Audio / Spectrum Analyzer

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 (4 types of waveform)
- Pitch meter display.


[Setting items]
[1. View Type]
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. Sampling Rate]
Select sampling rate.
32k, 44.1k, 48k, 96k, 192k[Hz] (* '96k','192k' are available in the Pro version.)
The spectrum frequency range is set according to the sampling rate (up to the Nyquist frequency).

[3. FFT Size]
Select FFT size. (number of samples used when performing FFT)
1024, 2048, 4096, 8192, 16384 (* '16384' is available in the Pro version.)

[4. Window Function]
Select the window function (multiplied immediately before performing the FFT).
- Hann: Hanning window
- Hamm: Hamming window
- Blkman: Blackman window
- None: No window function

[5. Spectrum Average (N Ave)]
Number of spectrum average for a display of spectrum. (init value: 1) (1, 2, 4, 8)
(* '4','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]
Select the frequency weighting. (Used when measuring sound pressure level with a sound level meter.)
- Flat (Z-weighting): No frequency weighting.
- A-weighting: Frequency response that takes into account human hearing.
- C-weighting: Relatively flat response that covers a wider frequency range than A-weighting.

[7. Peak Hold]
When ON is selected, displays the results of holding the past maximum values (peak values) of the spectrum.

[8. Octave Analysis]
Set the spectrum to be divided into octave bands.
Division method:
- FFT: Spectral display (conventional method)
- 1/12, 1/6, 1/3, 1 octave: Display divided into octave bands (the larger the value, the larger the band width)
Calculation method:
- Max: Displays the maximum spectrum value in each band
- Average: Displays the average spectrum value in each band

[9. Frequency Axis Scale Type]
Select how the X-axis (frequency) of the spectrum is represented.
- Linear: Distributed at equal intervals
- Log: The intervals increase logarithmically

[10. 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.


[Other]
- Background color: Black, White
- WaveForm: Line Color (Green, Yellow, Invert), Line Width (1.0 ~ 5.0 px)
- Spectrum: Bar color (Green, Yellow, Color patterns)
- Spectrogram: Colormap, Display range (-150 ~ -60 dB), Display time (4 ~ 15 sec)
- Scaling of Waveform / Spectrum display in the Y direction.
- Scaling of Spectrum / Spectrogram display in the X direction.


The Pro version offers Ad-Free Viewing and High-Resolution Analysis (FFT size: 16384, Sampling Rate: 96k/192k, Spectrum Average: 4, 8).