Advanced Voice Analysis

Calculate formant-corrected H1*-H2* voice source measure

get/api/calculate-h1-h2

Request

  • Base URL: https://platform.vocametrix.com
  • URL: https://platform.vocametrix.com/api/calculate-h1-h2
  • Auth: API key in header X-API-Key

Query parameters

svFileIdstring required

ID of the sustained vowel audio file (previously uploaded) - REQUIRED

genderstring required

Speaker gender for optimal formant analysis: "male"/"1", "female"/"2", or "other"/"3" - REQUIRED. Determines formant ceiling: Female=5500Hz, Male=5000Hz, Other=F0-adaptive

Response

Successful response

H1_H2number

Raw (uncorrected) H1-H2 in dB. Amplitude difference between first and second harmonics without formant correction. Use for comparison with corrected value. Example: 5.88

H1_H2_CORRECTEDnumber

Formant-corrected H1*-H2* in dB. Primary measure accounting for vocal tract resonance effects using Iseli & Alwan (2004) algorithm. Higher values may indicate breathier voice quality. Example: 10.93

MEAN_F0number

Mean fundamental frequency in Hz. Averaged across all valid frames in the stable vowel portion. Example: 134.76

F1_MEANnumber

Mean first formant frequency in Hz. Extracted using Praat Burg algorithm. Vowel height correlate. Example: 473.00

F2_MEANnumber

Mean second formant frequency in Hz. Extracted using Praat Burg algorithm. Vowel frontness/backness correlate. Example: 1183.97

B1_MEANnumber

Estimated first formant bandwidth in Hz. Calculated with the Hawks & Miller (1995) bandwidth: 5th-order polynomial in the formant frequency (separate coefficients below and above 500 Hz), scaled by S = 1 + 0.25 × (F0 − 132) / 88; coefficients as in VoiceSauce. Used for formant correction. Example: 36.95

B2_MEANnumber

Estimated second formant bandwidth in Hz. Calculated with the Hawks & Miller (1995) bandwidth: 5th-order polynomial in the formant frequency (separate coefficients below and above 500 Hz), scaled by S = 1 + 0.25 × (F0 − 132) / 88; coefficients as in VoiceSauce. Used for formant correction. Example: 43.28

FRAMES_ANALYZEDnumber

Number of valid frames analyzed. Frame shift = 1ms, window = 3 pitch periods. Higher counts indicate longer recordings or more stable voicing. Example: 2977

GENDERstring

Gender classification used for formant analysis. Determines formant ceiling frequency. Example: "Male" or "Female (F0-based)"

Changes

No recorded changes to this operation across all 1 revision of this API.