October 2014

Skoffin' Up Food For Thought
Use Your Ears, That's What They're For!
Roger Skoff writes about the best tools of all.
Article By Roger Skoff

  In a recent advertisement for high-end cables, one manufacturer wrote:

"Don’t take our word for it, let the most sensitive listening devices on earth, your ears, confirm to you that ________ products deliver the truth, the whole truth and nothing but the truth... so help you Stradivari if you settle for the second best! _____ Cables - Love at First Sound."

When this ad was posted on one of the hi-fi group sites, one audiophile responded with this:

"Don’t take our word for it, let the most sensitive listening devices on earth, your ears", not my ears or any human ears are even close to the most sensitive listening devices known to man on this earth. Laboratory test instruments are orders of magnitude more sensitive to frequency, phase, time, decibels in micro-decibel increments, etc. How would listening to a recording with _______ cables allow me to decide what the truth was when I was not present at the original recording to know what the truth was in reality?

I have to agree with the part of his comment about not being able to know the truth because he wasn't there, but I also have to point out that even if he had been there, unless he had been listening from the exact locations of all of the microphones (a difficult feat at best) he still wouldn't know what the truth was – because he wouldn't have heard it the way they did. He would, though, be able to make a pretty good guess at the truth, and would, by virtue of having bypassed the entire recording/playback chain, probably have heard more of it better than would be possible from almost (and I say "almost" only as a courtesy and to cover my butt) any Hi-Fi system in existence, regardless of price or any other consideration.

As to the other part of that person's comment, though – the part about "... Laboratory test instruments are orders of magnitude more sensitive...", I can't agree at all. The fact of it is that, for three reasons, their own ears really are very best test instruments that anyone could ever use. Two of those reasons have to do with numbers. Here's the first: Do you remember when you were just getting into hi-fi? Do you remember how you knew you knew nothing about what was good and what wasn't, and how you tried to correct that by learning everything you could about the hobby and its equipment? How you collected product literature, and memorized product "specs" just the way fans memorize baseball statistics? Do you remember how shocked you were when you finally went into a hi-fi shop and listened to the stuff you had lusted after for so long, only to learn that the numbers don’t always apply, and that flat frequency response and 0.00001% THD don’t really have a whole lot to do with whether a product sounds any good? Or with whether its sheer realism will set you grinning and grabbing for your wallet? The fact is that a product’s specifications and its ability to convince you that you’re listening to the real thing may or may not be related, and he only way you’re ever going to find out is by listening!

The second reason may seem to cancel-out the first, but, in reality, it's what makes the first one true: Your ears really are – not just subjectively, but in measurable fact – very much better than even the very best electronic test equipment:

The normal threshold-to-threshold range of human hearing is typically stated as encompassing 100dB, from about 30dB absolute, the "threshold of perception" (where sound first becomes audible to most people) to the "threshold of pain" at about 130dB absolute (equivalent to the sound of a Boeing 747 taking-off just 50 feet away.) Because decibels are a relative measurement, calculated logarithmically; because they represent not any specific sound level, but the ratio of one sound level to another; and because each successive 10 times increase – one full order of magnitude -- over the prior sound level results in an increase of just 10dB, thus a 100dB increase over an original reference level (in this case, 30dB absolute, also called 30dBSPL) indicates an increase in sound pressure of 10,000,000,000 to 1 (ten billion to one) over the reference level!

Put differently, the "threshold of perception" (30dBSPL) reference level is only 0.0000000001 as loud as the 1.0 level (130dBSPL) at the threshold of pain. How many test devices have you ever seen that could read that? How many – in any field of science or technology, for any purpose whatsoever -- have single-scale resolution to ten significant digits? None? Well, your ears do!

Picking-up on that word "significant", here’s where it gets interesting: Suppose we were still back in the days when we were concerned with product specs and we saw that (for example) an amplifier had just one one-thousandth of one percent fourth harmonic distortion (0.001%). Would we be impressed? Would we want to rush right out and buy it?

To figure that out, let’s start with two single tones – sine waves of 200 and 1600 Hz, both of which are well within the frequency range of human hearing (or even of the average old-time telephone). Now, let’s play those frequencies through our amplifier, with the 200Hz tone at a robust 100dBSPL and the 1600Hz tone quieter, at 50dBSPL. Because both levels are comfortably within the range of normal human hearing and because the tones are significantly different in frequency, even though one is 50dB louder than the other there should be no "masking" effect and we should easily be able to hear two separate and distinct tones.

Now let’s take those same two tones, played at the same relative volume levels through that same amplifier, and run the amp’s output into a Distortion Analyzer. What will it show? Well, remember that the 200Hz tone is 50dB -- 100,000 times -- louder than the other. Or, to turn it around, the 1600Hz tone is 100,000 times quieter than the other, being just 0.00001 times (0.001%) as loud as the 200Hz tone. Whichever way you describe it, because the tones are exactly three octaves apart and because of the way test instruments work, the Distortion Analyzer won’t "see" the amplifier’s output as separate tones at all, but will indicate a 200Hz tone with one one-thousandth of one percent fourth harmonic (1600Hz) distortion.

Is that 0.001% distortion "significant"? It better be! If we were to rely on the test instrument reading instead of our ears, and insist that 0.001% distortion can’t possibly be significant, we might find ourselves listening to just one tone and losing the other one, entirely!

The fact is that the only thing that instruments do better than ears is quantification.  Unlike test instruments, our ears don't have a meter-needle or a digital display to indicate exactly what it is that we're hearing ("...in micro-decibel increments...", as that audiophile commenter wrote), but we do hear it, nonetheless, and that, finally brings us to the third reason -- the non-numerical one -- why our own ears are the very best test instruments we can use:

When we listen to anything at all, whether words, music, or just ambient sounds and noise, we're not measuring. Instead, we're seeking something entirely different. From words, we're trying to garner information or meaning ; from music, what we want is an emotional response or the kind of kinesthetic magic of tone and rhythm that sets our spirit soaring and our body dancing.; and from background sound we want warning of impending danger, notice of what is around us, or just the soundtrack for our lives. In every case, though, the input from our ears is run through our brain and filtered or highlighted to conform to our own interests, priorities, emotions and hierarchies of value.  That's what ears are for, and nothing does it better.

So forget measuring; leave that to the manufacturers and engineers who are trying to build things to please you. Instead, why not just relax, put on your favorite disc, and...

Enjoy the music.