Adding External Hardware FX to Your DAW

Yes, the virtual and real worlds can live in harmony

By Craig Anderton

That vintage hardware reverb that sounds so good…the tube compressor that cost a week’s salary, but was worth every penny…are they all eBay candidates now that you’re working in the DAW’s digital domain?

No way! All you need is a hardware interface with multiple ins and outs that can interface with your hardware (digital and/or analog, depending on what gear you want to connect), and a little know-how of to tweak tracks. All other routing can be done within the DAW. We’ll use Cubase SX 3.1 as an example because it has a special feature designed to feed external hardware, but the same principles apply to other DAWs.  

In short, you assign one of your DAW’s output buses to a hardware out on your interface, patch that to your effect in, then patch the effect out to an interface hardware input. You’ll also need to make sure any drivers feeding the external ins and outs are enabled; you might want to dedicate certain I/O ports to using external effects for consistency’s sake. For example, I use Creamware’s SCOPE system, so I’ve patched channel 8 (stereo) of its ASIO output drivers to the interface’s stereo analog out. This provides an analog signal to the external effect. Similarly, the card’s stereo analog in feeds channel 8 (also stereo) of the ASIO input drivers, and this is where the effect output returns.

When you create a bus to send the effect, name it something like “ToExtFX” to avoid confusion. Different programs have different ways of assigning buses to outputs. In Cubase SX, you’d use the Input and Output tabs of the VST Connections window. Starting with Cubase SX 3, though, this window added a new tab for External FX. It works very much like adding standard Input and Output buses, but includes additional fields so you can add a delay if needed to compensate for delays through the external device, change the send and return gain levels, and include a “friendly name” for the device you’re feeding and its associated bus.

In Cubase's VST Connections window, under the External FX tab, the ToExtFX bus is assigned to output 8 (left and right channels) of the Creamware SCOPE out. Within SCOPE, this is assigned to the analog stereo hardware output.

To send a track’s signal to the external effect, turn up its send control to the appropriate bus. The meters on your external hardware should show that it’s receiving signal. Now turn your attention to creating an effects return within your DAW.

In versions of Cubase prior to SX 3, you do not want to use its dedicated FX tracks because they are designed for use with plug-ins. Instead, create a standard audio track, then set the track’s Input field to the input that’s receiving signal from the external effect.

This shows the channels involved in feeding external effects when using versions of Cubase prior to SX 3. The left-most channel is a drum track, which is about to be trashed by a Line6 PODxt. Note that its effects send is enabled and set to pre-fader. The Master Out channel is simply the entire mix of the song. The ToExtFX channel is a bus which is assigned to the hardware out that feeds the POD. Finally, the FromExtFX channel receives the POD’s output via a hardware interface input.

With Cubase SX 3, the external device is treated as a plug-in. Thus you use a dedicated FX track to accept the external device’s return, select the external device as a plug-in in the desired audio channel (or group channel), and you’re done.

WHAT ABOUT LATENCY?

You will likely need to compensate for delays due to the signal going out the audio interface, through an effect, then back into the system. Here are your options:

If the effect can blend dry and processed sound, set it for the desired blend. Then turn down the volume of the original track feeding the effect, set its Send to pre-fader, and listen only to the effects return. To compensate for latency compared to the non-processed tracks, slide the original track forward in time (to the left) by whatever amount compensates for the delay.

If the effect provides processed sound only, “clone” the track to be processed, feed the clone to the external effects bus using pre-fader send, and turn down the clone’s main volume so it doesn’t contribute anything to the mix. The original (non-cloned) tracks provide the dry sound; bring up the effects return level for the desired amount of effect, then slide the cloned tracks ahead in time to compensate for latency.

Another option is to record the audio produced by the effect into the assigned track, and slide that track ahead while mixing to compensate for any delay. You may need to do this anyway if you want to use lots of external effects, but don’t have enough I/O to handle them all in real time: Insert one effect at a time, record the results, then move on to the next effect.

In Cubase SX 3, as mentioned previously, there’s a parameter that provides delay compensation. This simplifies the process considerably.

And now you know how to return your rack mount gear to being productive members of DAW society. I’m sure they’ll be much happier.

THE FUTURE

Steinberg and Yamaha have collaborated to create the Studio Connections initiative, an open standard that builds on SX 3’s ability to accommodate external effects, and results in a tighter level of integration (e.g., including a graphic interface that resembles working with a software plug-in). This will greatly simplify the above process for compatible gear that includes a suitable software graphic interface (basically, a MIDI plug-in based on an enhanced version of the OPT MIDI plug-in standard). The standard even has a semi-automated way to compensate for any delays created by going out to external gear, then back in again.

As of this writing the standard is still in its infancy, but even if the rest of the industry doesn't adopt it, it will probably be incorporated in future Steinberg software.

Craig Anderton is Editor Emeritus of Harmony Central. He has played on, mixed, or produced over 20 major label releases (as well as mastered over a hundred tracks for various musicians), and written over a thousand articles for magazines like Guitar Player, Keyboard, Sound on Sound (UK), and Sound + Recording (Germany). He has also lectured on technology and the arts in 38 states, 10 countries, and three languages.