(SRC) A digital processor or computer algorithm able to convert digital audio signals recorded at one sample rate to a completely different sample rate, eg. from 96kHz to 44.1kHz. In the case of a downward conversion, the appropriate anti-alias filtering is applied to ensure the new file doesn't contain any source componets above half the new sample rate. For an upward conversion, the upper regions of the bandwidth in the new sample rate will carry no information as there was none available in the source file due to the restrictions of its lower sample rate. Not all SRCs are as accurate as they should be, but the best are essentially a perfect and transparent process.

See Turnover Frequency 

Relates to filters and equalisers and is defined as frequency where the response has risen or fallen by 3dB. Sometimes  called the 'corner frequency' 

A filter that removes or attenuates frequencies in a defined range or bandwidth, while letting through those frequencies both above and below the band. A wider form of notch filter.

A filter which only removes a very narrow band of frequencies, or even a single frequency in extreme cases. A notch filter has an extremely high Q value (narrow bandwidth).

Small Diaphragm Capacitor microphone — a microphone with a diaphragm diameter of between about 10 and 15mm 

Large Diaphragm Capacitor microphone — a microphone with a diaphragm diameter of more than about 20mm

LU — Loudness Units. A measure of loudness normalisation relative to the target loudness. If the integrated loudness of a track measured -21LUFS, but the target loudness was -23LUFS, the meter would show a +2LU discrepancy.