levels of audible distortion originating in the amplifier, which adds a harsh, gritty sound to the music you're listening to.

Contrary to popular belief, a speaker is more likely to be damaged by trying to get too much volume from a low-powered amp or receiver (than from a high-powered one).

MAINTAINING THE APPEARANCE OF RM SERIES SPEAKERS

Your new speaker cabinet is made of a rugged material that can be dusted or cleaned with a moist cloth. Avoid harsh detergents and cleaning fluids; they can permanently damage the finish of your speakers. Gently vacuum the grilles to remove dust.

TECHNICAL ASSISTANCE OR SERVICE

If, after following these hook up directions, you experience difficulty, please double- check all wire connections. Should you isolate the problem to the speaker, contact the authorized Polk Audio dealer where you made your purchase, or call Polk Audio’s friendly Customer Service Department at

1-800-377-7655 (calls from US or CAN only) from 9am to 6pm Eastern Standard Time, Monday through Friday. You may also contact us via email: polkcs@polkaudio.com.

14 15