Orchestral Voicings Part 3: Low Interval Limits 2

As I wrote in the last part, the handling of the Low Interval Limits is pretty straight forward:

You basically check all the intervals in your voicing whether it stays within the limits mentioned above and if they do you're safe from mud. There is one general exception to this however:

If the lowest note of the voicing that you are checking is NOT the root note of the chord you have to presume the presence of the root note and then check again.

Let's check some examples to clarify:

This C major triad stays perfectly within the limits:

Neither the major third between C and E nor the minor third between E and G nor the framing perfect fifth between C and G violate any of the Low Interval Limits so this voicing will not sound muddy. In fact we could go a major second down from that to Bb major before reaching that limit.

This A minor triad looks fine as well:

Neither the major third between C and E nor the perfect fourth between E and A or the major sixth between C and A violate any of the Low Interval Limits.

HOWEVER, this is one of the exeptions mentioned above. As the lowest note C is not the root but the third of the chord, we have to presume the presence of the root below and reevaluate, like so:

In this case you see that the minor third between the low A to C is lower than the limit for a minor third and in this case there would be the danger of this voicing being muddy.

So much for the "written rules" that can be applied and will most likely always work. However in the real world, we need to differentiate a little more. Generally you should be aware that these limits are no brickwall. It doesn't happen that over the span of a semitone within the limits and out of the limits your voicing will suddenly become an indifferent pile of mud but the further you get away from these limits the more problematic it will become.

I also mentioned it in the last post about this topic that mud is extremely depending on dynamics. Louder dynamics usually come with more harmonics which are the reason for mud. So if you play a voicing really softly it might still remain relatively transparent in spite of being lower than suggested. Also, in some cases mud might be absolutely desirable. If you decide to write a low and ominous musical structure, you might simply want to go down to this register.

Here's an example from my piece WE HAVE TO SHAKE THEM OFF which I'm currently also discussing in great detail in an ongoing Composition Walkthrough:

https://soundcloud.com/robin-hoffmann/whtsto-brass-bars-5-11/s-mlbjh

I blatantly ignore several Low Interval Limits here. Particularly the first few bars are  far below what would be acceptable. But this is a deliberate choice. I want a dark and ominous feeling. Also notice the dynamic curve. The higher the dynamics get over the course of the "fanfare" the higher I move the chords and out of the way of the low interval limits. If I had played the very first few chords in ff, it would have definitely ended up in a very unintelligible sound structure.

Also in such complex harmony the exeption of the rule mentioned above is pretty much void as you see that if I had just checked the voicings of the upper three notes, even presuming their root in inversions wouldn't have helped much as the actual bass note is not even part of the chord. So the general idea should always be to check the complete voicing simultaneously over all instruments and sections to get a clear image of what needs to be fixed.

In more tonally centered music however, it is definetely advisable to have a look at the LILs.

Here's an excellent example for how to properly follow the limits. This example is the low brass accompaniment of the Island Fanfare from Jurassic Park as heard here at 1:30 right before the trumpet theme kicks in:

https://youtu.be/tTMtNly-A-M?t=90

This is an actual excerpt from the original score sheets showing the low brass voicing. All staves in Bass Clef, the two upper staves Trombones, the lowest one Tuba.

Observe how this chord actually follows the Low Interval Limits exactly. The low fifth between Tuba and Tbn4 and the Major 6th between Tbn4 and Tbn3 are just exactly the limits possible for this. 

Interestingly this is how he voices it just one bar later when the trumpets enter:

Notice the subtle difference of what the 4th Trombone is playing compared to the voicing above. 

Nothing else changes in the texture of the rest of the orchestra except the Trumpets entering. Now I can't say for sure why there is the change but I have a very strong suspicion. In my opinion the explanation for this subtle switch lies in the second half of this bar, where the harmony changes to a (lydian) C/Bb. If the 4th trombone would have stayed on the F there would have been entered a strong dissonance to the E which of a major 7th which I think he simply wanted to avoid. He could have stayed on the F for the first half and then jumped up to the Bb in the second half, however this would have been less elegant as it might have been a noticable shift in "resonance" in the low register. 

However coming back to the Low Interval Limits, also the second half of the bar is perfectly within the limits.

This whole passage shows how well worth it is to not shy away from the lower register if you manage it properly. The nobility of this harmonic fundament and its resonance exists mainly due to the choice of voicings. The noble sound texture of the trombones help but are not the deciding factor here.

So if these rules are the straight forward to use, why do I still see them so often violated? One of the most common causes for violations is not failing to properly voice an accompaniment and avoid low interval limits there but actually in the interplay with melodic content. The biggest danger is octave doubled melody lines where you simply decide to "double a melody an octave lower in the Celli/Bassoons/Trombones/Horns etc." In such cases it is very well possible to get into a register where it might introduce mud to the rest of the orchestra. It is essential to understand that ANYTHING that moves that low needs to be taken into consideration, not just sustaining chords that you declare to be accompaniment. When in doubt you need to check every rhythmical value of your low melody against the underlying harmony for possible conflicts. Same goes for any side lines or arpeggios.

As I said in the last part, it is definitely worth for learning composers/orchestrators to memorize these limits by heart, however the more important thing is to become aware of this register and develop an internal focus on such problematic situations.

I can say that after learning about this when I studied, I memorized those as well and followed them strictly. However by now I have forgotten most of them as I simply developed a feeling for what works and what doesn't over the years. With experience you will learn to bend the rules to your benefit as well as simply feel when things are not where they should be.