Biro Technology

A Basic Guide to Evaluating Audio Electronics

by Mithat Konar

As the final component in a chain that typically comprises at least one source, a preamplifier, and a power amplifier, a high resolution loudspeaker will only sound as good as what it is being fed. It is therefore impossible for the electronics used to drive a high quality loudspeaker to be too good. In fact, many "problems" typically attributed to poor loudspeaker performance are actually due to poor electronics performance. The use of great care in the selection of your associated equipment will reward itself ten-fold in the quality of your listening experience.

When evaluating electronics, it may be helpful to consider the performance in terms of the three basic spectral regions--bass, midrange, and treble--and ask yourself the following questions:

Is the bass tight and detailed? Many power amplifiers have inadequate low-frequency damping abilities, and this can lead to loose, indistinct, or overpowering bass. Power supply modulation, inadequate current drive capacity, and thermal modulation effects can plague all audio electronics--and these too can lead to a bloated and tiresome low-end.

Indeed, the "one-note", "bloated", or "indistinct" character frequently attributed to ported systems is very often due to dynamic low-frequency problems in the associated electronics. Vacuum tube amplifiers are usually the worst offenders in this area, but solid-state designs are by no means free of these problems--particularly almost all IC op amps and a lot of power amplifiers.

Is the midrange clear and open? Listen to a number of vocal recordings with a wide dynamic range. When the singer sings loudly, does it sound as though someone is sticking a sock into his or her mouth? It shouldn't--unless it was recorded that way. Listen to the ambiance on a favorite recording. (Simple recordings made in natural environments work best for this test.) Can you clearly distinguish individual elements of the reverb? On good recordings played back on high-quality electronics, you should have no trouble making out the distinct "early reflections" which give performances a palpable sense of space.

Are the high-frequencies clear and extended without being harsh or wiry? All too often, listeners (even experienced ones) mistake high-frequency distortion for added extension or detail. Unfortunately, over time such distortions will manifest themselves as an irritation and will quickly (once your brain has had enough of it) detract from your listening pleasure. Listen very mindfully to the texture of the high frequencies. They should sound liquid and unforced. If over a range of recordings the sound is consistently hard, peaky, chalky, etched, or "zippy", there may be a high-frequency distortion problem present.

High-frequency distortion in the associated electronics will make the best high-frequency drivers sound as though they are peaky and harsh when in fact they are flat and smooth. Most CD players and DACs--especially those of the "1-bit" type--are particularly bad in this respect. While it can be a bit difficult to confidently determine whether a high-frequency problem is caused by a loudspeaker or its associated electronics, trying a broad range of electronics and sources should help.

After you have listened to the three basic spectral regions above, sit back and listen to the big picture. A system that is working properly will sound natural and be free of "hype"--unless the recording engineer put it there. The more "hype" a system creates, the more "music" it eliminates, and the less "music" you get.

Of course, it is very possible that a given piece of equipment be a good performer in one or two of the above areas but not all three. For example, it is not uncommon for well-designed tube amplifiers to deliver smooth mids and liquid highs but have a soggy bottom. In fact, this type of inconsistent performance--even amongst the best equipment--is the rule rather than the exception. Therefore, you will likely be called upon to prioritize your requirements. With the best of audio electronics available today, you can achieve excellent results broadband, but there will always be a particular piece of equipment somewhere that does one particular thing better than the rest. So no matter what, you can't have it all--but if you are careful you can come very, very close.

copyright © 1998 Mithat Konar--all rights reserved


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