Spectral Analysis

LTAS, Alpha Ratio & CSID Assessment

Measures

LTAS (Long-Term Average Spectrum): Averaged spectrum over the entire recording showing your voice's spectral "fingerprint." Helps visualize hyperfunctional patterns (elevated high frequencies).

Alpha Ratio (Spectral Tilt): Ratio of energy below vs above 1000 Hz. Indicates pressed (more negative) vs breathy (more positive) phonation.

CSID (Cepstral/Spectral Index of Dysphonia): Multiparametric index derived from CPP, the L/H spectral ratio, and their variability (σCPP, σL/H) (Awan et al., 2010). Available only for connected-speech recordings.

Recording Guidelines

Best: connected speech (30 seconds)

Reading passage (e.g., "Rainbow Passage") or counting from 1 to 30

Also accepted: sustained vowel (3-10 seconds)

Sustained /a/ at comfortable pitch (best for H1-H2; LTAS measures prefer connected speech)

Quiet Environment

Record in a quiet room; background noise shifts spectral shape

Device Consistency

Any device works, but use the same microphone across sessions to compare a speaker over time

Drop your voice recording here

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Supports: WAV, MP3, M4A and many more • Maximum: 25MB