PCRECORDING.COM - - Mixdown Suggestions.
The art of the audio mixdown has been a subject of numerous articles and discussions on a variety of web forums. So why write another article? Well, a few basic principles should apply to most, if not all, situations in this process. The important point is that it is a process with a capital P. A process that is unique to each individual user and setup. There is no "best" way to do a particular thing. I will cover a few helpful points in this article.
First a big caveat. When you originally record a track, do your best to get it right. Get a good strong level, at the right tone, in a quiet environment. Never assume you can "fix it in the mix." This is not true and if anyone tells you they can and you believe them, you have been had. Your sound will only be as good as your weakest link. Of course, stuff happens that you will have to deal with in a mix. You may run out of time pursuing that perfect track. Just do the best you can every time and you will save yourself grief later.
Now, another big caveat. I suggest that you do not mix on the same day you do the recording. Recording is hard enough and you will likely be tired and your ears dull. Give it a rest. Mixing is hard enough as it is.
Know your system:
First of all, you must know your system and how it interacts/affects sound. Everything that touches your sound affects your sound in some way. By system I mean:
Your PC CPU/Harddrive speed and configuration will have an effect on how quickly you can make adjustments to a mix. Latency, particularly on slower PCs can present significant challenges to mixing. For instance, at high latency, a PC may not react quickly enough to your mix change adjustments. Latencies of seconds are not unheard of in slower systems. Of course, ideally you will optimize your system to lower latency as much as possible. (For more on this see, optimization tips). In addition, some software packages are making great gains in latency reductions. However, in a slow system, even optimization will not be enough. Therefore, you will need to study and memorize your song so that you can anticipate when you will need to initiate the change relative to when the system will actually implement it. (It is kind of like leading a receiver when you are throwing a pass - - it is remarkable how accurately you can anticipate how far in advance to implement the throw/change).
Ultimately, you may need to sub-mix particular tracks to lessen the load on your PC and then mix the resultant sub-mixes with other sub-mixes to end up with a final mix. It is an imperfect solution but may be the only option. The crux of the matter here is to know what your system can and cannot do. Naturally, if you are running a Pentium III 850mHz chip with an Ultra-Wide SCSI drive and 256 meg of RAM, latency will not be as much of a problem. Nevertheless, the principle remains the same. You need to figure in the ability of the hardware in your assessment of how to go about mixing your music.
Know your software. Know how to optimize its performance via the buffer settings, coupled with optimization of the OS. Secondly, if you intend to mix via software, learn its mixing environment so that it becomes intuitive. Nothing slows you down more than frantically moving the mouse around to make an adjustment - - learn if there are any keyboard shortcuts you can use or create for your needs. Many software packages have automation features as well that allow you to process aspects of a mix, putting the changes into memory for later playback. This can be very handy, particularly for simpler parts of your mix. This allows you to concentrate on more detailed portions of your mix as required. In addition, employ whatever features your software has such as fade in/out, crossfading tracks, etc. Similarly, if you are using an external mixer, learn it too. You will still need to deal with your system latency issues but the physical interface of an external mixer is easier to use. That is, unless you are mixing to tape, ADAT or such. Then, latency with an external mixer is not a problem.
It is very important to understand the effect the software has on your sound. Different multi-track software packages may sound different on a given file. More importantly, understand the sonic effect of the effects you apply. For instance, a reverb may have a tail that leaves high tones lingering longer than you would like. The tendency might be to cut high frequencies via EQ when the better thing might be to change the reverb. Remember, it is all a process, everything that touches the sound affects the sound.
Know the sonic characteristics of your soundcard and its latency response. Optimize it accordingly. Many soundcards come with software patch routers/mixers that may assist you in routing signals separate from the multitrack software. This could prove to be useful in given instances. Additionally, a particular card may amplify certain frequencies that you will need to adjust for during mixdown. Understanding your soundcard capabilities and sonic characteristics is critical before you begin to mixdown. For instance, some cards may be able to cleanly drive a -1dB signal whereas others may clip at -2dB. You need to know this stuff. As to latency response, not all card drivers are made the same. Some will suffer from greater latency than others.
Understanding your recording room acoustics in critically important. I briefly covered this subject in my acoustics page. Essentially, depending on the dimensions of your room, what is in it and what the walls are made of, your sound will vary. Whether you will have "standing" waves or "early reflections" will depend in large part on the dimensions of your room and whether you have acoustically treated it. Acoustical characteristics can be largely anticipated with a little mathematical analysis of your room. Understanding where you are likely to have a problem can lead to effective elimination through acoustical treatment and/or accommodation in your mix settings to counteract the "perception" your room gives you when you mixdown. For more, please read the article on acoustics and refer to the related links.
Perhaps the single most important element in a mixdown setup is the monitors. Monitors come in a different shapes, sizes and sounds. Monitors are not designed to make all music sound good. The best monitors are brutishly honest, giving accurate representation of how the music sounds - - good or bad. However, not all monitors sound alike. Understanding the sonic characteristics of the monitors - - whether it be near-field, mid-field or regular stereo speakers will be critical to making an accurate, universally good-sounding mix. Study the specifications from the factory and in reviews you may have read. Trust no one completely though. In a word, you must test, test and then test some more to get a good feeling to where your monitors are strong and weak. The best way is to take a reference CD, whose sound you admire or wish to emulate, and listen to it on a pair of known acoustically accurate monitors. If you have know someone at a professional studio with a pair professional studio monitors, use them to test the sound of your reference CD. It is worth a beer/latte to have a chance to listen. Keeping in mind the sound you hear at the studio, compare it to your monitors. Then, adjust accordingly. For instance, if you know your monitors tends to amplify high frequencies you may need to adjust those frequencies during mixdown to accommodate - - otherwise they will be over represented in your final mix.
