Instant width with stereo filtering

Unlike reverb, delay, modulation and wideners, filters aren’t the obvious tool for spatial enhancement; yet modern frequency-sculpting devices offer plenty of features for broadening stereo width. Some – such as UAD’s Moog filters or Elektron’s Analog Heat hardware – feature a stereo offset parameter to invert filter values for the left and right channels. If working with dual filters, reach for each’s pan control to position them.

Andrew Simper of Cytomic discusses stereo filtering. “The most basic stereo effect is a chaser-type ‘swirling’ sound. This is done using a stereo filter, by controlling the cutoff frequency using an LFO that allows for stereo spreading of the left and right signal of the LFO. Placing this spread amount at 90 degrees produces a ‘chasing’ sound, while at 180 degrees you get more of a ‘pingpong’ effect. If the rate of the LFO is increased to audio rate, then the individual swirling can no longer be heard, but instead turns into a blurring of the stereo field.”

Before you go crazy with width-inducing filtering, Andrew has some final advice: “You do have to be careful with mono compatibility when using stereo filters, so always make sure to preview them in mono!”

UAD’s Moog Multimode Filter XL allows you to change the different EQ results on stereo channels, which is a great way to add extra stereo interest. You can also create the effect manually with two EQs, of course