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Surround Mixing In Studio One

Studio One Tips & Techniques
By Larry the O

Screen 1: A simple method of creating surround from a  stereo mix is to use reverb to generate surround channel signals. Screen 1: A simple method of creating surround from a stereo mix is to use reverb to generate surround channel signals.

Studio One doesn’t officially support surround mixing — but that doesn’t mean it’s impossible!

Most audio production today is still stereo, but surround sound has become a consistent part of the landscape, especially with the rise of television mixed in surround. If you are doing a lot of surround work, Studio One is not the tool to use, both because it has no built-in surround facilities and because much surround work is to picture and Studio One’s video capabilities are sharply limited, as well. But if you were asked to deliver a basic surround mix of some music you created in Studio One, it can be made to serve, and this month I will show you how.

For the purposes of this article I make the following assumptions:

  • The surround format is 5.1. Anything more than that is highly unlikely to be practical in Studio One.
  • The objective is to produce stems in surround, especially music, not to try and mix a surround project entirely in Studio One.
  • Fancy stuff isn’t on the table. Dynamic panning moves may happen now and then, but creating a lot of fly-bys can get awkward when proper surround panning facilities aren’t in place.

If these constraints are too severe for your situation, then you will be better off ponying up the money for one of the available tools designed to handle surround mixing.

Easy Rider

The very simplest option is to ‘upmix’ a stereo mix to 5.1 surround using a plug-in designed for that job, of which there are several. However, don’t look for perfection, because it’s a tough job those plug-ins do. Sometimes plug-in algorithms can react poorly to certain source material and produce artifacts that may be a problem.

The next simplest option, which avoids artifacts, is a cheap-and-cheerful upmix method. In this scenario, we use reverb to generate our surround channels. Since the source material is stereo, we are talking here about 4.1, with no centre channel. Many music mixers avoid the centre channel other than for dialogue or vocals anyway, and if you are producing a music stem for a larger production, the mix engineer has the opportunity to route music to the centre during the final mix, if that is desired.

First, create a stereo output and name it something like ‘surround out’ or ‘SL-SR’. Now insert the same reverb on it that was used as the main reverb in the stereo mix (or the closest thing you have to it). For now, set the wet/dry mix to 100 percent wet, dial out most or all of the early reflections, and route the output pair to the surround (rear) speakers. Finally, create a send to this ‘SL-SR’ output on the channel for the stereo source. (See Screen 1 above.)

With the basic setup in place, it’s time to tune a few variables to the needs of the situation. Increasing the decay time on the surround reverb to be a little longer than the front reverb can add some immersion, as will increasing the reverb width, if there is a setting for that, but don’t go overboard. If you find you can easily tell that the surround reverb is longer, back off its decay time just a little. You can also give a mix more of an ‘in your face’ feeling by mixing some early reflections into the surround reverb; on a spoken-word project where the director wanted more of an ‘in the head’ sound, I placed a very short (less than 5ms) delay before the reverb, then made the surround reverb less than 100 percent wet.

Put It Where You Want It

If you have access to the mix project with all of the individual elements, rather than just mixed stereo files, you can place instruments more precisely. Let’s look at two ways to do this. The first way uses the same pair of stereo buses as in our ‘easy rider’ solution (Screen 2). However, there are a few differences in how the setup is configured:

  • A send is created on each channel you want routed to the surround speakers, so surround placement is per channel (or, often, per submix).
  • The surround reverb is placed on a bus channel that feeds the ‘SL-SR’ output, allowing signals such as vocals to remain panned to the front but still feed reverb in the rear.
  • The surround speaker send will usually be pre-fader, so that the surround speaker level is independent from the front speaker level set by the channel fader.
  • Unless you are looking for an effect, make sure the channel pan and send pan controls are set to the same position.

Screen 2: A mix project with individual channels assigned to surround channels using a send. Note the ‘rear verb’ bus channel with a  second instance of Altiverb on it. This allows sources to be routed to the surround reverb without any of the dry signal going to the surround.Screen 2: A mix project with individual channels assigned to surround channels using a send. Note the ‘rear verb’ bus channel with a second instance of Altiverb on it. This allows sources to be routed to the surround reverb without any of the dry signal going to the surround.

