# Three original A/B timbre cue candidates · educator hold

The generated files are mono 16-bit PCM at 22,050 samples/s and 2.40 seconds long. Four separate 0.12-second events begin at **0.10, 0.60, 1.10, 1.60 seconds**. Each has a 10 ms fade at both ends and a quiet gap before the next event. A uses only a 330 Hz sine component; B uses 330 Hz plus a 990 Hz third harmonic. Thus the **stated fundamental is 330 Hz for both recipes**, while their waveforms differ. This is an original technical contrast, not a named instrument, voice, song, culture, or guaranteed perceptual category. Different programmed component amplitudes and digital peaks do **not guarantee equal perceived loudness** on a speaker.

All three are **candidate** files, **not cleared** for classroom playback until a human **educator listens** to each on intended equipment, checks comfortable **volume**, distortion/harshness and child choice, and retains the full **no-sound** route. They are not set to autoplay. No child recording or data is captured.

| Candidate | Exact event transcript | Complete quiet source-plan route |
| --- | --- | --- |
| [cue-a-only.wav](cue-a-only.wav) | A pure 330 Hz at 0.10, 0.60, 1.10 and 1.60 s; each event lasts 0.12 s; quiet between and after. | [B one-source board](../print/one-source.svg): four broad A circles on fixed numbered places; explain that one recipe is planned throughout. |
| [cue-b-only.wav](cue-b-only.wav) | B 330 Hz fundamental plus 990 Hz harmonic at 0.10, 0.60, 1.10 and 1.60 s; each event lasts 0.12 s; quiet between and after. | Use the [A two-recipe legend](../print/two-recipes.svg) and place four striped B cards on the [B board](../print/one-source.svg). |
| [cue-aabb.wav](cue-aabb.wav) | A at 0.10 and 0.60 s; B at 1.10 and 1.60 s. A is 330 Hz only; B is 330+990 Hz. Each 0.12 s event is separate, with quiet gaps. | [C switch board](../print/source-switch.svg): A A B B, with a broad change marker at the 2→3 boundary. |

The educator's human review decides whether any cue is tolerable and useful. Opening or generating a file does not show that a child heard a difference, can name a timbre by ear, reproduced it, or wanted to listen.