SC-226 MEETING MINUTES Working Group JANUARY 14 ... - RTCA

RTCA Paper No. 021-13/SC226-010
February 6, 2013
Another question was raised concerning whether the graph in the Bose paper takes into account the
female voice. Bose will look into this.
Bose offered to write some proposed language for the standard based on their paper. The other
manufacturers participating agreed with the information proposed. The committee welcomed Bose’
paper.
Boeing and Airbus both agreed that with new language based on the paper by Bose, they will be able to
select amongst varying manufacturer’s ANR headsets and have a consistent way to make a comparison
between them, and thereby more easily certify the headsets for their aircraft without significant testing
as was needed in the past.
Bose also suggested that instead of using power as the input to test the headset, voltage should be used
as active headsets no longer have the same impedance as passive headsets. Input power is less
important when an active circuit is connected in between the input and the speaker. A consistent input
voltage is deemed to have more value for both passive and active applications.
Bose will also get with Sennheiser and Bosch to discuss all aspects of their paper to come to consensus
prior to returning to the next meeting with their recommended language.
They will also address how to insure that ANR headset meet the same DO-160 audio performance
requirements from DO-214 section 2.5 as are required by other microphones.
Participants responsible for headsets (ANR and passive) work are:
Anthony Mangiameli – Bose
Dan Gauger, Bose
Steven Parker – Bosch
Jorg Buchberger – Sennheiser
Christian Grone – Sennheiser
Christian Kast – Holmco
Fifth item of discussion: EASA Deviations
EASA deviation paper ETSO.DevP.52d.pdf (Deviations requests #52 for an ETSO approval for CS-ETSO
applicable to Headsets, Speakers and Aircraft Microphones (ETSO-C57a, C58a) Consultation Paper)
should also be addressed as part of the headset working group’s efforts on how to best measure
sensitivity. Current language in the standard is as follows:
2.3.3.1 Headsets and Handsets
When tested in accordance with the test procedure of subparagraph 2.7.2.1a,
each ear phone shall have a sensitivity of 90 ±5 dB SPL (re: 20 uPa) with
an input power level of 1 mW (RMS). A volume control may be provided to
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