The Systematic Approach Blogs by Steve Elford – Part 2 'Damaging Effects'

In Systematic Approach part 1, I introduced the idea of the two root causes of 'hidden' sound quality faults. I call them hidden, although they are far from hidden in terms of the bad sound they cause, but hidden because simple hi-fi thinking that only considers traditional circuit design, the format of recordings or the size of your speakers, largely overlooks these problems.

The two causes are, of course, Radio Frequency Interference (RFI) and Vibration. But now we need to look at the way they damage sound quality.

RFI induced distortion:

  • Unwanted RFI in analogue circuits raises the noise floor which masks fine detail and smears phase information (blurring the image). It also 'intermodulates' with mid and upper frequencies, causing a noticeable harshness and edge. In digital circuits, RFI raises digital distortion and effectively reduces the fidelity of the reproduced recording, making it sound significantly flatter and more compressed.  

Vibration induced distortion (microphony):

  • Unwanted acoustic vibration causes extensive damage to sound reproduction because almost all electronic components are to some degree 'microphonic' - that is, if they are vibrated, they will turn some of that vibration into a small unwanted electrical signal, which is literally added to the actual signal we want to process. Many electronic components act like mini microphones! Just vibrating a few of these components, or allowing this issue to effect the whole system, produces increasing amounts of damage, ranging from subtle loss of precision and detail, right up to gross blurring and distortion. The damage varies massively with level too, so usable headroom is curtailed and important timing cues from percussion peaks are lost.

If you have not heard about these causes and effects before, or seen these sort of descriptions, they can all seem rather complex, and perhaps not really plausible - after all surely, over the past 6 or 7 decades of hi-fi design, these things would have been fully explained and tackled. But up until recently, they have been almost totally ignored. What we are doing at Quiescent is continually identifying and analysing all these effects and designed techniques to counter them.  

And there's a very good reason why we do this - when the damaging effects described above are significantly reduced, the improvement in audio reproduction is massive.  

In my next Systematic Approach blog, I'll describe how a typical system full of systematic faults sounds and behaves.