Allen & Heath’s design team first established digital mixing for the installation market in 1996 with the revolutionary DR128, followed the next year by the DR66, both of which provided a high level of control and offline programming for installed sound systems. From this excellent base, the team went on to produce the iDR Series, which provides more processing, flexibility and a large number of remote control options for installed and live audio. Not only was the new product highly flexible and capable, but it also featured excellent sound quality, rivalling the sound of the company’s long-established analogue mixers.
How was this achieved?
Rob Clark, Allen & Heath’s chief DSP engineer, explains the company’s development methodology:
“We spent a long time listening to our input and output circuitry along with the ADC and DAC circuits. We worked hard at minimising distortion, while maintaining headroom and avoiding digital clipping.
“The input pre-amps are discrete circuits, incorporating the same low noise transistor front end as many of our large consoles, with the gain element being replaced by digitally controlled switches.
“Careful power supply and ground plane design and maintaining clean voltage rails were also critical, while keeping sample clocks clean improved jitter performance and HF clarity.
“As ever, close attention to quantisation noise, and care over how the analogue processing counterpart works, were also essential in delivering natural-sounding digital signal processing”. |
