Owner`s manual

Figure B. The more bits there are available, the more accurate the

representation of the signal and the greater the dynamic range.

Your Echo card’s analog inputs use 24-bit ADCs, which means that the incoming

signal can be represented by any of over 16 million possible values. The output

DACs are also 24-bit; again, over 16 million values are possible. The S/PDIF

inputs and outputs also support signals with up to 24-bit resolution. Your Echo

card processes signals internally with 24-bit resolution to insure that there is no

degradation to the audio signal as it is processed through the system.

The number of bits available also determines the potential dynamic range of the

device. Moving a binary number one space to the left multiplies the value by two,

so each additional bit doubles the number of possible values that may be

represented. Each doubling of the number of values provides 6dB of additional

dynamic range (see decibel section below). So, a 24-bit system can theoretically

provide 144dB of dynamic range. (6dB times 24 bits = 144dB) versus a 16-bit

system with a maximum dynamic range of only 96 dB.

Also important to the quality of a digital recording is the frequency with which the

samples are stored, called the sample rate. In order for a waveform to be faithfully

digitized, it must be sampled at a minimum of twice the highest frequency to be

stored. Failure to sample frequently enough results in a kind of distortion called

aliasing. (If you like technical issues, do some research on The Nyquist Theorem

which explains why this happens). In addition to aliasing, sampling too slowly

will result in reduced high frequency reproduction. Your Your Echo card allows

you to sample sound at up to 96,000 times per second.

Once the waveform has been transformed into digital bits, it must be stored. When

sampling in stereo at 96kHz using a 24-bit word size, the system has to

accommodate 4,608,000 bits per second. In the past, storing this vast amount of

data was problematic. Today, computer-based digital recording systems record the

data directly to the computer’s hard disk. Today’s hard disks are capable of storing

large amounts of data, though the performance of hard drives can vary

substantially. The speed and size of your hard drive will be a major determining

factor in how many tracks of audio you will be able to simultaneously record and

playback.