Week 6

Decibel  is a logarithmic value that expresses the ratio between two quantities. 

Watts the difference in dB: two values 12W & 6W, devide the high number by the low number 12W / 6W = 2, log the number log10 2 =0.3 Bells, multiply by 10 0.3 x 10 = 3dB.

dBSPL = 20 x log(value/reference), dBV = 20 x log (value/reference), dBu = 20 x log (value/reference), dBm = 10 x log (value/reference).

• dBSPL: Sound pressure (Pascal)

• dBu: Electric tension (Volts)

• dBv: Electric tension (Volts)

• dBVU: Electric tension (Volts)

• dBFS: Bits

• dBw: Potency (Watts)

Log10 1000 = 3 | 10x10x10=1000

the difference between 2 watts and 200 watts 

200/2=100

log10 100 = 2

=2 Bells

2 Bells x 10 = 20dB

1.23v = +4dBu = 0dBVU

Localization:

We use both ears to localize a sound source and its called spatial or binaural localization. This is based on three acoustic cues received by our ears.

1. Interaural intensity differences IID

2. interaural time differences ITD

3. the effects of the pinnae

Interaural intensity differences is for perceiving direction of high frequencies

interaural time differences is for perceiving direction of low frequencies

The pinnae creates a delay used to determine the "front to back" and vertical panning due to the shape of the pinna.