Mastering with Ozone™ Tools, tips and techniques © 2003 iZotope, Inc. All rights reserved. iZotope and Ozone are either registered trademarks or trademarks of iZotope, Inc. in the United States and/or other countries. Other product or company names mentioned herein may be the trademarks of their respective owners.
INTRODUCTION........................................................................................................ 4 What’s Wrong With My Song? .................................................................................. 4 Intended Audience For This Guide ............................................................................ 4 WHAT IS MASTERING? .............................................................................................. 6 The “Commercial Sound” ..............................
Dynamics Meters ................................................................................................. 46 Overall Compression Strategy................................................................................ 49 Bringing Limiting and Expansion into the Mix ........................................................... 49 Limiter ............................................................................................................... 50 Compressor .........................................
INTRODUCTION You’ve just finished recording what you think is a pretty good song in your project studio. The playing is good, the recording is clean and the mix is decent. So you burn it to a CD and proudly pop it in your CD player. But when you hear it played after a “commercial” CD, you realize that something is wrong. What’s Wrong With My Song? • It’s not loud enough. It sounds wimpy next to other CDs. Turning it up or mixing down at a higher level doesn’t solve the problem.
want to give something back in return (in addition to iZotope Vinyl2). This guide can be freely copied or distributed for noncommercial purposes for that reason. • If you don’t understand mastering but do have Ozone, you’re in luck. Ozone gives you the tool to get “that sound” and this guide shows you how to do it. • If you have Ozone and know the basics of mastering, this guide will still show you tricks or techniques that are possible in Ozone.
WHAT IS MASTERING? Although there are many definitions of what “mastering” is, for the purpose of this guide we refer to “mastering” as the process of taking a mix and preparing it for manufacturing. In general, this involves the following steps and goals. The “Commercial Sound” The goal of this step is to take a good mix (usually in the form of a stereo file) and put the final touches on it. This can involve adjusting levels and in general “sweetening” the mix.
WHAT IS OZONE? A Mastering System Technically, Ozone is a plug-in, although it really encompasses several modules to provide a complete system for mastering (or technically “pre-mastering” as it addresses the processing but not the CD layout, file conversion, etc.) In addition to providing audio processing, it provides meters, tools for taking snapshots of mixes, comparing settings, and rearranging the order of the mastering modules within the system.
driving, you spend a lot of time looking at the speedometer. Over time, you develop an instinct and need the meters less. But from time to time, we’ve all looked down and thought “hmmm, I had no idea I was driving that fast”. Whether using Ozone or not, whether you’re just starting with mastering or have been doing it for years, you can always benefit from the second opinion that a good set of visual displays can provide. UI Efficiency A mastering session can be long and tiring.
GETTING SETUP FOR MASTERING Software and Sound Card To master on a PC you need some type of editing software and a sound card. There are plenty of reviews and articles on software and sound cards, so we defer to other sources for you to make your choice. One important point is that when mastering you’re really just focused on improving a mixed down stereo file. Applications such as Wavelab, Sound Forge, and Adobe Audition (Cool Edit) are designed specifically for working with stereo files.
We don’t think there’s any single “correct” order for effects when mastering. In Ozone, the default order of the mastering modules (the path the signal follows through Ozone) is: 1) Paragraphic Equalizer 2) Mastering Reverb 3) Multiband Dynamics 4) Multiband Harmonic Exciter 5) Multiband Stereo Imaging 6) Loudness Maximizer 7) Dither This order can be changed. In fact, you should experiment with different orders.
your listening. For studio monitors, the most common problem is lack of bass, specifically below 40 Hz or so. These monitors just don’t have the size or mass to move that much air at that low a frequency. One solution is to complement a pair of studio monitors with a subwoofer. If so, make sure you adjust the subwoofer so that it doesn’t exaggerate the bass. How do you do this? If you have a mic that’s flat down to 20 Hz, here’s a quick and dirty way to do it.
