Audio Digitisation QC Quiz #2

This is the next instalment of our audio home quiz challenge exploring quality control of digitised audio.

WARNING: this is much tougher!

How well can you identify these 5 issues within digitised audio?

(NB: won’t work in Internet Explorer sorry!)

Question 1:

The batteries begin to run out during the recording of an oral history interview. When you play the tape back later on a correctly powered machine, does the resulting audio seem to speed up or slow down?
It speeds up, with their voices sounding more high pitch
It slows down – with their voices sounding more low pitch
Nope, sorry
The tape just stops
This one wasn’t even mentioned in the question!


After you’ve answered listen here:

Example of batteries dying during an oral history interview.

As the power in the batteries drains, the capstan motor turning the tape in the recorder is slowing down. This means that increasingly less tape is being passed over the record head as the audio signal is being recorded. Conversely when you play this tape back on a tape deck with full power, the capstan motor is running as normal and the tape is being played back at the correct speed. So this means that the original signal goes over the playback head and sounds much faster to our ears as it was recorded on a shorter portion of the tape, which creates the effect of it speeding up rather than slowing down.

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