Can you hear the differences between car amplifiers?


Buck Pomerantz

Buck Pomerantz was born and raised in Philadelphia. His parents bought their first television set when he was born. He figured out how to run it by the time he was two. Besides athletics, his formative interests included electronics, amateur radio, music, and stage crew work. He got his BA in writing from Brown University. Then he joined a rock 'n roll band as their soundman and moved to Charlottesville, Virginia. After that venture failed, he spent time in Boston, New Orleans, and Berkeley. He worked in a music store in Austin manufacturing, installing, repairing, and operating sound systems for recording studios, clubs, and bands. He moved back to Charlottesville, ran a little recording studio and finally joined Crutchfield as a copywriter. He has 2 grown children and 3 grandchildren, but after a good nap he can still rock out.

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Amplifiers all sound alike, right? No they don't. Many amps just make your music loud enough to overcome road noise. Other amplifiers handle music more carefully to promote higher fidelity. Small technological differences between brands often make for large differences in sound. A recent test in our training room proved it to everyone who took part.

Jeff, a car product merchandiser here at Crutchfield, set up an A/B test so we could all hear the differences between equal-powered amplifiers of different cost and quality. We would listen to the same music through the same speakers and switch between two amplifiers. Normally, such tests would involve listening to a selection of music and then stopping it to change the connections of the speakers to a different amp, and then starting the music up again. Such a delay makes comparisons very difficult. Fortunately, Jeff had an electronic switch that quickly switched between two amplifiers while leaving everything else the same. We could hear the differences between the amplifiers alone, even within the same musical phrase.

Jeff put on some music and let us work the switch and hear for ourselves. The test was between a popular and very inexpensive amp and a name brand amp that costs about $150 more, or over twice as much on a per watt basis.

I didn't know which amp I was hearing at first. The music was full, spread out evenly in front of me, and sounded pretty good. When the switch was made, the sound stage narrowed vertically and moved to the left, the high end got thin, and the bass cloudy. I could understand why the off brand amp sounded thinner and more muddled - cheap electronic components just don't produce the same quality sound as more expensive parts do. But why had the balance moved to the left? The explanation for that is that the internal wiring of the two amps differ so much that even the symmetry of the parts on the circuit board makes an audible difference. A company that uses better components and a smarter circuit design will produce a better-sounding amp, which is well worth the extra cost if you care about sound quality.

Charlie, a Crutchfield web editor, put it this way, "The less expensive amp sounded fine, the bass was full, the balance good. I couldn't imagine what could possibly change. When we switched to the other amp, the sound stage widened to about five feet beyond the speakers, the bass improved dramatically, and the high end came alive."

Everybody in the room heard the difference - it was not a subtle effect. And it brought home the old adage about getting what you pay for.

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