Audibility of Jitter, Proposing a series of tests Options

[cabbagerat]

The threshold of audibility of phase noise in ADC and DAC clocks is a fairly contentious issue in the HiFi and audiophile world. Some sources claim that jitter is clearly audible at low levels, and some claim that high levels of jitter are inaudible. The literature describes several tests, many with conflicting results.

One of the chief difficulties in testing the audibility of jitter is that it requires a complex hardware setup, which means that many listeners would be required to be present for an time consuming (and expensive) on site test. Over the last couple of months I have been thinking about organising a distributed listening test to look at the audibility of jitter in audio applications, based on algorithms for simulating the effects of jitter on signals. These algorithms are fairly well described in RF and telecomms engineering literature, and would be interesting for comparison purposes.

The kind of thing I have in mind is this:
Use samples which are accepted to sound good -> simulate jitter -> perform listening tests -> perform more tests at different levels of jitter depending on results

The purpose of this thread is to get ideas of the Hydrogenaudio community about performing these tests. Some of the things I would appreciate input on are:

• Would such a test be useful
• Would the results of such a test be valid?
• What sort of test procedure would be best?

[Arnold B. Kruege...]

We hear very little about people hearing jitter during LP playback, yet there is jitter in LP playback that is commonly less than 60 dB down.

But Arny, LP jitter is good jitter. You know, the type that Mikey F. prefers.

Yes, high end reviewers are quite the hoot. Not only do they hear faults that aren't there, they fail to hear egregious faults that are there. I true study in the power of perception.

BTW I found a scientific paper about this. It is called:

Golden Ears and Meter Readers: The Contest for Epistemic Authority in Audiophilia
Author(s): Marc Perlman
Source: Social Studies of Science, Vol. 34, No. 5, Special Issue on Sound Studies: New
Technologies and Music (Oct., 2004), pp. 783-807

This is a peer-reviewed scientific paper.

Abstract:

ABSTRACT Scientific claims to knowledge and the uses of technological artifacts are
both inherently contestable, but both are not usually contested together. Consumers
of 'specialty' audio equipment (known as the 'high end'), however, connect both
forms of resistance. These 'audiophiles' construct their own universe of meaning
around their equipment; they cultivate a distinctive vocabulary and set of attitudes.
In this they resemble other groups of users dedicated to supposedly antiquated
technology. But they also engage in controversy to defend themselves against
knowledge-claims that would delegitimize their universe of meaning. These debates
concern recording formats or media (the relative merits of the compact disk [CD] and
long-playing record [LP]), user 'tweaks' of purchased equipment, and the supposed
audibility of differences between different brands of amplifiers, cables, or CD players.
In all of these cases, audiophiles resist the claims of audio engineering by privileging
their personal experiences, and they argue against scientific methodologies that seem
to expose those experiences as illusory. Some of these patterns of epistemic
contestation resemble those in non-musical domains (such as biomedicine). But
audiophiles also make epistemic use of values crucial to their identity as music-lovers.
They appeal to a common understanding of music as an exemplary locus of
subjectivity, emotion, and self-surrender, in order to ward off the criticisms directed
at them from a science they construe as objective, detached, and dispassionate.

[udauda]

BTW I found a scientific paper about this. It is called:
Golden Ears and Meter Readers: The Contest for Epistemic Authority in Audiophilia

I just obtained a copy- and it is rather a rhetorical paper that gives an overview on the fight between subjectivists & objectivists, and its long history. Thnx for the recommendation tho.

By the way, I found this powerpoint presentation which goes over most of the studies related the audibility of clock-jitter. Since I found the info extremely valuable, I made a excerption out of it:


Hopefully the authors don't get angry at me because of the unauthorized excerption..

This post has been edited by udauda: May 27 2010, 06:00

[Arnold B. Kruege...]

How many of the references that went into this page meet TOS 8?

2?

This post has been edited by greynol: May 31 2010, 21:31

Reason for edit: Removed unnecessary full quotation of the previous post.

[udauda]

How many of the references that went into this page meet TOS 8?
2?

No need for sarcasm.

[1] yes- and it is quite well-known.
[2] yes- done by Dolby.
[3] objective measurements only- no need to meet TOS 8.
[4] yes- and we have discussed it on this thread. Also there is an addendum from the authors.
[5] not referenced above- no need to meet TOS 8.
[6] no- written in 1970, well before David Clark's test in 1982.

[Arnold B. Kruege...]

How many of the references that went into this page meet TOS 8?
2?

[1] yes- and it is quite well-known.

OK

[2] yes- done by Dolby.

OK

[3] objective measurements only- no need to meet TOS 8.

IOW, it sheds no light on audibility

[4] yes- and we have discussed it on this thread. Also there is an addendum from the authors.

The first link is broken, the second link's contents sheds no light on audibility

[5] not referenced above- no need to meet TOS 8.

IOW, it sheds no light on audibility

[6] no- written in 1970, well before David Clark's test in 1982.

IOW, it sheds no light on audibility.

[Soap]

[4] yes- and we have discussed it on this thread. Also there is an addendum from the authors.

The first link is broken, the second link's contents sheds no light on audibility

Works here.

[Arnold B. Kruege...]

[4] yes- and we have discussed it on this thread. Also there is an addendum from the authors.

The first link is broken, the second link's contents sheds no light on audibility

Works here.

Works here, now. I haven't changed anything.