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Attenuation at Threshold (REAT) method was discussed during that meeting. Several decisions were made in that working group meeting that might eventually lead to revi- sions to the ANSI/ASA S12.6 test method for REAT testing.
Florianopolis is a wonderful Brazilian city which provid- ed a beautiful setting for the meeting.
Report by Laura Ann Wilber
ISO/TC 43 held its meeting in Florianópolis, Brazil from 26 to 30 November 2012. The first part of the week was devoted to working group meetings. I attended WG 1 “Threshold of Hearing” as a member of the working group, and WG 9 “Method for calculating loudness level” as the con- venor of that working group. In addition I attended the ple- nary session on TC 43/SC 1 and the plenary session of TC 43, at which I presented a report on the actions of WG 9.
TC43/WG 1 Threshold of Hearing: I have been a mem- ber of TC 43/WG 1 since the late 1970’s. The Working Group is concerned with threshold measurements (e.g., Reference Equivalent Threshold Sound Pressure Levels (RETSPLs) for supra aural and circumaural earphones). At the ISO level there are currently standards for each type of transducer. In ANSI/ASA standards the tendency is to include all of these in one document (ANSI/ASA S3.6). Recently this working group was asked to take over the work on ISO 1999, Acoustics—“Determination of occupational noise exposure and estimation of noise-induced hearing impairment.” At the meeting in Florianopolis much of the time in the WG 1 meet- ing was spent going over suggested revisions to ISO/DIS 1999, most of which were editorial. ISO/DIS 1999 is being prepared for circulation as a Final Draft International Standard (FDIS). The group agreed on the changes which will be incorporated into the draft by the project leader, Stig Arlinger.
We also discussed recommended changes to ISO 389-3 Acoustics—”Reference zero for the calibration of audiomet- ric equipment—Part 3: Reference equivalent threshold force levels for pure tones and bone vibrators.” Again, most of the comments were general or editorial, almost all were submit- ted by the U.S., and most were accepted.
There was some discussion of a proposed working draft of PWI 7029 Acoustics—“Statistical distribution of hearing thresholds as a function of age.” Considerable work in this area has been carried out in Japan and it is hoped that the final revision will extend the age range to 80 years. WG 1 has been involved with levels by age and sex for some years—and this data is incorporated in other standards it has promulgated.
There is a preliminary work item for revision of ISO 389- 1 Acoustics—“Reference zero for the calibration of audio- metric equipment—Part 1: Reference equivalent threshold sound pressure levels for pure tones for supra-aural ear- phones.” There continues to be concern, especially in Europe, that the TDH-39 earphone is not consistent from one ear- phone to another—and that there is an error at 6 kHz. This appears to go beyond the known concern of the changing grid cloths in this earphone. On several occasions it has been suggested that this earphone be deleted from the ISO stan-
dard, but since it is still widely used that has not yet been done. We will continue to be in contact with the manufactur- er to determine whether this problem can be resolved.
There was further discussion of whether or not to revise ISO 389–7, –8, and –9. In the case of 389–8 which relates to circumaural earphones, there was concern as to whether the earphone referenced in the standard is still available.
Because of the limited time, it was agreed that the proj- ect leaders would circulate their documents for on-line review. There is no plan to meet again until the next plenary session of TC 43 in 2014.
TC43/ WG 9 (Loudness) has had somewhat of a con- tentious history because there are two different approaches for measuring stationary loudness—the revised Zwicker method (which is a DIN document) and the Cambridge method (Moore-Glasberg) which is essentially the same as the ANSI/ASA S3.4 standard on measuring loudness. We had been told that a standard could not contain two procedures which yielded different results. As a consequence the major- ity of members of WG 9 decided to support the Moore- Glasberg procedure. This position was initially supported by the member bodies, but at the last vote the document was rejected. Since the time limit for completion of the document had expired, it was not possible to continue revision. Thus this rejection ultimately led to the recommendation that two separate standards be created–one using the revised Zwicker method, and the other the Moore-Glasberg procedure. This suggestion was approved by the member bodies, and as a consequence two project leaders have been selected and pre- liminary work has begun on each document. These docu- ments may also contain methods for measuring non-station- ary (or fluctuating) noise. There was some discussion of each procedure and finally it was agreed that the project leaders would submit draft documents for review by the entire work- ing group. In addition a preliminary date for a face-to-face meeting in Canada has been set to take place at the ICA/ASA/CAA meeting in Montreal in June 2013. Colin Novak, the project leader for the Moore-Glasberg document, will look into the feasibility of having this working group meeting in Montreal. In the meantime we will continue to exchange revision proposals will be exchanged via e-mail.
As the convenor of this working group, I also had to present a summary of our work at the plenary session. It should be noted that although TC 43 is the parent group (and the place that WG’s 1 and 9 reside), the majority of proposals in TC 43 come from the several working groups in TC 43/SC 1.
It should also be noted that the Brazilians were most accommodating to us at the meeting—the food was great, and some of our delegation revealed great dancing skills at the banquet.
Detailed report of committee activities by Robert Hellweg
I. ISO/TC 43/SC 1/WG 28 “Basic machinery noise emis- sion standards”: William Lang has been convenor of WG 28 for many years, and I served as acting convenor of the meet- ing at his request. The United States had two other represen-
32 Acoustics Today, January 2013