A bit of Digital Blah-blah

Digital audio picks-up several samples per second on you original signal, at a frequency called the sampling frequency.

The most common are the 44.1 kHz of the CD format and the 48 kHz of several other formats, including the ADAT, the DA-88, and professional multi-track tape machines, etc...

Each sample is then converted to a number, expressed as a certain number of bits, which is refered to as the resolution of the converter.

The standard resolution is still 16 bits, even though more and more machines work on a resolution of 20, and even 24 bits.

To evaluate the computer memory required by one minute of digital audio, all you have to do is follow these simple calculations :

GENERAL FORMULA

EXAMPLE

Sampling Frequency

x

Resolution

x

60 seconds

Recording to a Direct to Disk at 48 kHz, 24 bits :

48 000 x 24 x 60 =

69120000 bits

The number you get is the number of bits. This unit is seldom used in the computer world. They prefer to speak in bytes (groups of 8 bits). Let's divide that number by 8 to get the number of bytes...

69120000 / 8 =

8640000 Bytes

This number is very big, let's divide it by 1024 to get Kilo-Bytes (why 1024 ? It's a long story, too long to explain here.)...

8640000 / 1024 =

8437,5 kB

Since that number is still quite big, let's go to expressing it in Mega-Bytes, by dividing, again, by 1024...

8437,5 / 1024 =

8,2397460938 MB

All you have to do is round that number to make it a bit more human, no computer is going to rule my life !!!

8,3 MB