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Complex DP Monitoring Techniques

Digital Performer Notes & Techniques
Published February 2008
By Robin Bigwood

Everyone performs better when they can hear exactly what they need in their headphones. After our guide to simple DP monitor mixing options last month, we follow up with ideas for those with more complex monitoring requirements.

Monitoring 'in the box' with DP. This looks a little complicated but actually is very straightforward. Two pre-recorded tracks (bass and drums) are shown in red. Two tracks currently being recorded (vocals and guitars) are in green. There are 'Aux masters', for controlling headphone monitor level, in blue. As DP records, the engineer in the control room can set up a working mix on the main audio-track faders. Meanwhile the Aux sends are used to create two entirely independent headphone mixes. They're routed via buses to the blue Aux masters, and these output to headphone amps that are connected to separate outputs of an audio interface. When you set up like this, if the vocalist decides they don't want to hear any drums, for example, you can just turn down the topmost send level on the drums track. The other mixes are entirely unaffected.Monitoring 'in the box' with DP. This looks a little complicated but actually is very straightforward. Two pre-recorded tracks (bass and drums) are shown in red. Two tracks currently being recorded (vocals and guitars) are in green. There are 'Aux masters', for controlling headphone monitor level, in blue. As DP records, the engineer in the control room can set up a working mix on the main audio-track faders. Meanwhile the Aux sends are used to create two entirely independent headphone mixes. They're routed via buses to the blue Aux masters, and these output to headphone amps that are connected to separate outputs of an audio interface. When you set up like this, if the vocalist decides they don't want to hear any drums, for example, you can just turn down the topmost send level on the drums track. The other mixes are entirely unaffected.In last month's Performer workshop I started an in-depth look at Digital Performer's monitoring facilities. Good monitoring is all about providing your 'talent' with a useful headphone mix while they record a new track. That mix may well consist of a click track, 'guide' tracks you've already recorded, and a live feed of the track that's currently being recorded, and being able to properly control the relative levels of these, with the option of adding a bit of reverb to the track that's being recorded, lets you provide a really useful, supportive monitor signal, improving your chances of building a great recording.

When you work in a small, one-room project studio environment, your approach to monitoring can be fairly straightforward. Typically you'll only record one live track at a time, and you can afford to make your standard 'control room' audio outputs do double duty for both mixing and monitoring. This is what I described last month, and it's a quick, convenient and intuitive way of working that is a real strong point of a modern project studio DAW setup. You can seamlessly flip between writing, mixing and tracking at all stages of project development.

The 'main mix through the heaphones' approach is less suitable in a bigger studio, though, or when monitoring requirements become more challenging. For starters, you're probably going to have a separate control room and live room (or at least a booth), acoustically isolated from each other. With this little luxury in place there's no need to turn down the control room speakers every time someone records something in the live room — at which point maintaining separate control room and monitor mixes becomes a useful possibility. You can give your talent exactly what they want to hear in their headphones without having to mess up the 'working mix' you're building up as the project develops. And you can go further, providing more than one simultaneous monitor mix for when you're recording more than one person at a time and they want different things in their headphones.

In the old days, when we sat behind huge analogue mixing desks looking cool, setting up separate control room and monitor mixes was comparatively easy. The different areas of the mixer — main mix, monitor section, groups and aux sends — could all be pressed into service. You effectively had lots of individual mixers in one box, each doing one clearly defined job.

With a typical DAW setup, things are not always as straightforward. First, there are so many ways of going about monitoring. You might still use a hardware mixer, or the zero-latency mixing and routing of a PCI, Firewire or USB audio interface. You might even take on the menace of latency and set up monitoring 'in the box' in DP. Every combination of Mac, audio interface, external hardware setup and project requirement throws up different possibilities for how monitoring might work in practice. To top it all, we often set up mixes in more than one place — perhaps one (or more) in DP itself, and others in our audio interfaces' mixer applications, or on an external mixer or monitoring controller.

So what are the best ways forward? That's what this month's Performer Notes is all about. Because it's impossible to consider every conceivable setup, I'm going to describe how you might take on 'bigger studio' monitoring using several typical setups. These cover all the main approaches using DP, so you should find something close to your own setup.

Routing The Click

Complex DP Monitoring TechniquesComplex DP Monitoring TechniquesIf you double-click DP's metronome button to configure the way it works, it appears that it can only be routed to a single output at a time. If that's the case, how can you route it to several monitor signals at once — not to mention having it at different levels (or turning it off) in each? The answer is to route it not to a hardware output but one of DP's buses. Then you can create an Aux track using the same bus as its input, and your control room outs for its output. This effectively gives you a 'click track' in the Mixing Board, and you can then treat it just like any other pre-recorded track, using Aux sends to send it in varying amounts to your headphone mixes.