2) The bass will typically be under-represented on small studio monitors. 3) Monitors are very focused in terms of their soundfield, and the imaging is typically more pronounced than on other systems. Headphones Heaphones are another option for monitoring. There are entire sites and forums dedicated to headphones (such as http://headroom.headphone.com) so again we’ll leave our hardware recommendations out of it and just advise you to ask around on forums.
SEVEN SUGGESTIONS WHILE MASTERING Before you jump into a marathon mastering session, here are seven things that are good to remind yourself of periodically. 1) Have someone else master your mixes for you. OK, in most project studios we realize that the same person is often the performer, producer, mixer, and mastering engineer. At least get someone else to listen with you. Or find someone who will master your mixes if you master theirs. You’re too close to your own music.
EQ A reasonable starting point when mastering is equalization. While most people understand how equalizers work and what they can do, it’s not always easy to balance a mix with one. What’s the Goal of EQ when Mastering? When we’re trying to get our mixes to sound good, what we’re shooting for is a “tonal balance”. Any instrument specific equalization has hopefully been done during arranging and mixdown, so we’re just trying to shape the overall sound into something that sounds natural.
Each band of parametric equalization typically has three controls: Frequency The center frequency dictates where the center of the band is placed. Q and/or Bandwidth Q represents the width of the band, or what range of frequencies will be affected by the band. A band with a high Q will affect a narrow band of frequencies, where a band with a low Q will affect a broad range of frequencies. A Narrow Filter (Q=12 ) A Broad Filter (Q=0.
EQ Shapes Any of the eight filters in Ozone can be configured to be a bell (also referred to as a peak filter), lowpass, highpass, lowshelf or highshelf. You can specify the shape of a filter by clicking on the “Show Info” button and selecting a different shape for the filter from the table. Bell Filter As shown below, a bell filter has a width (Q) as well as a gain. The gain can be positive or negative – to boost or cut the specified range of frequencies within the bell.
Lowshelf and Highshelf filters Like lowpass/highpass filters, these filters also are “one sided”. Shelf filters, however, don’t drop off indefinitely. Instead, they resemble, well, a shelf, as you can see below. In this case, the horizontal handles provide a slope control which specifies how tall the shelf should be – or how much cut should be applied before leveling off to a constant (horizontal) line.
cursor over a value and change it by turning the wheel of a wheel mouse. You can also disable bands with this table by clicking on the square box to the left of a band. 7) You can select the shape of a filter by holding down the Ctrl key and right clicking on the EQ filter. This will cycle it through the lowpass, highpass, bell, lowshelf, highshelf shape options. Ozone™ Mastering Guide Page 18 of 66 ©2003 iZotope, Inc.
EQ the Midrange So you’re ready to EQ. Now what? Listen and try to identify any problems that you hear. Start with the midrange (vocals, guitar, midrange keyboard, etc.) as this will typically represent the heart and soul of the song. Does it sound too “muddy”? Too nasal? Too harsh? Compare it to another mix, perhaps a commercial CD. Try to describe to yourself what the difference is between the two mixes around the midrange.
EQ the Bass In comparing your mix to commercial mixes at this stage, you’re probably tempted to boost the bass using the equalizer. Resist the temptation. Don’t worry, your mix will get that low end punch, but we’ll do it using a multiband compressor. A reasonable use of EQ in the low end is to apply a shelf or highpass filter below 30-40 Hz. Purists might find this alarming, as yes, we can hear down to 20 Hz and some musical information can be lost.
EQ the Highs Finally, take a listen to the higher end frequencies in your mix. - Don’t be surprised if when comparing your mix to commercial CDs yours sounds a little dull or muffled. You could compensate for this with some high frequency EQ, with a low Q (wide bandwidth) band around 12-15 kHz. Alternatively, you could skip the EQ and add some sparkle and shine using a multiband harmonic exciter. - Be careful boosting around 6000-8000 Hz.
EQ’ing with Visual Feedback The key to setting the tonal balance of a mix with an EQ is developing an ear for what frequencies correspond to what you’re hearing. The most appropriate visual aid in this case is a spectrum analyzer. The spectrum analyzer from Ozone is shown below, although others provide similar views and options. The green line represents the spectrum or FFT, calculated in real time, ranging from 20 Hz to 20 kHz, the range of human hearing.
