Continued from The Basics of Mixing (Part 2)

Special Effects/Spot Effects
Special Effects and Spot Effects are like the engineer’s solo in the song. These are the parts that the band may not have been able to do without the help of the engineer. The trick here is to use the effect sparingly and tastefully. Again just because you can do it does not mean that it supports and enhances the song. As the engineer you can take pride in adding these effects, but you also must listen to the band if they do not think that it matches their artistic vision. This is job security territory so that is about all you’re going to get out of me, but keep a copy of all the work you do and experiment when you have time on a slow an rainy day.

Finishing Touches
The finishing touches include any last minute edits or mix tweaks. Remember to apply a dither if you are bouncing down for CD (you did track at 44.1kHz or 48kHz with a 24 bit bit-depth right, there is no good reason not too anymore). Dither is one of the hardest things to describe, everyone understands that it makes a 24bit file 16bits but what does it really do? The best analogy that I’ve heard is this: Imagine a painting in the distance, you are viewing the painting through a window that you are holding. The window isn’t quite big enough to allow you to see the whole picture at once, but if you move it slightly in any direction you can see that edge of the picture. Now imagine that you could shake that picture very fast, like inhumanly fast. If you shook the window frame fast enough you would no longer see the frame and you would be able to see the whole picture (like looking through a fan). This basically what dither does to sound, but most of us can see a loss or resolution when looking through a fan, and some of us can hear the loss of resolution due to dither. Dither does effect the resolution of the sound so it’s a good idea to apply master fades after dithering the mix. I don’t think we will use dither too long as the only drawbacks of publishing audio as 24bit files is slightly more storage space and the fact that most hardware does not yet accept it, but things will change, the always do.


If you are going to have you track mastered don’t dither anything, just bounce files that are the same data type as the rest of your session. A mastering engineer (especially one that masters digitally) can do a lot more with a 24bit file than a 16bit file because there is more head-room. Chances are the mastering engineer will have a nicer dither algorithm as well. Another note when prepping for a mastering engineer. Leave them some headroom to work with, this will let him or her do what they are best at, instead of trying to apply work-arounds to a mix that has no head-room left. Usually 2-3dB is a nice amount for them to work with. The higher the quality of file you can bring them the better, I’ve even heard of people brining the computer and interface they recorded with and bounced the mix directly into the mastering engineers hardware. (check to see if your mastering house offers this and if the charge more/less for that kind of thing)

Test Monitoring
This possibly should have gone before for the later step, but many find that this is where the mix is really completed. When you have bounce your mix be sure and demo it on as may practical sources as possible. Play it in your car, on you iPod in headphones, on your home stereo, on a boombox, through your cheesy computer speakers (or nice ones if you have them). Make sure that your mix has consistency from player to player and adjust accordingly. One of the olds sayings is that if you can get a mix sounding good on a pair of Yamaha NS-10s (studio monitors that are very unforgiving) then your mix will sound good anywhere. If you get a chance listen to some of your favorite CDs thourgh NS-10s you’ll be surprised at how hard they are to please (or get anything pleasing out of). That’s it easy as pie right. Good luck and have fun.

Continued from The Basics of (Mixing Part 1)

EQ
EQ is arguably the most important part of the mix. It is the practical and mathematical part of mixing. I helps me to try an visualize the frequency spectrum and come up with a general plan of where I want each track/instrument to sit. This is always a trade off with making things fit together and making each instrument sound good by itself. For example, acoustic guitars will often sound unnaturally boomy without cutting some frequencies out around 200 Hz, this also makes some room for the bass guitar and sometimes the toms of the drum kit. This is a balancing act that is a whole new monster with each mix so all of the above are very loose guidelines. The purpose and goals of the EQ stage are three fold: to establish a good balance, to enhance the frequencies that you like in each track, and take away the ones that detract from the sound, and to eliminate any masking of one instrument over another. Here is a post dedicated to EQ.

Compression (dynamics)
Compression also has multiple uses in the mixing environment, it has uses as a tool, and also as an effect. Compression is often used as a tool to control the dynamic content of a track. In this scenario I am usually trying to control stray loud or soft content and regulate them so that they are approximately the same volume as the other surrounding content. Note that not every track will require compression, if the performance is consistent (which is more often than not the case with well practiced musicians) then compression may not be needed in this capacity. As a general rule if it doesn’t need compression then don’t apply any, at least not locally. On a side note I often will mix with subtle compression on the mix bus at all times, I find that I require less compression on each individual track and gain some consistency between all the tracks. (Maybe there is some truth to the statement that the SSL quad compressor is like mix glue)

Compression can also be used as an effect, but I find when used this way it is best used in a send/return format. (This is often referred to as parallel compression) I will often send the close mics of my drum kit to a bus where I will compress the heck out of them, with not too fast of an attack, because the purpose of this compression is to make the drums punchier I want to keep the transients. This sound on it’s own is not that great to listen to on it’s own, but bring it up slowly in the mix and blend it with the original close mics for a punchier and edgier sound. I also have a post that explores compression in more detail.

