I've been a mobile electronics installer for nearly 30 years. The KTP-445 is a nice amp, but the buyer should be aware of its purpose. This amp is not designed to run subwoofers. Its primary use is to improve the response and lower distortion of four typical full-range speakers. Used with modern Alpine head units, it is a simple plug-in installation. Just unplug your radio at the back, plug one harness back into the radio and the other into the harness you removed. That's it! The amp is so small, it will fit behind most radios or under the dash. There's a fair amount of harness to make it easier to locate. You aren't going to experience a great deal more of volume. Remember, practically all head units today already output from 18-23 watts per channel, so this amp is only about twice that and you don't add that to the radio's power, you REPLACE it. Doubling power gives you only about 3 decibels more volume, barely detectable to the human ear.
Finally, notice that this amp DOES NOT have RCA inputs. It can be wired to other brand radios, but you need to know what you're doing: Not advisable for the novice.
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