Bit Transparency

Introduction

A digital audio device achieves bit-transparency if it passes digital audio data without affecting the data in any way. This device may be hardware, software, or a combination of both.

Testing for Bit Transparency

To determine if a device is bit-transparent, it can be tested by sending a pseudo-random bit sequence through it and monitoring the digital output. We typically generate the pseudo-random sequence using an Audio Precision digital signal generator. The Audio Precision includes a digital analyzer that is programmed to detect the pseudo-random sequence produced by the generator. The analyzer detects any differences between the generated sequence and the received sequence. The number of differences is tallied by a counter. A digital channel that is bit transparent will show no differences between the transmitted and received pseudo-random sequences.

EXAMPLE OF A SUCCESSFUL BIT-TRANSPARENT TEST:

11100011100011 -> Device -> 11100011100011

EXAMPLE OF A FAILED BIT-TRANSPARENT TEST:

11100011100011 -> Device -> 11100011100010

A device would fail a bit-tranparency test if it converts the sample-rate of the audio, shortens or lengthens the word-length, applies gain changes, applies eq or any other DSP or plug-in, or any other type of data manipulation.