I wanted to make a screencast and show you a useful way to use VU metering and calibration. During the recording and mix process I find it’s useful to change the calibration and it’s a very simple way of metering in general but there’s no one calibration that fits all genres and all specific areas of audio.
So the metering comes from a system called the K20 metering system and the formula is K-20 dbFS = 1.3, 1.23 Volts which equals 0 VU. So the first calibration that I have is I guess you can call the K20 but because my converters are about half a db different mine is -19.5 db. So when I send this 1K signed wave out of my converters at -19.5 it reads 1.23 Volts on my multimeter and that is calibrated to 0 VU.
So I use this metering for the tracking and preliminary mixing phase. The tracking because when I’m tracking my signals I’m trying to hit 0 most of the signals coming in because that will give me enough signal and enough gain of the mic without clipping any transients or anything like that. It’ll give me about 20 db-s so some of my transients can get through. And then when I start my preliminary mix I for instance will put the bass at around -4 VU and I kind of go through the different tracks and find their space until I get to where I send all those tracks to a 2 bus or a 2 mix.
Then I change my calibration to what’s called the K14 calibration. And what that is it’s 6db-s louder so instead of sending a -19.5 I actually send -13.5 db-s and that will double my voltage from 1.23 to 2.45 or something like that. And we want to do that because the K14 is, it’s raising the RMS signal of the 2 mix and not individual tracks. If it’s individual tracks you’re going to have – your 2 mix will be overloaded.
So you put the K14 metering on your 2 bus or your 2 mix and I’m going to play this sign tone and I just switch my VU meter panel to the second calibration which is calibrated at -13.5. So now that I have that I’m going to send all 5 signals of my bass recording here to this 2 bus and my VU meter panel will be measuring it with the K14 calibration.
Now, if I needed to adjust the overall signal on this calibration then I would just – I have a general balance of all the mics already so I’ve grouped them together and I can push or pull the faders into this 2 mix.
So now that I have kind of the signal in the sweet spot so to speak I believe I need a little bit of compression. So at this point my goal and purpose of compression is just to compress the bass on those low notes when the RMS signal is surpassing 0 VU and getting to a +1 +2 and +3. I don’t want it to turn on anytime before 0.
So what I try to do with the compressor again is just I’m only compressing about a db of gain and I’m trying to set the attack and release to only compress the signal when it’s reaching the threshold and then of course when you’re reducing gain you have to make it up on the output and from that point I believe my goal usually is just to have the bypass signal and the un bypass signal to be almost transparent as far as volume attenuation.
And so that’s it. And that’s on the – that compression is on the 2 bus and I do have a maximizer or maximum that I have on just to grab any kind of peak transients that may jump through because I’m going to be putting these tracks on a CD. So it’s kind of a poor man’s mastering.
So that concludes our video. This is just an example of using a K20 – K14 calibration on your VU meters. Yes, you can use peak meters but I feel VU meters are very musical and they’re metering the average signal which I think is important. When we focus just on peaks we’re generally just using our eyes and not our ears in that manner.
So I hope this video was informative and if you have any questions or comments please leave them below or email me at firstname.lastname@example.org.
This is an unedited transcript from our video series from Acoustic Fields. There will be some errors in grammar and sentence structure that occur during this translation process.
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