If you are reading this article, you are undoubtedly already aware of the benefits of using Reference 4 by Sonarworks to compensate for the irregular or colored frequency responses inherent in most listening environments. If the goal is to create a mix that translates well to as many listening situations as possible, you need to have a neutral space to listen, unaffected by the acoustics of the room, the particular reference monitors being used, or your headphones. A flat frequency response across the spectrum is the holy grail sought by all audio engineers in professional studio spaces or home project studios alike. That is why the corrective equalization applied by Reference 4 is essential and should be a regular part of your workflow.

The way you use Reference 4 in your DAW (Digital Audio Workstation) of choice may differ, depending on how you like to work, the nature of your projects (e.g. music, sound design, post-production, etc.) and the capabilities of your set-up.

Before going on, I will assume that you are familiar with how calibration works using Reference 4 and that you have configured corrective equalization presets for your headphones and reference monitors as instructed by the Reference 4 manual. It is suggested that you use one of the RTA mics and associated calibration files supplied by Sonarworks and/or a pair of headphones, also individually measured and supplied with a unique calibration file for best results. See the Sonarworks product page to see what is currently available.

There are two things that are crucial to remember when using the Reference 4 plugin:

  • Be sure to audition your reference tracks through the Sonarworks software when comparing your mix. If you’ve imported the tracks to your session or are routing them through a record-enabled track, there should be no problem if you’ve instantiated the Reference 4 plugin at the end of your final effects chain. But if you are playing the tracks from an external source through your interface, you will want to use Sonarworks Systemwide, which applies the necessary corrective equalization to the output of your computer, as opposed to your DAW output only.
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The more choices you have available in terms of reference monitors and headphones, the better you can hear how your mix will translate to other listening scenarios

  • Always remember to BYPASS Reference 4 when bouncing. Clearly, you would not want corrective equalization to be printed to the track itself. The idea is to compensate for the way your particular system or headphones color the sound, so you can make mixing decisions based on a sonically neutral listening environment. Bouncing the corrective effects of Reference 4, which are specific to your situation only, would not make much sense.

Routing for Quick Comparison

If you are like me, you will ultimately want to listen to your mix both through your headphones and your reference monitors to get a better idea of your mix. Listening through headphones negates the HRTF (head-related transfer function) that affects the stereo image you hear when listening through speakers, so it is always important to get a sense of how a mix is imaged in both contexts. Also, you may have multiple speakers you want to compare. All three of these scenarios require different corrective equalization curves. It would also be good to have a fool-proof workflow that would not necessitate engaging the bypass switch on the Reference 4 plug for the final bounce. Depending on the DAW there are various solutions to optimize signal flow with these concerns in mind.

Using a AUX Send Solution in Pro Tools

Notes:

  • For the sake of simplicity I have not used any group or stem busses, inserts or effect sends in this session in order to focus on the routing for multiple Reference 4 inserts.
  • This example is using an RME Fireface 802 that has two dedicated Headphone Outputs (Channels 9/10 and 11/12) Your interface options may be different.
  • Key commands are for Mac only.

In the i/o bus settings:

Create a stereo bus called toPreMaster
Create a stereo bus called toPreR4
Create a stereo bus called HP1 – with Output set to Phones 9-10
Create a stereo bus called HP2 – with Output set to Phones 11-12
Create a stereo bus called Main Mon – with Output set to Analog 3-4
Create a stereo bus called Alt Mon – with Output set to Analog 5-6
Re-label Output 1-2 to Bounce Mix and make sure Output is set to Analog 1-2

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Create a Send on every track and set it to toPreMaster (hold Option key [⌥] while selecting one track)

With all tracks selected use the Copy to Send feature to duplicate track fader and pan settings to all the Sends. Use [⌥][⌘][H] to get “Copy to Send” dialog box to copy all Track fader/pan settings to Sends while the tracks are selected (also available under the Edit menu).

