The soundcard is a key element of my setup. It acts as a translator in real time, much like an interpreter during a UN conference. It translates real-world electric audio signals into numbers that the computer can read and process, and translates the digital output back into plain electric audio signal. The device which translates the electric signal into numbers is called an analog-to-digital converter(ADC). The translation from numbers to an electric signal happens in a digital-to-analog converter (DAC).
The ADC samples the incoming signal : it measures its value at regular intervals (very short) and sends it to the computer. The DAC, unsurprinzingly, works the other way around.
Because an electric audio signal is mostly periodic (more or less a sinusoid, or more generally a sum of sinusoid), the “speed” at which the ADC samples the signal is important.
(Add graphs – from Miller’s?)
In short, I use a soundcard :
– with a 6.35mm jack “instrument” input,
– with adjustable input and output gain,
– capable of running at a 48Khz samplerate,
– with a 6.35 mm balanced jack output.