Final answer:
The 'IN' button on the SSL EQ section is used to engage the EQ and it accepts the signal from the patch point routed into it, typically from the post-mic preamp and pre-fader. The specific patch point can vary and is determined by the mixing console's configuration or the studio setup.
Step-by-step explanation:
The “IN” button on the SSL (Solid State Logic) EQ section is typically used to engage or bypass the EQ processing on a channel.
When pressed, the EQ section accepts the signal from whichever patch point is routed into it, usually post-mic preamp and pre-fader. The specific patch point can vary depending on the configuration of the mixing console or the signal routing set up in the studio.
For instance, in a classic SSL console, the EQ section can be part of the channel strip where the signal is routed from the microphone preamp into the EQ and then through the rest of the channel strip, including dynamics and fader controls.
The patch point could be a direct out from the channel preamp, an insert send point after some other processing, or even a return from an external processor if that's how the studio is set up. It's essential to be familiar with the signal flow of the particular SSL console to understand precisely where the “IN” button is receiving its signal from. In many cases, this will be outlined in the console's manual or signal flow diagram.