Mastering Your Recordings:
With a focus on using IK Multimedia’s new T-RackS 3 Mastering Suite
Demystify the basics of mastering and learn how to make your band or choral concert recording sound better than ever. IK Multimedia’s Product Manager Dan Boatman walks us through the mastering process with a true-to-life Jazz Band example provided by Stanley Middle School in Lafayette, CA. But don’t worry, even if you don’t have T-RackS, you’ll find this article extremely valuable and informative. Send in your concert recording and you could be featured next!
Mastering is the final recording step of preparing your recordings for inclusion on a CD or conversion to MP3. With the explosion of student and school recordings, it’s important to include the mastering step in your recording process, since it adds a professional sheen to recordings and helps fix any issues coming from poorer quality recordings or entry-level equipment.
Since mastering is often seen as a difficult or mysterious process, Academic Superstore has asked me to write a series of articles exploring this subject in depth. In this instance, we’ll be mastering a live recording performed by the Stanley Middle School Jazz Messengers and recorded by their band director, Bob Athayde.
For this example, I’ll be using IK Multimedia’s new T-RackS 3 Mastering Suite. Because this is a live recording, I’ll be doing this round in the T-RackS stand-alone application, but in future columns we can explore using T-RackS as a plug-in for your favorite recording software. So if you like this article, send in those multi-tracks and you can be featured in an upcoming column!
T-RackS 3 is a powerful application that lets me open up the .wav file for this song, process the audio, monitor the results and create a new processed file very easily. Right now, I’ll stick to the basics of mastering and just make a few improvements.
First, I’ll load the song into T-RackS. If you want to follow along, you can download a 10-day trial of T-RackS 3 here. Install it, open it up, and hit the ”Load“ button to load the song below – you’ll see the shape of the wavefile appear in the T-RackS window. Take a quick listen to the song before we start.
You’ll see that the main window has the track section at the bottom and a metering section above that. Right now our ”gear“ section is blank, since I haven’t loaded any tools.
T-RackS is especially useful because it loads software recreations of some of the best classic analog mastering gear. This means we get the sound of using expensive, high-end units without the price – perfect for students and music programs on a budget.
If I hit play, the metering section will engage and give me some useful information about the song:
Peak is the maximum instantaneous volume of the song. This is usually created by loud, short sounds like snare hits or brass staccato notes. Monitoring this is essential to making sure your recordings don’t distort, which sounds ugly and harsh. (Digital distortion isn’t the same as the relatively pleasant sounding distortion that comes from guitar amps. If we want to add that to our mix, there’s a dedicated ”tube distortion“ model we can load.)
RMS is a more averaged sense of the overall volume in the track. Since T-RackS can process multiple tracks at once, you might want to make sure all the tracks on your album have a uniform RMS level, which makes burning CDs a lot easier.
Perceived Loudness is exactly what it sounds like – how loud the track will ”sound“ to your ears. Because your ears hear certain octaves louder than others, this is essential for processing multiple audio files with different arrangements. Bass-heavy songs won’t sound as loud as songs where most of the instruments are in the middle octaves.
Phase lets us make sure we have a nice, balanced stereo image. If the mics on this recording were poorly placed, we’d need to do some fixing to avoid having one speaker play louder than the other.
The Spectrum Analyzer gives us more information about the balance of instruments in the track. If the bass or kick drums were recorded poorly, this will alert us to where improvements might be needed.
Step 1: Compression
Compression is a technique for processing audio. Put simply, a compressor looks at an audio signal and if it gets above a certain loudness level, it turns that signal down. This is useful for evening out songs with very loud and soft sections, which helps playback on less-than-hifi sound systems (like car stereos and iPods).
Compression is also useful at faster speeds for changing the character of certain sounds. Since this track uses a lot of horns, we can actually bring out the attack of the horns using a compressor. To do this, I’ll load a compressor into one of the slots on T-RackS virtual gear rack:
This loads the compressor view, so I can make some adjustments:
Brass instruments usually have a sharp attack followed by a smoother sustain, so if the compressor is set to a medium ”attack time“ (i.e., how quickly the compressor turns the volume down after it goes above our threshold) the horns’ attack will slip through and the compressor will turn the volume down on the rest of the sound. That means I can turn the overall volume up, and give the impression that the attack of the horns is punchier and more upfront.
