Intonation Struggles

For practically every orchestral instrument, intonation is a huge deal. People who come from a piano background or work mainly with samples are usually not aware of the relevance of this topic and might be unpleasantly surprised once they get the chance to work with real musicians.

Intonation in general means to hit the right pitch and not be slightly too low or too high on it. What seems like a really trivial concept has much more to it than meets the eye. Talking about this issue in detail opens up a can of worms which requires to even look back at musical fudamentals to fully grasp the relevance of this topic.

As you all might know, western music is based on the equal tempered tuning system which decided to split the octave into 12 equal half steps and consequentially accepting that none of the intervals (except the octave) are perfectly in tune. For instance the perfect fifth is slightly too big in the equal temperament to be perfectly in tune. There's a lot of maths and physics involved in this which would be too much to cover in this post, if you have a lot of time, you can read the Wikipedia article on this topic.

For our discussion it is enough to know that we live with a tuning system that is compromised but the best approximation to solve an unsolvable mathematical dilemma.

Now, every woodwind, brass and string instrument works slightly differently than a piano. Depending on embochoure or finger position there is some room for "pitch fluctuation" around the note that you're targeting. So if you target let's  say a c on these instruments, there is not that one key on that you hit and it comes out perfectly in tune like on the piano but you land in a "ballpark around c" and have to adjust your embochoure, finger position in a split second to adjust the tuning if you didn't hit it dead on.

We all know the painful sound that can be produced on a violin by a student whose pitch perception is not refined enough to notice or counteract slightly out of tune notes.

But even for the most professional musicians, intonation always is an issue. In spite of our tuning system generally relying on the equal temperament, in an orchestra we more often encounter just temperament which means that the musicians adjust to the current sound to be as "in tune" as possible with it. And the differences can be more than subtle.

For instances, on string instruments the concept of an f# and a gb is fundamentally different in spite of being the same note on a piano. For string instruments, an f# is a raised f and a gb a lowered g. The f# will be quite a bit lower than the gb. The players will always use their ears to intonate as well as possible in the surrounding sound of the orchestra which might not be the "correct" tempered pitch but more often the more clean sounding just tuning as of course our ear automatically gravitates more toward more "clean" sounding structures.

Knowing that has some strong implications on recording real musicians. The very popular striping of an orchestra (where you record sections separately to have a better control over them in the mix) makes life for the musicians more tricky. The fewer reference points they have to intonate, the more of a guesswork it becomes. Even if they hear the rest of the orchestra over headphones, it is much trickier to intonate for them, especially in very sparse orchestration.

I once had the problem in a recording session that I had written a solo for a flute and a trumpet who play the same line in unison and due to striping and missing that point in the preparation we only realized when recording the brass stem. We tried a few takes but it was really not possible for the trumpet player to intonate properly with the earlier recorded flute. The factor of a mutual "give and take" by the two musicians that would be happening if they played together was eliminated and eventually we decided to go for the flute alone and tacet the trumpet on that line.

Similar problems can arise in heavily "sharp" or "flat" key signatures that exceed more than 5 flats or sharps or possibly even use double flats or double sharps. For strings, besides the stress of reading all these accidentals, their mental concept of creating these notes can cause a tremendous problem regarding intonation in the orchestral context.

The world of perfect samples that are tuned to their exact tempered tuning pitch might often make us forget how tricky it sometimes is for musicians to find the right pitch in context. Especially in musical contexts that don't allow to settle into a chord or harmonic situation due to being too harmonically complex, it will become quite a guesswork for your players. 

One of the orchestration strategies that I really like a lot is to orchestrate dissonances not within sections but between different sections. For instance writing a clearly understandable major triad in the trumpets and another major triad in the horns that creates dissonances with the trumpet triad makes life for the players much easier. The players who sit next to each other can intonate much easier by orienting themselves on each other in an easily understandble harmonic situation and yet you can get a bone shattering dissonance out of this. If you placed that dissonance within the sections, it would be trickier for the players to find their role in the sound. One prime example would be to divisi a string section into two pitches a minor second apart. The tendency of the players to listen to each other and correct their pitch accordingly will very often lead in this situation of the minor second being to small and consequentially sounding out of tune.

For a composer/orchestrator being able to anticipate where there might be intonation issues when recording an orchestra is based on a lot of experience in working with real musicians. Even the best players on the planet will sometimes not be able to intonate perfectly and need to do another take. Often this is based on not hearing each other perfectly on the stage and therefore losing a reference point for their own intonation. From the perspective of someone overseeing the recording from the booth it is indeed often a valuable information for the musicians if you point out where a note was slightly flat or sharp beyond the struggle to hit it and in most cases, in the next take it will be better.

The bottom line here should be to be aware of these issues when you write music and even more so if you plan to record your music live. Mostly problematic issues in this can usually be solved with one or several more takes (as long as the intonation issues aren't caused by testing the technical limits of your players) but of course it is desirable to anticipate or avoid such problems by writing the music accordingly as it will make life for your players easier and get to results quicker in the session.