Mixing in 4-D

Earlier today our youth group 'took over' the main services at our church. The change in band, music styles and presentation was quite a departure from our regular worship service. It was awesome to see our next generation of worship leaders on stage. For some, I have no doubt it was too much of a change and they're probably looking forward to a return to our regular service. Hopefully, most will have been able to worship despite the different style of music.

There are many different styles of worship music. Some I like more than others, but I certainly respect any music that is well written, performed and produced. A good mix can make simple music beautiful. A good mix can clean up little irregularities and tighten up average playing. Unfortunately, it cannot make up for plain bad playing.

Many years ago, I learned the concept of mixing in 3-D and it has governed all of my mixes and engineering. Mixing in 3-D is mixing tall, deep and wide. I've added one more dimension to what I originally learned and that is called mixing true. That gives you mixing in 4-D; tall, deep, wide and true. Let's look at each dimension.

The first dimension is tall. If we look at the sound a musical instrument makes, there will be fundamental frequencies and overtones. These will fall somewhere in the frequency spectrum. 0hz - 20khz is what we will consider tall. Each instrument, or voice, will occupy space in this frequency spectrum. If many instruments, or voices, occupy the same sonic height the sound can be muddy or indistinct. That is, unless they're very well in time with each other and on pitch. In an amateur performance this can be difficult to achieve however. The mix can be cleaned up by cutting certain frequencies from the individual instruments. The difficult task is to determine which frequencies to cut. Experience and knowledge of instruments and their frequency range is of major significance here.

The second dimension is deep. We can create space by making instruments seem closer or further away. Each instrument will maintain its own distance from the listener. Effects are commonly employed here, particularly reverb and delay. A dry instrument will seem nearer. Adding reverb to an instrument and sending more effected signal through the mains will make the instrument seem further away. That is very much a simplification of the process. Effected signals are also commonly EQ'ed to further enhance the effect.

The third dimension is wide. Width is the distance between FOH speakers or the apparent stereo spread between two sound sources. One of the major challenges occurs when one speaker is significantly louder our closer to the listener. In this situation, a mono mix becomes more appropriate. Panning instruments left and right will give them their own sonic space between the speakers. Instruments like bass or the kick drum and snare are generally left in the middle of the stereo spectrum with other instruments panned right or left to various degrees.

So far, we've learned about tall, deep and wide. Instruments can occupy their own space with the frequency spectrum, depth of effects and stereo spread. Overlapping instruments can build a stronger mix as long as they compliment each other.

The last dimension I added isn't really a dimension. I call it true. The short explanation to true is that after making any of the above changes, the instruments still sound like what they are. By that, I mean the guitar still sounds like the guitar onstage, the vocalist still sounds like a vocalist and so on. It is important to avoid being excessive in cutting frequencies from an instrument. If it becomes necessary to heavily EQ a sound source, we may need to look at the sound source and change micing. That will have to wait for another discussion.

There's over 20 years of mixing in a nutshell. The concept in itself is very simple. It still takes time and practice to put these concepts into practice. It can help to try visualizing the mix in three dimensions. See what instruments overlap or hang out in their own space. Listen to your favorite recordings and try to visualize the mixes. Learn what you like!