The 17^th online meeting of COOMET TC 1.2 "Acoustics, Ultrasound, Vibration" was held on 11 May 2023. Representatives of 8 COOMET member countries (Armenia, Azerbaijan, Belarus, Georgia, China, Russia, Turkey, Uzbekistan) took part in the meeting.

The progress in the implementation of the current projects within TC 1.2 and other issues, provided for in the agenda, were discussed at the meeting: changes in the TC membership, proposals to the COOMET Program of Comparisons; issues on the implementation of the CIPM MRA.

The main adopted decisions:

• To endorse the report of the TC Chair on the TC activities for the year.
• To appoint field coordinators ("Acoustics of the air": A. Nikolaenko, VNIIFTRI, Russia; "Ultrasound": G.Lukin, VNIIFTRI, Russia) and the TC Secretary (F. Gorbachyov, VNIIFTRI, Russia).
• To continue work on the supplementary comparisons under COOMET project 757/RU/18 "Comparisons of national measurement standards of the sound pressure units in air in the infrasound frequency range from 0.1 to 100 Hz" (COOMET.AUV.A-S3).
• To exclude COOMET project 846/RU/21 "Regional key comparisons in the field of ultrasound power measurement in water" from the Program of Comparisons owing to the irrelevance of the project for all the participant.
• To include additional bilateral comparisons in the field of microphone calibration in the COOMET Program of Comparisons, in order to confirm the calibration capabilities (services) in microphone calibrating (participants: UzNIM, TUBITAK UME).
• To discuss in due course the possibility of organizing trilateral pilot comparisons (VNIIFTRI, BelGIM, TUBITAK UME) in the ultrasound range of air acoustics.
• To continue the discussion of works on the projects, proposed to the COOMET Program of Comparisons according to the results of the 16^th TC 1.2 meeting: comparisons of calibrations of tone audiometers, comparisons of calibrations of ear simulators and calibrations of mechanical couplers.
• To request E. Sadikoglu (Turkiye) to prepare proposals from TC 1.2 on the subjects of courses for the BIPM e-learning platform and to send them to TC members for feedback and further discussion online.
• To include the following persons in the list of TC 1.2 technical experts on CMC review and peer review of QMS: G.Lukin (VNIIFTRI) in the field of ultrasound, A.Matveev (VNIIFTRI) in the field of acoustics of the water, A.Kozlyakovskiy (VNIIM) in the field of vibration, D.Golovin and A. Polikarpov (VNIIFTRI) in the field of acoustics of the air.

The representatives of NIM (China) expressed their readiness to host the next TC 1.2 meeting in September 2024. The exact venue and date of the meeting will be specified in due course.