The IEC standard on measurement microphones (IEC 1094) will need a part to describe methods for free-field calibration of working standard microphones by comparison with laboratory standard microphones. This project is intended to produce some technical input to the standards making process for that part.
Some issues that will need to be covered include:
- Is a free-field room necessary or can signal processing and gated signals in an ordinary room provide adequate results?
- If a free-field room is used can we specify a minimum performance criteria for the room?
- What are typical reproducibilities between different laboratories with different types of free-field room?
A meeting to discuss the project, generate ideas and produce an agreed proposal is expected to take place in conjunction with the next acoustics Euromet meeting in May 97 in Finland. Potential partners are encouraged to contact the proposer before 28/2/97.
NPL proposes to act as co-ordinator. Final report was published as NPL report CMAM 57, September 2000