Stretch Tuning vs. Equal Temperament Tuning

Stretch Tuning vs. Equal Temperament Tuning: The Proper Way to Tune Your Rhodes, Wurlitzer or Clavinet.

 

What is the difference between Stretch Tuning and Equal Temperament Tuning? And why can’t you tune a piano with a guitar tuner?

 

If you took a high school or university physics class that had a unit on the physics of sound, you may recall learning that notes an octave apart have a frequency ratio of 2:1. These are the place holders for the two ends of a scale. Taking this basic knowledge, it may seem reasonable to take the twelve notes of the scale and divide the octave into even portions. If this were the case, over the course of several octaves as on a piano’s keyboard manual, the harmonies would begin to sound dissonent. But why? In the most simplified terms, this is because as intervals move further apart, the human ear finds the beats generated by the two or more frequencies unpleasant. Luckily, there are alternate methods of tuning that produce more appealing harmonies.

When two intervals are played together, the combination of the two or more frequencies produce beats. The rate of the beats is a function of the differences in frequency of the two pitches, which is one of the components of how the human ear interprets harmonies. In order to produce the most appealing harmonies in a piano or ensemble, a number of tuning philosophies exist that create more pleasant beats, and can even account for inharmonicity within the instrument (more on inharmonicity in a later post). The philosophies typically use more pure major thirds, minor thirds, fourths, fifths—you name itsome temperaments even go as far as taking into account the specific key signature that will be used.

Side Note: Even the Greek philosopher and mathematician Pythagoras conjured a superior tuning methodology that resulted in tuning that is close to tuning to perfect fifths (on a ratio of 3:2). Each tuning methodology has it’s strengths and weaknesses, and unfortunately for Pythagoras, the most dissonance that results from his tuning methodology is on the major and minor thirds that results in dissonant major and minor triads.

Without getting too detailed into the technicalities of these tuning paradigms, the fundamental philosophy of stretch tuning is to make up for the frequency ratios of various harmonies within the scale (or targeting inharmonicity of the instrument) of an instrument by compensating for the variance of the harmonic tones produced by a string, tine, or reed. In its most basic form the solution is to ‘stretch’ the lower octaves to be ‘flat ‘and the upper octaves are a little ‘sharp’ compared to equal temperament tuning in 440hz.

Most guitarists that use digital electric tuners may recognize 440hz as the frequency that they set their tuners in order to sound in tune with other instruments. But if you tune an entire piano to 440hz the result will be that notes played within the same octave will sound relatively in tune whereas notes spaced further apart or paired with other instruments will sound dissonant and as if they are out of tune. This is why you can’t tune a piano—or electric piano—with a guitar tuner.

Stretch Tuning Chart

Notice: at each end of the chart for stretch tuning of an 88 key piano that notes are tuned to roughly 13 cents flat and sharp (or 13/100ths of a half step) which is offset more than 10% “out of tune” from equal temerament.

In order to do this with an electric tuner, you will need a much more accurate tuner than a common chromatic guitar tuner. For instance, The Chicago Electric Piano Company uses the precision of a strobe tuner that is rated accurate to 1/10 of one cent (or 1/1000 of a half step). It also visually represents the series of the overtones produced by a piano adding to its precision. Strobe tuning also allows you to offset equal temperament tuning by intervals of 1/10th of a cent so you can accurately set the tuner to account for the tuning methodology of your choice.

For more on the tuning methodology specific to Rhodes and Wurlitzers, please stay tuned for our follow up post on inharmonicity of electric pianos.

 

The Chicago Electric Piano Co. is the Midwest’s electric piano tuning expert for Rhodes, Wurlitzers and Clavinets. After studying and comparing the outcomes of various tuning methodologies, our shop endorses a stretch tuning methodology that is used industry wide by the most reputable piano tuners. If there is an alternate or historical temperament that is called for, we can tune to any temperament of your choice with the highest level of precision–guaranteed. Our goal is to provide the most accurate electric piano tuning to recording studios and musicians nation wide.

 

 

Relevant searches:

What is stretch tuning? How to tune a piano. Tuning philosophies. Strobe Tuners and Chromatic Tuners. Can you tune a piano with a guitar tuner?

8 comments

  1. Thank you for your informative blog article. I have been a tuner for almost nine years and use the Verituner 100 set usually at equal temperament.