Panning
Now that I have most of the frequency and dynamic content spaced out and balanced I find I need to add some width to the recording. I will apply panning to the tracks at this point usually starting with the drum kit. Panning the toms can make the kit sound bigger/wider, but I usually don’t pan them hard left and right as that can be a little distracting on tom rolls. If you used spaced pair overheads or as room mics on the kit I would pan them according to the same principals. As a general rule I will pan instruments with similar frequency content to either side such as an electric guitar slightly left, and acoustic guitar slightly right. If you’ve seen the band play live visualize where each player stood as this can be a natural panning image to try and recreate. The human ear loses the ability to place sounds below a certain frequency and above another so panning will become ineffective. The effective frequency range for panning is between (150Hz and 1.5kHz). For content above 2.5kHz, if you have a stereo signal to begin with, differences in EQ between each channel that will create phase effects that will place sounds off center in the stereo image. For content below 150Hz, if you have a stereo signal to begin with, you can use the Haas panner (precedence) effect by delaying one of the signal by a very small amount (0.2-0.44 msec). Once your stereo image is in place, the practical side of mixing is essentially complete and the more artistic and creative part is applied. These are the techniques that will make your mixes unique and stand out.

Send Effects (Reverbs and Delays)
The use of effects is very much up to personal taste or the taste of the band that you are mixing for. This part of the mix should be very much inspired, one of the signature sounds of an amateur mix is the misuse or overuse of effects. Remember your job as the mix engineer is not to define the sound of the band, but to support and enhance the music that the band has produced. It is OK to take some ownership of the music, but ultimately it is the bands/clients music. Even if you are mixing your own bands music it helps to treat the mix process this way. This stage of the mix is where you will define yourself as an engineer, so I cannot tell you exactly what to do, just offer some tips and guidelines. Reverb and delay can be used effectively to ad depth to a mix. Listen to the drum kit with your eyes closed as you add a big long reverb as you increase the reverb the kit should start to sound like it is farther away. You can use this principal on all of the tracks to give the mix depth. You probably also noticed with the drum kit that as you increased the reverb the cymbals became really splashy and wishy-washy. Often it helps to EQ and filter the signal that you send to the reverb. I typically will band pass filter my reverb and delay sends because to much top gets splashy and too much bottom gets muddy. Many of the new convolution reverb plug-ins give you tremendous control over the reverb tail and decay times this is where you should reach if you want to make your reverb sound more natural or more out of this world. I tend to like plate reverbs and short reverbs for vocals as you the can add a reverb effect to the voice with out moving it from front and center. Slapback reverbs can be nice to really get a crackin’ snare. Really though all of these things depend on the style of music, and the sound that the band is going for. For more on finishing up a mix please see The Basics of Mixing (Part 3).

There are no hard and fast rules when it comes to mixing or any part of the music production chain for that matter. Everything mentioned in this series is meant to be a guideline or a suggestion, and absolutely not the only way to do things. This is will series will follow the basic flow that I go through when a dig in to mix a track. It is also worth pointing out that what I consider mixing is the process of blending the sounds that are to be used in the song together, therefore I typically will have all tracks recorded, all overdubs and BV’s tracked, and all editing done. It doesn’t always work out like this, but I find that if I can take care of as many of those things as possible before I sit down to mix the whole process of mixing is more streamlined and inspired. I will also assume that this mixing session is to be conducted in the box on a computer as this will apply to most people reading this post. (There are some significant differences when mixing on an analog console from a media such as tape.)

Gain structure
The first thing that I do when mixing is set up the gain structure. In the digital world ideally this would have been taken into consideration when tracking. When tracking digitally and mixing in the box there is a significant chunk of the typical signal flow missing from the signal chain. It is the preamp from the tape machine back into the mixing desk. This is not available when mixing in the box. You are very much at the mercy of you record levels. Getting good signal to noise ratios is important (both in the digital and analog realms), but when mixing digitally you don’t want to record too hot either. Firstly, because digital clipping sounds awful, and secondly, you don’t have that extra preamp when setting the gain structure. When tracking digitally I try to get the sustained levels of each track to be around -3dB. This will give me (and eventually the mastering engineer) a little more head-room to work with. Notice I said each track it is always tempting to mix a little bit with the record levels when tracking, but would suggest trying to level the playing (volume) field for all tracks when tracking.

