Music 265B Week 12 Mixing Part 3
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We’re almost done with the mixing phase. So far, we used various plug-ins to shape the tone & texture of each individual instrument. For the rest of the mixing phase, we will focus on Blending & Balancing our tracks together in context. This can be a vague term with many different meanings, but for now, think of blending & balancing as an attempt to recreate the live performance of a band on stage. We will use the Pan knobs to spread the band around on stage within the left & right spectrum, and the Faders to control how in-your-face or far away the instruments may be. We will first set some general levels, and finally use Automation to program any changes over time.
When a band plays together, everyone is expected to play at a certain volume relative to one another. In general, a soloist or featured instrument may “sit on top of the mix” as the loudest thing in the session, and the other instruments will support that featured player. In other words, those other instruments will be somewhat quieter than the lead. Even those supporting instruments have to follow a certain order within each section. The section leader may be the loudest member within that group, with the other instruments backing that part. For example, the lead guitarist is usually louder than the rhythm guitarist, who might be louder than the bass player. First-chair violin may need to be louder than the second-chair violin, second-chair may need be louder than the viola, who may need to be louder than the cello, etc. The melody and focus of the song may even jump around from one musician to another. On top of all this, the entire band may gradually get louder over time or (Crescendo) or gradually get softer (Diminuendo) together as the song moves from section to the next. If you have ever seen an orchestra play, the Conductor will blend & balance the instruments & sections together by gesturing toward the players: up is louder, down is softer. As the mixer, we blend & balance these tracks the way the live conductor would blend & balance the musicians.
Everything Louder than Everyone Else
At first, you may be tempted to just raise the volume on the tracks that “should be” louder in the mix. We may need to raise the volume at some point, but we will eventually run out of Headroom. The volume may get raised so much that it “crashes” into the ceiling at 0 dB, and causes the track or mix to peak into distortion – we don’t want that to happen. On top of this, the overall volume usually changes from one part of the song to the next. The chorus may be louder and more energetic than the verse. If we boosted all of our levels to the limit during the quieter verse, we have nowhere to go when the chorus needs to get louder. We lose the dynamic contrast in a song when everything is louder than everyone else. The song doesn’t have a chance to “breathe” when the volume stays constant. To save us the headache & ear fatigue from listening to an overdriven track, it is usually better to cut the volume on tracks than it is to boost them. We can set our featured track’s level during the loudest, most energetic part of the song, and then turn all of the other tracks down relative to that level. In other words, instead of making a few tracks louder, try turning the other tracks down first.
Looking Ahead, we have one final phase after we finish mixing: Mastering. We will cover the mastering process in the next lesson, but we want to keep one thing in mind as we finish our mix. Since we will do some additional processing and volume changing during the mastering phase, we want to give ourselves a little bit of Headroom in our mix. This means we don’t want our output volume on our Mix/Master fader to clip into the red past 0 dB on the meter. In fact, we want to leave a few dB gap between the level of our mix & the 0 dB limit.
Remember, the Pan knob controls our track’s relative position within the Stereo Image. Mono tracks have one pan knob, set to the center position by default. This means the track plays at equal strength out of the left & right speakers: it will sound like it is coming from the center area, between the speakers. If we pan a track to the left, it will play louder out of the left speaker, and softer out of the right. If we pan it all the way to one side, it will play at full strength out of that side, and not play out of the other. Stereo tracks have two pan knobs: one panned hard left for the left-field of the track, and the other panned hard right for the right-field.
We recorded our band in odd configurations in order to get better isolation between each group of instruments. More often than not, these aren’t the positions the band would normally use if they were playing onstage at a concert. When we use the pan knobs, we usually try to recreate this “live” performance position. This means our drums, bass, and featured instruments exist near the center of the mix, while our other tracks may be spread around to the left & right. In general, we will pan a stereo configuration, like our drum overheads, to the extreme left & right to accurately reflect our stereo recording.
Let’s focus first on balancing a single instrument on multiple tracks: the drums. In a typical drum recording, we used at least one kick drum track, one snare drum, and a stereo pair of overheads. We may or may not have used additional microphones to capture other parts of the kit, but we can start by focusing on these four channels. In most styles of music, the kick & snare drum are the primary focus of the drum kit, and they’re the heartbeat that drives our rhythm section. With that in mind, the most important thing in our drum tracks is the sound of the kick & snare in the mix, but not necessarily our kick & snare tracks. Listen to the stereo overhead drum microphones. Since they were recorded in a stereo configuration, we should start by Panning these stereo tracks to the hard left & right, respectively. If our microphone placement was correct, we should hear the kick & snare drum in the center of our overhead microphones. So how do the kick & snare sound in the overhead microphones? Are they well balanced, relative to the rest of the drum set, or are they too quiet? Are they missing some of the drum’s characteristic attack sound? If so, we can set the overall level for our overhead tracks (we don’t want them to peak into the red on the meter), and then we can gradually raise the volume on our isolated kick & snare tracks until they’re properly blended in the drum mix. If we used additional microphones on the hi-hats, toms, and cymbals, we should first Pan those other tracks somewhere in the left/right field (ask yourself: where do they sit on the drum set, relative to the kick & snare: to the left or right, and how far away?). Next, gradually blend those other drum tracks underneath the overhead drum tracks. If the mix sounds fine without those additional tracks, we can always Mute them. Then again, if they have something that the overheads lack, like more attack, more low end, and so on, then we can alter the EQ on those tracks to enhance the overheads.
