When used as an insert, Surround Delay’s taps will always follow the panning of the source track.
Now we know how to get immersive in Studio One, let’s add some delay and reverb to our Atmos mixes!
Having covered the basics of immersive and Atmos mixing last month, I thought it might be a good idea to have a rummage through two plug‑ins that are uniquely kitted out for the job: OpenAir2 and Surround Delay.
But first, I would like to go over the difference between beds and objects very quickly, because I’m not sure I fully grasped it until now, and I get the feeling that I might not be alone. A bed is a multi‑channel track or bus that maps directly onto the speakers within your setup. Its outputs feed physical output channels in the same way that a stereo track goes out to a pair of outputs. When you create a surround bed, you generate a number of individual audio tracks, one for each speaker, and they are routed back to those individual and specific speakers on playback. If you are missing a speaker, then you won’t hear that part of the bed.
By contrast, an object is not associated with any specific speaker or collection of speakers. It exists as a mono or stereo audio track that is mapped on playback to whatever speakers are available, based upon the panning and positional information that’s created when you render the Atmos file. So, it doesn’t matter how many speakers you have; an object will appear in the available speakers that are best placed to convey its position.
About Latency
Personally, when exploring effects, I like to load up a virtual instrument or a real‑life instrument and play it through them. It gives you the chance to interact with things in a way that a pre‑recorded sound source doesn’t. However, when you’re dealing with Dolby Atmos, you’re required to work with rather sloth‑like latency settings. At 48kHz you have to use a buffer of 512 samples, and at 96kHz you have to use 1024 samples. On my system, a 512‑sample buffer setting produces a little over 10ms latency for soft synths: playable at a pinch, but some people might find it a tad laggy. For live input monitoring of sources such as guitars, that latency doubles up as the signal has to come in and go back out again, so 512 samples gives a very noticeable and probably unplayable delay.
The alternative is to drop down to Surround Sound rather than Atmos. This gives the advantage of lower and more playable latencies, but you lose the binaural headphone monitoring, which is that marvellous thing that lets those of us without a 7.1.2 speaker array mix spatial audio. If you need to do this to achieve low‑latency monitoring, all you have to do is reduce the buffer size under Options / Audio Setup / Audio Device. Studio One will cleverly disable the Atmos Renderer but leave everything else in place, so all you have to do is return the buffer size to 512 to re‑engage the Renderer and continue mixing in Atmos. However, for the purpose of this workshop, I’m going to stick with Atmos and assume you’re either happy with the lag or using pre‑recorded source material.
Surround Delay
Let’s start by setting up an Atmos project. Go to New and select the ‘Mix in Surround’ template. This should enable the Atmos Rendering plug‑in and set you up with a default 7.1.2 speaker format. You may need to enable a second headphone monitoring output and set it to Binaural. All of this was explained in full in last month’s workshop, so please refer back to that if you need to.
There are two ways to use Surround Delay: as an insert or as a send. The choice is actually very important, as it affects how it responds to the source material, its interaction with the speaker setup, and the binaural interpretation of that.
At this point, I should offer a correction to my review of Studio One 6.5, which appeared in SOS December 2023. In the review I stated that, oddly, the Surround Delay had no presets. Well, PreSonus have since released an update that fixes a bug that caused them to be hidden. And there’s a whole bunch of them.
Create either a virtual instrument track or a stereo monitoring audio track (we’ll come onto mono in a minute) and drop the Surround Delay onto the track as an insert effect. It’s immediately a beautiful thing to play with, but let’s see if we can better understand what’s happening to make sure we can use it effectively.
By default, the track is set to the Surround Panner, so let’s start here. Open the Surround Delay editor and choose the ‘+init’ preset. For the purpose of this experiment, set the Mix to 50 percent, the Level to 100, and the Beats to 1/2. This will enable us to better see the response of the delay taps coming through the bed monitoring in the Atmos Renderer.
Set the first tap (the red active one called ‘1’) to fully right (the three o’clock position) and begin to play; ideally, use a staccato sound so you can clearly hear the delay. You’ll hear the repeat on the right in your headphones. You can also see the placement of that sound by watching the bed metering. Open the Surround Panner and pan the track around while continuing to strike a key. What you should experience is that the delay tap always stays to the right of the instrument’s position (depending on the width of the stereo spread), which is not necessarily to the right on your headphones. The position is always relative, not fixed. You can change the obviousness of this effect by expanding or contracting the width of the track’s stereo field. If you are using a mono sound source, such as guitar, you’ll find that the Surround Delay will only return taps to the same position where your instrument is panned.
