Mixing console tests don't present all the power and heat issues that can make power amplifier testing exciting, but they do present their own challenges–hundreds of knobs and settings, analog and digital inputs and outputs and a multitude of channels. Mixing consoles are often used in situations demanding extreme reliability–from a six channel unit on a film set, where down-time can cost hundreds of thousands of dollars, to a 128 channel unit in a televised concert being beamed live to millions across the world.
Multi-channel capability is essential for the fastest testing. The APx585 and APx586 are perfect for this application, with 8 outputs and inputs, and 8 outputs and 16 inputs, respectively. For higher channel counts, APx and 2700 Series both support up to 16 switchers for a total of 192 channels.
Because of the potentially overwhelming count of signal paths and channels, mixing console test benefits greatly from automation: a comprehensive set of measurements can be run quickly and efficiently, minimizing exposure to the human error factor common in highly repetitive procedures.
Audio Precision offers several alternatives for automated test. With its multiple channels plus the ability to make automated projects without writing any code (thanks to the Measurement Sequencer) and extensive LabVIEW and VB .NET support, the APx585 or APx586 is probably the AP instrument best suited to high channel count automation. Users requiring performance better than -103 dB THD+N, or needing to make electrical tests of digital interfaces, will be well served by the 2700 Series.
Even with automation, testing of analog mixing consoles demands a large degree of manual interaction and listening. Does the high EQ knob sound scratchy, or cut out at full rotation? Does the gain control have a dead spot? Does the limiter switch pop when it is engaged? Proper testing involves prompts to set EQ and other controls to various positions while listening for problems, and then running automated sequences to measure and graph the results. Both the APx Series and the 2700 Series let you define high and low limit curves, giving you both pass/fail reports and visual results. On boards with multiple main and auxiliary outputs, every combination of input and output channel must be tested.