Sound Quality Measurements

Tech Note
the 30th harmonic exceeds 0.003% this will be audible and has been shown to be
objectionable.
So in one case a system with 3% THD at 100dB SPL would pass the ‘no audible distortion’
criteria. While in another case a system with 0.003% THD would not pass the ‘no audible
distortion’ criteria!
This is of course hardly news, distortion audibility discussions are already known from dawn days of
high fidelity in the 1950's. Yet this article provides a summary of the Audio of Distortion Audibility ca.
1957 state of knowledge and sadly, not much progress has been made since:
http://www.r-type.org/articles/art-143.htm
This extreme ambiguity in terms of measured performance with subjective sound quality correlation
is one of the reasons why we do not generally publish extensive measurement results. It simply
would be a waste of time, bits, electricity and paper.
And realistically, while we have our own views how “good sound” may be measured, to develop and
promote such a system of tests is far outside the scope of a commercial operation and even if we
were inclined to do so anyway, it would be likely as much of a fool’s errand as the work of D.E.L.
Shorter of the BBC, Harry F. Olson of RCA and ongoing to Earl & Linda Geddes has been treated as by
the audio engineering profession in general. ‘Chocolate fireguard’ springs to mind!
Part 2: So what is our approach?
So there you have it. Measurements shed not much light on sound quality is our core belief. And
that’s the key reason behind why we measure minimally and audition maximally. And we mean a lot
of man hours.
As for our somewhat different stance, this is how we prefer to approach things:
1. To listen, listen and then listen even more, systematically and blindfolded as much as possible.
2. To show the internal components and the changes where we apply in our products.
3. To let people to listen and decide for themselves if they like the sound of the product or not.
‘Under the hood’ knowledge and personal experience is all they need.
OK, but to say that one has to listen isn’t good enough for many enthusiasts. As discussed previously,
measurements aren’t very helpful outside of our skunkworks, hence let’s leave these to one side for
the moment.
But we understand that some of you need something direct, a proof and a basis of an improvement
from one model to its next iteration. This we can happily provide. Below you’ll find two sides of
Micro iDSD Black Label’s PCB. These show the exact internal components which were upgraded in
comparison to the original iDSD model. Yes, 34 elements in total are behind why (thankfully!) people
are hearing for themselves from customers who have taken a ‘sip’ of our own Black Label.