Mixing in the Virtual Realm of the Sequencer
How to Set up your Software Mixer for Optimal Music Production
by Rich the Tweak
It was a cold night in my alley shack TweakLab in 1988. I had my brand new KM802 8 channel mixer and I could finally connect my 4 little synths and sampler to my 4 track cassette recorder. I read an article about virtual mixing and the author said something like "in the future, when we want more mixing channels we will simply click the mouse to make more. Everyone will have a 100 channel mixing console in the virtual realm with unlimited effects if they want one". I looked at the new 802, then peered into the Atari monitor. ""In there?" No way.
Behringer
MX2004A Eurorack Mixer 8 mono channels/4 stereo channels (all with faders), 3-band EQ (fully swept mid) on mic channels, and 4-band EQ (fixed) on stereo channels. 2 aux sends/2 stereo returns, 2+2 bus output. Tweak: This mixer has the ALT 3/4 bus you need to patch into audio interfaces. The price does not get better.
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Way. Many of us are going fully virtual. Or at least adding software synths and samplers, plugins and mastering processors to our hardware rigs. The question is: How to we mix all these different sources into one two track stereo wave file? Those who have worked with hardware mixers and consoles are realizing the software mixer inside of the sequencer application is a totally different beast and runs by different rules. I'm going to shorten your learning curve and pass on to you some techniques and setup options I've learned using sequencers. Then we'll boil things down to a few principles to observe when setting up a software mix that will save you time and give you the best possible audio result. I'll also show you how to set up your rig for the new generation of control surfaces, like Logic Control and Houston.
There are two different ways to set up your sequencer's mixer. The first way is for people that use an analog mixer as the "main" mixer to blend the different parts. I will call this the analog mix. The second way is for those who want to use the software mixer or control surface as the main way to blend everything. That will be called the digital mix. At the heart of both approaches is the audio interface (sound card). What is different in both these approaches is how the interface is connected to the hardware mixer. The digital approach, though it does not require a hardware mixer, greatly benefits from having one. As I have mentioned in other articles you can do it with just a preamp and a line in jack on the soundcard. But this article will assume you have both, and you should. After all, this is the advanced class I am talking to. It's the ideal way to go.
Time out: YOU! Are you lost already? (The Tweak scans the classroom and picks out someone with their tweak-hand twittering) "Aha, a newbie in here. Sorry, you need to go to the Newbie class. And the rest of you better not laugh as they leave..." (Many in the room cough hiding their wicked, pompous smiles)
Software to Hardware Mixdown: The Analog Mix
Connections. Connecting the interface to the board. This approach works well if you have a multi-output audio interface, like an 8X8 or 2X8. Basically, you connect each audio out of the interface to its own dedicated mixer channel. So channels 1-8 going Out of the audio interface become channels 1-8 IN to the board. You use the leftover channels for synths, mics, turntables, whatever else you need to connect. If you have a lot of audio hardware, this allows you to use it at the mixing board. If you have a large 16-32 channel board, it makes a lot of sense to do it this way. Even those with a small 8 channel board and a 2x2 interface and a couple of synths might like this method as well.
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| This is the Mackie 1402. Note that the ALT 3/4 bus (the third fader from the far right) is routed to the audio interface. By pressing the ALT 3/4 button above each fader, that channel is routed direct to the audio interface. |
Connecting the board back to the interface. All recording mixers have at least one extra bus, in addition to the L/R bus (the main outs). On small mixers this is called the ALT 3/4 bus. On a 4 bus mixer, it may be called Bus 1/2 and bus 3/4. On an 8 bus mixer you may have 1/2, 3/4, 5/6, 7/8. You don't need to connect all your busses back to the audio interface. Just one will do in all but the more exotic configs.
Role of the software mixer. The software mixer is not the final mixer but a "pre-mixer". That is, it treats the signals with virtual compressors, eq, fx for each internal channel and outgoing bus. This mix will contain 1. all of your audio tracks, 2. all of your soft synth and soft sampler tracks, an optional effects bus. At the hardware mixer, you "fine tune" these busses with another layer of eq (if necessary), and can use sends and returns to add bits of reverb and other effects. The goal here is simply to add polish to tracks that should already be sounding pretty good coming from the software mixer.
In the software mixer you will send different instruments to different busses. For example, you might send all the vocals to bus 1/2. On the software bus, you will probably add reverb, maybe patched after a slight delay. When it arrives at the hardware mixer, you touch up the eq, maybe send just a tad to a hardware reverb on the sends and returns, just for a bit more depth. Continuing on, all the soft synths and sampler might be broken down into those you want dry and those you want effected heavily. In the software mixer, send your dry stuff to bus 3/4. That might include bass, drums. Bus 5/6 might be synths. 7/8 might be wilder effects like stuff heavily laden with plugins. When 7/8 come into the board, you can further ram it down the effects sends to even more FX processing to get some really unearthly sounds. Or if you have a bus leftover, consider dedicating it just to a kick drum. How you divide the pie is up to you. Of course, it depends on the piece.
