Audio / Spectrum Analyzer

This RTA app supports simultaneous display of "audio waveform" and "amplitude spectrum" (size of FFT calculation result for each frequency) for audio signals input from a microphone.
(FFT: Fast Fourier Transform, RTA: Real Time Analyzer)

[Features]
- Supports simultaneous display of audio waveform / amplitude spectrum.
- Supports orientation both portrait and landscape.
- Selectable configuration of "audio waveform" / "amplitude spectrum" display.
- Selectable FFT size.
- Selectable window function. (used in amplitude spectrum calculation)
- Selectable the type of expressing the X direction (frequency) of the amplitude spectrum. (Linear/Log)
- Displays the peak level and its frequency of the amplitude spectrum.
- Peak Hold (displays the results of holding past peak values ​​of the amplitude spectrum).
- Octave Analysis (displays the amplitude spectrum divided into octave bands).
- Generates the audio signal (4 types of waveform)
- Generates the noise signal (white noise, pink noise)


[Setting items]
1. Screen structure :
Screen configuration can be selected.
- Wave: Display audio waveform only.
- Spectrum: Display amplitude spectrum only.
- Vertical: Display audio waveform / amplitude spectrum vertically.
- Horizon: Display audio waveform / amplitude spectrum horizontally.

2. Spectrum Color Type :
Select the color scheme for the amplitude spectrum bars. (green, colorful)

3. FFT size :
Selectable FFT size. (number of samples used when performing FFT)
1024, 2048, 4096, 8192
The smaller the FFT size value, the faster the display updates, but the fewer frequencies the amplitude spectrum can be acquired.
The larger the FFT size value, the slower the display updates, but the more frequencies the amplitude spectrum can be acquired.

4. Window function :
Selectable window function (multiplication just before FFT) used for amplitude spectrum calculation.
- Hann: Hanning window
- Hamm: Hamming window
- Blkman: Blackman window
- None: No window function

5. Spectrum X Scale Type :
Selectable the type of expressing the X direction (frequency) of the amplitude spectrum.
- Linear : Distributed at equal intervals
- Log : The intervals increase logarithmically

6. Spectrum Zoom Direction :
Select the zoomable direction of the amplitude spectrum from the X direction (frequency) or Y direction (amplitude).
(For ease of use, we have made it possible to zoom only in the selected direction.)

7. Peak Hold :
Displays the results of holding the past maximum values ​​(peak values) of the amplitude spectrum.

8. Octave Analysis :
Displays the results of classifying the amplitude spectrum into octave bands.
Division method:
- FFT: Spectral display
- 1/12, 1/6, 1/3, 1 octave: Display divided into octave bands
Calculation method:
- Max: Displays the maximum spectrum value in each band
- Average: Displays the average spectrum value in each band

9. Generates the audio signal :
Generates the audio signal of the selected waveform.
- 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 :
Generates the selected noise signal.
- There are 2 types of noise. (White noise, pink noise)
- The volume can be adjusted.


[Other]
- It can reduce / enlarge the screen in the Y direction of audio waveform / amplitude spectrum display by pinching in / out. (0.5 - 2.0)
- It can enlarge the screen in the X direction of amplitude spectrum display by pinching out. (1.0 - 16.0)
- The vertical line spacing in the audio waveform display is 2 mSec.
- The amplitude spectrum calculation uses the vDSP library.
- Supports selecting Bluetooth connection policy. (None, HFP, A2DP)


If you need multi audio signals, please try "Multi Wave Oscillator" from the link on the setting screen in this app.
This app generates the audio signal (Sine, Triangle, Squire, Saw) of 6 channels (Up to 16 channels).

This app can hide ads with In-App Purchase. If you like this app, we hope you can use it.