Studio Techniques: Monitor calibration & the power of pink noise

Hey people!

Today I want to discuss how you can go about calibrating your studio monitors, ensuring that you have the optimal listening environment for what you're working in, and what purpose you're using your studio for.

Unfortunately for me, with being a uni student in a share-house who is restricted to using headphones - I won't be able to fully take advantage of this blog, but it's definitely going to be super helpful as a reference when I eventually get to build my dream studio!

I'll be explaining the purpose of 'pink noise' in the monitor calibration guide, and at the end of the blog I'm also going to let you know how to really harness its power at the mixing stage!

Studio Monitor Calibration

So before we start, why should we calibrate our studio? What are the benefits?

Calibration is about setting the listening/reference level of your studio dependent on the type of audio mixing you are doing. Entertainment industries such as Broadcast and Film have mixing level standards in place; with the Game industry starting to follow suit with many companies mixing to Film/Cinema specifications.

> Broadcast or Small studio suites: 79dB SPL (sound-pressure-level)

> Film/Cinema/Dolby: 85dB SPL

(It's also worth noting that Dolby Atmos requires speakers to be capable of delivering 105dB SPL to the listening position - which is pretty insane.)

Whilst music doesn't exactly have a recognised mixing level standard, many mix engineers have adopted calibrating their studios to 85dB also; because at that level it seemingly gives you the flattest hearing curve due to the equal loudness contours of the human ear and the way our brain perceives it.

You have to also factor in the size of your listening environment, where for example 75dB may be a more appropriate calibration level in a smaller studio.

So what are some other benefits?

1. Balance & Standardisation

If you mix in a calibrated room, your mix should be transparent when you move to another studio that is calibrated to the same level.

By doing calibration, you are balancing the volume which emits from each speaker so that they are all level.

No listening environment is the same, and there is so many factors that can come into play: eg. the left speaker might be louder because its closer to a wall/corner or hard surface: some of its low-frequency energy will travel backwards out of the cabinet and reflect off those surfaces, returning in-phase and out of phase frequencies which will accentuate the levels.

(That's starting to go a little down the rabbit hole of room acoustics & treatment which I'll leave for another blog, but here's a great article if you're curious)

2. More Headroom

By calibrating your studio, you're forcing yourself to have more headroom and use more dynamic range in your mix!

The higher the calibration number, the more headroom you will have. This is because you will naturally mix things quieter, and you'll get a larger dynamic range.

3. Better Mix

For broadcast & film, once your studio is calibrated - dialogue is typically mixed at normal speaking levels. Not only does this make it easier to mix by ear and utilise references, but you'll also ensure that your dialogue doesn't need other elements to be ducked in order for it to cut through.

It will let you take advantage of the headroom & dynamic range, the louder sounds like explosions, gunshots etc. will sound huge and impactful because there is such a dynamic contrast between the quieter sounds.

For music, bring up some of your favourite songs and analyse the balance between all the elements. Your ears will become used to a standard listening level when mixing, which will in turn will allow you to better judge your own mix: the balance, dynamics and loudness by ear much more accurately. This means your mixes will become more consistent, and you'll be able to benefit more from using reference tracks.

Convinced? Alright let's get into it.

What you'll need:

- an SPL meter

(if you haven't got one, I highly recommend getting 'SPLnFFT' off the App Store. It's $5 but it's the most accurate SPL app I've seen)

- a pink noise generator

For this I would recommend grabbing the 'TestTone' plugin from MDA-VSTs. It's in a free bundle with a bunch of really powerful plugins so there's definitely a bonus from downloading it. (If you're running Pro Tools you can just bring up the native Signal Generator and lay down some pink noise from there.)

- Speakers/Monitors

It's better if you have monitors with their own individual volume pots (usually situated on the back of them) as you will be having to change the gain on each individual monitor.

- Mixer/Console/Monitor Controller/Interface

So that you can adjust the overall listening level once your speakers are calibrated, and so that you can mark where the ideal reference level is next to the volume pot.

