About resolution

Digital format

In the following article we will try to explain the digital format. Please excuse bad English of this articles series.

Digital format is a way the information is stored. In this case, in which we are storing information of how the air vibrates, we use two dimensions. In one dimension we follow time and in the other energy that an air molecule carries. We plot 96000 samples each second where each sample has a certain height, a certain number that represents energy or pitch, loudness, volume. Computer shall use 32 bits for storing this very accurate number. In other words our audio track has a resolution of 96 kHz times 32 bit depth.

If we were to burn music to a compact disc, we'd use 44 kHz and 16 bit, but since we are going to do other stuff, it is better to do that in higher resolution, because when we are going to apply some effects to our music for example, the new values of the samples will get calculated and it sounds better when this calculations are more precise.

Analogue format

A couple of macro photographs will be showing how music is recorded in an LP. To reproduce music from this LP, the molecules of vinyl plastic guide the gramophone needle through the groove causing it to vibrate. This vibration is transformed into electric signal, which is on the other end sent to speakers where the signal shakes the air shaking membrane.

LP makes 33 rotations per minute. By measuring the outer groove length to roughly 90 cm, we get the picture of how the information is stored in an analogue way.

Gramophone needle is shaking and bouncing in all directions much like the light in this picture is.

Picture of the surface of this rather dusty LP.

So a rotation being a 90 cm long path, having 33 rotations per 60 seconds, that is a rotation per 2 seconds, we will now size it down to 1 mm.

900 mm are used to store 2 seconds of music, so approximately a millimeter stores 2,22 milliseconds.

A millimeter long analog signal, pictured here in sort of two dimensions, to simplify our picture of plastic, will be encoded into 2,22 ms of digital signal.

Zoomed in to the size where individual samples can be seen.