Hilton Head Audioworks Tech Notes 1, 2, and 3 from the Session Tutorial page.
Tech Note #1
The very early part of the signal chain is the same of course, instruments or voices being picked up by microphones or direct boxes, sent through cables to the microphone preamps in the control room. Mic preamps perform the critical step of raising the level of microphones (which are generally incredibly low) up to something usable that you can actually record. From here on, things are completely different.
In the old days the mixer would be wired up to send and receive signals to the 24 track tape machine, but not these days, oh no! In order to record digitally you have to turn the music into digital data that a computer can store and manipulate. So you need an Analog to Digital Converter (ADC) in order to record the music and you need a Digital to Analog Converter (DAC) if you ever want to ever hear it again. For this function we use the MOTU 24 I/O box which gives us the ability to record 24 analog signals simultaneously…
This unit (combined with MOTUs ‘Cue Mix’ software also gives us a way to split off an 8-channel all-digital headphone mix that you the musician can control right at your performance position!
Tech Note #2
Software mixers and plug-ins are one of the big reasons computer based recording systems are winning favor with artists and producers everywhere.
The software (on screen) mixer itself works pretty much like you would expect a mixer to work, faders change the level of tracks, you have auxilary sends to send sounds to reverbs or other shared effects, and there are insert points for inclusion of signal processing in a specific channel.
The software mixer's automation system is modeled after the finest designs on quarter million dollar hardware consoles, with all the convenience and accurracy of a thoroughly designed interface. In fact, Digital Performer's automation is even more accurate than those other sytems, since it can be as precise as the sampling rate of your project (44.1 thousand times a second or better). Also you can graphically edit your automation moves, which is both more precise and is very economical on data. In the example below the inital few lines of the vocal were sung very softly, but suddenly got much louder. So we use the volume graph version of the automation to raise the level of the track to compensate.
This automation is so accurate (beyond a thousandth of a second) you can deal with individual syllables of words, or breaths, attacks of instrumental parts, whatever, there are no limits.
The other main great thing about the software mixer is it is created to match the needs of your project. If you have a 3 track project, you get a 3 channel mixer. Got a 45 track monster project? You get a monster 45 channel mixer! All of the main resources in the mixer (number of inserts, number of aux sends) are dynamically assignable, that is if you need more than the 4 aux sends the mixer starts with, just create another one. Need a 6th insert point? Add it!!! Amazing...
Insert points are at the very beginning of the signal chain in the mixer channel.Here you insert plug-ins to provide processing dedicated to that one mixer channel only. A plug-in is essentially a software version of what used to be a hardware effects unit you had to buy, some of which were really expensive (there used to be a whole bunch of reverbs you could buy in the $5000 and up range!) and you needed more than one (or two or three) of them to be flexible enough to accommodate all situations.
Plug-ins have changed all that now. Because they are just software code, you can use one limiter program in as many channels as you would like. Need a limiter on all 24 channels? No problem, just drop one in there. In the hardware days you would have to have picked the most important 4 channels and limited only those because you only had 4 limiters in your rack! Besides being useful they look cool and are easy to adjust because they have graphic interfaces which pictorially display the effects of the parameters you are adjusting. Here are some examples:
Like everything else in the software mixer, auxilary sends perform the same functions they did on their analog counterparts except you can have as many (or few) sends as the music requires, and are completely automated.
Panning (Left/Right Placement)
Panning is also completely automated on every channel using the same 'line and dots' interface as shown above for track volume. You can do some amazing things with automated panning; can you say "trippy"??? Sure, I knew you could!
In short, virtually all the limitations you had with hardware mixers is now removed, and there is an added extra bonus: since the "effects units" are just software modules now instead of physical units, you no longer have the possibility of those units introducing hum or buzz due to wiring/grounding issues or picking up airborne interference. Reverbs are hiss-less and 100% clean no matter how many you use! It's a beautiful thing!
Tech Note #3
Evaluating Your Mixes in the Real World
Ok, so you’ve done your first batch of final mixes on your project, we’ve put them on a CD for you and you are starting to play them outside the highly controlled listening environment of the studio. Now what? How do you really know that you’ve “nailed it”?
Well the first thing you’re going to notice is that the mixes sound frustratingly different every place you play them. Don’t worry about this, it’s absolutely normal and when you think about it, totally expected. There are literally thousands of kinds and brands of speakers in the world from stupendously horrible to amazingly good, as well as a huge variation in listening environments that your music will be played in so don’t expect your music to sound the same everywhere it gets played.
Here is a plan you can follow that will add some structure to your evaluations and give you some peace of mind that you are making the right decisions regarding remixes.
Choose a Control CD
The first thing you need to do is go through your own personal CD library or Spotify and pick out a CD on a major label, big budget artist that plays in a similar style to your CD. This would be a disc that always sounds great to you, no matter where you play it. A word of caution here: we are talking about sound quality and balance, not musical content, so make your choice of control CD based on those, not how much you like the songs. This CD should be one that if you could say “If my CD sounded that good, I’d be completely happy”
In a controlled environment with reasonably high-quality playback play first your control song for 30 sec or so and then switch as fast as possible to your song. The longer the time that elapses during the switch, the harder it will be to make an effective evaluation. If you can rig it so that you can switch instantly from one to the other, that is a best effort!
Keep switching back and forth listening for key issues. The main things that I listen for are:
- Overall amount of lows and highs on the control CD and my recording
- The relative balance of lows to highs on the control disc and on my disc
- How far above (or below) the music is the lead vocal on the control CD vs. my disc
If these three key issues are ok, you are ready to start playing your CD around in the outside world. If these three issues are not ok, before you panic choose another control CD and do the above three comparisons again. If things are still not ok, then you are probably looking at refining your mixing approach back at the studio. Bring your control CDs to your next mix session and be prepared to tell your engineer what it is that you particularly like about the sound of those recordings.
Ok so your mixes pass the first test: good compatibility with your control CD; now it’s time to play it around. The five main playback environments are:
- Home stereos
- Boom Boxes
- iPods (mp3 players)
- Computer speakers
The frustrating thing is that your mixes will sound different in all of these systems. The trick is to look for a tendency that is consistent across many of the playback environments. For instance if the recording sounds bass-heavy in your car but fine everywhere else, you probably wouldn’t want to change anything because decent quality car systems are bass enhanced on purpose to compensate for the rumble of the road noise while driving.
However, if the lead vocals are too out-front on your home stereo, your iPod and your computer speakers but acceptable on a boom box and in your car, then you might want to think about shading it down a notch. The trick is to have agreement about a mix element in at least 3 of the 5 playback environments to be sure that you need to do something substantial.
You should repeat this process for all songs on the CD until you have mixes of all songs that sound good in a majority of playback environments.
Once you have all your tunes on disc, mixed well, there is still one final step before you’re ready to send it to the duplicator: the overall loudness check. This test should be done in a moving car since the road noise actually helps to reveal problems. The goal is to be able to play your entire CD in a moving car without feeling like you have to reach for the volume knob on certain cuts as they come around. If your CD passes this test, has consistently good bass/midrange/treble balances from song to song and is mixed to your satisfaction, you are done! Congratulations!!!