Level setting in the software mixer. Using this approach, level setting is not critical in the software mixer, you can go with your ears with what sounds good. If you are getting audible distortion, notch stuff down a bit. The Master out of the software mixer can be anywhere, it does not have to be a 0db like it does in the software only mixer config. What you have to do to get the best sounding signal at your hardware board is to solo each channel and adjust the trim so the peak of the audio hits 0db This assures that the board will add minimal distortion in the mix. While you are soloing these channels, listen carefully for distortion coming from the software mixer. A few "overs" on the software mixer are not critical. You can probably get away with 3-4 db before you start hearing distortion. Do this for all the channels. Naturally you reference your hardware synths the same way so they peak at 0db. Then you move the hardware faders till it locks into a great image, or at least close to one. Then comes the back and forth process of subtle tweaks on both the software and hardware mixers as you add the touch of beauty to your creation.
Advantages
- On channels that hold your mics and synths, all you need to do is press the ALT3/4 bus button to pipe the output into the audio interface for recording.
- Your final mix is tweaked at the board, on real knobs and faders, with real eq and effects processors
- Software mix levels are not so critical to get technically correct
- The mix is analog, It can be sweeter, smoother and warmer than a purely digital mix. You can mix to DAT, tape decks, reel to reel.
Disadvantages
- The mix is analog. You left the digital domain on your softsynths and samplers and went out a DAC; now you have to go through another DAC to get it back to digital.
- If you want to go back and remix in a few months you better write down all your board settings. Once you move the faders those "perfect settings" are gone for good!
- You can use a control surface, but it too is a sub mixer and not the final mixer.
Hardware to Software Mixdown: The Digital Mix
Connections.
If you have a hardware mixer, (not required) you may set it up as follows. As before, your ALT 3/4 bus connects to the audio interface or soundcard. Your main outs connect to your monitoring system. We're going to assume this is a 12 track board, for simplicity, but it will also work with massive consoles. Connect the Outs 1-2 of the audio interface to hardware mixer channels 11/12. We are only going to use this bus for monitoring so you can hear what's going on in this all digital, software mix. Put the trims on these last 2 channels at their line level rated setting (-10, usually) Set the faders at 0db and the pans 100% Left and Right. You will never touch these again. Channels 1-10 hold your mics and hardware synths. For each of these channels press down the ALT 3/4 bus button. That's right on ALL of them except ch 11-12 which are the only two channels going to the main mix on the hardware mixer. What this does is it routes all your mics and synths direct to the audio interface where they can be controlled totally by the software mixer, and recorded as audio tracks. If you want to use your outboard effects at this part of the process you can remove them from the returns and patch them into unused channels. (Side Note: If you have a full featured "expensive" hardware mixer, you may be able to route the FX returns to other busses with a switch and get them to the software mixer that way. But on most small mixers, you will have to bring them into unused channels that have the ALT 3/4 switch.) Those of you with 8x8 audio interfaces and 4 or 8 bus hardware mixers will benefit from being able to send different groups to different audio inputs. The person with just a small 2x2 audio interface has no option other than recording all tracks as audio tracks. That is all your synths are going to have be recorded as audio, as well as all your audio tracks. Those with at least 4 audio inputs can use input 1/2 for recording and use input 3/4 as an audio-thru channel. In Logic 5 for example, these are called input objects. What the input object does is allow you to route your midi controlled synths through the audio interface. This allows you to control the volume of these synths directly in the software mixer without having to record them as wave files. You generally raise your alt 3/4 fader on the hardware mixer to maximum and set the levels of the individual hardware channel faders all at 0db.As the audio comes through the interface, you control it with the fader on the input object. One fader for my rack of 10 synths? Are you mad?! Hehe. Right now you are probably scratching your head wondering why the Tweak would say this logic defying rule. Stay with me. Because we are using the software mixer, we are controlling each MIDI track with midi volume and pan controls. Remember, the software controls are the important ones.
OK, time for a question. You, digihead, in the back...
DigiHead: But Tweak! How can you add plugins and effects to all those midi tracks coming in one bus? It'll all sound like mush!
Tweak: Your absolutely right. Gold star for you! You can't. When you want something to be effected by plugins you record it to a seperate audio track and plug away. But some synths have good sounding FX out of the box. You can let these stay analog all the way through till the final bounce.
