Recording Part 3
One aspect of recording music that took me a few years of experience before I truly comprehended it and even longer before I understood how to achieve the right results by using it, was the role of the audio spectrum and the placement of instruments within this spectrum. While it’s easier to put on paper and explain what it means, it really takes years of training your ears to recognize when a recording is missing, conflicting or lacking in a certain range.
What is the Spectrum?
Well, in simplest terms it’s the bass and treble controls on your basic stereo system. If you‘ve ever worked with a graphic equalizer then you should have a really good visual grasp of the concept of the audio spectrum. Depending on the type of instrument, it will have its own unique harmonic qualities that give it a range and place it somewhere within the spectrum of tones that a human ear can recognize.
Scientists have actually discovered that objects even the size of planets have a resonating frequency within the audio spectrum, they are beyond the realms of human hearing but they exist none the less. Every object in the universe possesses a resonating frequency that places it somewhere on the musical scale. Luckily, in audio recording we’ll only be dealing with the frequencies that a stereo speaker can reproduce and not all of the frequencies that are present in the cosmos. Still, it’s something to think about the next time you’re rearranging your furniture. In music, most of the tonalities we’ll be dealing with are represented on an 88 key piano.
From low to high it’s easy to recognize the differences in tone between say a bass guitar and a crash cymbal of a drum set. Each instrument resides in its own place within the audio spectrum. Guitars have their place much like the strings of a violin or the human voice itself, all of these instruments possess a unique frequency range that a skilled recording engineer must recognize and contend with in order to achieve a proper balance in audio mixing. There is an awesome interactive chart that you can review here that shows many instruments and where they reside on the tonal scale.
The Challenge = Achieving Balance
The true job of an audio engineer is to make the decisions and adjustments necessary to balance this tonal scale for the benefit of the song or composition they are mixing. From looking at the chart one can surmise that many instruments share the same range of frequencies and therefore when they are all represented within the same composition, they will actually begin to fight each other. In many cases, tonal equivalent instruments can even cancel each other out all together, to the point that they can’t be heard at all.
If you’ve ever been to hear a rock band live and thought that the sound was bad, think about the audio spectrum and it’s easy to understand why. Guitars, the human voice, and snare drums all reside in the same frequency range and when you place them all within the same box (ie. the club) and turn them up really loud; chaos can ensue and many times does. The principles of balance is what it means to mix a song. Some instruments will require more focus than others and some instruments may even be deemed unnecessary depending on the song when compared to other instruments that are represented in the mix. Deciding on the instrumentation of a song can drastically alter the feel and the emotion of a piece of music and it is just as much a part of the artistic process as writing a lyric or tuning the guitar.
Tried and True Formulas – Instrumentation
One of the best examples of a formula that works in harmony is the drum set itself. The drum set is a set of percussive instruments that when combined, fill from low to high, the entire audio spectrum. From the low frequencies of the bass drum to the high frequencies of the high hats, the kit represents probably the greatest challenge to an audio engineer for this very reason. It is an instrument that spans the entire audio spectrum and if not balanced properly, can drastically effect the quality of a recording. The balance and skill required by the drummer performing on the kit can also drastically determine the size of the job an audio engineer has to contend with when mixing the drum kit. A truly musical drummer will recognize and do much of this themselves in the performance.
The four piece rock band is another tried and true formula that potentially balances the audio spectrum. Bass guitar, drum kit, guitar, and voice all blend together nicely (if done right) and have the ability to fill the spectrum in a harmonious manner. Well, harmonius to those that enjoy rock music anyway. Taste is entirely another subject all together.
On a grander scale the orchestra is indeed the pinnacle of mans ability to harness the audio spectrum. The orchestra came together long before the days of recording or amplification and just the layout of how an orchestra assembles on a stage is a testament to our understanding of the audio spectrum and where the instruments are spaced within it.
Let it Go
In a nutshell this is what mixing your song is all about on a technical level. The real key is harnessing this knowledge, using it, while at the same time, forgetting it so that you can just do the work necessary for the song that you are working on without getting lost in the minutia. Much like learning anything, there are building blocks involved. One must learn the language to truly begin to speak it well. So take the time and teach your ears how to recognize and evaluate the audio spectrum in detail. Then you will have an entirely new understanding of what’s going on within your mix. Above all else, don’t be afraid to experiment. While many things are tried and true, there is always room to discover more possibilities that exist within the audio spectrum of the cosmos.