As engineers we pour thousands of dollars into subtle little pieces of gear to try to get our mixes to the next level. But if we are not listening to our mixes properly it is all for naught. For around $50 you can easily acquire the classic analog Radio Shack SPL Meter, with a nice, old school VU Meter (or for $.99 if you have an iPhone you can get one mimicking this classic hardware). This tool can be one of the best investments you ever make for a small price.
Often times, when mixing we do the wrong thing, we keep turning up our mix louder and louder. 10 years of mixing records on a daily basis later, I still catch myself doing it on a rare occasion. One of the best ways to keep from doing this is to establish a few mixing volumes and do not allow yourself to touch the volume knob without SPL meter in hand. I have 3 volumes I work at during mixing
- Eqing/Compressing/Reverbs etc. – This is at 82 db, I will do most of the work on my tones and small adjustments to the mix at this volume.
- Quiet- This is at 70 db, I use this to set many of my volumes and check the vocal level.
- Loud- This is at 98 db, I listen at this volume once or twice as my last check just to see how it plays out at this volume, and if I hear anything I missed at the quiet volumes. I find this to be the most useless listening level.
As we told you earlier, the Fletcher-Munson Curve tells you the optimal volume to mix at for even frequency response in your hearing. But how do you know when you are mixing at 82 db? This is where an SPL Meter comes in handy. Simply dial your control room volume until the meter reads 82 db and you are set.
When mixing we often A/B between or mix and someone else’s. In order to get an ideal A/B you need to make sure both your reference mix and your mix are at the same volume. This is another place where the SPL Meter comes in handy.
SPL Meters have a few different settings. When judging mixes there are two main settings you will want to use. For weighting most people use one of two settings, Flat or C-weighting which is based mostly off of midrange content. You have a choice between fast and slow for response, most mixers like slow since it gives them a bit more of an average level.
Not Just For Mixing
Some of the real tech geek engineers will use their SPLs to make sure loud guitar amps won’t blow their expensive ribbon microphones. As well you can use the SPL meter to set Mic Pads by looking at sensitivity graphs on the spec sheets that come with microphones.