Class Notes (836,163)
Psychology (5,217)
PSYCH 3A03 (56)
Paul Faure (56)
Lecture

Audio Demonstrations.docx

3 Pages
65 Views

School
Department
Psychology
Course
PSYCH 3A03
Professor
Paul Faure
Semester
Fall

Description
October 2 , 2013 Psych 3A03: Audition Audio Demonstrations Measuring Noise Amplitude - 10log (N )0= 10log(TP) – 10log(BW) White Noise Versus Pink Noise - Pink = -3dB per doubling Resonators - Damped sinusoidal motion: a free vibration in response to a single input force - Standing waves develop as a result of continuous forced vibrations from external force - Most acoustic events result from forced or driven vibrations - Objects naturally vibrate at their natural frequency Frequency Selective Attenuation - Filters perform a frequency selective attenuation on a sound - Filters work on both simple sounds and complex sounds Filter Cutoff (fc) = -3dB Frequency - The cutoff frequency of a filter is the frequency where the signal energy decreases by one half (i.e. -3dB) - The f cs the frequency where the output energy of the gilter drops to ½ of the input energy - Band pass and band reject fiters have both a low pass and high pass cutoff frequency Filter Rate of Attenuation (Roll-Off) - Filter cutoff frequency defines ½ power (-3dB) point - The amount of attenuation is known as the roll-off rate - Filter roll-off rate is measured in dB per octave (=slope) - Octave = frequency doubling - Roll-off rate is in decibels of attenuation per doubling of frequency starting from the filter’s cutoff frequency (f )c - E.g. 6dB/octave; 10dB/octave Filter Bandwidth - A filter’s bandwidth is computed as the frequency range or difference between the high pass and low pass cutoff frequencies - BW = f -lp (hpw pass cutoff frequency – high pass cutoff frequency) - The bandwidth determines the range of frequencies that can pass through a filter with little or no attenuation - Bandwidth is always a positive number - Broadband filter: wide BW - Narrowband filter: narrow BW (this is a relative comparison) Filters Also Change the Time Domain - Filters also introduce phase delays to signals that pass through the filters - Some frequencies may experience more of a phase shift than others - To fully describe a filter we must specify: 1. Filter type (e.g. low, band, high pass, or bad reject) 2. Cutoff frequencies (f ) c 3. Filter bandwidth (BW) and center frequency (CF – middle position of the filter) 4. Roll-off rate of filter attenuation (dB/octave) 5. Phase delay at each frequency (phase spectrum is very useful for this) Equivalent Rectangular Bandwidth (ERB) - This is an alternative way of specifying the bandwidth of an auditory filter - The equivalent rectangular bandwidth is simply the bandwidth of a rectangular filter with the same height and frequency area as an auditory or electrical filter - We will discuss ERB’s later in the course More on Filters - The characteristics of a filter can be obtained by conducting a Fourier analysis of the filter’s resp
More Less

Related notes for PSYCH 3A03
Me

OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Join to view

OR

By registering, I agree to the Terms and Privacy Policies
Just a few more details

So we can recommend you notes for your school.