The Harrison 32C Channel EQ

June 23, 2010 9:51:10 PM PDT by Dave Crane

Editor’s Note: This article was originally featured in a previous edition of our Webzine. We're running it again because of the ongoing relevance of the original hardware, the availability of the award-winning Harrison 32C EQ plug-in at the UA Online Store and in remembrance of Michael Jackson, who died one year ago on June 25th, 2009. Long live Thriller.

Harrison 32C SE Channel EQ
Harrison 32C Channel EQ Plug-In
Harrison 32C SE Channel EQ
Harrison 32C SE Channel EQ Plug-In

This month, we’re taking a listen to the Harrison 32C Channel EQ. This EQ was modeled using the same techniques we use to model our other EQs: component and circuit modeling in combination with listening tests. We use upsampling to achieve the sonic accuracy we’re famous for with the Neve, Pultec, and Helios EQs.

The Harrison EQ is not just another EQ plug-in; it is different from the other console EQs we have modeled. How is it different? For one, it's modeled after the very console that recorded many hit records, including the highest-selling album in history, Michael Jackson’s Thriller. The console is owned by engineer Bruce Swedien.

Also, the frequency bands interact in a unique way that is different from our other EQs, giving the Harrison a unique sound. It has four fully sweepable, overlapping frequency bands, and none of our other console EQs have as much overlap.

The high and low pass filters have a unique sound all their own, and are noted for their extremely smooth response and wide range, which is wider than any of the high and low pass filters on our other console EQ emulations.

Another great feature is adaptive Q, or “Auto Q.” This means the Q, or bandwidth, of the boost and cut gets sharper as the amplitude increases (or decreases). This is a great feature, as gentle boosts (and cuts) work better with a wide Q because more frequencies are affected. If we look at boosting a frequency on the Harrison 32C, as you increase the amplitude the Q gets sharper, affecting a smaller frequency range. If the Q remained wide throughout the range of the gain control, the signal would gain a lot of energy and you would need to turn down the output gain (or fader) on that channel to adjust for this. It would also be difficult to pinpoint a frequency range to work on. The same situation applies to cutting frequencies, but has the opposite effect.

The Cambridge EQ can also do something similar to this in “Type III” mode, but it will not sound the same as the Harrison because the filters are different and not a model of any particular console.

This technology also saves time while mixing. Auto-Q means that the engineer does not have to keep adjusting the Q as he or she adjusts the frequency and gain controls.

The Harrison 32C includes an SE version, which is a DSP "lite" version, but still retains many of the Harrison 32C’s characteristics.

You can read more about the Harrison EQ in the December 2008 Analog Obsession article. You can also watch the video and hear the Harrison in action.