I know I said you don’t start mixing until everything else is done, but good and consistent record levels really are the first step of mixing, you need a foundation on which to build. Setting a gain structure was typically done with the missing preamp in the digital audio chain, which is why I mentioned getting good record levels. Try and get all the tracks to equal volume (this most likely will not sound good). The reason I stressed record levels is because normalize and gain plug-ins are the bullies of digital audio (especially the ones that re-render wave files) an have a very high potential of mangling your pristinely recorded tracks. If you didn’t record at all equal volume I would suggest using the next step to make up any gain on any track that you are missing.

Filtering
The next step when setting up a mix is filtering. During this process I toggle solo on the tracks often so becoming familiar with this function would be a good idea. I work my way through the tracks filtering out the top and bottom of each track so that it contains only the sounds that I want from the track. For instance an electric guitar an amp rarely produce any musical content below 80 Hz so I will set a high pass filter around 80 Hz on all the guitar tracks. People often ask “how come I can’t get my track as loud as all the others out there, even when I limit and compress the hell out of it.” Often times they have not taken the time to take out the noise that resides at the top end and bottom end of every track. We can’t even hear this noise sometimes, but electronically or digitally it is eating up our head-room, so take the time to knock it out, you’ll thank yourself when you enter the “loudness wars.” Another thing to think about when doing this is exactly what sound am I trying to get out of this track. For example often time the drum kit comes in on several tracks and suppose there is a close mic on the hi-hat as well as a mic on the snare and some overhead and or room mics. That hi-hat track can often be pared way down in the frequency spectrum as you will be able to collect the missing parts of the signal from the rest of the mics. Another rule of thumb, if you can’t figure out what sound you are trying to get out of a track, don’t use it, it is just eating up space in your mix.

Signal Routing
Once I have the gain structure and filtering under control I move on the signal routing. In Pro Tools I will set up all the sends for my send effects, I will set up my virtual stereo master bus, and any other sends or auxiliaries that I plan to use. I will set up a big or long reverb send, a medium one, and a short one as well as a plate (four different sends). I will also setup at least a couple of delays: one short and one long, and any other time based effects like chorus or flanging effects with their own send. This may look like you are adding a lot of tracks, but by setting them up as sends you can share the effect across many of your recorded tracks, which will actually save you computer power in the long run. I also often like to parallel compress the close mics of the drum kit so I will setup a send for them as well. Remember that sends can be taken pre fader or post fader. A pre-fader will send the signal straight from the recorded signal with no effects applied, a post fader send will send the signal after it has been processed by any effects in the channel.

At this point I am ready to set up my basic mix, I will pass through the faders and get a good balance between the tracks making sure to leave about 5 dB or head-room for when I return my send signals back to the master stereo bus and to leave some room for the mastering engineer to work with. (Continued in The Basic Mixing (Part 2))

Sequencing is the process of programming a performance into a computer program to allow the computer to play the performance back to you. In this way a single individual can make music by programming the computer to play multiple performances simultaneously. Today this is typically done through a protocol called MIDI (Musical Instrument Digital Interface). MIDI is most commonly displayed in a Piano Roll format that shows when notes (Events) occur vertically, and time horizontally. Sometimes this information is also displayed in a list, but most musicians find the Piano Roll more comfortable, there are even some people that the “Piano Roll” display may replace traditional music notation. There are three basic ways to accomplish sequencing.

The first is to record a real-time performance from a MIDI controller. MIDI controllers are most commonly keyboards, but there are many new interfaces such as guitars and flutes. These controllers send performance data (not actual sound) to the computer or sound card, which the computer then records and stores against time. Essentially the computer is able to replicate the performance, giving the composer the ability to tweak and adjust the sound(s) associated with the performance. This is often the most efficient way to input a sequence.

The second way to accomplish sequencing is by manually placing notes on the timeline. Most software packages offer the ability to manually enter notes (and other performance data) directly on the time-line, this is usually using a “Pencil” tool. In this way a composer can write music that he/she may not have been able to perform otherwise. This procedure does not require a MIDI interface and is available to most composers out of the box with their recording application.

The final way of accomplishing sequencing is through a process often referred to “Step Input.” Step Input involves entering the performance using a MIDI controller, but not in real-time. The composer is able to enter notes one at a time and often use auxiliary buttons or keys on the controller to advance through the time line. As an example if the composer wanted to enter a C major triad, he/she could press the C key, then the E key then the G key, and then press the button to advance to the next time slot. Often other auxiliary buttons are also available to change note durations. This method takes some time to get used to, but down the road can be an efficient way to input a sequence.

