Focusrite ISA220-SESSION-PACK

The ISA 220 Session Pack provides all you need to record your session with precision and Focusrite sonic performance. It features many of the original circuits of the flagship ISA 430 Producer Pack along with some new features of its own. It also features the same digital option as the ISA 430, providing you with a high quality digital route direct from the 220 into your digital recording system.

The unit begins with a Precision VU meter which is switchable to allow you to monitor either input level or compressor gain reduction. Situated above the VU meter is a 32 LED digital meter for monitoring from either the internal input or an external input which gives access to the second channel of conversion on the optional high quality stereo A/D card. To the right of the Digital Output meter is a global bypass switch to allow for real A/B comparisons.

Three input options are provided to give compatibility with Mic, Line or Instrument sources. Switching between these input options is available on the front fascia with LED’s indicating the active input. All inputs are transformer based contributing to that all important Focusrite signature sound of clarity without colouration, with incredibly low noise and distortion figures.

The Mic Pre is the classic Focsurite transformer based design as featured in the ISA 110 and Red 1 and 8 (see pages 3, 8 and 9) with illuminated switches for Phantom power and Phase reverse, all immediately available on the Front fascia.

Other switchable controls available on the front fascia include controls and indicators for the Digital option, in/out selectors for each of the sections and a select switch between Mic, Line or Instrument inputs. An instrument jack is immediately available on the front fascia for quick ‘plug and play’ access.

The EQ featured on the 220 is similar in design to the Red 2 and ISA 110 with the exception of the Shelving EQ’s having four positions rather than six. The focusrite EQ is renowned for its musical empathy. For more on the Focusrite EQ, please refer to pages 10 and 11.
Prior to the Compressor section, which utilises the same compressor circuit as the ISA 430, the ISA 220 features a ‘Compressor Pre EQ’ switch. Normally the compressor is featured post the EQ. With this switch you can choose to place the Compressor either pre or post EQ. Also featured in the compressor section, alongside the auto release is the new Blend feature, a unique feature to the ISA 220 allowing smoother compression at more extreme settings. When switched in, ‘Blend’ allows you to mix the uncompressed signal with the compressed, thus retaining a variable level of dynamics from the original source.

Just prior to the Output section, the ISA 220 features the same De-esser as the ISA 430, based on a low distortion optical technology design, letting you transparently remove excessive sibilance from a vocal performance. The circuit uses a combination of threshold dependent EQ and phase cancellation to create a de-esser smoother and less intrusive than traditional compression based designs. You also have the option here, with ‘De-ess listen’ switched in, to monitor the exact frequency you are effecting. Selecting ‘De-ess listen’ inverts the operation of the De-esser and allows the user to monitor only those selected frequencies which will trigger the activation of the De-Esser, rather than hearing the overall effect in a complex signal.

The output section of the ISA 220 features the same frequency adaptive limiter as the ISA 430. The limiter uses three separate stages of Optical based circuits with different limiting properties to give true distortion-free limiting. Fast limiters tend to have problems with complex signals that contain sustained low and mid frequency information and tend to "chop holes" in the audio when HF transients trigger the limiting. The ISA frequency adaptive limiter has three frequency bands with different attack times as follows: LF slow attack, MF quick attack and HF very quick, to catch fast transients. The Limit-in LED illuminates when the limiter is active. An upper threshold is fixed at +20dBu to prevent overload of the internal (or an external) A/D converter.

Finally, a variable control adjusts the module output level between -60dB and +6dB ensuring optimum levels exiting the unit.

Features:

• Precision VU metering of input level or compressor gain reduction (switched)
• 16 LED Digital Output meters for both internal and external inputs.
• Classic Focusrite transformer based Mic pre
• Switched High and Low pass filter controls
• Switched High and Low shelving filter frequency controls
• Optional Stereo A/D – 24 bit 96 KHz Delta Sigma converter running at 128KHz oversampling - dithers to 20/16 bit
• Proprietory Focusrite discrete Class-A VCA Compressor side chain design for lower distortion & Noise performance
• Illuminated push button for switching the compressor between pre and post EQ
• New Blend feature for adding dynamics into the compressed signal path
• New De-esser design based on optical technology for lower distortion and transparency
• 'De-esser Listen' for precise control over sibilance
• Frequency adaptive limiter to avoid critical digital overs