Caption: Figure 2: (a) Top panel shows white noise with 500 sample points; Middle panel shows the MSE for various time series (TS) lengths; bottom panel shows normalized MSE (for scale factors [tau] = 1, 2, 3, and 5) and SE; (b) top panel shows
pink noise with 500 sample points; middle panel shows the MSE for various time series (TS) lengths; bottom panel shows normalized MSE (for scale factors [tau] = 1, 2, 3, and 5) and SE; (c) top panel shows brown noise with 500 sample points; middle panel shows the MSE for various time series (TS) lengths; bottom panel shows normalized MSE (for scale factors [tau] = 1,2,3, and 5) and SE.
The sounds used were a combination of white and
pink noise in varying proportions--the same encoding used for the game described in the previous section.
The experiment showed that within the corpus of the research material
pink noise provides better protection of the utterance than white noise at equal integral level of signal-to-noise ratio (for all tested levels) in terms of the following indicators: detection of speech signal in noise (see Figure 1), correct identification of the utterance language (see Figure 2), and correct perception of the semantic content of the utterance.
Consequently, this type of
pink noise modulation is excellent for local heating (other important effects of
pink noise modulation are discussed elsewhere [11]).
With babble noise, the mean durations over 61 subjects were 143, ms (SD 37 ms) and 349 ms (SD 76 ms), and correspondingly with
pink noise, 130 ms (SD 32 ms) and 341 ms (SD 79 ms).
(21) Input = 1 + STEP (step height, step time)+ (pulse quantity/TIME STEP)\times PULSE (pulse time, TIME STEP)+ RAMP (ramp slope, ramp start time, ramp end time) + sine amplitude \ times SIN (2 \times 3.14159 \times time/sine period) + STEP (1, noise start time) \times
pink noise Units: dimensionless
The beats were superimposed on a background of
pink noise. The control tape consisted of the
pink noise only.
(4) For an analysis of
Pink Noise, see my essay "Toward a Poetics of Noise: From Hu Shi to Hsia Yii," Chinese Literature: Essays, Articles, Reviews 30 (2008), 167-78.
Industrial noise, generated broadband noises (e.g., white or
pink noise), tonal sounds, road traffic, and jet engines primarily increase catecholamine levels, such as norepinephrine, and corticosteroids, such as cortisol.
To measure the noise isolation properties of the earphones, the test chamber was filled with non-correlated
pink noise. A measurement of that noise was taken directly by HATS with no headset.
Four types of additive noises were used: white noise,
pink noise, factory noise (plate-cutting and electrical welding equipment) and F16 cockpit noise selected from Noisex-92 database [15].
First impressions were of high transparency and clarity, and as I walked about listening to de-correlated
pink noise to optimize placement, I was struck by the complete lack of coloration as I moved up and down, side to side, and all around.