Rob’s Tech School Part 3 – Audio (Part 1)

Posted by on February 4, 2013 at 8:35 pm
Music to my ears

Music to my ears

Signal to noise ratio…Frequency response…Surround Sound…dB…Dynamic range.

These are all terms you’re going to come into contact with when you’re out and about looking at any kind of audio gear. From headsets to speakers to ear buds, you’re going to see this stuff all the time. Since most people aren’t audiophiles or trained audio engineers, I figured I’d take a few minutes to put something together which covers just what in the hell these terms mean, and how they relate to what we want when we’re out lo0king to spend our hard-earned dough.

The first of the these subjects, which I’m going to touch on in this article, is “frequency response”. I’ll also touch dynamic range, just because it relates quite closely. First, on to frequency response. This one is big because every piece of audio equipment in the world will use this as a selling point.

So what is frequency response? It’s a range of values that tell us which sound frequencies a piece of audio hardware can reproduce. The normal range of human hearing lies in the range of 20hz (hertz or “cycles per second”) and 20,000hz. Thus, it is no surprise that most pieces of audio equipment claim to be able to reproduce all of the frequencies in that range.

That’s all well and good. Most things will reproduce 20-20,000. The big question is what the tolerance is. You see, the perfect sound reproduction comes when a device reproduces every frequency between 20 and 20,000 hertz at a tolerance of ± ZERO dB. Unfortunately, that’s pretty hard to do.

And why is it so important? Well, a speaker may be able to reproduce 20-20,000 hz but if the tolerance is, saaaaayyy ±6 dB, that means that you could get really heavy bass, with crappy mid and high ends because there’s such a difference in the sound levels. That’s BAD. So what we’re looking for is to get as close to ± zero dB at 20-20,000 hz. Super easy for things like amplifiers, not as easy for things like speakers, because producing the signal is easy, while reproducing it…not so much so.

Just get as close as you can.

You’re also going to want to look at “dynamic range”, because that kind of relates. Dynamic range is a measurement of the lowest possible output of something, versus the highest possible output…basically. If you want to get really technical, it is a ratio of the intensity (amplitude) of the lowest possible (undistorted) signal to the highest possible amplitude noise signal. So it’s safe to say that the higher the dynamic range, the better. (FYI, the DR of human hearing is about 140 dB for most people with average hearing and the DR of human speech usually covers about 40 dB).

Now you’re on your way to being an audio aficionado! Tomorrow I’ll cover signal to noise ratio and we’ll talk about what the hell this dB thing is all about. Check back!

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