PreSonus Blog

Add Lookahead to the Fat Channel Compressors

The Fat Channel is a versatile channel strip plug-in that, because of all the other cool Studio One individual processors, is easy to overlook. But it has several outstanding features, including the ability to choose from a variety of compressors—sort of like plug-ins within a plug-in (fig. 1). Three are stock; the rest are optional at extra cost from the PreSonus shop.

Figure 1: A fully loaded Fat Channel can choose from 11 compressors.

However, none of these compressors has a lookahead feature. Lookahead delays the audio we hear, but the compressor monitors the audio in real time. Thus, the compressor knows in advance when it needs to apply compression. Without lookahead, if you’re using heavy compression (like for guitar sustain), you’ll hear a nasty pop because the compression can’t kick in until the audio exceeds the threshold—and by that time, it’s too late. Some of the audio has already passed through uncompressed, which causes the pop. The first audio example exhibits this pop. Also note that the first and second audio examples are both normalized—but this one sounds really soft, because the pops are so loud you can’t raise the level any higher without bumping against the headroom.

The solution is simple. What’s more, it applies to not only the Fat Channel, but any dynamics processor, from any manufacturer, that doesn’t have lookahead.

Create a bus, and insert the Analog Delay. Edit the parameters for 2 ms of delay, delayed sound only, and no modulation (fig. 2). Insert the Fat Channel after the Analog Delay, and choose your favorite compressor.

Figure 2: Analog Delay settings for the lookahead function.

At the audio track you want to process, create two pre-fader sends. One goes to the bus, and the other to the Fat Channel’s sidechain. Turn down the track’s fader so you hear only the audio coming from the bus. This accomplishes our goal: The audio applies compression to the Fat Channel 2 ms before the audio enters the compressor. So, the compressor is primed and ready to go when a transient hits (fig. 3).

Figure 3: Track and bus setup for Fat Channel lookahead.

Now compare the next audio example to the first one—the nasty pop is gone. Yeah! Also notice how it’s much louder, because the headroom doesn’t have to accommodate a pop.

However, there’s a catch. Studio One plug-ins with a lookahead function delay the signal by 1.5 ms, but apply plug-in delay compensation so that all the other tracks are delayed by 1.5 ms. This keeps the tracks in sync, and you don’t really notice a delay this short. However, our “faux lookahead” doesn’t have plug-in delay compensation.

Then, move the track forward on the timeline by 2 ms to align it with the other tracks. You can do this via the Delay setting in the Event Inspector (F4).

  • Craig Anderton

    The Fat Channel’s origin was in their live performance mixers, where look ahead would not only be impractical, but undesirable. You’d need to ask PreSonus, but I wonder if adding lookahead would break the 1:1 compatibility between Studio One presets and StudioLive presets. Besides, this tip also applies to any third-party dynamics processor that doesn’t include look ahead, so its usefulness extends beyond the Fat Channel.

  • ℌ𝔞𝔫𝔡𝓎

    You know what would be even better? Just adding a pre-delay feature to the fat channel compressors.

  • Umberto Fabbri

    NICE!

  • Franco Maldonado

    This is a solution but not much more practice. Anyway, thanks for sharing Craig https://media0.giphy.com/media/BD9iCmAdbp6Q8/giphy.gif

  • Craig Anderton

    Thanks for the comment, it’s always nice to know people read these things 🙂 With typical release settings of 50 to 200 ms, delaying the release phase by 2 ms is for all practical purposes negligible. The only way to prevent the release from “going along for the ride” in terms of timing is to delay the onset of the release by as much as you advance the sidechain, but I can’t think of any way to do that other than building both the sidechain advance and the release delay into the plug-in.

  • Craig Anderton

    Yes, that would produce the same final result. But the tradeoff is that you wouldn’t know what the part sounded like until after you recorded it. The advantage of this method is that it’s near-real time, so you can hear how the lookahead affects the sound while you’re playing..

  • Stefan Keller

    Can’t you just make a copy of the track you want to compress, move this by –2ms, and feed this into the compressor’s sidechain?

  • Chris Share

    A nice technique but doesn’t this mess up the Release timing? Have a look at Dan Worral’s video “The Least Exciting Compressor Feature” to see what I mean. Cheers!