I've read several posts and videos on tuning (e.g. Andrew Zajac) which mention "beating" as being undesirable when playing chords. What is beating and how do I listen for it?
Beating is usually heard on the harp when you play an octave and the two notes are not tuned properly. You'll hear a low frequency tone over the top of the other notes that is the difference between the two tones.
Breath control can be a big factor with beating octaves. If you play too hard you're likely to pull one note flatter than the other and get beating.
When I tune harps, I tune the individual notes. Then I go back and fix any beating octaves.
Here is a good description of the beat frequency phenomonon. It has some sound samples you can play on you computer as well as a good basic description of the physics involved.
Here is a more mathematical description. Notice the complexity of the sum of two sin waves equation and how it simplifies to the beat frequency is the difference between the two frequencies. So if you play a tone at 440 and a tone at 445, you will hear 5 beats per second.
I understand that many piano tuners shoot for a beat frequency of 3 Hz. Can anyone with more knowledge of piano tuning than I have refute or confirm this?
Last Edited by STME58 on Oct 18, 2016 12:33 AM
@ tmf714, I note by your post count that you are no rookie, so I retract my 1st impression that you might be mistaking vibrato for beating. So you must be saying that Clarke & Musselwhite (and probably a few others) are consciously using the tremolo effect of slightly out of tune reeds in their music(?) Taking that 1 step further, is it a happy accident or do you think they tune their harps for it?
Piano tuning: The art of tuning perfectly imperfect intervals.
It is more complicated than just aiming for a beat frequency. When laying down a temperament, the 5ths are squeezed a bit (tuner listens for 3 beats over 5 seconds) and the 4ths are expanded a bit (tuner listens for 5 beats in 5 seconds).
Octaves and unison are tuned without beats. Some more advanced thinking tuners will start to stretch the octaves just a bit as he moves upwards through the treble section.
Being a piano tech, I've found the Clarke/Musselwhite beating octaves to be a little painful to hear. ---------- The Iceman
Nothing's really 'in tune' in blues harp is it. That's part of the charm.
Do you have any examples of the Clarke/Musselwhite chord or octave effect? I particularly like CM's techniques - e.g. substituting blow bends for draw notes at the top end. Certainly tuning isn't an issue there.
I don't know much about piano tuning but what I do know is that the partials aren't necessarily in harmonic series, so the fundementals of two notes could be in tune but the rest of the partials won't be. All very complicated - but that's why it sounds like a lovely piano and not a bontempi organ.
Those bothersome beats in one context (tuning your harp on the workbench) could be a shimmering, shifting sound in another. People like chorus effects and rotary speakers. When you do vibrato, it's not just the wobbling that sounds good, it's because the sound mixes with its multiple reflections and makes it expand.
Last Edited by MindTheGap on Oct 18, 2016 6:13 AM
Iceman, I always appreciate your depth of experience and your willingness to share it.
I have a Khim (Thai hammered dulcimer) that I hope to start learning soon and I will be experimenting with the tuning, both the temperament and the tuning of the multiple strings per note.
Chords played on a harp tuned to ET will beat somewhat. Chords played on most compromise tuned harps will beat, but to a lesser extent. Chords played on a just intonation tuned harp generally don't beat. Beating is not a phenomenon restricted to octave stops, but it is more noticeable when playing octaves.
STME......hammer dulcimer....have fun. After you are done tuning it, breathe on it and it goes out of tune. (kinda joking, but kinda true. The nature of hammer dulcimer is that it is not an instrument that encourages or keeps solid good tuning). The "offness" adds to the quaint quality of this instrument.
For anyone slightly interested in piano tuning, the beats listened to and used to set a temperament are not at all the same beats being discussed above for octaves. The beating is the same concept, but it is buried within so many other sounds and overtone interaction that the casual ear will not be able to focus on it. It takes training and an awareness of what not to listen to. ---------- The Iceman
Last Edited by The Iceman on Oct 18, 2016 10:20 AM
On the subject of pianos, tuning and complexity: I learnt some technicals when I was searching for a decent 2nd hand one. Someone told me to watch out for "The Untunable Piano". You go to look at one that seems in good shape and a good make, the right kind of frame and action, but the only thing wrong is it's out of tune. Easily fixed you think and buy it, but sadly you find that it can never be tuned. It's a failure of the bridge pins which means the string change their pitch according to how hard they are struck - and not in a controlled way.