    • mbrink says:

      Tuning a Wurlitzer or Rhodes following the stretch tuning chart above has produced the best results. Since the tines and reeds were cut by hand the level of inharmonicity that occurs isn’t as perfect as this chart would suggest, but it’s a great starting point. Fine tuning with a well-trained ear after following this chart will produce spectacular results. (More on inharmonicity of tines and reeds in a later post–stay tuned).

      • Schluter of Deagan Chimes, inventor of A-440 particulars, when tuning chimes, was always fighting “Wavers”. what are those?

      • Gauri says:

        November 22, 2008 at 4:33 amWading In Dangerous Waters Wow! What a question to start thgins off.I am somewhat uncomfortable critiquing another technician, but I guess there is no way to avoid it and still answer your question. So let me point out a couple thgins:College piano work is hard . You re asked to work on pianos that are in constant use generally you’re under time constraints and usually the pianos are abused. Colleges never want to pay what a high quality technician is worth so college piano tuners are underpaid.In other words, working for a college is not necessarily an indicator of a skilled technician. If you were a piano technician of high quality, would you want to work for an institution where you are asked to work harder than normal and yet paid less?The best money in this business is not with colleges or even for concerts, but your best opportunity for real money is working for Mrs, Smith and Mrs. Jones that is where the real money is and the most pleasurable working environment. Reply

        • Nick says:

          The piano is a full range instrument, mieanng it has low bass notes at the bottom going to high treble notes are the top. The guitar is a midrange instrument, mieanng that it lacks the low bass notes. Therefore, if you want to find the E chords that sound the same, you have to find the lowest E chord possible on the guitar and match it to the piano. Then you have to find the highest E chord on the guitar and match that to the piano. Now you know the lowest and the highest. You can find every E chord in between. The low E string on the guitar corresponds to the E below middle C on the piano. Knowing that, you can map out the E chords on the guitar. The only other reason the chords wouldn’t sound the same is if the intonation on your guitar isn’t correct. So, first you tune your guitar . If your piano is in tune, then use that as a guitar to tuning your guitar. Secondly, you need to make sure the harmonics on your guitar are also in tune and this is referred to as the intonation. If the harmonics are not in tune, then you have to adjust the saddles on the bridge. If you don’t know how to do this, then take your guitar to a guitar tech who will set it up and show you what to do. If you have an accoustic guitar and the bridge is not adustable, then you will have a hard time getting your guitar to the correct intonation, so again, see a guitar tech.

  2. Alexa says:

    you can buy a helluva nice uphrigt for around $400. then belly up to the bar. and as far as electric’s, ive only seen a few that were perfectfully warm. most electric keyboards are to perfect, equating to only playing by yourself, because, you couldnt play along with a guitar,bass etc, unless they tuned to you. now this creates the problem of their instrument not being perfect, so it will not play right. From experience i know that most guitars, even when when warmed over by a good setup person will not chord true when tuned to an electric piano. ive found a few that will play nicely with an acoustic or a scaled fret instrument. I wont go into it, except the cheapest ive seen them is $1200 roughly and i was hoping to leave with it for slightly less. an old uphrigt that is tightened will tune to your ear as well as to an imperfect reference. and as far as tuning by ear, its like a timing light, the tuning fork is only a reference point. first step after timing an engine is to drive it to check for ping and performance. first step for tuning a piano after tuning(that is jethro bodine ) is to start chording. you’ll notice most pianos dont have a perfect harp or wishbone( jethro bodine ), so using perfect reference points create harmonic imbalance in the damned thing. this is due to not being able to adjust the intonation for the machine. what i do is to tune perfectly, but to tune the keyboard in 2 planes, enabling me to play with just about anything close to being in tune.

    • mbrink says:

      Thanks for sharing, Alexa. We have found that majority electric pianos that come into my shop have been tuned by their owners with inexpensive guitar tuners. Also, many of them have admitted to tuning with tools that I would never put anywhere near a rare vintage instrument.

      I think that you would find that a well-tempered electric piano from our shop will give you the best results when playing with an ensemble.

      MB

  3. Thanks for finally talking about > Stretch Tuning Electric Pianos like Rhodes
    and Wurlitzers < Loved it!

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