While panning is an obvious way to manipulate the stereo image of a track, the Hass Effect is another technique that’s popularly used by producers to create the same impact on a mix.
The Haas Effect, also sometimes called the precedence effect, is a psychoacoustic phenomenon that causes a listener to perceive a space and direction of a sound when there is a slight delay between stereo channels. The listener perceives that the sound takes place in the direction of the first, or preceding, channel–even if the delay between the two channels is only a few milliseconds.
It works like this, if you create two of the same mono track and pan one hard left and the other hard right, you can affect where the track sits in the stereo image by adding a slight delay to one of the tracks. If you delay the right-panned channel by five milliseconds, so that it plays slightly behind the left-panned channel, the track will sound like its much more prominent in the left channel, despite the fact that the levels are the same on both.
The more delay you add, the more directional the sound feels. However, once you go beyond around seven milliseconds of delay, it will have more of a widening effect on your mix than a directional one.
Where panning manipulates a sound’s stereo image using by affecting the levels of the left and right channels, the Haas Effect does so by affecting the timing of those channels. You may have noticed that panning doesn’t always cut it, too. A track panned halfway to the left can still sound somewhat in the center in your mix. This is why some producers have opted to only use the LCR method of panning, which has all tracks either all the way left, right or right in the center of the mix.
Some producers feel that using the Haas Effect actually adds more focus in the stereo image than panning. It’s also, however, a great way to add stereo dimension to a mono track without using reverb. When you’re experiencing directional masking in your mix, and panning doesn’t seem to help, applying the Haas Effect to a track can also be the solution that you’re missing.
Many stereo delay plugins work by manipulating the Haas Effect.
The Haas Effect is a great way to add depth to your mix, reduce masking, and improve the stereo imaging and space of your mix. It’s also a great technique to have in your mixing toolbox when you’re not sure how to make a mono track sound more spacious without adding reverb.