Orchestral Voicings Part 2: Low Interval Limits 1

The management of the lower registers is one of the most essential elements that define whether a voicing sounds good or not. This register is a two sided sword. On the one hand using it properly will result in incredibly rich, sonorous and warm sounding voicings and just create harmonic situations that might send a shiver down your spine while and on the other hand bad handling can result in a complete train wreck.

So it is not a solution to generally steer away from this register to just avoid any problems as you will also steer away from resonance and substance by doing so.

Fortunately there is a pretty defined set of rules to follow when writing in this register called "Low Interval Limits". Still, this is one of the most common problems I see in compositions and orchestrations by learning composers.

No matter how clear your voicing is, if you put it too low it will start to become muddy and unfocussed. Compare these two triads which are identical except for the fact that they are two octaves apart:

https://soundcloud.com/robin-hoffmann/low-interval-limit-demo/s-gNvOI

While the first one sounds transparent and is easily "understandable" the second one gets unfocussed and muddy and it is very hard to hear which notes are playing.

In its essence, every interval of two notes sounding together has a maximum low end that you can place it at before it starts to sound muddy. This is depending on the degree of consonance. More consonant intervals can be placed lower while dissonant intervals need to stay higher in order to not sound muddy.

However interestingly the source for mud is usually not the fundamental frequency but rather the higher harmonics. I recently wrote an article about the role of the third in a triad and how its harmonic spectrum has influence on the general sound. The same applies for every interval. While consonant intervals overlap parts of their harmonics, the more dissonant the intervals become the more their harmonics will clash. Now when you put these intervals too low, their harmonics will also move into the more audible and easier distinguishable range and create more obvious clashes which we hear as mud.

This is also the reason why mud is extremely depending on dynamics. If you play an interval softly on most instruments this will cause fewer high harmonics to ring, which will avoid clashes which makes it possible to move the intervals lower without muddyness.

So the following chart is NOT written in stone. The interval limits there are chosen so that you definitely will not create mud with them, no matter on which instrument and which dynamic you play them.

For learning composers it is best to memorize them up to the octave. You can extrapolate any larger intervals by just removing an octave and use the limits you know. (Eg. the limits for minor 2nd and minor 9th are identical just with an octave added)

Notice how the perfect fifth due to its consonance allows to go much lower than many other intervals.

Their use is pretty much straight forward: look at the intervals that your chord consists of and check if any of those is lower than in the list. If not, your voicing is safe to not be muddy.

There are a few exceptions and additions to that list so we're gonna have a look at a few specific examples in the next part. Stay tuned!