For now, we want to find a nice, overall balance for the drums. These levels may need to change as we add in more instruments. To make our job a little easier, we can route all of our drum tracks to a drum “sub mix” track. To do this, create a Stereo Aux Input track, (remember to give it a name, like “Drums”). Route the Output of all of the drum tracks to an Empty Stereo Bus. Next, assign the Input of our new drum mix track to that same stereo bus, and assign the drum mix track’s Output to the main mix. Now, we can raise or lower the fader on our drum mix track to raise or lower the overall sound of the drums, while maintaining the same balance within the drum set. We can even place plug-ins on this drum mix channel in order to process the sound of the entire drum kit.
Drums will be the most complex multi-tracked instrument to balance, but we can do the same process for other instruments. For our bass & guitars, we may have used a clean direct signal, as well as several microphones on the amplifier. Using the same concept, we can blend our guitar tracks together to complement one another, and we can use the same bus routing trick to send every guitar track to a different guitar sub mix. In that case, create a new stereo aux input track, and follow the same steps: be sure to use a different bus so we don’t mix the drums and other instruments together. Keyboards can receive the same treatment, along with any other individual instrument that we recorded with multiple microphones.
Balancing Within A Section
We may be dealing with families of instruments organized into sections. In a standard jazz big band, there is a Saxophone section with various types of saxophones, a Trumpet section, a Trombone section, and a Rhythm section (piano, bass, drums, guitar, and others). In each of the horn sections, the members play a different part. The section leader (or first-chair) usually plays the melody, or top voice, with the other chairs harmonizing below. Together, they play a chord. To balance within the section, we can place the highest-pitched part on top of the section’s mix, with the other instruments slightly softer in order from the second-highest part to the lowest-pitch. For example, in a typical saxophone section (2 alto saxophones, 2 tenor saxophones, and a baritone saxophone), the lead alto usually has the highest part in the section, followed by the 2nd chair alto sax. Next, the tenor saxophones harmonize below them, with the baritone sax at the bottom of the section. Beyond this, the players are usually physically spread out across the stage, in different chairs. We should use our Pan knobs to emulate this: the lead player (like the lead alto sax) usually sits in the middle (or center) of the section, and the other members are spread out to the left & right. We should also route each section to their own sub mix track, just like we did with the drums.
Section Against Section
Just as each instrument has a part to play in its section’s blend, we need to balance each section against one another to balance our mix. Just as the higher-pitched instruments sat on top of the lower ones in the section’s mix, the violins may sit on top of the lower strings, or the trumpets may play over the trombones. If we used our sub mix track technique, we can simply adjust the volume on each section’s sub mix track. Again, this lets us retain the balance within each section, while raising or lowering the overall section’s level against another section. Going back to our orchestra example, an entire string section may be grouped together on one part of the stage (slightly to the conductor’s left, for example), while the drums & percussion may be spread out across the back row, from left to right. To avoid potential phasing issues, we probably wouldn’t adjust the panning on these sub mix tracks. Instead, we should adjust the pan on our individual tracks instead.
Soloists & Featured Instruments
At some point, someone might take a solo. This might involve the lead guitarist pressing a few effects pedals (completely changing the tone of the instrument), and playing louder than everyone else. If an ensemble player ever jumps out to take a solo, it may be a good idea to put this solo part on its own track, and treat it like a separate instrument in the mix. That way, the solo part can be altered & blended to fit its important role, without altering the rest of the same player’s background parts. Otherwise, we may need to use Automation.
When we first start mixing, we begin by setting a general fader level and pan position for each track. We can move a fader or knob up or down, and that setting will be applied to the entire track. Sometimes, things need to change over time. The music might have a Crescendo or Diminuendo: it might need to get louder or softer over a short period of time. Then again we may just need to boost the volume on one specific note to create a musical Accent. If the musicians didn’t play the part that way, or if we need to exaggerate the change, we can do this with Automation. Automation will allow us record and program position changes in the volume fader, pan knob, mute button, bus sends, and other functions in Pro Tools. For example, if we “ride the fader” as the song plays, Pro Tools can record our movement, and follow those same motions every time through automation. However, as soon as we record any automation data, our track will lock itself to that position until we reprogram it. Because of this, we should try to get our general settings for the entire track “close enough” to what we want before we start writing automation data.