A 1/3 octave display splits the spectrum into bars with a width of 1/3 of an octave as shown below. Although the spectrum is split into discrete bands, this option can provide excellent resolution at lower frequencies. The critical bands option splits the spectrum into bands that correspond to how we hear, or more specifically how we differentiate between sounds of different frequencies. Each band represents sounds that are considered "similar" in frequency. A critical band representation is shown below.
Bonus Tip: You can turn off the spectrum display from the Ozone main options dialog to conserve CPU or to minimize visual distraction. Snapshots Spectrum snapshots are powerful tools for comparing the tonal balance of your mix to other songs. In Ozone, these snapshots can be accessed by clicking on the Snapshots button. You have access to eight Snapshots, marked with the buttons labeled A through H. Clicking on a button takes a snapshot of the spectrum at that instant in time.
Bonus Tip: Ozone uses several "digital" algorithms - such as the digital EQ and digital multiband crossovers - that result in a delay of the signal. That is, Ozone needs some time to "work on" the audio before it can send it back to the host application. That time represents a delay when listening or mixing down. Fortunately, many applications provide "delay compensation" - a means for Ozone to tell the application it has delayed the signal, and the host application should "undo" the delay on the track.
What this does is puts the spectrum in an infinite averaging mode. Instead of displaying the real-time spectrum, it will calculate and display an overall average spectrum for your mix. While this isn't technically necessary for using the Matching EQ, you most likely want to match the overall spectrum of a mix, as opposed to an instantaneous spectrum. 3) Click OK to close the Spectrum Options. 4) Open the Snapshot window by clicking on the Snapshot button as shown below. 5) Start playing your file.
10) Open the Snapshots windows again. Play your Target file, increase the Matching amount slider, and your Target file will be EQ'd to match the Source. As you increase the Matching amount, you'll notice a red EQ curve appearing. Most likely, the more you increase the Matching amount the more "jagged" this Matching EQ curve will become, with increasing peaks and valleys.
General EQ Tips 1) Try cutting bands instead of boosting them. 2) Cutting or boosting more than 5 dB means you probably have a problem that you can’t fix from the stereo master. Go back to the multitrack mixing step. 3) Use as few bands as possible 4) Use gentle slopes (wide bandwidth, low Q). 5) Shelve or highpass filter below 30 Hz to get rid of low frequency rumble and noise. 6) Try using bass dynamics (i.e.
MASTERING REVERB What’s the Goal of Reverb when Mastering? If you’ve done a good job with reverb on the individual tracks and as a result have a cohesive sense of space, you probably won’t need to add any additional reverb to the final mix. In some cases, however, a little mastering reverb can add an overall finish to the sound. For example: 1) A recording made “live” in an acoustic space might have troublesome decays or room modes.
The Ozone mastering reverb was also designed to provide you the controls you need, and just the controls you need, for optimizing your mixes. There are no gate, reverse or other “special effect” reverb controls that might be great for individual tracks, but not for overall mixes. Think of it almost as a “coating” reverb for track reverb.
overall mix will blend things together better. In general, if we’re going to apply mastering reverb we usually end up with Wet around 5.0 to 15.0 (and Dry at 100.0) • Another interesting effect to play around with is to use a small room size, anywhere from 0.1 to 0.3, and turn up the wet slider a little more to 20 or 30. In some cases this can create a fuller sound by adding a short reverb or doubling to the mix. It can also make some mixes sound terrible.
modules, but instead control the rolloff of the reverb signal in this module. You can drag the lines to the left or right to change the bandwidth of the reverberated signal that is returned and mixed back into your mix. The area between the lines will be the reverb signal that you hear. Note: As you drag the handles, wait a second to let the filters fully affect the signal. The reverb in Ozone uses analog modeled cutoff filters that have a time constant.
