What is parallel compression?

Before we get to Parallel Compression, let’s talk simply about parallel processing. Parallel processing is the action  by which you play two identical tracks simultaneously and treat them differently. So this process can be used with multiply methodologies, not just compression. However, we are going to talk about the most popular method: Compression. However you can use this method with any effect you wish.

Parallel compression is synonymous with “New York-Style Compression” and the phrase was actually coined by the beloved mastering engineer, Bob Katz in the 1990s. He has described it as an implementation of “upward compression”, the increase in audibility of softer passages. What’s great about this is that you get the punchiness of heavy compression, but the dynamics of not compressing. It’s literally the best of both worlds. You can have your cake and eat it too!

Parallel Compression

So with parallel compression, once you’ve duplicated the track you want to process, you’d process one of the tracks with compression as needed. You can even go pretty hard with it. Why not? If not, pull it back a tad. And you’ll leave the other track alone. Together they will play as one track that’s processed and one track that’s as-is.

Unprocessed Drums:

100% Processed Drums:

Parallel Compressed Drums:

Bypassed and Active:

So how does this work? The human ear is sensitive to loud program audio being quickly attenuated in loudness, but less so to soft sounds being increased in volume. So parallel compression really takes advantage of this difference. Unlike normal limiting and downward compression, fast transients in music are retained in parallel compression, preserving the “feel” and immediacy of a live performance. Because the method is less audible to the human ear, the compressor can be set aggressively, with high ratios for strong effect.

This method can be used pleasantly to fatten or beef up a track, by careful selection of attack and release times on the compressor. These settings may be adjusted further until the compressor causes the compressed signal to pump or breathe with the song, adding its own character to the sound.

We parallel compression on drums all the time. It also sounds great on vocals, bass and anything else you want to add a little mojo to. What’s cool is that you can do this in a lot of plugins with click of a mouse button. Many plugins have a “mix” pot in their settings. Pull this back to 50% and you have instant parallel compression.

Parallel Compression

And thanks to John Burkhardt from Thunder Club for wailing on the drums and to Sean Mercer for masterfully engineering at Magpie Cage Recording Studio.