The basic Compressor plug‑in is an excellent place to start your compression experiments.
We talk you through the many compressors available in Studio One...
Studio One comes with a number of compression plug‑ins. Some come as standard, some are only available if you are a Studio One+ user, and others are optional extras. The plug‑ins in question are Compressor, Fat Channel, Multiband Dynamics, RC500, Tricomp and VT‑1. Of those, the Fat Channel, RC500 and VT‑1 are channel strips that combine compression with EQ and other bits and bobs. For devices that aim to do the same thing, compressors can be confusingly different, so for this workshop, we’re going to do a crash course in how compression works and then identify that process in each of the Studio One compressors so that we understand them better.
Compression is often seen as a means of making stuff louder, but its core action is actually doing the opposite. A compressor reduces the level of the loudest parts in a recording, by applying negative gain when the signal goes above a user‑determined value called the threshold. The idea is that this helps present a more even level throughout a performance or take. If you want the whispers to come across at the same level as the shouts, then this is exactly what compression loves to do.
Compressor
The standard Compressor plug‑in is a great place to learn about compression. It’s very visual, has some simple controls, a few automatic options and some more advanced features like side‑chaining. For this tutorial, I’m going to be pulling in the ‘Main vocal.ogg’ file from the ‘Emmavie — Electro Genie’ demo song, which, if you’ve downloaded it, should be locatable in the Browser under Files / Studio One / Demos and Tutorials / Songs / Emmavie — Electro Genie / Media.
The default setting on Compressor has some things going on, but because the vocal level is low, it’s not really having much of an effect. As you play back the track, you can see in the display that the vocal level ranges between ‑12 and ‑24 dBFS. What we’re aiming to do is reduce that gap to just a few dB so that the louder “Now that I’m here please don’t push me away” is closer in level to the later “I’ll be your genie” line.
Crossing The Threshold
We have three knobs to turn that will, in combination, help us achieve what we’re after. The first is Threshold, on the left of the display. Threshold sets the point at which compression will start to occur. The display can help us understand what’s going on. You’ve got two blue meters on either side. The one on the left is the input, whereas the one on the right measures the output of the compressed audio. As you lower the threshold, the output meter will no longer reach the same level as the input. There’s also a small orange line that stretches down from the 0dB point. This line represents the amount of gain reduction being applied to the audio.
The next control is Ratio. The ratio sets the degree by which we want to turn down any audio that exceeds the threshold in level. The default in the Compressor plug‑in is 2:1, which means that any signal crossing the threshold is reduced by half. This is represented visually by the blue line in the graph. Below the threshold, it runs diagonally at 45 degrees; above the threshold, it flattens out to an extent determined by the ratio setting. As you pull down the threshold, you’ll see the bend point on the diagonal line move lower and lower. If you rotate the Ratio knob all the way around to 20:1 you’ll see an almost flat line, and you’ll hear that all the louder vocals will be reduced almost to the same level as the quietest. That’s definitely solved the problem of the dynamic range, but the vocal is no longer sounding very natural and it’s now all quite quiet. So, while aggressive compression does a great job of reducing the difference between the loud and soft parts, you lose all sense of the energy injected into the performance. You should dial back on the ratio and experiment with the threshold until you find a balance that evens the level out without sucking all the air out of the room. On this vocal, I found that a ratio of around 8:1 and a threshold of ‑25dB sounded pretty good to me.
Knees Up
Another tweak to consider is whether you prefer to enjoy a hard or soft knee. This strangely named function refers to the bend in the line at the threshold, where it transitions from the 1:1 uncompressed signal to the shallower slope indicating the onset of compression. A hard‑knee setting gives you a sharp transition between not compressing and compressing, which shows up visually as a sharp angle. By contrast, a soft knee gives you a gentler curve and a more subtle onset, where compression begins to be applied gradually as the level approaches the threshold. Generally speaking, hard‑knee settings are good for drums and instruments with strong attacks, whereas soft‑knee compression works well for vocals and more dynamically complex instruments. For our purposes, putting the knee setting to about 12 o’clock would make for a good vocal response.
Finally, we have to deal with the output level. When we compress, we reduce the volume of the louder bits, and so, overall, the level of our vocal track drops. We’re currently dealing with it in isolation so the drop doesn’t matter, but in a mix, a compressed vocal might get lost in the rest of the music. To solve that particular conundrum, we turn it back up again to compensate. Studio One’s Compressor plug‑in has a knob called Makeup under the Gain section. Once we’re happy with what the compressor is doing to the vocals, we can use make‑up gain to raise the output level. If we apply enough make‑up gain to bring the peaks back up to the level that they originally reached before we compressed them, we’ll actually have increased the average level of the track, which is why compression is often viewed as a means of making things louder. Our Compressor plug‑in has a useful Auto feature here, which adjusts the output gain to match the input level to save you from having to dial in an amount manually.
There are some other features in Compressor to help you further tweak the compressor’s processing, which we won’t go into in depth here. The envelope dictates the speed with which the compression is applied and then released. The side‑chain is a fascinating function that lets you route other signals in to control the compressor; we’ll keep that for another workshop.