MIDI offers much more data than just note placement and duration. MIDI data can be assigned to control virtually any parameter of a sound, but some of the most common are the Velocity, Sustain, and Pan. Velocity is a measurement of how hard a note is struck and can have a large effect on the timbre of the sound. Think about how different a guitar sting sounds when picked softly or very hard, there are differences in the sound other than just the volume, velocity tries to emulate these performance differences. All of this data is then fed to a sound generator.

The sound generator (typically a virtual instrument, sampler, or synthesizer) interprets this data and creates an audio signal. One of the advantages of capturing a performance via midi rather than acoustically is that you can apply that performance to any sound generator you would like to. In this way a keyboard performance can sound like drums, or guitar, or french horn.

The major drawback of MIDI is that it rarely can sound as authentic as a real acoustic performance. This is due to the fact that rich sample libraries cost a lot to produce, and can take an infinite amount of space depending on how accurate you would like to make them. MIDI also suffers from some latency and a limit to how much data can be transferred in “Real time.” MIDI data is transmitted serially (one 0 or 1 at a time), the transmit speed is only, 31.25 Kilobits per second (over a traditional MIDI 5 pin connection). This is fast enough for us not to hear the small amount of time that resides between the sounding of each note in a chord, but if several performances are being transmitted to several sound generators via the same MIDI connection some of these timing issues become recognizable to human perception.

That’s the basics, and the major advantage and disadvantage of MIDI and sequencing. For detail on how to implement MIDI in your home studio refer to your owners manuals for your gear.

Equalization (EQ) is one of the fundamental steps in mixing audio. Wether it’s a live performance, a music record, or sound for film, EQ is used to along side volume or gain to create balance in your mix. It helps me to visualize the frequency spectrum of human hearing in my head when I begin to plan a mix. EQ is the main tool that I have to set certain instruments in particular frequency ranges. If we tried to push all the elements or instruments in a mix at all the same frequencies there would be not definition, and all the instruments would sound mushed up together. The first sign of a good mix is always the balance. It doesn’t matter how many cool effects are in a mix, or how much genius automation, if the balance is off it will never reach it’s full potential. So how does one achieve a good balance? Read on my friend.

Like I mentioned earlier I try and visualize the frequency spectrum in my head and then make a plan as far as which instruments I will place where. The first step when applying EQ is filtering. The recording process is not perfect, and I can’t see how it will ever be, plus I’m a subscriber to the theory that when one is tracking one should capture the whole sound (i.e. I don’t EQ signals when actually recording them to tape or disk) Filtering is the process of eliminating all the parts of a signal that you know you don’t want, and or won’t use.

EQ Video

I will typically roll off the bottom end of almost all the tracks (possibly not the Kick drum or Bass guitar… possibly). For instance the electric guitar (especially through and amp) rarely outputs anything useful below 80 Hz. Rumble and other non-audible frequencies like to hang out down there as well so it’s good to deep six those before they start taking up your precious headroom. As a general rule you can pass though each of your tracks with an EQ plug-in or use a desk/console if you have one, and roll off the low frequencies until you can hear it effecting the sound of the instrument and then back it off a little. This will do wonders for your headroom and tighten up your mix. On some tracks I will apply the flip-side of this tactic and roll off the top end, but one must be more careful with this. A lot of times it’s hard to tell when to stop rolling of the top and it’s easy to end up with a very flat sounding mix.

Next I will start to place certain instruments in certain frequency ranges. The video in this post goes over this as well. The electric guitar often encroaches on the frequencies that I plan on using for the bass guitar so I will cut some of those frequencies out of the electric guitar signal (typically somewhere around 200-300 Hz). The definition of an electric guitar, and most instruments for that matter, usually happen in the 2.5 kHz to 7 kHz range. This is also known as the presence range and these are the frequencies that humans hear “best.” That makes this band of frequencies very important, because not every thing can be there at the same time. Spend your time experimenting with you balance here in these frequencies. I tend to boost electric guitars on the low end of the presence range and save the bulk of it for the vocals. I also boost the electric guitars up around 7 kHz to let them sparkle and sizzle a little.

That’s the gist of it! The important thing is to be conscious of where in the frequency spectrum each element of the mix is going to live, and then of course getting good levels. Listening to a mix at very low volumes can often tell you what is hot in the mix and what is being drowned out and masked, I do this often when getting a balance.