// Studio Monitor Calibration

At some point during your journey as a sound practitioner of any description, you will inevitably find yourself with the task of calibration. Coupling this with sound treatment for your room of choice will be one of the most important tasks you undertake to aid your mixing decisions.

// Monitor Placement

Where you place your monitors is the jumping off point for a properly calibrated set up. Before you even start positioning them, it’s wise to choose the placement based on your room. Now while the majority of us are not graced with purpose built spaces (I, like many others have to make do with a spare room at home), there are few things you can do to maximize your effort.

  1. Move your monitors away from the wall to avoid exaggeration in the low frequencies. This will also assist in providing air circulation to keep your monitors from overheating. A distance of at least 6 inches is advisably.

  2. Position your monitors so they fire into the longest portion of your room. Ideally they should be situated centrally in this walla horizontally, but not vertically. They can either below or above the halfway mark between floor and ceiling, and will help to reduce acoustic issues caused by reflection points in the room.

  3. If your monitors are placed on your desk, pick up some isolation pads to shield the work surface from vibrations. Or alternatively, get purpose built stands to remove from the surface entirely. This one is great as it also frees up your work space and gives a little freedom to adjust the height, which should ideally be with the tweeters pointed directly at your ears when in your listening position.

    Some people prefer to position the tweeter slightly above to attenuate the higher frequencies, but for now we’ll stick with the tried and tested method. Feel free to experiment with the variables to get the most consistent, flat sound you can from your room.

Next up, position your monitors so that they make the shape of an equilateral triangle with your head. This is where isolated stands can be beneficial, as it gives you more freedom to position your monitors based on the distance between yourself and the sound source. This configuration will give you a much better stereo image, and can minimise potential issues with delayed signals that could wreak havoc on your decisions. A mic stand or tripod can help you to freely measure the listening positioning.

Once you’ve got the most ideal placement, taking into account the layout of your room, you’ll need get hold of a few tools. Namely an SPL (Sound Pressure Level) meter, and a mono recording of pink noise (C-Weighted, -20dBFS RMS)… I know, just stay with me.

// C-Weighted Pink Noise

Pink noise can be somewhat likened to the familiar white noise static of crackly radio transmissions, and TV broadcast breaks; in the days before digital technology took its now firm grasp on consumption of media. The difference between the two is that pink noise has an EQ curve present that is more closely to the way that perceive sound. White noise is flat across the whole spectrum, and pink noise has a roll off on the high frequency content.

You can find ready made recordings of pink noise here.

// Taking Your Reading

For this step, with the monitors off, increased the volume of your soundcard/interface so that it rests at the 12 o’clock mark. This will essentially be your new reference level to give you a consistent listening experience. This gives you a chance to learn the character of your room and monitors over time, making it much easier to make good mixing decisions.

Fasten your SPL meter to the your stand of choice (heavy duty tape works wonders) and position it at the listening point, set to detect RMS as opposed to peak, and reset both monitors volume output to zero. Play your pink noise recording through each monitor separately, and slowly turn up their individual volume controls until the SPL meter reads around 83dBFS (decibels relative to full scale).

The subject of what dB to calibrate your monitors to varies from room to room. In all fairness, as 83dBFS is more professional studio level. For anything smaller, more conservative values can be used, personally I have mine calibrated to 73dBFS due to the size of my room and to minimise issues with reflections. Here are the recommended levels based on your monitoring preference.

  • 79dBFS – Broadcast or games
  • 85dBFS – Film (Dolby recommended)

You can find more information on calibration levels here.

And that’s pretty much it! Not too painful.

The benefit of performing this procedure is really long standing. You will end up with a consistent listening environment every time you sit at your desk, which can then replicate but setting your level to the same value as the calibration. After testing different mixes on other systems you will end up discovering what they are lacking, and this will allow you to make more refined decisions when it comes to balance, panning and EQ.

Feel confident? How about adding a few extra speakers in?…

// 5.1 Surround

If you are working in film mixing and have the money, space, and inclination to set up a 5.1 listening environment,  the procedure is really not that different to your standard 2.0 stereo configuration. The major adjustments being that you now have 3 extra speakers and an additional subwoofer available. It really is ideal to have the same make and model of each monitor so that you are hearing a consistent sound from each direction.

// Center

The centre channel is positioned between the initial stereo configuration, and is mainly used for character dialogue in movies. It is calibrated to the same dB chosen at the start of calibration, and helps to fill out the phantom center left by the gap between the left and right speakers.

// LFE (Low Frequency Effect)

The .1 refers to the subwoofer which contains all of the frequency content below 80-110Hz. Placement of these can be a little time consuming and is primarily based on the shape of your room. Ideally you want to minimise the damage caused by the acoustics of your room. The sub is calibrated slightly differently to the other speakers, with a reading of around +4dB relative to your initial calibration.

// The Rears

These are a little different to their left and right counterparts. While they still take the same dB reading as the front speakers, they are positioned off axis with the opposing front speaker to avoid phasing when firing equal levels of signal towards your listening position. An angle of 110° would be used as opposed to the value of 30° advised above.

// Final Thoughts

I really cannot stress how important proper positioning of your monitors. Coupled with acoustic treatment, this has the potential to transform your listening experience for the better. The subject of acoustics is a bit rabbit hole of information, and takes a level of determination that few people see through in home studios, but it really is worth it if you’re in any way serious about progressing in the field of audio. Proper monitoring positioning is the first step in a lengthy journey in your quest to create the “perfect listening environment” for you to work in.

 

References
https://www.kmraudio.com/studio-monitors
http://www.soundonsound.com/techniques/monitor-wizard
http://arqen.com/acoustics-101/surround-sound-speaker-placement/
http://en.dahnielson.com/2008/03/home-studio-acoustics-the-basics/
http://audiodesignlabs.com/wordpress/2008/05/professional-monitoring-system-calibration/
https://www.gearslutz.com/board/mastering-forum/1024714-depth-bob-katz-k-system-tutorial.html
https://ask.audio/articles/7-mistakes-to-avoid-when-setting-up-studio-monitors
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