The humble Compressor plug‑in is simple, versatile and good for any source material...
So, overall, the humble Compressor plug‑in is simple, versatile and good for any source material; the range of presets attests to that. If it was the only choice in Studio One, then it would be a good one. Let’s take our basic compression skills and apply them to the other plug‑ins in Studio One’s arsenal.
Fat Channel
The Fat Channel is based on the channel strip in PreSonus’ StudioLive range of mixers. It includes a high‑pass filter, noise gate and EQ along with the compression section. This provides a drop‑down menu offering three different types of compression. The Standard mode is very similar to the Compressor plug‑in we’ve already covered, whereas the other two offer emulations of the classic Teletronix LA‑2A and UREI 1176 hardware compressors.
The Fat Channel, with the compressor section in the centre. Here, the Tube LA‑2A emulation is selected. Unlike the Compressor plug‑in, this doesn’t feature an adjustable ratio, just a simple Peak Reduction control which is akin to a threshold setting.
Tube mode selects the former, and the first thing you’ll notice is the absence of all the sensible controls we’ve just learned about. Instead, we have a single Peak Reduction control, which is in effect a threshold setting, and a Gain knob which applies make‑up gain to the compressed signal, as well as adding some simulated valve saturation. So, where’s the ratio control? There isn’t one: this is emulating the behaviour of an opto cell, which applies a fixed and rather complex soft‑knee compression curve as the signal goes above the threshold.
FET mode selects the 1176 emulation, which simplifies things in a slightly different way. Here, there’s no threshold control, but there’s an input gain control as well as a make‑up (output) gain setting. The threshold in this design is fixed, and to increase the amount of compression, you simply push up the input gain control so that the signal exceeds the threshold more often. You can then adjust the output gain to achieve the right overall level. FET mode has ratio buttons, which provide control over the compression slope that’s not available in the Tube mode. We’ve also got Attack and Release time settings, as in the Compressor plug‑in. The 1176 is renowned for the snappiness of this envelope at its fastest settings, which can give it a very brutal sound when pushed.
The two vintage modes offer a lot of character and colour that you won’t find in the Standard mode or the regular Compressor plug‑in. But when used gently, they can also be transparent and nuanced, once you understand what they’re doing.
RC‑500
The PreSonus RC‑500 was originally a 1U rackmount solid‑state channel strip. It had a preamp, three‑band semi‑parametric EQ and a FET‑based compressor. It now exists only inside Studio One, as the State Space emulation RC‑500 FET Modelling Channel Strip. Compared with the 1176 emulation, this loses the ratio buttons (it’s fixed at 3:1) but we’ve gained a Threshold knob. However, we still have the input Gain and Master output through the preamp, and it’s those controls that, for me, offer the most intuitive compression experience.
The RC‑500 is based on an old hardware PreSonus compressor. It is a FET‑based design, and offers fast attack times that make it ideal for drums and other transient‑rich material.
The short attack time of the RC‑500 makes it ideally suited to drums and instruments with loud transients. It’s available either standalone as a channel strip or as a compressor for the Fat Channel.
VT1
Another optional extra is the State Space emulation of the VT1 valve‑modelling channel strip. It comes as part of the Channel Strip Collection, along with the RC‑500, or as a compressor for the Fat Channel for Studio One+ subscribers. The valve emulation relates to the preamp; the compressor is based on solid‑state technology, just like the RC‑500. However, it does offer separate Threshold and Ratio controls, just like the standard Compressor, so you might find this one more intuitive to use.
Multiband Options
A multiband compressor can be a very useful tool. In essence, it splits your audio into multiple frequency bands, which you can then compress separately. Multiband compression is often applied to full mixes, though you can of course also use it on individual sources.
Tricomp is a three‑band compressor that offers an approachable entry into the world of multiband dynamics processing.
Studio One offers two multiband options. As its name suggests, Tricomp offers three bands of compression. This time we have a Compress knob front and centre, which sort of pulls together threshold and ratio into one auto‑sensing control. To the left of this you’ll find Low and High knobs; these control the amount of compression being applied to a higher frequency or lower frequency band relative to the central band. It’s a simple but effective approach and can contribute some nice tonal flavours to individual tracks.
Studio One’s Multiband Dynamics is a much more comprehensive tool that makes for a superb mastering and finalising compressor. In fact, it’s five independent compressors designed to work across your whole mix and across whatever range of frequencies you want to set. It’s very visual, glowing at you as it gets to work on the input signal, and it gives you full control over the gain and two separate thresholds, allowing you to define an upper zone where compression should stop, as well as a lower threshold to determine its onset. The display and controls are very similar to our original Compressor, so you should be able to apply what we’ve learned about compression directly to the Multiband Dynamics.
The Multiband Dynamics plug‑in features a comprehensive set of controls over its five bands of compression.
Compress To Impress?
Compression is an important part of the mixing process. From salvaging a wayward performance to balancing tracks and bringing important elements to the front, getting the hang of these plug‑ins will be immensely rewarding. Once you’ve found your feet in the standard Compressor I would recommend diving into the Fat Channel for a bit of character and to start feeling the compression working rather than working by the numbers.