Sometimes, you just ought to crank up the volume. Hatchback audio systems must overcome a good deal of ambient noise--a vehicle traveling down the highway in the cortege of other loud engines is surrounded by a immense background noise level. Factory-installed head units have a modest amount of amplification (generally about 10 watts per channel or less), and many aftermarket head units have at least twice that.

• The amassed power the amp included with your CD or cassette muscle man delivers, the cleaner the hearty from the speakers

• But be careful--a receiver rated at 50 watts maximum Car Amplifiers competency probably has no more than 20 watts of clean power
• For that reason, serious mobile listeners eschew the modest amplifiers built into head units and instead opt for powerful external amplifiers.
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