So, as an insert effect the Surround Delay can only place taps within the stereo field of the source. This is because the plug‑in is expecting to use a surround output and we’ve inserted it on a mono or stereo channel. If you look at the GUI for the effect you’ll see the single speaker (mono) or pair of speakers (stereo) in the main display. So, is it wrong to use Surround Delay as an insert on a mono or stereo channel? No, because it’s an interesting delay with very configurable taps that are good in any situation. However, it is designed to be used in surround...
Sends & Sensibility
For the Surround Delay to access all of our immersive speaker potential, it has to be loaded as a send effect. Do that, and you’ll find that the output of the Surround Delay can be placed anywhere in the 3D soundfield. As you play, you’ll notice that the metering on the FX track is showing the individual beds. If you switch the panning of your instrument track to Spatial, this will become even more obvious as the source audio is now an object rather than part of the bed structure.
Here, Surround Delay is configured as a send effect, with spatial panning. The delay taps can now be panned independently of the source.
Let’s be a little bit more daring this time and add two taps to our Surround Delay. Load the ‘+init’ preset again, reduce the delay time and add tap 1 to the four o’clock position and tap 2 to the eight o’clock position. As you play, you’ll be able to hear those two taps in your headphones to the right and left. If you move the panning in the Object Panner, you should be able to hear that the source is changing but the delay taps are not. You can also see, now that the source is no longer being metered in the beds, that the bed metering remains the same regardless of where the source is panned.
With the Surround Delay as a send effect, you can place delay taps exactly where you want them to be in the space.
This means that with the Surround Delay as a send effect, you can place delay taps exactly where you want them to be in the space. You could go further and place each delay tap as an object within the Atmos space, but then you would have to set the output of the FX channel to mono or stereo and create a new channel for each tap you wanted to place. That can get very complex and unwieldy very quickly, which is why the Surround Delay is brilliant as designed. Either way, it’s a lot of fun.
Now we understand where to use the Surround Delay, let’s check out the features. Ultimately, you have a chain of eight delays, which you can configure independently. For each tap you can set its position in the chain, its placement in the surround space (both direction and elevation), level and feedback. The controls along the bottom for Mix, EQ and Time are applied globally.
Along the top are a few useful buttons. The Snap button turns on a magnetic pull to the speakers so that your tap placement snaps to one speaker. This enables perfect delay placement. The other buttons, Level, Direction and Elevation, change the display to show positional information for each delay.
OpenAir2
Is it the same situation for the three‑dimensional spaces within the OpenAir2 reverb? Yes, it is. If you drop OpenAir2 onto your track as an insert, it will follow the stereo placement of the source around your surround sound space. With a reverb, that sounds very strange, almost as though you’re standing outside the room in which the instrument is being played. To stand inside the same room, you need to load OpenAir2 on an FX channel and send your track to it.
Like Surround Panner, OpenAir2 works best when used as an auxiliary effect.
OpenAir2 comes with a good selection of immersive presets that you’ll find under the 3D‑IR folder. The contrast to the standard ones is quite amazing and utterly convincing. The reverbs are generated using recorded impulse responses. You can use your own IRs for this if you wish, and we’ll tackle that in a different workshop.
As with Surround Delay, as you pan your instrument track, the OpenAir2 reverb will remain stubbornly all‑encompassing and directionally agnostic. However, it doesn’t have to be. If you open the Surround Panner for the reverb channel, you can use the Spread parameter to bunch up all the reflection channels. Then you can position the output of the reverb in the surround sound space to better match the position of your track.
In terms of editing, OpenAir2 offers two levels of control, one being super‑simple while the other provides plenty of complexity if that’s your thing. On the front panel, you have a little bit of control over the size, early/late reflection mix and pre‑delay. That’s plenty for most of us. However, there’s a whole parametric EQ in here, along with detailed editing of the impulse response. You can even set levels for the individual surround speakers to find exactly the balance of reflections you need.