Phase; Insert; Filter - Focusrite ISA428 MkII Handbuch

Gain adjustment during recording
When small amounts of gain adjustment are needed to correct for performance level variations during recording, use the trim
knob rather than the stepped Mic/Line gain knob, as switching the 10dB gain steps would be much too intrusive. It is therefore good
practice to apply some Trim gain before using the 10dB stepped gain knob to find the optimum recording level so that the Trim
control can be used to gently add or take away gain later, if so required.
+48V
Pressing the +48V switch provides +48V phantom power, suitable for condenser microphones, to the rear panel XLR microphone
connector. This switch does not affect the other inputs. If you are unsure whether your microphone requires phantom power, refer to
its handbook, as it is possible to damage some microphones (most notably Ribbon Microphones) by providing phantom power.

Phase

Pressing PHASE inverts the phase of the selected input, to correct phase problems when using multiple microphones, or when
incorrect wiring polarity has occurred.

Insert

Pressing the INSERT switch (illuminated) breaks the signal path of the channel, so that the channel input signal is sent out of the
unit from the rear panel Insert Send connector and returned to the same point in the signal chain via the rear panel Insert Return
connector.

Filter

Pressing the FILTER switch makes the Hi pass filters active in the audio path. The filter provides 18dB/octave roll-off. A variable
control allows the roll-off frequency to be set within the range of 16Hz to 420Hz.
High Pass
0 dB
-18 dB freq
Z In - Impedance
Pressing the Z IN switch steps through each of the four transformer pre-amp input impedance values, as indicated by the
corresponding LEDs. By selecting different values for the impedance of the transformer input, the performance of both the pre-
amp and the microphone connected can be tailored to set the desired level and frequency response. The impedance values are as
follows:
Low – 600 Ω
ISA 110 – 1k4 Ω
Med – 2k4 Ω
High – 6k8 Ω
A guide to setting input impedance is available in the Applications section.
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