Getting Started

Here are our basic ways of working:

  • 'In the box' mixing, using only Digital Performer's Mixing Board.
  • Mixerless, but using audio interfaces with zero-latency monitoring facilities.
  • Using an external hardware mixer.

Each of these requires a certain minimum of audio hardware too:

  • A multi-output audio interface (possibly with zero-latency monitoring facilities).
  • One headphone amplifier (and headphones), capable of being driven by a mono or stereo line-level signal, for every headphone monitor mix you need.

If you're using a MOTU audio interface, make sure you select 'Monitor record-enabled tracks through effects' in Setup / Audio System / Input Monitoring Mode. The other mode you'll see there is a convenience feature for simpler monitoring, as covered last month, and isn't suitable for this more advanced work.

Let's now have a look at the setups in detail. In each case, we're going to create two separate headphone mixes for a guitarist and vocalist, in addition to a separate control room mix, working on a project that already has a bass and drums backing track.

Doing It All In DP

With this quite bold approach you use DP's Mixing Board for everything — to set up all your real-time monitor signals, with effects if necessary, as well as manage your tracking and control-room mix. There's no need for your audio interface to have any monitoring facilities, so you could use an older MOTU 2408 or 1224 model, for example. In fact, if your audio interface does have zero-latency monitoring, either disable it or just mute all of its zero-latency mixes. Also, choose Blend in Studio menu / Audio Patch Thru, to ensure we hear both track audio and live inputs on record-enabled tracks. We're going to make all audio pass through DP, so latency will be unavoidable. Running a small buffer size in the Configure Hardware Driver dialogue box can make it workable, but you'd better have a fast Mac...

The basic idea is that your control-room mix is what's on the main track faders, which are routed to the main outs on your interface, which in turn feed your control room speakers. A headphone mix is then set up using an Aux send on each track — specifically a pre-fade send, so that its level is not affected by the tracks' main fader or pan positions, or their Mute or Solo status. The sends are routed (via buses) to an Aux Track feeding an output or pair of outputs (separate from your main outs) on your audio interface. This output then feeds the headphone amp for a musician's monitor mix. Since DP lets you create a lot of sends, you can set up a lot of separate headphone mixes. Sends have their own level knob, pan pot (if they're stereo) and Mute button, so they're like a little mini-channel within the main Mixing Board. It's actually just like one of the traditional ways of working with a hardware mixer, and very intuitive.

What's very nifty about this approach is that the Aux track for each headphone mix becomes that mix's overall volume control; on a hardware mixer it would be called an Aux master. This is very useful, and allows you to change the monitor level in a musician's headphones without having to adjust all the send-level knobs that contribute to the headphone mix. You can then set up a new Aux send on the 'headphone mix' Aux track, routed back to your main control-room outputs. Normally you'll keep this muted, but if you unmute it you'll hear the monitor mix on your control-room speakers: a useful thing to check, especially if your musician starts complaining about it!

Adding a bit of reverb to a particular input that's present in a headphone mix couldn't be easier: just instantiate a reverb plug-in on its channel and you're away.

Zero-latency Interfaces

Working without an external mixer but using one or more audio interfaces with zero-latency monitoring facilities is becoming increasingly common these days. It's a streamlined and cost-effective approach for many studios, and the challenge of avoiding latency by running very small buffer sizes is sidestepped.

When your monitoring needs are anything other than very basic, though, this approach requires you to work with two mixers. The first is DP's Mixing Board, and it's here that you set the levels of pre-recorded tracks. The second is the 'live mix' of the signals being recorded, and you usually configure this in a separate application which effectively controls a digital mixer built into your audio interface. For example, MOTU have the CueMix Console application, which looks like a mixer and controls the interface's on-board zero-latency mixes.

Working with DP and a zero-latency interface's mixing application. This is similar to the previous setup, but monitoring for the tracks being recorded is now set up in the CueMix Console shown opposite.Working with DP and a zero-latency interface's mixing application. This is similar to the previous setup, but monitoring for the tracks being recorded is now set up in the CueMix Console shown opposite.Let's consider our little scenario once more. How do we give our vocalist and guitarist what they want to hear as they record? First of all, we don't want DP contributing to input monitoring at all — that's going to be handled elsewhere. So in the Studio menu / Audio Patch Thru, choose 'None'. Then, create Aux sends and Aux masters, linked via buses, as I described for the 'in the box' approach above. These allow us set up our separate headphone mixes. But this time don't bother creating Aux sends for the tracks that are record-enabled. Remember, DP's input monitoring has been disabled, so we're going to use the audio interface's mixing features to co-ordinate the live signals instead.