Tracks have several Automation Modes to choose from, available under the AUTO section in the track’s Mix window, or below the track view selector in the Edit window. Read mode will follow the track’s current automation programming. If we haven’t written any yet, every knob & fader can be changed freely at any time. Write mode will record automation data in real time, much like how we recorded audio. Simply set a track’s Automation mode to Write mode, press play, and go through the motions of moving the faders up & down as the song plays. Even if we don’t touch anything while in Write mode, Pro Tools will record the current fader & knob positions. If we go back over a spot while in Write mode, it will erase any previous automation as it records the current positions. If we record in Write mode and then switch back to Read mode, Pro Tools will follow the written automation. Off mode will ignore any automation data: it will follow the current fader & knob positions.
There are two specialized Automation modes that require a control surface in order to work properly, but they are still useful. Touch mode works like Write mode; it will write automation data as long as you are touching the fader. As soon as you let go, it will move back to the previous automation setting. This is useful when you need to manually correct some automation. The last one, Latch mode works like Touch mode, but it will write new automation after you let go of the fader.
If you don’t have access to a control surface, or aren’t comfortable with flying faders, all automation data can be programmed manually with the mouse through each track’s Automation Lanes, available in the Edit window. To see the Automation Lanes, we can either change the track’s Track View Selector from Waveform to Volume (fader), Mute (button), or Pan (knob). Alternatively, we can show these same lanes by clicking on the dropdown arrow in the bottom left corner of the track in the Edit window. If we have Sends enabled on a track, we can automate those as well.
To manually create automation, click on a track and select one of the Automation Lanes: Volume to control the fader, Pan to control the left/right position, and Mute to turn the track on or off in the mix. In any lane, we will see a line drawn across the lane: this Automation Line represents the fader, knob, or mute button’s current position. For volume settings, up is louder, down is softer. For pan settings, up is left, middle is centered, and down is right. Stereo tracks will have two pan automation lanes: one for the left pan knob, one for the right. For mute settings, up is unmuted, down is muted. There is no in-between setting for the mute button.
Let’s look at a simple automation trick: the Studio Fadeout. We use a fadeout when the band didn’t write a proper ending for their song: they repeat the last section over and over again while the volume gradually fades down to nothing. We can create this effect with some simple volume automation. Open up the volume automation lane on either the main mix channel (like the Master Fader). First, set the mix track’s volume fader to its default position: 0 dB (hold down the Option button and Click on the fader to set it to 0). Typically, the Master Fader should always be set to 0. Next, find the place where we want the fadeout to begin, and use the Grabber tool to click on the Automation Line. A Dot will appear, marking an automation point. This dot will lock the channel in place. Next, go to the place where the song should finish fading out (like the end of the recorded audio), and make another dot. Click and Drag this second dot down to the bottom of the lane. If we did everything right, the first dot will remain in place at the 0 dB mark, and the line will slope down to this second dot. From now on, this mix fader will fade out along the line whenever we play this section.
Throughout the song, we may want to raise or lower some of the faders from time to time, in order to create accents, crescendos, and diminuendos. We can automate the fader volume just as we did during the fadeout, but we will use more dots. To create a smooth transition, place two dots before the section that we want to raise or lower, and two dots after. The outer dots will preserve the track’s volume settings before and after the automation. We can raise or lower the two inner dots to change the volume. A steep slope in the automation line will create a more rapid change, while a more gradual slope will take more time.
When we use a special effect like Delay, we might not want to leave it on all of the time. For example, using a regular delay on a singer’s vocal track may cause the lyrics to sound muddled. However, adding an echoing delay effect to the last word or syllable in a phrase might sound tasteful. To do this, we can automate the Mute button on one of our Sends. This method can be a little bit complicated at first.
Let’s assume we have a vocal track outputting to the main mix. We might have a separate Stereo Aux track for reverb, with a Send going from the vocal to the Reverb channel’s input. We can use this same routing process for the delay: Create a Stereo Aux Input track with a delay plug-in on one of the inserts. On the vocal track, we can activate another Send, which is routed to an empty stereo bus. We’ll need to assign that same bus to the Delay track’s input. Next, we should raise the Send Fader on our vocal track until we can hear the delay effect alongside our vocal. Next, we will automate the Mute button on our delay Send. In the Edit window, go to the vocal track and select the delay Send’s Mute automation lane. This time, we should start in the Mute position (bottom of the lane). Since we want to add the delay effect to specific words & syllables, we can use the Smart Tool to highlight the lane around those syllables, and drag the automation up into the Unmute position. Now, the Send will activate at that syllable, and quickly deactivate so no other words make it through to the delay. After this, we can click and drag the dots around to correct any mistakes.
During the mixing phase, we shape the tone and texture of our tracks through Equalization (EQ), and other signal processors. We use the pan knobs and volume faders to replicate the sound & performance of the band onstage. We use automation to create changes over time. Once we have finished mixing our tracks, we prepare our songs for release through the Mastering process: our next lesson.