Report of the meeting of SC-02-01 Working Group on Digital Audio Measurement Techniques of the SC-02 Subcommittee on Digital Audio, held in New York, NY., US., 2005-10-08
The meeting was convened by chair S. Harris
The agenda and the report of the previous meeting, 2005-05-29, were accepted as written.
Open projects
AES-6id-R: Review of AES-6id-2000: AES information document for digital
audio - Personal computer audio quality measurements
The current draft was discussed. Working-group members should send comments to the reflector, comment period will end Oct 22 2005. T. Kite will post an edited document with his comments.
We discussed whether MIDI latency measurements should be included or not.
We discussed whether channels that you are not in use should be muted, including MIDI and PC speaker channels.
We discussed loudspeakers, fan and disk drive noise and electrical noise. People who are interested in working on acoustic fan noise, hard disk drive noise, please send email to the reflector. There was previously a project in SC-04-01 for acoustic noise from PCs. Harris and the secretariat will investigate a new project within SC-04-01. J. Johnson will come up with some names of potential contributors from PC manufacturers.
Sample Rate Converters - an additional test for SRC quality is needed.
W. Jones will champion the work on the next revision of AES6-id. This work will start immediately.
AES17-R: Review of AES17-1998 (r2004): AES standard method for digital audio equipment - Measurement of digital audio equipment
I. Dennis stated that only one person, M. Poimboeuf, had signed up to help with the revision work. Kite also volunteered to help. Dennis will organise the topics between Ian, Thomas, and Michael.
Goal is a PTD document before Christmas 2005
Development Projects
AES-X102: Liaison With IEC PT 61606
61606-4 "Audio and audiovisual equipment - Digital audio parts - Basic measurements methods of audio characteristics � Part 4: Personal computer": The CDV has passed with no negative comments received. The IEC may skip the Final Draft International Standard (FDIS) stage, so the standard may be published in March or April 2006.
61606-3 "Audio and audiovisual equipment - Digital audio parts - Basic measurements methods of audio characteristics � Part 3: Professional use"
Will reach CDV now. The next meeting will be at the AES Convention in Paris, 2006-05. Standard is expected to be published in April 2007.
AES-X118 : ITU-R study group 6 liaison
This project embraces two issues, loudness measurement and peak measurement.
Input on peak measurement is requested by the ITU group for their meeting on Monday. They want to complete their document by March 2006. Preliminary draft will be posted to the document site. [see also AES-X141, below]
AES-X151: Jitter performance specification
No progress to report.
AES-X141: Accurate measurement and indication of peak signal levels to avoid
overload of digital media
A number of topics were discussed. It was felt that:
S. Nielsen commented that the upsampling filter should be clearly specified.
DC blocking - ITU are proposing to have a switch to turn on or turn off DC blocking.
There is no requirement to accommodate pre-emphasis.
A table of oversampling vs resolution of peak detection is needed.
There is no need to allow for any downstream processing by predicting peak detection.
Dennis agreed to write a short paper about peak detection and using oversampling, including a table indicating the improvement in resolution as the oversampling ratio is increased. He will post this document to the SC-02-01 reflector by Sunday. [This paper was received and passed to the ITU group]
Mr. Okamoto introduced his (NHK) peak level meter. The need for oversampling was discussed.
Liaisons
There were no other liaison issues.
New Projects
No new projects were received or proposed.
New business
There was no new business.
The next meeting will be scheduled in conjunction with the AES 120th Convention in Paris, France, 2006-05.