Create 5 new Stereo AUX Tracks and name them:

HP1 (Headphones 1) – set Input to: toPreR4 – set Output to: HP1
HP2 (Headphones 2) – set Input to: toPreR4 – set Output to: HP2
Main Mon (Main Monitors) – set Input to: toPreR4 – set Output to: Main Mon
Alt Mon (Alternative Monitors) – set Input to: toPreR4 – set Output to: Alt Mon
PreMaster – set input to: toPreMaster – set Output to: toPreR4
Insert a Reference 4 plugin on the tracks: HP1, HP2, Main Mon, Alt Mon, with the appropriate corrective equalization preset for each.

This particular set-up would allow you to hear corrective equalization specific to 2 sets of headphones and 2 pairs of monitors without affecting the final bounce. Since the Master track does not have the <a href=Reference 4 as an insert, you will never forget to bypass the plug before bouncing, because you simply won’t need to."/>
This particular set-up would allow you to hear corrective equalization specific to 2 sets of headphones and 2 pairs of monitors without affecting the final bounce. Since the Master track does not have the Reference 4 as an insert, you will never forget to bypass the plug before bouncing, because you simply won’t need to.

Additional Notes:

  • Be sure to duplicate whatever mastering effects chain you are using on the Master Fader to the PreMaster Track.
  • Be sure to route other AUX effects tracks in the same way as the main tracks.
  • You will need to route the output of your system to the appropriate monitors via hardware settings, as needed to audition multiple pairs, depending on your particular system.

Using Output Sends in Pro Tools

You could also Output all tracks to the toPreMaster bus and set that as the input for the AUX tracks: HP 1, HP 2, MON 1, MON 2 and PreMaster.

With this approach, the PreMaster track would feed the Master Fader and would be the only AUX track to affect the Bounce. This would eliminate the need to copy fader settings as in the first example. However, any additional inserts before the Reference 4 plugin would need to be duplicated on every AUX track.

Once again, the idea here is to isolate the <a href=Reference 4 equalized version of what you are hearing from the bounce and allow for different listening scenarios without the need to the change the plugin settings each time you switch speaker pairs or headphones."/>
Once again, the idea here is to isolate the Reference 4 equalized version of what you are hearing from the bounce and allow for different listening scenarios without the need to the change the plugin settings each time you switch speaker pairs or headphones.

Logic Pro and Sonarworks

Below is a similar idea implemented in Logic Pro. Setting up busses in Logic can be helpful or annoying, depending on what you are used to. When you create a Send on a Track, a corresponding AUX is immediately created. To set up several AUX tracks to receive from the same bus, you will need to duplicate the first AUX as many times as needed. Also, if you want to show the AUX track in the Main Window, you will need to select Create Tracks for Selected Channel Strips under the Options menu in the Mixer View.

3 Creative Routing Solutions for <a href=Reference 4 in Pro Tools, Logic Pro, and Cubase Pro - Google Docs 2018-08-29 11-21-12"/>

Cubase Pro Control Room and Sonarworks

The Control Room Feature in Cubase Pro allows you to set up various speaker or headphone outputs for quick switching and listening comparisons. What makes this functionality even more useful is that each output scenario can have its own effects chain independent of each other.

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Therefore, you could instantiate a Reference 4 plugin in each chain with the appropriate setting without affecting your bounced track. This is perhaps the easiest solution of all that have been discussed thus far. Cubase has essentially built-in the routing solution via its admittedly awesome Control Room feature.

Conclusions

The way you use Reference 4 in your day-to-day workflow in recording, mixing and mastering will be dependent on your audio interface and your DAW of choice. The more choices you have available in terms of reference monitors and headphones, the better you can hear how your mix will translate to other listening scenarios so you could make intelligent choices and the necessary adjustments. Ideally, you should be able to apply the corrective equalization specific for each situation quickly and easily, and be able to audition the results without inadvertently affecting the final bounce by neglecting to bypass the plugin. Every DAW is capable of a little creative signal routing to accomplish this task. I encourage you to experiment and develop a solution that works best for you.