This 23-minute video takes an informative look at the analog vs. digital quality debate. It demonstrates sampling, quantization, bit-depth (and more) to explore digital audio behavior on real equipment using both modern digital analysis and vintage analog equipment. Teachers: Half the fun of this video is the entertaining style of author Christopher Montgomery, an electrical engineer and open source software creator. You can download the source code for each demo and try it all for yourself.

website

Want to give your students a challenge? Listen to this 3.5 minute video and try to tell the difference in three recordings made at different sampling rates (the same music selection is used throughout). The first recording was done at 44,100 samples per second (44.1 kHz). This is the standard sampling rate for most audio CD's. The second was recorded at 22.05 kHz. The third was recorded at 11.025 kHz. Your students will easily detect the loss of frequency ranges from 44.1 kHz to 11.025 kHz. In other words, sampling rate matters! The higher the sample rate, the greater the frequency reproduction.

website

Teachers: One reason we really like this video is because it features Cato Zane, a female audio engineer. (Females comprise less than 10% of audio engineers.) The video does a great job explaining the concept of bit depth in digital audio production: the number of bits of information in each sample. Bit depth is just as important as sampling rate, perhaps more so. This video would be great coupled with the one above on sampling rate. The two videos could be a springboard for discussion of considerations in converting signals from analog to digital.

website

Are your students interested in using their newfound understanding of A-To-D to get into audio or video coding? (Of course they are!) Software creator/electrical engineer Christopher Montgomery provides a engaging overview for your budding audio/video production geeks. This 30-minute video gives a short history of digital media, the difference between analog and digital, a summary of sampling theorem, and audio/video formatting basics for raw beginners. Note The first half of the video deals with audio; the second half with video.

website