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Audio can only carry frequencies up to half the sample rate — the Nyquist limit. Use this to check whether a frequency is reproducible through your device's audio output.
The Nyquist–Shannon theorem says a sampled audio signal can only represent frequencies below half its sample rate. Most phones output at 44.1 kHz, giving a Nyquist limit of 22,050 Hz. Frequencies above that fold back (alias) into lower, incorrect tones — so very high sequences may not deliver as intended through audio.