Last Edited by MindTheGap on Oct 19, 2016 4:19 AM
Unless the Beating is SUPER bad, I dont really mind it too much. Having said that ... Everytime I tune a harp I get rid of the beating.
It's really not hard to do once you figure it out. Andrew's site is golden for things like this.
I suppose it does depend on your tuning though. I never thought of the ET or other tuned harps, but I'm glad you brought it up. That's interesting.
I tune most of mine to 19 limit. And the other few to 7 limit. The only harps I have that are close to ET are the Manjis and I have yet to tune on of them. Dont think I could resist the urge to make it 19 limit ... lol.
"Someone told me to watch out for "The Untunable Piano". You go to look at one that seems in good shape and a good make, the right kind of frame and action, but the only thing wrong is it's out of tune. Easily fixed you think and buy it, but sadly you find that it can never be tuned. It's a failure of the bridge pins which means the string change their pitch according to how hard they are struck - and not in a controlled way."
Visual examination of the bridges will reveal if there is a crack running along the pins. Usually happens to the bass section if at all. Can be repaired - not too difficult.
Other aspect is loose tuning pins. If pins are not snug, piano will not hold tune. Can be determined by tuning lever feel on pins. Can also be repaired - larger pin replacement. Sometimes pin block lamination is failing, and in that case, rebuild is necessary.
When in doubt, call in a pro. ---------- The Iceman
To me, beating indicates that the notes I am playing together are not in harmony. When two or more notes are in harmony, they sound greater than the sum of their parts. To that end, compromise tunings where the tonic, fifth and third (blow 1 to 10 and draw 1-4) are not in harmony all sound as "bad" as ET to my ear. (Not BAD, just not harmonious). My point is that there is a big jump forward when you get the tuning just right.
Some players use beating sound for effect. You can control the "wetness" (the magnitude of the beating) of an interval or octave by breath control and by bending.
For those who use that effect in their music, it's probably a lot easier to put to use if you are using a well-tuned harp and all of your intervals start off at the same point - a point of YOUR choosing (start wet and clean them up or the other way around?).
All that being said, if you tend to fill your harp with saliva, one type of "wetness" will create the other type of "wetness" whether you like it or not.
I like beating....cover plates to open them. You get to use a hammer to hit em. It's a way of getting back at the harmonica for ruining my life. Normally I just pull weeds when I see or hear them things but I've beaten a few and I'm not ashamed. ---------- Have good day. M.A.P. .
Beating is a physical phenomenon related to two notes going in and out of phase with another which changes the total amplitude.
In the most recent version of "All About Harmonica Microphones, and then some" I have added a section on this - because when beat notes beat fast enough - they are perceived as a bass note, not beats. And THAT is WHERE THE BASS COMES FROM.
"Compromise temperament" is something of an awkward term, as all temperaments are by definition some sort of compromise. However, this term and the similar term "compromise tuning" have in the harmonica world been used to describe a fine tuning of the harmonica that is neither Just Intonation nor 12 Tone Equal Temperament, but somewhere in between. The idea of these tunings is to give smoother chords than those given by 12TET, without having the harmonica deviate too far from the tuning of the accompanying instruments.
The degree to which the tuning is compromised is a matter of personal preference. Perhaps the most obvious place to start is with what guitarists have come to call "half tempered" tuning. As the name suggests, this involves tuning a given note halfway between its equally tempered value and where it would be if you were to tune justly. As an example, here are a couple of chords (2 3 4 draw and 3 4 5 blow) on a C harp played in three different tunings.
First, here is the 12TET version:
As you can hear, the chords sound rather rough.
Here are the same chords tuned in JI:
Typical nice smooth chords of Just Intonation.
Finally, the same chords tuned midway between the ET and JI versions (the roots of the chords are tuned to +/- 0 cents on the tuner, the fifths are at +1 and the thirds are at about -7.5):
Not surprisingly, this tuning gives chords that are smoother than the ET version, but not quite as smooth as the JI version. Some people prefer the slight beating effect of this sort of tuning, feeling that the JI version is rather lifeless in comparison. Others, after playing compromise tunings for a while, finally decide that they prefer Just Intonation.