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annotate Audio-tone-amplitudes @ 99:c28a1518d268

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Speech-codec-selection: document AT%SPVER
author Mychaela Falconia <falcon@freecalypso.org>
date Tue, 06 Jun 2023 03:54:53 +0000
parents 8ce3bd7c0164
children
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8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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1 In our current Luna development setup, we use a wired headset (currently
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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2 FC-HDS4, previously iWOW's) as our primary audio device, connected to Iota EAR
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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3 output, and the same arrangement will be used on FC Venus, our planned successor
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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4 to FC Luna. The gist of the situation is that the firmware "thinks" that we are
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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5 in the classic handheld setup, but in reality it is a headset inserted into the
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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6 developer-operator's ear canal.
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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7
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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8 The amplitudes of various audio tones emitted by the firmware through the DSP
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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9 need to be adjusted for this in-ear headset reality, in order to provide
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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10 reasonable ear comfort to the developer-operator and to prevent hearing damage.
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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11 The "classic" amplitudes for fw-generated audio tones (-7 to -5 dBfs) make sense
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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12 for a true phone handset with a 32 ohm earpiece speaker, and furthermore, these
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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13 "classic" tone amplitudes are only appropriate when the tones are generated
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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14 while the user holds the phone away from her ear - otherwise they are too loud.
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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15 But in our use case where an FC-HDS4 headset stays in the developer-operator's
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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16 ear canal for an entire work session, we need much lower tone amplitudes.
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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17
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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18 Basic keybeep: the empirically found amplitude for operator comfort is -26 dBfs
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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19 for each of the two single tones.
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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20
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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21 DTMF keybeep: the empirically found amplitude for operator comfort is -29 dBfs
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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22 for the low tone and -27 dBfs for the high tone.
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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23
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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24 Approximately good amplitudes for the remaining tones:
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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25
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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26 Call waiting tone: -23 dBfs
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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27 Ringing tone: -28 dBfs
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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28 Radio acknowledge (currently unused): -26 dBfs
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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29 Busy/congestion/dropped: -27 dBfs
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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30 SIT error tone: -28 dBfs
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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31
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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32 All of these dBfs numbers listed above should be regarded as starting points
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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33 for possible further tuning once we implement the necessary framework in our
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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34 firmware for generating audio tones at configurable amplitudes - and this
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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35 implementation most likely won't happen before FC Venus: Condat's entanglement
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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36 between audio tones and the buzzer needs to be detangled first, and that task
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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37 requires a platform with a working buzzer.
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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38
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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39 With our present firmware, the only way to test different audio tone amplitudes
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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40 is via AT@TONE test command, which requires 16 numeric arguments. The high
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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41 effort of repeatedly composing these complex AT@TONE commands for each tested
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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42 amplitude of each tested tone creates fatigue, which then interferes with the
8ce3bd7c0164 Audio-tone-amplitudes article written
Mychaela Falconia <falcon@freecalypso.org>
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43 original objective of psychoacoustic testing of different amplitudes.