What is gain staging? Why is it important in modern recording and mixing? What is V.U. meter and how can they help during these processes?
These questions are constantly being asked. There are thousands of comments on the Internet about gain staging. It’s often one of the topics that generate the most confusion, but trust me, it’s much easier than it seems. We will attempt to shed some light on these subjects and show you how to use plugins like Britson and Satson in your DAW to give you more control over this process. With a few tips and some basic principles to keep in mind, your mix can likely benefit substantially.
What is gain staging?
Let’s start with the first question: What is gain staging?
In a nutshell, we could say that gain staging is the process of defining the correct level of an audio signal chain or an audio recording. But, how do we know what the correct level is? Back in the day when analog reigned supreme in the audio world and “640 KBytes ought to be enough for anybody”(*), the correct level for an audio signal was one where the noise level added by the equipment and tape was at a minimum. That sweet spot where we would get that analog warmth we all love, plenty of dynamic range to play around and no noticeable hiss. That level was standardized by manufacturers and measured to be 1.227volts in an analog signal, also known as +4dBu. But you might be more familiar with its equivalent value of 0 V.U. when reading in the needle of a console meter.
What is V.U. and why is it useful?
V.U. stands for Volume Unit. It was a metering unit developed in 1939 and it was adopted to relate to the perceived loudness of the audio signal. It has a slow response with a ballistic (or how quickly the meter reaches the targeted value) of 300 ms and an overshoot (the error of the needle) between 1 and 1.5%. These characteristics rely on the mechanical nature of the metering device and the performance of the needle. It can never reflect the instantaneous signal peaks and therefore it is not a good indicator of peak performance. The peak value is inferred between 6dB and 10 dB higher than the reference level.
For that reason, during recording, the engineer would aim for the needle to target that sweet spot of 0 V.U. to get a good and healthy audio signal. That made it easier to find the right level of the recorded elements in the mix.
For example, although we all love to see the needle of our meter bouncing around with a groovy drum beat, each jump in the needle shouldn’t really reach 0 V.U.; It would most likely stay around -6 V.U., so the peak value would be around the magic value allowing enough headroom for adding the rest of the instruments.
This doesn’t mean that you couldn’t record hotter. In fact, going over the 0 V.U. on the meter or even peaking in the analog world could be a desired effect. So this would add saturation and distortion to your signal making it harmonically richer and perhaps more interesting.
Digital recording: What happens now with gain staging and V.U. metering?
Although all this is still current nowadays, computer recording and modern audio interfaces changed the way we record and understand gain staging.
Digital recording today is virtually noiseless, even with some of the cheapest audio interfaces on the market. It seems logical to record as hot as possible without digitally clipping, taking advantage of the whole dynamic range that modern technology can give us, and without losing any bit of information. But this practice can turn mixing into a mission impossible: summing multiple signals together at this level will normally cause the mix bus to exceed 0 dBFS, obviously causing clipping in the process.
Also, most software developers and audio interfaces use the signal sweet spot of 0 V.U. to calibrate the input of their plugins and converters, which has been standardized by most manufacturers to the magic number -18 dBFS.
This means that you can record as hot as you want, but before you start mixing you should trim your audio clips or tracks to around -18dBFS.
And this is where plugins like Britson and Satson are super helpful. Because they not only give you the sound and saturation of an analog console; they also allow you to gain stage your signal with a V.U. meter calibrated to -18dBFS(**).
“Plugins like Britson and Satson allow you to gain stage your signal with a V.U. meter calibrated to -18dBFS, plus the sound and saturation of an analog console”
How to use plugins like Britson/Satson for gain staging
So now that we know how a V.U. meter works, we just have to place Britson/Satson as our first plugin, get a healthy level on the V.U. meter for each track, and then continue mixing as we’d normally do. The rest of the plugins in your chain will benefit from this and you will find yourself moving the faders in your DAW with more resolution, having more control over your volume, and more headroom to mix.
And we are only scratching the surface on the advantages that Britson or Satson have to offer. Their smooth filtering section can help clean up your tracks, creating more space in your mix. And with more advanced tools like buss summing, grouping, or stereo crosstalk, your mixes will become less sterile and more alive. You can even use Britson or Satson as an effect by emulating more aggressive saturation with the console using the output compensation setting. Very much like driving your real console preamp over 0 V.U. for analog saturation!
I hope all that fear and confusion surrounding this subject matter goes away for good. As I hope you’ll find out, a high-quality plugin with the appropriate features (such as Britson or Satson) can simplify this whole process, and give you that much-coveted sweet spot.
Make sure to check our blog for future tips and tutorials on how to use all these great features.
(*)At a computer trade show in 1981, Bill Gates supposedly uttered this statement, in defense of the just-introduced IBM PC’s 640 KB usable RAM limit.
(**)Users can choose to calibrate Satson or Britson using the values: -20, -18, -16, -14 and -12 dBFS. This is normally done to match the audio interface internal calibration in case it’s different to -18dBFS.