Colored Noise Generator app for iPhone and iPad

”Colored Noise Generator" is a new noise generator that can be used to as the sound source for a variety of acoustic measurement and auditory effects.

This app can generate standard noise signals such as white noise, pink noise, brown noise, blue noise, purple noise and gray noise.

In addition, it can generate a specific octave band noise signal by using the band-pass filtering of 1/1 octave band with ideal steep attenuation characteristics.

Octave band noise can be used for various purposes as a reference sound source for environmental sound measurement, sound tuning, sleep sound effect, tinnitus relief and sound masking.

Octave band noise can be created as a multi-band coupling signal by 1/1 octave band filter with a center frequency from 63Hz to 8kHz.

Features:
- Noise generation : white noise, pink noise, brown noise, blue noise, purple noise and gray noise
- 1/1 Octave band noise : Octave band filter - 8 types, center frequency - 63Hz, 125Hz, 250Hz, 500Hz, 1kHz, 2kHz, 4kHz, 8kHz.
- Octave band noise can be selected multiple bands simultaneously. So this combined signal contains the frequency components of the multi-band.
- Frequency range : 20Hz - 20kHz.

Note :
Octave band noise is also useful to adjust the characteristics of the audibility of earphones or headphones. For example, by selecting the pink noise and playing the 1/1 octave band noise in the order of 125Hz, 1KHz, 8kHz of the center frequency, you can determine the intensity of each frequency band on the audibility. If you know the characteristic of frequency band, you will be able to adjust the earphone in the equalizer to your favorite sound easily.

For processes of testing and equalizing rooms and auditoriums, it is convenient to have broadband noise signals. Typically, white noise or pink noise is used. In order to further measure in detail, Octave band noise will be able to take advantage of the testing noise signal that some part of the octave band is divided.

- White noise
White noise is noise signal whose amplitude is constant throughout the audible frequency range. Twice the power corresponds to a 3 decibel increase, so white noise is said to increase 3 dB per octave in power.

- Pink noise
The power spectral density is a noise signal that drops by 3 dB per octave as the frequency rises. Since the energy for each constant frequency band becomes uniform, it is noise suitable for the purpose of evaluating the volume of each frequency band. In other words, pink noise is often used for acoustic adjustment and measurement because the magnitude of the sound is the same in any octave band.

- Brown noise
The power spectral density is a noise signal that drops by 6 dB per octave as the frequency rises.

- Blue Noise
Power spectral density is a noise signal rising by 3 dB per octave as frequency goes up.

- Purple noise
Power spectral density is a noise signal that increases by 6 dB per octave as the frequency rises.

- Gray noise
It is a noise signal that shows a power spectrum close to an equal loudness curve like psychoacoustics.

- Octave band noise
Octave band noise is generated the multiple frequency divided band signal by using the band-pass filtering of 1/N (N is a natural number) octave band. It can be used in order to measure and evaluate the sound level of a certain frequency band on the basis of the octave. This signal contains all the characteristics of the source signal in the split frequency band.

- The octave band filters are compliant with "IEC 61260:1995" and "JIS C 1514:2002".

Attention :
When using this application with wireless communication such as Bluetooth or AirPlay, there may be cases that limitation of the playback frequency, lowering the output level and irregular noise, etc., may occur under the influence of wireless environment, communication equipment and communication state. Please note that this is not to guarantee that this application operates as configured specifications under the wireless communication.