Measurement

You can measure an audio device.
In fact there is a hell of a lot to be measured.
Now if you measure all that can be measured, do you know how it sounds?
Can you combine all these different measurements in a score?
I don’t think you can.


On the other hand, if a DAC measures bad on jitter, would you buy it?

This is what Miller Audio Research does.
They measure the equipment and if its performance on a certain test is below average, they say it fails the test.

HRT Music Streamer


Over 900 different CD/SACD and DVD/DVD-A players have been characterized by the Jitter Measurement Suite.
If you register on their website, you get access to all the test reports.

 

Jitter measurements

Often the Audio Precision audio analyzer is used to measure DACs.

 

The manual of Resonessence Labs Invicta DAC contains a lot of these measuments including a short explanation. Very instructive.

Distortion

You can measure distortion.

If you can choose between two components, one with a higher and one with a lower level of distortion, what would you choose?
Sound like a rhetorical question, the one with the lowest distortion is of course the best. It does the least damage to the recording.
The funny thing is, a lot of audiophiles prefer analog.
Digital sounds too clean, is lacking warmth.
According to Hugh Robjohns the beloved analog warmth is a matter of distortion….

 

Fifty years of tape-machine design evolution reduced wow and flutter to extremely low levels by the 1980s, but it couldn’t be removed completely, and even the mighty Studer A820 two-track machine’s specifications quoted a wow and flutter figure of 0.04 percent when the tape was running at 15ips (inches per second). This is a tiny amount, certainly, but word-clock stability — which is the equivalent of wow and flutter in modern digital systems — can’t even be measured, as digital systems are orders of magnitude more stable in the time domain.

 

So what audible effect would such low levels of wow and flutter introduce? Well, the minute cyclical speed fluctuations of flutter, and particularly scrape-flutter, create subtle ‘side-bands’ and noise modulation around the recorded audio. These add a perceptible low-level ‘grunge’ to the sound, and while better-designed and maintained tape machines suffered lower levels of this grunge, it was always there to some extent. Although technically flutter is a fault, many argue that its side-bands and noise-modulation effects are an intrinsic part of the sound character of all analogue tape recordings, and that we’ve come to accept (and expect) them as part of recorded sound — and as part of what we call analogue warmth.

Sound on Sound February 2010