Versatile Dual Mode Compressor
The compressor section features both a transparent VCA circuit, which can be used to apply significant amounts of compression without audible artefacts, and a vintage optical design that brings with it the characteristic feel of a traditional compressor. Optional auto release and “blend” control add to the section’s flexibility, the latter by allowing mixing of the original signal with the compressor output, maintaining as much as possible of the natural dynamics without losing the benefits of compression.
The Gate/Expander section is based on a transparent VCA design and includes a “hysteresis” setting that stops the gate chattering on difficult signals, while the de-esser is based on phase cancellation at the chosen frequency, rather than being compressor-based, leading to improved naturalness of sound.
Focusrite ISA 110 Derived EQ
The EQ section is exceptional, with HPF and LPF, two separate bands of parametric EQ (each with normal and x3 ranges for maximum versatility), and HF and LF shelving sections. In addition, individual parts of the equaliser can be switched into the side chain of the dynamics sections, allowing frequency-conscious compression, gate keying and other effects, while a “Listen” button allows you to audition the side-chain so you can tweak the EQ to get exactly the dynamics effect you’re looking for.
Class-Leading A-D Conversion
And finally, there is an optional A-D converter card which adds two channels of flawless 24-bit A-D conversion at sample rates up to 192kHz and with 120dB of dynamic range, preceded by a soft limiter to prevent clipping. Like the other parts of the ISA430 MkII, it can be used as part of the channel strip or as a completely independent unit.
The Most Versatile Channel Strip
Bring these elements together and you have the most versatile analogue channel strip available, with uniquely flexible patching and routing in addition to four powerful processors that can be used completely independently. And all with that unique Focusrite heritage sound. The ISA430 MkII. Nothing sounds like it – in so many ways.
The mic pre features a transformer-based design, with variable input impedance from 600 to 6800 ohms – so it will get the best out of any microphone, from modern condensers to the most finicky ribbon types. Depending on your choice of setting, you can maximise flatness and transparency or deliberately bring out the special features of your chosen mic, such as a presence boost or high/low-end rolloffs. And there’s a special “air” button that brings in an inductor to enhance the effect without needing additional EQ. 
