Music Frequency Analyzer

"Music Frequency Analyzer" is a new sound source analysis tool for digital music content.

Do you know what kind of sound characteristics your favorite music source has? This app allows you to check the sound characteristics of music sources.

For example, you can find out the bass and treble frequencies, the frequency overlap at the beginning and climax of the music, the recording condition, the background noise level, and more. It can also be used as reference information for acoustic evaluation when the same sound source is played back on audio equipment.

This app analyzes the information in the music file and displays the sound characteristics by FFT analysis and 1/3 octave band analysis in real time. It can also display quantitative analysis of their peak hold and average values.

In addition, with the fluctuation analysis, you can also see the degree of "1/f fluctuation", which shows the trend of frequency distribution of the sound source.

Features: 
- Supported files: PCM, ALAC, AAC, MP3 format , Sampling frequency: 44.1kHz, 48kHz
 *Only music data synced with the Apple music app or iTunes can be used. iCloud Music Library is not available.
- Source information display: title, file type, bit rate/quantization bit, sampling rate
- FFT analysis: 4096 points / -110dB to +10dB
-- Peak hold (Hold)
-- FFT Average (Off/1s/10s/All): Off / Approx. 1s / Approx. 10s / Whole music
-- Fluctuation analysis (1/f): 20 to 20 kHz, red line (instantaneous) / blue line (average)
-- Channel selection display (L-ch/R-ch) [Monaural sound source is displayed on L-ch].
- 1/3-octave band analysis: -100 dB to +10 dB
-- Peak hold (Hold)
-- Simultaneous 2-channel display: L-green, R-yellow  [Monaural sound source is displayed on L-channel].
- Snapshot (Snap): Save image of analysis display

How to use:
- Click List button to display the song list, and select the song you want to analyze.
- Select the song you want to analyze.
- You can use the time slider to move to an arbitrary time.
- You can save a snapshot of the sound characteristics at the point you want to know.

Fluctuation Analysis: 
In physics, "fluctuation" is the variation of energy from its average value over space and time. The 1/f fluctuation is said to be a pleasant natural rhythm, such as the murmuring of a stream or the lapping of waves.
The 1/f fluctuation has a characteristic that the Fourier-analyzed power spectrum is inversely proportional to the frequency. This app's fluctuation analysis determines the degree of fluctuation of a song by calculating the slope of the power spectrum of FFT analysis.
- 1/f0 (0dB/Oct): White noise
- 1/f1 (-3dB/Oct): Pink noise
- 1/f2 (-6dB/Oct): Brownian noise
In general, it is said that sounds with a -3dB/Oct characteristic, such as pink noise, which attenuates gently in the high frequency range, are pleasant to listen to.

Remarks:
- Even if the audio format is playable on the iOS system, playback of all files is not guaranteed. Depending on encoding parameters and data size, playback may not be possible. (Linear PCM data can be analyzed up to about 15 minutes.) It also depends on the hardware performance of your iPhone device.
- This app accesses to music files that exist in the music library in the iPhone. Music files must be downloaded to the iPhone. For example, if you have music files on your Mac/PC that you have ripped from CDs, etc., you can import the music files to your iPhone through device synchronization. Music files purchased from Apple Music subscriptions or the iTunes Store must be added to the library and then downloaded to the iPhone.