Key to its design philosophy is the way the Iso-Q2 handles its three bands of equalization. The front panel has separate Bass Frequency and Mid-High Frequency sweepable controls that set the exact lower and upper crossover frequencies between the Bass frequency and High frequency equalizer sections on either side of the central Mid-Range equalizer section.

The Low Frequency sweeps from 50Hz to 400Hz while the Mid-High Frequency sweeps from 3.1kHz to 12.6kHz. It gets fun when I figured out that the three, large detented Bass, Mid-Range Gain and Mid-High Gain controls range from off at fully CCW and up to +15 dB of boost at full CW. They are at unity gain position straight up in the 12noon position; essentially reproducing that band of frequencies at whatever level is presented at the input.

For program equalization, it easy to "build up" the spectral "shape" of a mix by defining these three bands with the application of different amounts of boost or cut using the three bands' gain controls.

However, the SBS Iso-Q2 does not have frequencies or gain amounts silkscreened on the front panel and this encourages the engineer to listen to what it sounds like. I liked the smooth operation of these controls and the super clean sound. Probably because it is controlling a large amount of very hearable frequencies, I also found the Mid-Range Gain level to be a little touchy to set compared to the Bass and Mid-High Gain controls. It seems that the range of boost/cut in the Mid-Range section could be spread out on the control.

Calibration

I wanted to accurately set up the Iso-Q2 for my first use. I set (as a kind of default) all three Gain controls and the Bass Frequency control fully CCW and put the Mid-High Frequency control at full CW. I then passed a 1kHz tone through the unit and obtained unity gain at the output when only the Mid-Range Gain control was set straight up at 12noon. I found little interaction (overlap) of the other controls for this measurement.

It would be a nice touch if there was a way to have this Mid-Range Gain control "click" when at unity--actually I'd be fine with silkscreen marking unity gain on the front panel. The calibrated Mid-Range Gain control (at unity), the Bass Frequency at CCW, the Mid-High Frequency at CW and both the Bass and Mid-High Frequency Gain controls at full CCW or off would be my starting setup whenever I would begin using the ISO-Q2 during a session.

The SBS Iso-Q2 has no hardwire bypass feature so when I connected it to my Pro Tools HDX system's I/O, I set up two stereo paths (one with the unit in the path and one without) to A/B, with and without, the Iso-Q2's effect quickly just like when using any other equalizer in the studio.

In The Studio

I tried the Iso-Q2 on full program mixes and individual instrument and vocal stereo tracks in my Pro Tools mixes. I found the unit to be super quiet and noise-free and best suited for overall equalizing of finished mixes, stereo keyboards--pianos and synth pads, orchestral strings, and stereo drum loops. The manual offers several tips for usage along with the approximate knob locations of the Bass and Mid-High frequency points on the front panel.

The Iso-Q2 has balanced XLRs input and output connectors as well as unbalanced inputs and outputs on RCA jacks. There are also RCA jack connections for a selectable unbalanced loop insert path along with a rear panel master gain control.