Module analysis 

FFT-based frequency analysis for recorded signals

This module provides functions to analyze recorded audio signals and extract:

• Frequency spectrum (magnitude in dBFS)
• Phase spectrum (compensated for latency)
• Latency estimation via cross-correlation
• Microphone compensation for calibrated measurements
• Standalone WAV buffer analysis (wav2csv functionality)

Structs

AnalysisResult

Result of FFT analysis

CrossCorrelationEnvelopeResult

Result of cross-correlation with analytic envelope detection.

MicrophoneCompensation

Microphone compensation data (frequency response correction)

WavAnalysisConfig

Configuration for standalone WAV buffer analysis

WavAnalysisOutput

Result of standalone WAV buffer analysis

WindowedFrequencyResponse

Frequency responses computed from different time windows of an impulse response.

Functions

analyze_recording

Analyze a recorded WAV file against a reference signal

analyze_wav_buffer

Analyze a buffer of audio samples and return frequency response

analyze_wav_file

Analyze a WAV file and return frequency response

compute_average_response

Compute a log-frequency weighted reference response level in dB.

compute_clarity_broadband

Compute Clarity (C50, C80) from Impulse Response (Broadband) Returns (C50_dB, C80_dB)

compute_clarity_spectrum

Compute Clarity spectrum (C50, C80) using octave band filtering Returns (C50_vec, C80_vec)

compute_coherence_from_realizations

Magnitude-squared coherence γ²(f) across N complex spectra that should be measurements of the same deterministic transfer function. Per docs/gd_opt_v2_plan.md §2.2:

compute_group_delay

Compute group delay from phase data Group delay = -d(phase)/d(frequency) / (2*pi)

compute_impulse_response_from_fr

Compute impulse response from frequency response via inverse FFT.

compute_rt60_broadband

Compute RT60 from Impulse Response (Broadband) Uses T20 (-5dB to -25dB) extrapolation

compute_rt60_spectrum

Compute RT60 spectrum using octave band filtering

compute_spectrogram

Compute Spectrogram from Impulse Response Returns (spectrogram_matrix_db, frequency_bins, time_bins) window_size samples (e.g. 512), hop_size samples (e.g. 128).

compute_windowed_fr

Compute frequency responses for different time windows of the impulse response.

cross_correlate_envelope

Cross-correlate a probe with a recording and compute the analytic envelope.

deconvolve_sweep

Deconvolve a single recorded log sweep by dividing the recording’s spectrum by the emitted sweep’s spectrum, producing a complex frequency response on the FFT grid [0, Nyquist].

estimate_noise_floor_db_from_silence

Estimate per-bin noise floor in dB from a silence window.

find_db_point

Find a frequency point where the magnitude reaches a specific dB level

plan_fft_forward

Get a cached forward FFT plan for the given size (f32).

plan_fft_inverse

Get a cached inverse FFT plan for the given size (f32).

read_analysis_csv

Read analysis results from CSV file

smooth_response_f32

Apply octave smoothing to frequency response data (f32 version)

smooth_response_f64

Apply octave smoothing to frequency response data (f64 version)

write_analysis_csv

Write analysis results to CSV file with optional microphone compensation

write_wav_analysis_csv

Write WAV analysis result to CSV file