Play sound (audification)
DataView allows you to play any trace as a sound. This may be useful because our ears are often better at detecting subtle changes in frequency or pattern than our eyes. (This facility of course assumes that you have sound enabled on your computer. It also requires that the DirectX sound package be installed on your computer.) If you have more than one axis selected, or more than one trace displaying on the selected axis, then the trace with the lowest ID number plays.
- Load the file sound. (This was recorded as a wav file and then saved in Dataview format. )
- Select the Sound: Play menu command.
The selected trace plays as a sound, and a vertical cursor scrolls across the screen indicating which part of the record is currently playing. Wasn’t that nice?
Normally the Play command plays data at the same sample rate (frequency) that it was recorded at. However, Windows cannot play sound files with a sample rate less than 500 Hz, so if the recording was made at a lower sample rate it is played at 500 Hz.
- Load the file ecg.
This shows an electrocardiogram (heartbeat). It was recorded with a 10 ms sample interval (i.e. 100 Hz).
- Click the Show all toolbar button (
). - Select the Sound: Play menu command.
You can just about hear the low rumble of the heartbeat, but it is hard to distinguish any features.
- Select the Sound: Play 5kHz menu command.
You can now clearly hear the changes in heartbeat during the recording, which may or may not be informative.