Video: car amplifier features

What to look for when buying an amp

By

Ken Nail

Ken Nail has written about car audio for Crutchfield since 2003, after four years as Crutchfield Sales Advisor, and 10 years as a music teacher. He's an avid music listener, whose favorites are classical and film music. When not chained to a desk, Ken spends most of his time training for triathlons and marathons, and likes getting outside for backpacking, downhill skiing, and bicycle touring. He attended West Virginia University, where he received a Master's Degree in Music Performance and a Bachelor's Degree in History.

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Zak Billmeier

Zak Billmeier grew up in southern Vermont and coastal Maine. After graduating from Mary Washington College with a Geography degree he still isn't sure quite what to do with, he eventually settled in the mountains of Central Virginia. He spends his free time chasing his daughter around, taking pictures, gardening and cooking. He joined Crutchfield's car A/V writing team in 2007 and is now a lead producer on our video team.

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This short video describes some of the common features you should look for when you're shopping for an amplifier for your car audio system. Not every amplifier will have all of these features, so make sure the amp that you get has the ones you need.

Video Transcript

Zak: Depending on the kind of amp you're getting and how you're going to use it, there are some features built into most amps that you should think about while you're shopping.

Ken: These can include high- and low- pass filters, bass boost, and speaker-level inputs. High-and low-pass filters have an important job to do. They make sure that your amp is only boosting the frequencies that you want it to. High-pass filters strip away the low frequencies from the signal the amp is boosting. You'll use the high-pass filter when the amp is powering smaller speakers like those in the front doors of your car. This way your amp will direct its energy to making the vocals and instrumentals sound their best.

Zak: Low-pass filters do just the opposite. They take out the highs so you're only amplifying the lows. You'll want a low-pass filter when you're using the amp for powering a sub, that way the amp can concentrate its power on kicking out the low notes.

Ken: We should mention one other type of filter, the subsonic filter. A subsonic filter blocks ultra low frequencies that you can't hear from getting to the subwoofer. This lets the sub operate more efficiently.

Zak: Yeah and there's a couple other important things to look for in your filters. Some filters are variable. They let you select the frequency for the filter. Others are fixed, meaning that they limit you to a specific frequency.

Ken: Variable filters let you tailor the output of your amplifier more precisely than you can with a fixed high-or low-pass filter. And there's one other feature to look for: a bass boost.

Zak: Yeah, a bass boost augments the low frequency output of the amp so you get a bigger bass output with your subs and your larger speakers.

Ken: A bass boost frequency can be fixed or variable and the amount of boost can be fixed or variable too.

Zak: Yeah kind of like the filters we talked about. Variable bass boosts give you some more choices in how you tailor the sound that your amp puts out so keep an eye out for this feature if you're planning to amp subs. Now besides the number of speaker output channels we talked about earlier, amplifiers have other outputs and inputs that you may want to look for.

Ken: The first is speaker-level inputs. Most amps get their signal from the receiver through RCA inputs which are connected to your stereo's preamp outputs. The factory radios rarely have preamp outputs so if you're connecting your amp to a factory radio the amp will need speaker-level inputs like these. They'll let you tap into your car's speaker wires for the signal your amp requires.

Zak: If you're going to put together a system with multiple amps, you might want to think about an amp like this one. The reason is it has preamp outputs so you can send a signal into the amp and then out again and into another amp without having to run any extra cables all the way from the stereo.

Ken: To see all the amps we carry go to crutchfield.com/amps and be sure to check out which wiring kits we recommend.

Zak: To learn more about choosing the right amplifier, go to crutchfield.com/ampguide.

Ken: And for personal one-on-one help, call 1-800-555-9408.

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