MU 1770 Digital Audio pt 2 (asst 6)
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1. A client comes to your studio to make a CD for his dog. He wants to record her favorite dog whistles so she can listen to them while he’s at work. Dog whistles generate high-frequency ultrasonic sounds, beyond human hearing. You know that some dogs can hear frequencies up to 60,000 Hz. What is the minimum sampling rate you need to use to be sure the dog hears everything on the recording that she hears in real life? *
2. Open an Audacity project and create a new track. The track header should indicate a 44,100 Hz sample rate. If it is different, change it by clicking the “...” drop-down menu in the track header (shortcut shift-M) and setting the Rate to 44,100 Hz. 

Go the Generate menu and select Noise -> White, at a moderate amplitude (around .5) and for a duration of 15 seconds.

Create a new track with the same settings and generate pink noise. 

Create a third track and generate Brownian noise (also called Brown noise or red noise).

Audition the tracks. Solo each track in turn to compare them. Describe and contrast the three sounds, using any descriptive language (whether technical or metaphorical) you like.
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3. Open a new track and set its sample rate to 8000 Hz. Generate a white noise signal with the exact same amplitude and length as before. Listen to the new track alone (SOLO it and/or MUTE the first track). Describe the difference in sound between the two tracks, and explain as best you can why it is different. *
4. Delete or clear all tracks to clear up space. Then create a track, set it to a 44,100 sample rate, and create a slow glissando by selecting Generate > Chirp > Waveform: Sine. Set the chirp frequency to go from 100 Hz to 8000 Hz, at Amplitude 0.4, with Interpolation set to Linear, for a duration of about 10 seconds. Listen to the result. 

Then open a new track and set the sample rate to 8000 Hz. Generate a chirp in this new track with the exact same settings as before. BEFORE you listen to it, write down what you think you will hear.
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5. Now audition the new track by itself (be sure to mute the first track or solo the second track). Describe what you hear. *
6. Why did this happen? Answer as best you can. If you are unsure, speculate! Notice that you can zoom in in Audacity until you are seeing individual samples. Looking at very high zoom levels may prompt some ideas. *
7. Now go to Yellowdig and get your discussion on about this or related topics of interest. If you have anything you want to say to me directly about the recorded lecture or this assignment, please write it below (optional).
A copy of your responses will be emailed to the address you provided.
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