• If you’re applying a wide reverb (room width up between 2.0 to 3.0) keep an eye on the phase meters, and use the Channel Ops (especially the mono switch) to check to make sure it doesn’t completely fall apart in mono. Bonus Tip: If you wrap old tennis balls in aluminum foil and bake them slightly in the oven, you can sometimes get some bounce back into them. Just checking to see if you’re still paying attention. Ozone™ Mastering Guide Page 33 of 66 ©2003 iZotope, Inc.
MULTIBAND EFFECTS A standard compressor or stereo widener can be a useful tool for processing your mix. The possibilities become even more interesting when you’re working with multiband effects. With multiband effects, you can apply processing to individual bands or frequency regions of the mix. This means that you can choose to compress just the dynamics of the bass region of a mix, or just widen the stereo image of the midrange.
represent the crossover points of the multiband effects. You can adjust the band cutoffs by clicking and dragging them with a mouse. You can also use the arrow keys after selecting a band cutoff, which is indicated by the horizontal arrows pointing to the band. Setting Multiband Cutoffs So where do you set the bands? In general, you want to try to split your mix so that each region captures a prominent section of your mix.
To select the crossover type, right click on the mini-spectrum and select the “Crossover Options” menu item as shown below. Once selected, the Crossover Options screen appears. Here you can specify whether to use analog or digital filter models for the crossovers. Note that if you use digital crossover, you can also specify the slope or “Q” of the crossovers. Which should you use? As always, it’s a matter of taste.
MULTIBAND HARMONIC EXCITER Let’s start with a Multiband Harmonic Exciter as our first venture in Ozone multiband processing. It’s an easy effect to hear, and is very powerful when used as a multiband effect. Before we get started with the Multiband Harmonic Exciter in Ozone, though, here’s a little background on the principle of exciters. An exciter is typically used to add a sparkle or presence to a mix.
more harmonic excitation in the higher band relative to Band 3. Use this to your advantage when adding excitation: Higher bands can usually bear higher amounts of excitation. In most cases, the Mix slider can be left at 100. This represents the level of the saturated signal that’s being mixed back into the original signal (sort of a Dry/Wet mix control for the tube saturation/excitation).
MULTIBAND STEREO IMAGING Throughout the development of Ozone, we spent countless hours downloading independent (typically “un-mastered”) songs from mp3.com and analyzing them. There are some really well mastered material songs there, but there are also a lot of songs that could use a little Ozone. In particular, we found that the stereo imaging was a common problem on these independent projects. Granted, stereo imaging is a tough task.
Using Multiband Stereo Widening in Ozone This module is almost as simple to use as the Multiband Harmonic Exciter. Each band has its own widening control. As you increase the fader, the widening is increased for that band. A value of 0 means that no widening is applied to the band. Positive values represent widening, while negative values represent “negative widening” or summation of the channels to bring them towards the center. As you widen the channels, keep an eye on the meters to the right.
correlation as well as the most common regions. Note that you can reset the region drawn by the “phase needle” by clicking on the meter. In general, most recordings have phase correlations in the 0 to +1 region. A brief readout towards the left side is not necessarily a problem, but could represent a possible mono compatibility issue. You can perform a quick check of mono and phase compatibility by clicking on the Channel Ops box.
• If you want to turn off the peak hold display you can turn it off in the Options Screen. Multiband Stereo Delay We saved the most interesting part of the stereo imaging module for last. Ozone offers a stereo delay control that allows you to offset the delay between the left and right channels. At first glance a delay might not sound that exciting, but a multiband delay can provide some very interesting stereo imaging effects.
• Even though multiband widening and multiband delay are completely different effects, the settings of one can affect the other. There are no rules here, just be aware that a different widening setting can change the effect of a delay setting. • Keep checking mono compatibility with the Channel Ops menu. • Ozone supports DirectX automation, which allows you to change values of controls over the course of a mix. One popular trick is to automate the widening of a mix – i.e.