A source is positioned with this setup using the channel fader and pan control to set the amount and placement of signal going to the front speakers, while the level and pan controls for the send handle signal going to the surround speakers.

For static placement, this is a workable scheme, but it can be improved if you have any kind of physical controller, by using Control Link to map a physical fader both to the channel level (for front) and, with inverse response, to the surround level, thus making a crossfader. Link another physical fader to the channel and send pan controls and you can pan a source using two controls: left/right and front/back. Should you have an X/Y controller of some sort, you can use it as a full surround panner.

The second method is more precise but more work, and that is to use separate sends and buses for each surround speaker. Make two stereo outputs — front left/right and surround left/right — and two mono outputs, for centre and LFE (Screen 3 below). Now make sends to these outputs on each channel you want to place in surround. With routing being accomplished entirely with sends, the channel fader can become a source level that affects all outputs, as long as the sends are post-fader.

Screen 3: Six channels of sends are used on each mix channel for placing that channel in the surround field. The sends are post-fader, but could be made pre-fader if necessary. The Main stereo output provides a  separate two-channel mix without the need to downmix.Screen 3: Six channels of sends are used on each mix channel for placing that channel in the surround field. The sends are post-fader, but could be made pre-fader if necessary. The Main stereo output provides a separate two-channel mix without the need to downmix.

Panning Stereo Sources

Stereo sources can be accommodated, too, but there’s a trick. A pan control on a stereo channel (or, for that matter, a bus channel) changes left-right channel balance. But when you place a stereo source in surround space you usually do not want to lose any channel information, you just want to place it, meaning that what is needed is not changing channel balance but collapsing and panning the image. The Dual Pan plug-in (Screen 4) pans the left and right channels independently, making it easy to preserve signal from both channels and simply collapse the image.

Obviously, the front-back bus is used to pan between the front and back speakers.

Screen 4: The Dual Pan plug-in enables us to pan stereo signals without the loss of channel information that happens using the channel pan control (which is a stereo balance control). The pan position knobs can be mapped to a physical knob using Control Link.Screen 4: The Dual Pan plug-in enables us to pan stereo signals without the loss of channel information that happens using the channel pan control (which is a stereo balance control). The pan position knobs can be mapped to a physical knob using Control Link.

Bass Management

Up until now, I haven’t really addressed the issue of bass management and the LFE channel, other than saying you should create an output for it. While there are bass-management plug-ins, we’re staying close to the bone here, so the DIY approach seems appealing. That just means putting a low-pass filter on the LFE channel at 80Hz or 120Hz (the two most common crossover frequencies), and a high-pass filter at around that same frequency on each of the other channels.

In practice, I often find myself high-pass filtering submasters more than individual channels, and I’ve had a few projects on which it wasn’t necessary to do any high-pass filtering at all for bass management.

Dynamic Positioning

I tried to tell you not to get fancy with surround in Studio One. But would you listen? No. All right, then, I’ll throw in a tip for creating dynamic movement in Studio One.

The easy way to move a sound through a surround space is using a joystick or X/Y controller that can generate MIDI. If you have such a controller, you need only use Control Link to map the X axis to left-right panning and the Y axis to front-back panning. Front-back panning crossfades levels between the front and back stereo pairs, with inverse fader response on the surround stereo pair. Left-right panning (for a source placed anywhere between front and back) requires that the front and back pan controls both be linked to the X‑axis controller.

It would be convenient if there were a virtual X/Y controller right in Studio One, and in fact, there is one in the Channel Editor, but it can’t be used for this purpose because it only controls parameters of the plug-ins on a single channel. Without an X/Y controller, motion must be performed as a gesture using two controllers, performed in multiple automation passes, or drawn in as automation.

Conclusion

There are many conventions and subtleties of surround mixing I have completely ignored, and if any of those conventions and subtleties rear their heads, you’ll be left with no alternative to porting your session to some other environment that has surround mixing facilities. This can be a lot of work and there is a strong chance you won’t get it to sound the same as the original. Given that, the rudimentary methods I have shown here are worth trying if you need to generate a surround mix of a song you created in Studio One.

Published October 2016