The Systematic Approach Blogs by Steve Elford – Part 3 'The Sound of Systematic Faults'

In my Systematic Approach blogs parts one and two, I covered the basics of the causes of systematic faults – RFI and vibration in essence. But it's also important to understand what damage these things do sonically. A simple description might be:

  • With gross Systematic Faults a system will sound bright, flat and two-dimensional. Heavier music will be fatiguing (limiting programme choice), bass will be lumpy and untuneful and tonal detail will be limited. Treble will be spitty with no subtlety. Timing will be poor, with different rhythmic elements of music seemingly disjointed. The system will not be transparent, so rather than the speakers and room disappearing, the listener is always aware that the sound is coming off the face of the speakers.

But we can be much more analytical about the problem. Some time ago we devised what we called 'The Letterbox Volume Test', and this has proven to be a great way to quantify the systematic condition of a system. 

Lets assume we own a system that is poorly put together. It has electronics that are not appropriate for the environment, the speakers and room are not a good match and there is no protective system infrastructure to defend against RFI and vibration. (supports, mains etc).

One of the major characteristics of such a system is that it will have a poor response to different volume settings. At low volume it sounds weak and flat, there is not much tonal expression, rhythm or musical involvement. When playing low, the listener is instinctively aware of this problem and keeps wanting to turn up the volume to get the involvement he desires. When we do turn it up a bit we get to a volume level where generally the system sounds a little better - there seems to be some of the involvement we are after - but we are also aware that other sound quality aspects might not be as good as we would like, but this is what we have come to expect from this system.

There are also times though, when we want a louder, more stimulating experience, and want to crank up the volume 3 or 4 notches. And this is when things become considerably worse of course, the reality being (although we might not want to admit it) that the sound becomes bright and harsh, less controlled and timing is jumbled. Fatigue levels go up considerably.

This is what we call the 'letterbox' effect; a narrow usable volume range where the dissatisfaction is minimised, and where, above or below this setting the system always runs into significant problems. It's like lifting the narrow flap of a letterbox, and squinting at your music through it.

However, as a system is improved by applying the systematic approach, we hear significant gains at different volume settings. Overall the music is smoother, richer and far more involving, and this quality remains at lower volumes. But the mechanisms of RFI/EMI and microphony are energy level dependent of course, so the greater the volume, the greater these distortions interfere with the sound quality. A well set up system, that is defended from these threats, has the ability to play louder but smoothly and richly, with control and scale, delicacy and detail at the same time as drive and drama - and all of this without fatigue! In reality you don't need to go up hugely on the volume setting, and you don't tend to notice a great increase in the volume anyway because the system is not shouting (and it's this bright sort of distortion that sounds 'loud').

So may I suggest you try this test on your system. And use all types of music too, remembering that busy rock or jazz will trip things up more. And if you honestly find that your system doesn't pass the test with flying colours, (as any good system should), then can I make a second suggestion? Drop us an email to discuss what's happening.


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