Sonarworks Reference 4 Demystified - How To Understand What All The Frequency Response Curves Show In The Speaker Calibration
Do you struggle getting your mixes to sound good both in your studio and out in the real world? Maybe you find that the level of bass in your mixes sounds spot on when you listen to your work in your studio but sounds either too weak or overpowering when played back in your car? If so, your studio and monitoring maybe working against you.
Most studio monitors promise a flat frequency response out of the box. However the moment you put them into a room, the room has an impact on how the speakers will sound. Mixing through monitors with a near flat frequency response can make it much easier to mix tracks which can also help your mixes translate better in the real world. On the other hand using monitors in a room without taking the room acoustics into consideration can mislead our ears and so our mixing instincts, which together can mean that we misjudge important elements in a mix, such as the overall level and energy of bass.
One way of achieving a neutral sounding monitoring environment is to build a recording studio from scratch, based on design decisions made with lengthy mathematical equations, but this approach can be expensive and out of the reach of a lot of audio producers. These days with software developments, there are other ways to achieve a near flat frequency response in your monitoring with software solutions being very cost effective and simple to use, as part of your solution.
Sonarworks Reference 4 is one such software solution that calibrates the frequency response of studio monitors and studio headphones. It can be used either as a plug-in within your DAW or as a systemwide app.
This article explains what all of the coloured frequency response curves displayed within Sonarworks Reference 4 mean, because at first glance, they can be a bit puzzling to understand.
If you are new to using Reference 4, or you are planning on downloading the demo at some point in the future, then this article will help you understand each of the curves and how to adjust the settings within the application to help you get the very best sounding results from your calibrations in your studio setup.
But before we start, if you are unsure what Sonarworks Reference 4 is all about then check out our video reviews below to see both the Monitoring and Headphone calibrations in action.
Sonarworks Reference 4 - Speaker Calibration
Sonarworks Reference 4 - Headphone Calibration
Before - Blue
To complete your monitor calibration you will need to use a measurement microphone and the Reference 4 Measure app to run a series of measurements…
The first set of curves presented to you when completing the measurement process will be two curves displayed in different shades of blue representing the left and right speakers. These Before curves display the frequency response of your left and right monitors in and around your main listening position based on the positions of the measurement microphone. In the image above you can see a noticeable difference in response between my left and right monitors just below 100Hz.
If you use Reference 4 for correcting the frequency response in headphones then a headphone calibration file will need to be loaded. The good news is that a large number of headphone calibration files come bundled with Reference 4, these are referred to as average headphone calibrations (Visit Sonarworks for a list of supported headphones). If your particular model of headphone is not in the list of profiles then Sonarworks offer a bespoke headphone calibration service based on your own unique set of headphones. All you need to do is ship them your headphones for a short while to measure. These types of measurements are referred to as individual headphone calibration files and provide a much more detailed correction compared to average headphone files.
In short, the blue Before curves are a simple visual representation of what you are already hearing in your monitoring without any calibration.
Target - Red
Think of the red Target curve as the point you would like Reference 4 to get to. In the image above you will see that the Target is flat showing a flat frequency response. This is Reference 4’s default target. Target curves don’t need to be set to flat if you don’t want them to be. You can customise the Target using the Bass Boost and Tilt or Predefined Target Curve section if you want a slight alteration in the low or top end.
Correction - Green
The green Correct curves show what changes Reference 4 needs to apply based on both the blue Before and red Target curves. In the image above you can see the Correct corrections all but mirrors the shapes of the blue Before curves.
Simulated After - Purple
The purple After curve displays the actual correction, being the frequency response of your monitors or headphones after the calibration. You can see in the image above that there is a slight boost around 30Hz - 40Hz with the frequency response above 50Hz being nearly as flat as the Target curve. The After curve can change, this depends on how the Filter Type and Limit Controls are set.
Filter Type - Orange
The Filter Type is displayed in orange. It’s an important setting as different modes will sound different and introduce different amounts of plug-in latency. Zero Latency is a good mode to use during a tracking session as it provides basic calibration without any annoying delays. The Zero Latency correction works but won’t sound as precise as other options in the list. Mixed provides better sounding results but introduces some latency. For optimum results it is best to set Reference 4 to Linear Phase. The orange curve will appear pin straight in the display and results in a much tighter sounding stereo image but at the cost of higher plug-in latency, which shouldn’t cause you any issues if you are only working in mix stages.
Limits - Pink
The Limits curve isn't really a curve, more of a reference to the amount of boost applied to the green Correction curves. Limits can be adjusted from the menu at the bottom of Reference 4. Think of Limits as a line of defence, which can reduce the chances of clipping your monitors or headphones. Simply put, use the Limits control to literally limit the amount of boost in the Correction curve. If you have a powerful set of monitors try setting the Limits to Normal (12 dB boost) for full fat correction. For smaller monitors using small power amps you may find lower limits sound better. Also, if you find that your monitors are clipping then use the output gain slider to the right to globally attenuate the correction from Reference 4.
Dry / Wet
This simple control enables users to transition from uncalibrated systems to fully corrected. Those new to these types of products can feel as though the correction is too much of a difference at a first listen but don’t let the correction put you off. A good way of training your ears to learn the new sound of your monitors is to dial the Dry / Wet control down to 20% dry for a day or two and then slowly increasing the Wet amount over time. These value changes will adjust the strength of the green Correction curve, which is displayed at the top of UI.
We hope this article has helped you understand how Reference 4 displays all of its relevant information. Out of curiosity, if you use Sonarworks in your studio do you ever adjust the red Target Curve or do you leave it flat?