Before we go on, then, here's a run-through of how this setup works. Outputs 1-2 of the audio interface are feeding the control room speakers; outputs 3-4 are feeding a headphone amp for the vocalist; and outputs 5-6 are feeding the guitarist's headphone amp.

So, as before, set up the two headphone mixes of pre-recorded tracks by adjusting the pre-fade Aux send levels in DP. Then, in the zero-latency mixing application (in this case, MOTU's CueMix Console) create separate mixes for the control room and the two headphone amp feeds. I've called them Monitor 1 and Monitor 2 in the screen on the opposite page. Then bring up the live inputs to the desired level in each separate mix 'layer'. Inside the audio interface the live signals are mixed with the track audio coming from DP, and your two mixes are combined.

It's at this point that having the 'Aux Master' Aux tracks in DP comes in so useful. Let's say the vocalist asks for more backing track and less live signal in their headphones. You can simply increase the Aux Master 1 level in DP and decrease the Monitor 1 master fader level in CueMix Console. Alternatively, if you're using a non-MOTU audio interface whose mixing application includes a 'From Computer' channel fader, you could turn up the backing track level there.

What if you want to add some monitoring reverb to one of the live signals? You're laughing if you own an interface with built-in DSP effects (such as the Metric Halo 2882+DSP or a TC Studio Konnekt 48), as the reverb can simply be added within the mixing application. With MOTU, RME and other interfaces it's a little harder, but by no means impossible, and I'll be taking a look at this — along with a few other monitoring niceties — next month.

After recording vocals and guitar, you might want to configure Aux sends for their tracks in DP, ready to provide an even fuller pre-recorded track monitor mix for the next round of live tracks.

New Software From Audioease

Complex DP Monitoring Techniques I'm a big fan of Audioease's plug-ins for DP — all beautifully done, interesting and useful, and available in native MAS as well as Audio Unit format. Their newest is Speakerphone, which takes the convolution technology from the Altiverb reverb and bundles it with a clutch of other processors, including distortion, EQ, dynamics, delay and pitch-shift, and a big sound library of ambiences. The result is a plug-in that makes it almost ludicrously easy to make your pristine audio sound as though it was being heard in a railway station, or a car, or on a mobile phone connection, or being played out of an old-fashioned record-player. This ability to place audio in a variety of ambiences has obvious uses for film and TV work, but it has wider uses for audio production too. What Speakerphone excels at is imbuing audio with character, roughing it up, and giving it a bit of context. It opens up fascinating new possibilities for treating vocals, guitars, drums and piano, not to mention synths, and I can see it being fantastically useful for music production. It costs 395 Euros for a download that can be authorised to your hard disk or an iLok. More info from www.audioease.com.

Using A Hardware Mixer

It's arguable that, for maximum monitoring flexibility with minimum hassle, an external hardware mixer hooked up to an effects processor is still the best way to co-ordinate signals going into and out of DP. As I mentioned in this month's introduction, it's as if most hardware mixers were born for setting up monitoring. They generally have a number of aux sends on each channel, just begging to be used for monitor mixes. Even the little Mackie 1202 I use sometimes for live submixing has two, with plenty of extra facilities for incorporating effects units and so on. And more sophisticated models allow aux signals to come back into the main mix, or go out on groups, for subtly sophisticated routing that can deal with really fiendish requirements.

The CueMix Console application is maintaining three simultaneous mixes: Control Room 1, Monitor 1 and Monitor 2.The CueMix Console application is maintaining three simultaneous mixes: Control Room 1, Monitor 1 and Monitor 2.There are too many variables in the world of hardware mixers for me to be able to recommend specific ways of working with them — you could have anything from a £50 Behringer to a room-filling SSL hooked up to your 828MkII! But a reliable basic approach is to use your desk, not your audio interface, as the main studio 'hub'. First, you'll have your control room speakers hooked up to the desk's control room output. Second, the outputs from your audio interface will feed stereo input channels (or pairs of mono channels) on the desk, alongside channels for the mics, guitars and line-level sources you want to record. Then you'll use the desk's group outputs to get to the inputs on your interface, and its Aux sends to feed headphone amps. In this way of working, although DP is still responsible for mixing the pre-recorded tracks, it's slightly removed from the cut and thrust of input monitoring — and this is no bad thing.

In essence, you work with DP exactly as if you were using the zero-latency interface approach described previously. You still set up Aux sends to build separate headphone mixes, and you route them to separate outputs on your audio interface. But everything else happens on the mixer — balancing the relative levels of the DP mixes and the live signals, incorporating outboard monitoring reverb, and controlling the level of control-room and monitor mixes. The tactile nature of an analogue mixer, particularly, seems to make all this a whole lot easier. 

Published February 2008