Role of the software mixer.
Here your hardware mixer is the sub-mixer or pre-mixer. The software mixer is the final mixer everything goes through. All the audio tracks, each with its own plugins, all the midi tracks, controlled with MIDI controllers, all the soft synth/sampler tracks, all the software buses and input objects are all controlled on the computer screen. The final mix will not go to an outboard recorder (well, it can if you want) but will be a "bounce" a rendering to a single stereo wave file. The hardware channel controls just sit there and pass gain, you never need to touch them. You can use your external FX as before on your hardware mixer. As you get close to mix down stage you might want to record several tracks as audio. When you want to record MIDI to audio you simply mute all the midi tracks except the ones you want to record (or use solo in the software mixer). Once you record to audio you can delete or permanently mute the MIDI data. (I put it in a muted folder in logic).
Role of the Control Surface
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| Logic Control has automated motorized faders that are touch sensitive |
The control surface is not a mixer per se. Audio does not go through it. What the control surface is is a midi controller that controls you software mixer perfectly. You can control any MIDI track, audio track, audio instrument track and most plugins with automation you can record in real time, and later edit on the screen. The Control surface matched to a sequencer gives exacting control over all MIDI and audio sources. It is not required to have one doing this software mix configuration, but it is nice. Your control surface firmware interacts with the software so when you move a fader on the surface it moves on the screen and vice versa. Thankfully, there are only 2 cables to patch this up, just MIDI in and Out cables connected to you MIDI interface. The cool thing about control surfaces is they can get deep inside the software mixer easily and you have a real knob and fader to move. Even if it only has 8 fader channels you can control a hundred tracks if you want. There is no pre-level setting here, it's all done in the software mixer, no calibration routine. Inside the host application you will find a set of preferences. That's about it.
Level setting in the software mixer. Now we get to the beef. The tricky part of the all digital mix, that is, How the heck do you set levels without trims and a 0db reference? Because each audio track has plugins and eq, which changes the gain structure of the track, there is no useable reference except one. Rule #1 No audio track should ever exceed 0db. That's right, never. If it does, you need to notch down till it is within the 0db rule. Bbbbuttt..I can here you guys sputtering in disbelief, sometimes the level can barely be heard if the peak is under 0db it sounds WIMPY!... Answer to this madness: That's why you use software compressors, to limit the range of the peak and bring up the overall perceived volume. So. Which tracks do you think should be closest to 0db. You guessed it, the loudest, most important ones. That may include vocals, kick and snare, and bass. The rest need to be down significantly lower. They might be peaking at -10 for rhythm guitar, -15 for pads, -20 for background pads and this is after compression, eq, and plugin channel FX. Essentially, you set your loudest tracks first, then you bring up the rest till they sound right. Do NOT automate yet, we save that for near the end. Rule #2: Do automation as late in the game as you can, after you have all the levels and all the plugins tweaked to your satisfaction. You will save lots of time this way as you will only have to automate once.
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| Note the "healthy" level on this vocal bus which combines about 7 vocal tracks from my song "Spice". Even with plugins the meters never go over. Because I compressed each of the 7 vocal tracks I could get a uniformly hi consistent level. If I wanted, I could stick a limiter in the chain and make this bus even louder and it still would not go over. |
Groups and Busses. In a software mixer like Logic has, you have the option of using as many busses as one could conceivably want. If you have an 8 output audio interface, here's some cool things you can do with busses. If you haven't used your external FX boxes on the hardware mixer yet, you can connect them direct to the audio interface out 3/4 or 5/6 or 7/8. You can use the software bus and assign to it the audio interface out. Route what you want, take a send off the vocals and run it out through the bus, through out 7/8 to your lovely Lexicon prized reverb and bring it back in audio input 5/6 which you can assign to another input object. No Lexicon? Ok use the Nanoverb! You might be surprised, even the lowly NanoNano sounds "right up there" with some software reverbs. And the absolute cool, to die for, thing about this approach is that the sends to the Nano are all fully automatable as are the returns coming in the input object. So, go crazy, slap a stutter LFO plugin on your nanoverb when it's distorting like a buzz saw in a closet--oh wild and wicked tweaks are possible and they don't ruin the mix, or stick some old analog delay in sample loop mode with the significant other screaming "take out the trash, dear, take out the trash dear" and just fade it in/out when you are really bored.