Understand the difference between near-field and mid-field monitors. Typically, near-field monitors are intended to be used at a distance of about three feet or so. The monitors should be positioned in an equilateral triangle relative to the listening position you will be in. Ideally, the monitors tweeters will be at ear level. The reason near-field monitors work is that it lessens the acoustic effect of reverberations and echoes from your studio environment. Essentially, given the short distance you are from the speaker, the sound emanating from them will be less affected by reflections from your recording room, giving a more accurate, pure representation of your recording. Keep in mind, the fact that you are three feet from your monitor will not eliminate the effect of your recording room on your "perception" of the sound. Certain frequencies, based on the particular configuration of your room will still have an effect on you. For instance, even with near-field monitors, any early reflection that returns to your ear within about 20 milliseconds cannot be distinguished from the sound coming from the speaker. This may result in you perceiving an increased level of that frequency for which you adjust incorrectly.
Mid-field monitors should be similarly setup in an equilateral triangle at a distance between 5-6 feet with the tweeters at ear level. Given that the distance is greater, room acoustics may have a more significant effect on your perception of the sound. However, you will also have a better perception of stereo separation.
Ultimately, understanding the sonic contour of your monitors (based on your own tests) and how to adjust for them is critically important. Anticipating frequency response, peaks and valleys will go along way towards a fine sounding final product. For instance, many near-field monitors do not go down to 40-60 kHz, leading you to boost the bass signal too much. If you know this, you can adjust to it. In essence, having imperfect monitors is not fatal to achieving a good mix. Not understanding and adjusting for your monitors and equipment limitations will likely be fatal.
Next we will cover some suggested techniques you may wish to try. Keep in mind, this is not intended to be an end-all how-to list. Use your own valuable experience to judge whether this will work for you. Use your ears to assess whether a particular technique works for you and your setup. A few caveats, be aware of the limitation of your ears. Ears get tired like any other organ when they are overused. In addition, the ear can be overloaded by too much stimulus, such as listening to music at high volume over a period of time - - your ears lose their ability to discern fine volume differences. Moreover, the ears are connected to your brain which can overlook certain things because it is concentrating on another thing. By this I mean, you are trying to find that errant little "sniff" and miss the engineer's cough in the background.
Divide and conquer:
Divide up the mixdown into discrete elements. Do not try to do all things all at once. Listen to your mix from a variety of different physical and mental positions.
A. After making general settings, I like to listen to the song at normal volume through my monitors and compare it first to the mental image I have of how it should sound. I try to determine if it matches the soundscape I hear in my head. I make note of whether the levels and tonality of tracks match my general expectations. I take notes of where I sense a discrepancy for future reference. Note taking is critically important. The devil in mixing is always in the details.
B. For my style of recording, 8-10 tracks is usually sufficient. The following may be too cumbersome if you use 30-40 tracks so take it for what it is worth. What I like to do is highlight/solo each track I am concerned about by boosting its volume relative to the others. I still want to hear the other tracks for reference but definitely highlight the volume of the featured track. I then listen to it all the way through to see if I detect any sloppy errors within the track itself and relative to the other tracks. What I look for are note timing errors, background sounds, squeaking chairs, sniffs, excess finger/string noise, or my children. I do this for every track. In addition, I can get a sense of where each track sits in the whole sonic picture this way. I suggest you do this with both your monitors and headphones. Each will give you a different perspective on the sound. However, for me the key is highlighting the particular track. If in doing this you find errors it is better to deal with them individually now by either editing it out or rerecording it.
C. After eliminating the mistakes above, return the tracks to relatively equal playback levels. Make sure your track levels match in volume and tone. Try it at different overall volume levels. Keep in mind that the ear loses bass signal when the volume goes down. (Remember that "loudness" button on your home system? This is why those buttons are there). You can then make EQ adjustments as needed. Try to provide "space" for each instrument by adjusting EQ levels and cutoff frequencies, etc. as needed. Effective employment of stereo separation can similarly give space to sound.
D. One major mistake many make is to mix by addition rather than subtraction. That is, if you cannot hear one track well enough you turn it up. In addition, the level changes are oftentimes in increments that are too large. Take it easy, make small changes. Try bringing down some levels rather than just boosting them. Even changes as small as .1dB are significant and can be easily discerned.
E. After having gone through the above steps, you can now get ready for final mixing at full mix volume. Studies have shown that the human ear has flatter response at higher volumes. However, at too high volumes your ear will not be able to discern discrete volumes changes between tracks as well. In addition, your ears will tire quickly. Make sure your signal is balanced between the high, mid, and low frequencies. Listen to your piece numerous times trying to isolate different aspects of the tune. Just be sure to be aware that your ears will get tired and your perception to detail will get dull. Give yourself a rest, walk away from it for a time and then return. Try to do one thing at a time but do not forget to consider the whole project. Each time you return take a fresh different approach, you may find that you missed something before. Keep in mind that what you do first to a certain extent "conditions" what you do second. So, start from different points each time you return.
F. After you are satisfied with your studio mix, burn it to a CD. Play it on several different sets, including your car. You will find that it works better on some systems than others and may require additional adjustments. That about covers it for this segment. Good luck.