The main controls on a compressor are:
Threshold: After the volume exceeds this level, the compressor engages. This particular compressor doesn’t use a ”threshold“ setting – it has an input gain switch that raises or lowers the song’s volume going into the compressor, but it achieves the same function.
Attack time: How fast the compressor turns the volume down after it goes above our threshold. We’re slowing the compressor down in this example to let the attacks of the horns and drums come through uncompressed. When we raise the volume of the song, these details will appear more prominently.
Release time: How soon the compressor stops compressing after the volume drops back down.
Ratio: For every unit of volume (commonly called decibels, or dBs) that exceeds our threshold, how many dBs does the compressor turn the volume down? Lighter compression (say 2:1 or 3:1) has a subtle smoothing effect on the overall volume. Higher ratios have a more dramatic impact on the sound.
Make-up gain: Since the compressor is lowering the highest levels of the song, we can boost the overall volume back up post-compression to bring out some of the subtle elements of the song, like in this example.
Audio Example 1: Uncompressed and
Step 2: Equalization
Equalization (or EQ) is the process of boosting or cutting certain frequencies. This can be used to bring out individual instruments in a song, or shape the overall tonal balance to match a certain style. In this example, since this is a live recording and we donít have the luxury of having each instrument recorded separately, EQ is our best bet for boosting certain instruments in the mix.
I’ll bring up an EQ after our compressor. This is important, since boosting frequencies can impact the overall volume of our song and change how the compressor behaves. In the future, we can explore doing things the other way for some creative results, but right now we’ll stick to the basics.
Note: You’ll notice I pulled up our EQ in slot 6 above. If you want to see your entire signal chain in a single view, you can always click the ”Show Chain“ button in the top right to see where all your modules are located.
The first 4 slots are routed in parallel – meaning the signal is split in two – so you can process the signal two different ways and blend them back together. This is an advanced technique and it can achieve some very powerful results. Anyway, back to our EQ!
This is a 6-band EQ. That means we can boost or cut up to 6 different frequencies for some powerful tone shaping. Also, it’s ”parametric,“ which means we can choose the frequencies we want to work with. The other major type of EQ is a ”graphic“ EQ – the kind you probably have on your stereo at home, where the frequencies available to you are fixed.
The controls on this EQ are:
Gain: How much the selected frequency is being boosted or cut.
Frequency: Which octaves are being affected by the boost/cut.
Q: This is basically how wide a range of frequencies are being affected. A wide Q affects a wide range of frequencies, and is useful for broad, tone-shaping EQ. A narrow EQ affects just a specific frequency, and is most commonly used for singling out a specific instrument or getting rid of hissing, noise, or other unwanted effects.
Because this is a live recording, I didn’t get too deep into changing the overall frequency balance of this recording. I added a slight boost to the bass octaves to bring out the bass drum and bass. I used a wide Q, since the bass is playing over a wider range of notes, but kept things centered around the bass drum’s note. At times, I felt the cymbals were a bit hissy, so I applied a more surgical cut to one of the higher frequencies to tame that. I used a much narrower Q so my cut wouldn’t affect the sound of the horns or the overall song that much.
If you’re wondering how I knew which frequencies to affect, I let my ears be the guide. I dialed up a pretty large boost, and then used the ”frequency“ knob to sweep up and down until I heard it hit the sweet spot. Then I backed off the boost to leave it a more subtle effect. This is a great way to learn how to process audio, since it’s easier to hear exactly which frequencies are being affected with a big boost or cut. Then, you can back off to get just the effect you’re looking for.
Audio Example 2: No EQ and
Step 3: Process
There’s plenty more to play with in T-RackS 3, but even just applying compression and EQ can create major improvement in your recordings. Let’s process this file and compare it to the song we started with.
Hopefully, you can hear the increased detail, clarity, and better instrument balance as a result of these quick changes – no matter what tools you have available, these techniques will serve you well!
We stuck to a few simple tricks to use with any recording or mastering application to improve your recordings. In the future, we can delve into more advanced tricks, or using these tools inside your favorite multi-track recording application on individual instruments. Later, we’ll cover some of the unique features only available in the new T-RackS 3.
Got comments or suggestions? Want to send us your band’s recording to be featured in a future mastering session? Email me at email@example.com any time. Until next time!