Uh, class, that was a joke. (muffled mirthless laughter)
With busses you can also use them as internal groups. Say you have 5 vocal tracks. Instead of routing them all to the master out, you route them to, say, bus 1-2 and route bus 1-2 to the master out. On bus 1-2 you have one fader that controls all the vocals. Use bus 3/4 for all the drums. Use Bus 5/6 for all the soft synths. Use bus 7/8 to go out to analog (and back as I described above). Use bus 9/10 for all you input objects still streaming audio from the hardware mixer. You can put compressors and limiters and effects on any or all of these, and I highly recommend a limiter on each, if your CPU has room. Same rule as before. Nothing goes above 0db Ever! Got that? Never! Not a single peak indicator should flash. As we prepare for the final mix, we do tiny adjustments to these buses, the most critcal adjustments you will make. Here you go back and forth between the plugins and level faders for each bus, getting each exactly right, adjusting the compression and limiting.
Automation. Now is the time, you tweakophiles (smile, sorry had to use that). Do it with the mouse, do it with the control surface, however you do it, you watch the level meter as you go. If you pop in the red, adjust it till it is not in the red. Remember, if this was an analog mix you would be being very careful, right? Be careful here too. Tiny fader movements make a difference. If you must automate your core kick or bass, be very gradual or you will upset the balance you worked to achieve. However, for effects and wild stuff, get as crazy as you want. Make the panner revolve at 78 rpm, just keep the output under...what was that? I can't HEAR YOU (the class chants..."0db, 0db, 0db!!" Tweak: Yes! Rock On!
The Master Output channel. The master output channel sits at 0db and you never touch it, except for fading out at the end of the song. That is it's whole function. It is important to keep it exactly at 0db. Here's why. On your master output channel you want to patch in a limiter. A brickwall limiter like the Waves L1 UltraMaximizer is perfect here. You tell the brickwall limiter where to set the wall. Typically at -.02db. If the limiter is good, no matter what you do the final signal will not exceed minus .02db. Of course if all your tracks are flashing red, it's going to sound like utter garbage, but it will still be within limits. If you plan to master the final wave file later, try to do without the limiter by bypassing it, but use it's level meter so you can see if you are going over 0 db. It is essential that you do not go over 0db no matter what. Your final wave file will be ruined if you do. Now it should make sense why I have said this was a rule from the very beginning. The only way to make sure your overall song has bandwidth to breathe is to make sure no red lights are a flashing. If you did your automation too early, you will probably find you have to go back and lower the volume of ALL your tracks globally. See. You should have waited. Add at least an hour to fix this mistake.
The Final Bounce. Bounce the Master out to wave, or if you want to go to DAT instead, route the master out to s/pdif and connect your DAT to the s/pdif out. Slip into record mode on the DAT, then press bounce. If you want to go straight to Wave, just set the song in the locators, press bounce, type a file name and go to the refrigerator for the beverage of choice. Because you set the levels right, when you come back, you will have a sparkling wave file with the perfect gain optimization, ready for mastering to cd, mp3 or medium of choice.
Advantages
- Using this method, you stayed totally in the digital domain. Your audio tracks are cleaner, your soft synths are the best they can be, and your soft samples are as good as they were in the studio they were originally recorded in.
- You can totally control every element of the mix from your software mixer or control surface.
- You don't really have to have a hardware mixer, but as you see, it helps if you have lots of synths outboard gear.
- Your mix is perfectly repeatable two years later as long as you still have those synths (forever if you recorded all synths as audio)
- The mix is digital. You can do razor sharp effects you would need 10 arms and 100 fingers to do on an analog board. You can do 500 tweaks a stereo minute if you want. irm, just try that with analog.
Disadvantages
- The mix is digital. Sounds are mixed through mathematical processes in the computer. A good analog board might make a warmer mix, though not near as precise.
- It takes longer. You have to be careful about level setting every time you change a track, not just at the beginning when setting trims on the analog mix. If you decide late in the game the bass needs to be louder, you might have to go to all 30 other tracks to notch them down. If you already did you automation you know what that means--going in every track and globally reducing the overall level.
Summing up: Which method to choose?
It depends on the song and where you are at with it. I start all my songs in method No.1. When i am halfway through, I decide if I am going to go to digital or analog mix. I have my board patched so I can change over to either mix style just by pressing the buss buttons. Typically, if I just want to get a song out quick and dirty I will use the analog mix method. If the song is complex, I will go all digital. But it really doesn't matter. Work the way you like to work. A good mixologist will be able to make an analog mix sound as tight and digital as they want, and a good plug-in head can make their all digital mix warm and smooth like a reel to reel. Mixing, particularly digital mixing has a large learning curve. I hope I saved you some time and frustration with the above tips.
Mix On! Into the Wilderness of the Audio Uncharted.
I remain, Rich the Ruling TweakMeister of TweakHeadz Lab
(class dismissed)
copyright 2002 TweakHeadz Lab, all rights reserved. Advance permission granted to link to this article.