Tuning

The instruments on a recording should all be in tune with each other, right? In this short episode, I discuss how instruments are tuned, and why even with today’s remarkable tuning devices, there’s more to tuning an instrument than looking at a colorful display on the head of a guitar.

Thanks for listening, commenting, and subscribing on any of the dozens of podcast providers that carry My Take On Music Recording. You can reach me directly at dwfearn@dwfearn.com   I am always interested to hear which episodes you enjoy and which ones you find less interesting. And I am always open to your suggestions for topics.

email: dwfearn@dwfearn.com
www.youtube.com/c/DWFearn
https://dwfearn.com/

Transcript

60  Tuning                                                          3 February 2022

I’m Doug Fearn and this is My Take On Music Recording

One of the jobs of a recording engineer is to make sure all the instruments are in tune. At least I always felt responsible for that.

I am blessed, or cursed, with a fine sense of pitch. In controlled tests, I can consistently detect a pitch change of 1 Hz in the mid-frequencies. I hear things that are out of tune on just about everything I listen to. Often, it is no consequence to most listeners, who are not listening for such details. But even if they do not consciously hear that something is not quite on pitch, I believe it affects their enjoyment of the music.

When I started out, the studio piano was always the pitch reference. And to make sure that was accurate, most studios had their pianos tuned every week or two.

At the beginning of the session, everyone tuned to the piano, even if piano was not in the song.

Sometimes the reference would an electric piano or an organ. But always some fixed-tuned keyboard instrument provided the pitch reference for everyone.

My father played French horn in the Philadelphia Orchestra, and before every concert, there was a backstage speaker that emitted a 440Hz A for everyone to tune to.

This was also the cue for the orchestra to assemble on stage.

My father had superb pitch sense, which is probably where I got it. He was also a jokester, and on occasion, he would stand under the 440-speaker, before it sounded, and play an A on his horn, duplicating the timbre of the rich electronic note. People would start tuning and head for the stage.

I think he got away with this several times before the ruse was revealed. The players thought it was hilarious.

Today, everyone has their own electronic tuning device, usually a clip-on meter that they can put on the head of the guitar and tune the open note of each string. That eliminates the need to use the piano, and theoretically, everyone will be in perfect tune for the session and any subsequent overdubs.

But it’s not that simple.

If you watch most guitarists, they pluck the string, watch the tuner, and then tune until it indicates the note is right on pitch. Sounds easy. But there are traps.

For one thing, all string instruments change pitch as the note decays. If the guitarist tunes on some portion of that decay, then the initial attack of the note is likely to be a slightly different pitch. If the part they play is going to be staccato, it may not match the pitch of other instruments. Everyone is baffled, because the tuning device says they are right on pitch.

But if you watch the indicator, it will usually wobble around a bit before settling down to a fairly constant reading. And then it starts changing, going sharp or flat. Is that instrument in tune?

And it’s more complex than that. Not only does the pitch change as the note decays, but the note is never just a fundamental. There are always overtones, or harmonics, that are multiples of the original note.

Let’s say the guitarist plays an A4, 440Hz note. That note also contains the second harmonic at 880Hz, and all the integral harmonics of 440, in various proportions. Those overtones are one of the reasons why a guitar sounds different from a viola or a flute playing the same note.

Our brains like even-order harmonics – the ones that are at 880, 1760, and so on. Most of the even harmonics fall on notes that are musically related. Guitar makers long ago realized this and designed their instruments to emphasize the even harmonics.

But what about the odd-harmonics? They are in there too, but generally at a lower level. Our brain hears odd harmonics, such as 1320 or 2200Hz as discordant or annoying. These odd harmonics do not fall on actual notes in our Western scale.

That’s not to say that all odd-harmonics are bad. Odd harmonics add tension and drama to the sound, while the even harmonics add fullness and sonority.

A fuzztone pedal on an electric guitar might convert the original note to a square wave, which is defined as the fundamental plus all the odd harmonics in equal level. That’s not all that the pedal does, but you get the idea. And it’s  great sound for a lot of music.

And here’s where another tuning problem arises. Some instruments, if improperly set up, or imperfectly designed, can cause the harmonics to be out of tune with the fundamental. A misaligned neck or a slightly out of position fret can cause this.

Mostly, though, I believe this is an issue with the strings, and some strings are better than others, especially as they age.

New strings tend to sound harsh because some of the overtones are way out of tune and out of balance with the fundamental. There are other reasons why they sound harsh, but this is the one that applies to this discussion.

As the strings age, they tend to fall more into tune, with the harmonics blending in nicely. It is sort of like the plucking of a string that changes pitch through the decay of the note, but on a much longer time scale.

