Calibrating your playback system does not take very long, and does not require expensive gear. You will need: a sound pressure level (SPL) meter, a pink noise audio file*, monitors, and a knob that controls the speaker volume (*pink noise is used because its energy is distributed uniformly by octave throughout the audio spectrum). Having earplugs or shooting muffs handy will help keep your ears comfortable during the testing. Some professional monitor controllers (such as the Cranesong Avocet) are marked in dB, which is the ideal, but the method below will let you calibrate any monitor controller. Please note: Mastering engineers and those who work with acoustic designers go through a more rigorous and detailed process. But the following steps will help:
Load the stereo pink noise file into your DAW. Route it to play out the main Left and Right speakers with your faders at 0dB (unity gain) and pan pots set to full left for the left channel and full right for the right channel. Mute the right speaker on your monitor controller, or disconnect the cable to the right speaker. Then perform this adjustment on the left speaker, and repeat it for the right speaker. If the results for the left and right speaker are different by more than 0.5—1dB, then consider getting a new monitor controller, as yours must not be accurate enough to make good monitoring judgments.
Before playing the file, turn your monitor volume control down all the way, position the SPL meter to be between the speakers, as close to where your head would be if you were mixing. Set the SPL meter to slow (average) or RMS readings. If there is a weighting choice, choose “C,” which is tailored for music readings. Put your earplugs in, press play, and start to turn up your monitor controller. Keep going until the SPL meter reads 83dB (warning: This will be loud). Using tape, grease pencil, or whatever you want, mark this level on your monitor controller as “0.”
Now proceed to put marks on your volume control every 3dB. When you’re done, you’ll have marks at 0dB, -3dB, -6dB, going down to -18, which should be low enough. Now that your monitor control is calibrated, you’ll find that when working with normal, well-recorded music and with your loudspeakers at about 6'—9' from your ears, you’ll find a comfortable monitor gain at around -6 to -9dB. The lower you have to place your monitor gain control, the more compressed or squashed the recording must be. In other words, Snoop Dogg really is a hot recording, as you’ll probably have to put your monitor at -15dB or lower to keep your ears from bleeding. This means the peak-to-average level of the recording must be very low as the recording is compressed and all the transients and life have been pulled out of it.
On the other hand, if you have to turn your monitor up to -3dB to make the recording sound loud, the recording itself was likely either mixed low or it has a very high peak-to-average ratio. Then you have to make the decision whether it needs more compression in order to compete with other recordings, or whether you want to be brave because you like the sound quality of a recording with good-sounding transient peaks. Depending on the kind of music, a happy medium will probably be found when the monitor is somewhere between -6 and -12dB. The closer your loudspeakers are to your ears, the more you will have to turn the monitor control down, and you’ll have to learn where the sound quality turns for your particular monitor setup. Transients are a very important part of sound quality and if you pull them out even before the recording is mastered, chances are it’s going to sound spongy, squashed, or even smashed, and that distortion will translate to fuzzy sound, reduced stereo separation, and poor translation to the end medium, whether that be the radio, Internet streaming, iTunes, or CD.
Try to work at the recommended monitor gain as much as possible from here on out. If your average SPL on loud passages at your listening position is around 83dB with your monitor gain at around -6 to -9dB, you can be assured you are in the ballpark for producing open-sounding, pleasurable, wide-range recordings that compete with anything that was produced before the loudness race got really bad.
Also, turn down the monitor control further to see if the vocal level is not lost in the mix if people listen at lower levels. But get the bass right at your reference position (likely -8 to -9dB) or it will not translate to higher or lower levels because of that Fletcher-Munson effect. Turning up the controller to -5 dBFS is a great way to “get with the bass,” make sure there is chest-moving impact, and verify that the mix is not distorting or breaking up and that the bass is not too fat or muddy. (Fig. 2, below.)