MULTIBAND DYNAMICS Mastering the dynamics of a mix using compressors, limiters, expanders and gates is probably themost challenging step of the process, but the one that can make the most difference between a “basement tape” and a commercial sounding mix. Taking the time to master (no pun intended) multiband dynamics can be well worth the effort. There are a few things that make mastering dynamics challenging: 1) The effect is subtle, at least if done correctly.
In the screenshot above, the compressor is set with a Threshold of –25.2 dB, meaning that when the signal exceeds –25.2 dB the compressor will start compressing. The red line points to this point on the compression curve. The Ratio is set to 3.0, meaning 3:1. The grey curved line points to the segment of the compression curve affected by the ratio. Everything above the Threshold point is sloped a little less, specifically with a slope of 3:1.
Dynamics Meters Most hardware compressors indicate compression with a reading in dB of how much the signal is being turned down by the compressor. For example, in the previous picture we know that the signal is being compressed (turned down) 8.9 dB by the compression. How do we know that? From the thin blue line that’s displayed between the compression curve and level histogram. As the signal is compressed (i.e.
In the picture below, though, the signal has crossed the threshold and is being compressed. Simple enough, right? We promised that you could make your mix louder with compressors. At first glance, a compressor by itself is turning down the level by compressing peaks. But the side benefit is that you can turn up the signal as a whole without overloading, since the peaks have been brought down in level.
The final two settings related to a simple compressor are the Attack and Release controls. You can adjust these by clicking on the “Attack/Release Show” button. This brings up a panel of attack and release controls. Going back to our mixing engineer analogy, these relate to how long the engineer waits (the Attack) to turn down the volume after it exceeds the Threshold, and how long to wait (the Release time) before turning it back up after it drops back below the Threshold.
What’s important is that you understand the release time concept. Too fast a release time will cause either distortion or a “pumping” sound since the compressor is letting go and letting the output signal return to normal too quickly. A slower release time will let the level gradually return to its normal unprocessed value.
In the picture above, you can see that instead of having just one point or “knee” for the compressor, we now have three knees or points where the compression graph changes slope (indicating a different compression ratio). Limiter Starting with the top, there is a limiter. In the simplest sense, this is simply another compressor. You can use it to set the compression ratio for the upper level of the mix, which will typically have a higher ratio of compression than the middle levels.
2) You can use an expander as a noise gate, where any signals that are below the Threshold are effectively turned down completely. Back to our engineer analogy, the expander tells the engineer “when the level is BELOW the Threshold, turn it DOWN as indicated by the Ratio. As a gate, use a high Ratio (8 to 10 or so) and set the Threshold down at the point of the noise floor. 3) If necessary, you can use the expander as an “uncompressor” to expand an overly compressed signal.
So now you have control over multiband dynamics processing. Click on a band, and you can set the limiter/compressor/expander differently for each band. If you’ve followed the previous sections, what might have seemed like a lot of controls before is now just a set of controls for each of four bands. You have four bands of frequencies (low, low-mid, mid-high, and high) and a limiter/compressor/expander for each band. Bonus Tip: You can copy and paste settings across bands.
For this application, you can think of a mulitband compressor as an EQ that understands dynamics. With a ratio of 1 for the expander/compressor/limiter, you can just turn the gain of a band up and down and it behaves like an EQ. As you add compression (adjusting ratios and thresholds) it will still boost (or cut) the gain of the band, but only when the level exceeds certain ranges. For bass boost, you’re obviously going to be focused on the lowest band, Band 1.
Vocal Treatment A multiband compressor is great for controlling unwanted noises in vocals, including pops, “sss” sounds, etc. • The low band (120 Hz and below) can be used to limit and compress “pops” and related sounds. Use a relatively fast attack to capture the transient “pop”. • For controlling “sss” sounds (as a de-esser) start with the mid-high band (Band 3) ranging from 3 kHZ to 10 kHz and a ratio of anywhere from 5 to 8.
Note that too high a threshold can cause gating of the quiet sections of music. While it takes no time at all to get a rough setting, it can require some adjustment to balance between gating the noise and gating the music. Don’t become so obsessed with cutting out the noise that the mix just sounds sterile.9 Bonus Tip: In addition to individual band gain, you can set a global gain "post dynamics" to apply a uniform make-up gain to all bands of the dynamics module.
