We've made it to week 4. We're halfway through the course, and we've covered a ton of material so far, and now we're deep into the post-production process, looking at mixing. Specifically this week, we're going to be looking at dynamics, and specifically how we can actually control the levels of our tracks dynamically over the course of a song. It can be done manually by controlling automation on volume faders or we can use plugins designed specifically for controlling the dynamics of a track. Those will be your compressors, your limiters, expanders, and gates. We'll get deep into those this week. But before we get to that, I'd like to talk about just dynamics in general. We're going to be using this term dynamics all the time over this lesson. It's just like any of those terms in music, in that depending on the context, it can have different meanings. So I'd like to just talk about the different meanings dynamics can have. To a performer, dynamics is going to be the musical control of volume over the course of a song, and even if you look at a musical score, the dynamic markings in a score are the things like piano, and forte, and the hairpin indications. They're really indicating to the musician how to perform those variations. Now, the interesting thing about musical dynamics in that instance is it's not just a volume that changes. It's the intensity of the performance. You find that, as you play harder, it gets brighter, the timbre change, gets more aggressive. So dynamics in that instance is more than volume. It's really an instruction to the performer to get more intense, and it does change more than just volume. If we're talking about musical equipment like microphones, and noise gates, and compressors, and EQs, well, they're going to have a dynamic range, which is the range in levels that can come into it and go out of it that it reproduces accurately. In that instance, there's a dynamic range where it will reproduce the sound properly. Outside of that range, you're going to have some issues. The bounds of that range on the bottom end will be your noise or your noise floor, and on the top end, is going to be a ceiling when it starts distorting. We call this range, this dynamic range, the linear area, the range where it will reproduce the sound accurately, and outside of that, we're going to have issues. So in this lesson, we're going to look at the specifics of the noise floor and of distortion. We'll look at both musical uses and how we can avoid both of those things. Now, the human ear has a dynamic range also, but it's complicated, because our perception inside the dynamic range is changing all the time. Have you ever noticed that if you're in a quiet room, you start noticing the little sounds maybe you didn't hear before? Then if you're in a loud space, you have no problem, you hear everything, you hear the loud stuff, maybe the quiet stuff is gone, but you're still able to hear what's going on. We have this automatic gain control. When things get real quiet, our brain lifts up the volume automatically. When things get really loud, it brings it down, and that's great in day-to-day life. It allows us to adapt to the situation we're in and we use that as a way to locate ourselves even if we're not seeing what's around us. But in a mixing context, when we start getting into music production, that natural perception fights against us, because we don't have a set absolute level for amplitude, for volume, for loudness. Instead, we had this shifting scale all the time. So like we saw with frequency, I said it was nice to have a spectrum analyzer so that we can start associating the sound with specific numbers and hertz. Well, with amplitude, it's also nice to start relating what you're hearing to specific numbers. Amplitude or loudness is measured in decibels. If we're talking about sound in the air, we tend to measure it with dB SPL or decibels sound pressure level. Now, the decibel scale is a logarithmic scale, and honestly, it's hard to understand. I would suggest that you take some time to search on the web or talk to your classmates here in this course about decibels in general. Decibels is always a relationship. It's a ratio to a set point, and it can be used in a variety of contexts. So we need to always qualify. When you say decibel, what kind of decibel? You'll notice when I'm saying it , I'm saying decibel SPL or sound pressure level. What that sound pressure level does is it gives us an absolute reference point for the decibels. In this instance, the dB SPL, the reference point, is the threshold of hearing. It's the quietest thing. So zero dB SPL is actually the quietest thing we can possibly hear as human beings. If we go up from that, the max range is our threshold of pain. I'm sure you've been in a situation where if something is so loud, it starts hurting. Well, that's going to be the upper range. So we can say our dynamic range, the dynamic range of the human ear is going to be from the threshold of hearing, zero dB SPL up to the threshold of pain, and that's in the range of a 120-140 dB SPL depending on the study and who you're talking to. The thing is, loudness as we saw is a complicated thing, and that duration matters, and there's a lot of factors in it, but that gives you a good range of what the human being can hear. We're always shifting our focus inside of that. So because we're shifting all the time, because we had this automatic gain control, I think it's really useful to have some absolute, and to be able to get that, I would suggest getting a sound pressure level meter and walking around with it for awhile. The great thing about these smart phones, like you see over here, we can get a sound pressure level meter just for it. I would suggest as you're walking around your daily life and just getting a feel for the general levels. I know when I started doing this, I was surprised to see somethings. When I was in a quiet room, it would be still registering like 30 decibels, which was strange. Let's see it. So we started noticing the noise of my computer, the fan noise of my computer, maybe the air conditioning, all these things, and you notice when you do that, everything starts to seem to get loud. You start noticing all those really quiet things. Then the other thing I was surprised to notice was when I was on the train on my morning commute, it was at or over a 100 decibels the whole time. That's pretty close to the threshold of pain. Then I look around and see people with ear buds in, going even above that, trying to compete with that noise. That's dangerous. But we don't notice because we're constantly adjusting our level automatically. So getting a good sense of the decibel scale with the meter is a great idea. Something on your smartphone or just a real meter is a great idea. Also, when mixing, try putting it in front of you near your studio monitors. It's really effective to mix at the same level over and over and over. Because if you took chance to study the equal loudness contours or the Fletcher Munson Curves, if you study those, you'll actually find that our EQ, our built-in frequency response of our ears changes with amplitude. When things get quiet, we notice the mid-range more and more and more and the bottom at high-end drop off. When things get louder up to around 80 something decibels, it flattens out a bit, and above that, it gets painful. So if you're changing the levels of your monitoring all the time, you're actually not getting an accurate representation of the music. The frequency response will change in the whole time. So having that SPL meter out when mixing and just being consistent everyday about that will give you a much better sense of your mix, and you might have less of those issues I know. Before I started being aware of this, I would mix one day, maybe just at a level I wouldn't really be thinking about it, turn the monitor up and love how it sounded, and when I come back the next day and just turn on my system and listen, and I think "Oh, this sounds totally different, what was I thinking?" A large part of that was just that my monitors were at a different level, and that changes how everything sounds. So something to be aware of and consider. So over the course of this lesson, we're going to look at some more of the specifics of dynamics, particularly of noise floor and then distortion. We'll look at the corrective uses, how we can avoid noise, how we avoid distortion, and then also some of the creative uses. Why we might want to use distortion and why noise can actually be a creative thing. Then we'll look at ways of manipulating dynamic range over the course of a tune. Manual ways like riding in a fader to correct a vocal or a bass part, and then we'll look at automatic gain controls, things like compressors, limiters, expanders, and gates.