So firstly, generate some pink noise in your DAW, record a section of it at -20dBfs RMS and loop it so you don't have to keep going back to it to press play. Also make sure to have your Master Channel set to unity gain or 0dBFS.The reason we choose -20dBfs is at a practical recording sense, its giving us a headroom margin of 20dB. This precaution when gain staging allows engineers to focus more on the performance rather than having to frantically check levels. We can therefore avoid accidental clipping. As for film and games, -20dBfs matches normal dialogue levels - and that way you've got 20dB of dynamic range for those massive explosions to have their intended impact.

Before you run this pink noise through your monitors, we'll set up the SPL meter and re-position the monitors so that the meter is stood at the sweet spot or mix position:

The ideal monitoring setup is to have the listening position and monitors create an equilateral triangle, with the monitors turned in to face your ears (at a 30 degree angle to the centre-line) whilst having their height at ear-level. If you can't achieve this with your desk, I highly recommend grabbing a pair of monitor stands like these ones.

For a 5.1 surround setup, it's not overly different, more-so you just have to take into account the extra 3 speakers and a subwoofer or LFE (low-frequency-effect).

The left and right monitors remain the same, however you would position the centre monitor directly on-axis and the left and right surround shown above are positioned off-axis at 110 degrees (you could also consider the surrounds to have their tweeter placed two-feet above ear-level to give more of a sense of spaciousness).

So once you've placed the SPL meter at the optimal listening spot, it's almost time to run some pink noise through your monitors. Ensure your SPL meter is set to C-weighting and at a slow-response time. C-Weighting is a response type or form of measurement which more closely matches the way we perceive sound, relative to the other weighting types available.

Make sure that the volume pots on all the monitors are the lowest they can go to begin with, and that any EQ pots are set to +0dB. You may also want to wear some ear-protection. Finally, set your monitoring/output level on your interface/console to your desired position and mark it (maybe just have the pot set at 12 o'clock so it's easier to remember and reset when you are in another studio).

Turn up each individual monitor one at a time (with their gain pots on the back) until the SPL Meter reaches 79dB or 85dB respectively. Continue this until you've reached the desired level for each individual monitor.

Keep in mind for the 5.1 surround setup, the LFE or sub should be +4dB louder than the other monitors (eg. 83dB or 89dB).

Once you've gone through them all, you're done! ✔️

Now whilst you've got your pink noise generator ready in your DAW. Throw in some stems or open up a project you're working on. Since pink noise is shaped to mimic the natural frequency curve our ears perceive sound with, you can utilise the noise to very quickly build a balanced mix to begin with. Honestly, I didn't realise you could use it in this way to get such a great gain structure and balance, whilst saving a LOT of time and energy - where you can then spend more time on creative enhancement! Check this video out:

- Lachy

References:

Best Listening Level for Mixing | Rick Allen Creative. (2017). Rickallencreative.com. Retrieved 21 June 2017, from http://www.rickallencreative.com/production-buzz/best-listening-level-mixing/

CreativeCOW. (2017). Library.creativecow.net. Retrieved 21 June 2017, from https://library.creativecow.net/article.php?author_folder=bird_jonathan&article_folder=Editing-Suite&page=1

Dolby Atmos Specifications. (2017). Retrieved from https://www.dolby.com/us/en/technologies/dolby-atmos/dolby-atmos-specifications.pdf

How to Calibrate Your Studio Monitors - PreSonus Blog. (2017). PreSonus Blog. Retrieved 21 June 2017, from http://blog.presonus.com/index.php/2013/09/18/how-to-calibrate-your-studio-monitors/

Keep It Calibrated! Learn How and Why You Should Calibrate Your Studio Monitors for Video Game Audio. (2017). Play Dot Sound. Retrieved 21 June 2017, from http://www.playdotsound.com/portfolio-item/keep-it-calibrated-learn-how-and-why-you-should-calibrate-your-studio-monitors/

Monitor Wizard |. (2017). Soundonsound.com. Retrieved 21 June 2017, from http://www.soundonsound.com/techniques/monitor-wizard

Studio Monitor Placement — Finding the “Sweet Spot” - Blog - Universal Audio. (2017). Uaudio.com. Retrieved 21 June 2017, from http://www.uaudio.com/blog/studio-monitor-placement/

The Art Of Speaker Placement. (2017). SVS. Retrieved 21 June 2017, from https://www.svsound.com/blogs/svs/74790851-the-art-of-speaker-placement