Mastering with iZotope Ozone 5: Limiting (Part 9)
[mix being mastered]
I’ll be demonstrating the maximizer section of Ozone 5, and discussing some of the basics of loudness. To begin with I’ll be focusing on the limiter section and then in my next video I’ll move on to dithering.
One of the most well known aspects of mastering is it’s used to bring up the overall level or loudness of a track so it can be played side by side with another song you might hear on the radio, or on CD, or even downloaded to your computer. This is done primarily by controlling the dynamics of your track. I’ve already done some processing using a compressor earlier in my signal chain. Here at the end of my mastering signal chain I’m gonna use a limiter to bring up the level but make sure I’m not clipping the signal.
I’ve already got the audio printed, you can see right here I’m gonna turn on my Ozone plugin. Just the maximizer on my audio track. Now all my CPU can be devoted to processing the audio using the limiter in the master — at the maximizer stage here.
How you control the main output level is set by the margin here. It’s at 0 which means 0 dB full scale. That it means it’s basically the loudest possible signal is what you’re saying your limiter is possibly gonna go up to. The loudest possible signal that can go through your digital to audio converter. One of the things you have to worry about is inter-sample detection. Where it might cause the samples inside of your DAW to not go above particular level. Then your digital to audio converter might actually try and create an analog signal that goes above that level, which can be a problem. What I like to do is bring it down a bit. You might be thinking “oh, you’re actually bringing down the output level of the signal.” You can always make this up by using the threshold of the limiter to make sure that the overall signal is loud or perceived to be loud, but the peak is low enough so that it doesn’t cause any digital to audio, digital to analog clipping, alright. So let’s play it back and get into some of this.
[mix being mastered]
Looking at the meters you can see there are two things. The peak level and that’s the level that’s gonna either cause clipping or not clipping at your digital to analog converter. Then RMS level — that’s what’s gonna be more of the perceived level of loudness. What you want is you peak level to be low enough that it’s not causing clipping, but your RMS level to be loud enough that it’s right at the level of other comparable kinds of songs in this style of music. So for pop/rock, this country style, I shoot for somewhere between -10 RMS to -8 for the loudest parts. Some people go beyond that. I want my track to breathe so somewhere around -9 is alright.
[mix being mastered: adjusting limiter threshold]
The difference of my output is I’ve already brought the RMS by about 5 dB. It was hovering around -15 here and input was at -20. So, I’m gonna switch to the most advanced algorithm, the ISRC 3. I think it’s one of the best sounding.
[mix being mastered: adjusting the limiter]
You’re gonna have to watch because my voice isn’t actually going through the maximizer, so the levels are gonna be a lot different now between the maximizer and what you’re hearing in my voice. Another thing I’m gonna play around with is how fast the limiter responds. I want it to be a bit faster and make sure there’s no clipping. The slower I make it, it’s gonna bring up the level more and have more of a potential for clipping, but it might sound smoother. I know I’m using a fast limiter so I’m gonna use some of this transient recovery. It’s making sure that the things like the kick drum, snare drum, and those hits aren’t being completely destroyed by the limiter.
[mastering with Ozone 5 limiter transient recovery]
To my ears 75 sounded just about right for this transient recovery — everything still sounded natural and I made sure my drums were still punchy. Last thing to add in here is a stereo link to make sure that my stereo field doesn’t get thrown off by using the limiter where one side gets compressed independent of the other one.
As I’ve shown you in other videos, you can do things like automate some of these parameters to make it fit better with the different parts of the song. So that your RMS level is still somewhere hovering around -10 to -8 and that’s right the level you want to watch for your track to be comparable to other songs you might here on the radio. That’s all there really is to using the maximizer, at least the limiter section of the maximizer. In my next video I’m gonna move on to dithering. I’ll discuss how you can use it to prepare your mix for 16-bit for CD masters.