Audio / Spectrum Analyzer
Loop-Sessions.LLC.
This RTA app supports simultaneous display of "Audio Waveform", as well as the FFT-based "Amplitude Spectrum" (frequency magnitude) and "Spectrogram" (frequency distribution over time), for audio signals input from a microphone. (FFT: Fast Fourier Transform, RTA: Real Time Analyzer) [Features] - Supports simultaneous display of Waveform / Spectrum / Spectrogram. - Supports orientation both portrait and landscape. - Selectable configuration of Waveform / Spectrum / Spectrogram display. - Selectable FFT size. - Selectable Window function. - Selectable Spectrum average. - Selectable Frequency weighting. (Flat, dBA, dBC) - Selectable the type of expressing the X direction (frequency) of Spectrum / Spectrogram. (Linear, Log) - Displays the peak level and its frequency of the spectrum. - Peak Hold (displays the results of holding past peak values of the spectrum). - Octave Analysis (displays the spectrum divided into octave bands). - Generates the audio signal (Sine, Triangle, Squire, Saw) - Generates the noise signal (white noise, pink noise) - Pitch meter display. [Setting items] 1. Screen structure : Select the display screen configuration. View Num : 1, 2 View Type : - 1 screen : Wave (Waveform) / 1D (Spectrum) / 2D (Spectrogram) - 2 screens : W+1D (Waveform + Spectrum) / W+2D (Waveform + Spectrogram) / 1D+2D (Spectrum + Spectrogram) Layout : Vertical (displayed vertically), Horizon (displayed horizontally) 2. Frequency Axis Scale Type : Selectable the type of expressing the X direction (frequency) of Spectrum / Spectrogram. - Linear: Distributed at equal intervals - Log: The intervals increase logarithmically 3. FFT size : Selectable FFT size. (number of samples used when performing FFT) 1024, 2048, 4096, 8192, 16384 (* 16384 is available in the Pro version.) 4. Window function : Selectable window function (multiplication just before FFT) used for spectrum calculation. Hanning, Hamming, Blackman, No window 5. Spectrum Average Number of spectrum average for a display of spectrum. 1, 2, 4, 8 (init value: 1) (* 4 and 8 are available in the Pro version.) Higher value will make the spectrum less noisy and more smooth, at the cost of lower time resolution. 6. Frequency Weighting : Selectable frequency weighting. - Flat: No frequency weighting is applied. - dB(A): Frequency response that takes into account human hearing. - dB(C): Relatively flat response. 7. Peak Hold : Displays the results of holding the past maximum values (peak values) of the spectrum. 8. Octave Analysis : Displays the results of classifying the spectrum into octave bands. Division method: - FFT: Spectral display - 1/12, 1/6, 1/3, 1 octave: Display divided into octave bands Calc method: - Max: Displays the maximum spectrum value in each band - Average: Displays the average spectrum value in each band 9. Generates the audio signal : Set the audio signal to be generated. - There are 4 types of waveform. (Sine, Triangle, Squire, Saw) - It can set the value of the frequency in 20Hz - 20000Hz. 10. Generates the noise signal : Set the noise signal to be generated. - There are 2 types of noise. (White noise, pink noise) [Other] - Background color: Black, White - WaveForm: Line Color (Green, Yellow, Invert), Line Width (1.0 ~ 6.0 px) - Spectrum: Bar color (Green, Yellow, Color patterns) - Spectrogram: Colormap, Display range (-150 ~ -60 dB), Display time (4 ~ 15 sec) - Bluetooth connection policy selection (disabled, HFP, A2DP). - Scaling of Waveform / Spectrum display in the Y direction (magnification: 0.5 - 2.0). - Scaling of Spectrum / Spectrogram display in the X direction (magnification: 1.0 - 16.0). [Information] - The vertical line spacing in the waveform display is 2 mSec. - The calculation of spectrum and spectrogram uses the vDSP library. The Pro version offers Ad-Free Viewing and High-Resolution Analysis (FFT size: 16384, Spectrum Average: 4, 8).