With all this discordant stuff going on, it’s amazing we can make any decent music at all. But good players are aware of these things, consciously or not, and they compensate. They may change their part to avoid the discordant decay of the note. Or they can pull the note to make it stay in tune as it decays. These are the kinds of things that separate great players from average ones.

The ultimate strategy for keeping notes in tune is to use a fretless instrument. String players can change their intonation to best blend with each other and the other instruments. The players have learned to compensate for the short-term and long-term imperfections in their instrument, plus the needs of the music.

Players of stringed instruments can also add vibrato, which wobbles the pitch around the note center, just slightly, so avoid obvious clashing with other instruments that do not have the infinite pitch resolution that they enjoy. Guitarists can do this, too, to some extent.

But what about a string instrument like a piano? Pianists are stuck with a note that they have no control over. Well, that’s not entirely true. Good pianists can modify their part to avoid the worst of clashes. They have other techniques, too, that reduce the potential of out of tune harmonics. But they are beyond my ability to explain.

If you listen to a big, sustained chord on a piano, most people will hear that there is a lot of discordant sound coming out of the instrument. The piano is a wonderful instrument in the hands of a skilled player. But it can sound awful when someone sits on chords for an extended period. Good players know this.

As an engineer, you can’t do much about the piano, except maybe to suggest the player avoid the sustained chords. That is, if you are in a position to influence the arrangement. If you’re the producer, then it is appropriate.

As an engineer, your best bet might be to suggest to the piano player that they might try a different approach to those chords. Maybe voicing them differently would sound better. Or changing the part as needed. It’s just a suggestion. Record it and let them hear it. Generally, if it sounds better, and still serves the music properly, then you have a shot at convincing them.

And then there is the problem of scale. This is such a complex subject, and full of controversy, that I hesitate to step into it. But for every instrument with fixed pitches, like a piano or a guitar, certain decisions had to be made in the original design of the instrument that will affect how it blends with other instruments. The problem arises because our Western music is based on octaves being perfectly in tune, but the intermediate notes have to be tuned slightly off in order to come out right on the octave. And this is dependent on the key of the song. Suffice it to say that a piano, or other fixed-tuned keyboard instrument, is going to sound better in some keys than in others. But never perfect in any circumstances.

Is this a major problem? Usually not. It depends on the instrument tuning, the key of the song, how the player approaches his part, and the other instruments in the arrangement. Once again, good players know how to minimize the clash that can occur.

Perhaps sometime I will get someone who can explain these scale differences in detail. It’s pretty arcane, but it is useful for you to at least know about it. Sometimes you have some control over this but usually you don’t.

And this is one reason why it pays to have a really good piano tuner, who has tuned your piano many times. They will know exactly how to tune your piano for the best sound of that instrument. They use their ears, not a meter, to achieve this final polish on the tuning.

And guitar players can use this approach, too.

The electronic tuners are great devices, and save a lot of time and get everyone pretty close to being in tune, which will be important for future overdubs. But there is no substitute for the trained ear of the musician.  The tuning device gets you started, but the player has to take it from there.

And you as the engineer should be able to detect any tuning problem and suggest solutions.

And there is one more aspect of tuning that you should know about, if you don’t already. Our sense of pitch depends to some degree on the loudness of the sound.

Here’s an easy experiment to illustrate this. Listen to a recording that fades out at the end. Play it a fairly high level, and pay attention to what happens as the song fades. It goes flat. Every time. Once you become aware of this, you will hear it even at moderate volume.

If you could measure the frequencies, you would find that they are not changing at all. It’s just as artifact of how our hearing works.

And there is nothing you can do about it.

There is one additional aspect of this anomaly that you should be aware of. This is mostly a problem in very loud music.

Often the guitarist will tune at a relatively low volume, and then wonder why they sound sharp at ear-splitting level. Or they might tune at high SPL and then listen to the playback, at a more civilized level, and wonder why they sound flat.

I had this discussion all the time early in my career, when I was working with musicians who were often as inexperienced as I was. I knew the reason, but it was a difficult concept for them to grasp.

Sometimes I would go out to the studio and tune their guitar at a level more like how most people were going to be listening to the song. It then sounded a lot better when we listened back to the take.

Electronic tuners do not care about level, so they will indicate the correct pitch – taking into account the other factors I mentioned earlier. But our hearing is different, and sometimes we have to make compensations to make the music sound right.

So, the next time you are recording, pay attention to these things, if these are new concepts to you. It might improve the sound, and your clients will think you’re a genius.

Thanks for listening, commenting, and subscribing on any of the dozens of podcast providers that carry My Take On Music Recording. You can reach me directly at dwfearn@dwfearn.com   I am always interested to hear which episodes you enjoy and which ones you find less interesting. And I am always open to your suggestions for topics.

This is My Take On Music Recording. I’m Doug Fearn. See you next time.