LOUDNESS MAXIMIZER One of the most common complaints from “project studio artists” is that their mixes don’t sound loud enough. You burn a CD of your mix, put in your CD changer, and it just can’t compete in rotation with the commercial CDs you have. You turn it up, and it just overloads. What’s going on here? The secret is a loudness maximizer.
Using the Ozone Loudness Maximizer Using the Loudness Maximizer in Ozone is very simple. It operates on the entire spectrum (that is, it’s not a multiband module) and has three sliders, one mode selector and one option. Threshold The threshold sets the level at which limiting begins. As you move the Threshold slider down, you are limiting more of the mix, as represented by the white bars on the level histogram. The appropriate range for the Threshold depends on the levels of your mix.
analog limiter effect, so the choice is related more to the behavior of the limiter and the output level than a choice in sound quality. Intelligent: This algorithm provides intelligent digital loudness maximization of the signal. Unlike the analog modeled limiters (Soft or Brickwall), the Intelligent processor is designed for neutral or transparent limiting.
General Loudness Maximizer Tips • Use the Intelligent mode for transparent limiting, the Brickwall mode for analog limiting with a fixed threshold and the Soft limiter for gentle analog boosts of loudness. • Do not set the Margin above –0.3 dB. Technically, you can set the Margin to 0 dB so that the output of Ozone is maximized to the point of clipping, but any subsequent processing or editing of your mix could push it over the edge. Leave yourself a little room.
GENERAL OZONE TOOLS We’ve touched on these during the course of explaining different modules and effects, but here is a summary of the tools available to you in Ozone, in addition to the mastering effects themselves. Automation You can automate more than 140 parameters in Ozone using host apps that support DirectX automation such as Sonic Foundry Acid 4 and Cakewalk Sonar 1 and 2.
3 Automation Tricks: 1) Try using automation on stereo widening. Widen a chorus and tighten a verse for starters. 2) Try changing compression ratios between choruses (hard/high ratio) and verses (soft/low ratio) 3) Try increasing the exciter amount on light/quiet parts. Back off on the amount during louder/fuller parts. History List As you tweak controls, each movement is captured and displayed in the History list.
There are also times when you want to compare whether to use (for example) the harmonic exciter or a high frequency EQ band to bring out the upper end of the mix. Try one way, then try another way, and click back and forth on the History list to compare. If you want, you can assign a specific point to the A, B, C or D buttons for even quicker comparisons. The History list and any settings assigned to the A, B, C or D buttons will be cleared when you unload Ozone.
The multiband block actually represents three multiband modules: Multiband Harmonic Exciter, Stereo Imaging, and Dynamics. For convenience, you can reorder the position of the multiband modules in the signal chain using the single block labeled "MULTIBAND". If you want to reorder the three modules within the multiband module, select the multiband block and click the "Zoom In" button. This provides a view of the modules within the multiband block so that you can reorder the individual multiband modules.
• Selectively load settings from individual effects modules. For example, take the EQ settings from one preset and combine them with the dynamics settings of another preset. • Add comments to presets for easy reference.
• You can Undo or Redo your last change using Ctrl+Z and Ctrl+Y. Meters • You can zoom in and out on level meters and level histograms by holding down the Ctrl key and clicking with the right mouse button to zoom in or the left mouse button to zoom out. • You can reset the peaks or averaging of the spectrum by clicking on the spectrum. • You can reset the peak indication of the level meters by clicking on the meter, or reset the clipping indicator by clicking on the clipping indicator.
SUMMARY We hope that this guide gave you some ideas on how to use Ozone effectively as a mastering tool. The difficult part of mastering (and trying to create a guide like this) is that every effect, setting, and parameter is entirely dependent on the content of the mix, the genre, the desired result, etc. With this in mind, we don’t believe in products that fool you into thinking you can just select the “Hot Pop Master!” preset and you’re done.
