Stretch Tuning Question: Piano Vs Organ

[cassdad]

Question #1: My limited understanding is that in order for octaves to sound "in tune" to the human ear, at least on a piano, "Stretch" tuning is used in order to accomplish this goal. Is that correct?

 

Question #2: However, my understanding is that some instruments, such as an organ (let's say a Hammond rather than a pipe organ) are actually perfectly tuned, ie. the "A" above A 440 would actually be A 220. Is that correct?

 

Question #3: Furthermore: Is an instrument such as a Fender Rhodes tuned with or without "Stretch" tuning? In other words, is a Rhodes tuned more like an acoustic piano, or more like an organ?

 

Question #4: If an acoustic piano and an organ are tuned differently, if played together concurrently, are they both identically "in tune" across each instruments full range?

[dfcas]

I'm am aural acoustic piano tuner, so I'll give it a shot.

 

 

1 Yes pianos are stretched. The stiffness of the wire causes the overtones to run sharp, so for these to match the upper notes, the upper notes are stretched sharp.

 

2 I think a Hammond is temepered somewhat, but not stretched.

 

3 No idea about a Rhodes

 

4. No they are not identical. The piano would be slightly flatter in the bass and slightly sharp in the treble, but they are close enough that they still sound good together, unless the piano was excessively stretched.

[Tom Williams]

My Informed Amateur understanding (I used to do workshops on keyboard history, and I'm an acoustics / science geek):

 

(1) Yes, per dfcas, perfect explanation.

 

(2) Hammond's octaves are inherently perfect. The actual half steps, done by (rational) gear ratios to approximate the (irrational) 12th root of 2, are neither evenly spaced nor perfect per any other defined temperament. They are close enough to even-tempered (within just a few hundredths of a semitone) that no one seems to notice.

 

(2a) Pipe organs are tuned to even tempered (2**(1/12)) intervals, excepting chorale ranks.

 

(2b) Each octave up is a doubling, not a halving, of frequency. So, A above A440 is A880 on both Hammond and pipe organs.

 

(3) Fender Rhodes were normally unstretched as I recall, but sometimes modified with stretch tuning if they needed to interact with a "string" piano. Probably because 88 tines are easier to adjust than 220 wires.

 

(4) If required by the music, piano tuners in churches and halls where organ was played concurrently would sometimes reduce (eliminate?) the piano's stretch in order to better fit the pipe organ's tonality. 220 wires are easier to adjust than 20,000 pipes.

[The Real MC]

The key attribute is inharmonics.

 

The strings of an acoustic piano are a compromise. The bottom half of piano strings are overwound because the physics of an unwound string with descending fundamental pitches would require strings that are too long (the lowest A would be 32 feet long).

 

So the lower strings are overwound to add mass, to make the string vibrate slower and keep the string lengths reasonable. The tradeoff is inharmonics added by the windings. All the inharmonics are a psychoacoustic phenomenon to the human ear, which processes a "fundamental pitch" from those inharmonics.

 

Likewise the higher pitched strings are under such high tension to reach their pitch that they also produce inharmonics.

 

"Stretch tuning" is used for pitch sources that are largely inharmonics. You can't tune those piano strings by beat frequencies against a string an octave apart. The stretch tuning varies the fundamental pitch at both extremes so that the inharmonics sound "in tune" to our ears.

 

Sound sources with few inharmonics and largely fundamental tones - IE Rhodes, simple organ ranks - do not need stretch tuning. Complex tone sources in pipe organs can benefit from stretch tuning.

 

Don't expect a piano and an organ to be in tune with each other. Hammond tonewheel organs are imperfect due to manufacturing limitations. Non-tonewheel electronic organs are divide-down systems that aren't perfect either. Pipe organs, all bets are off. There's a reason why the piano is seldom played in unison with organs, or even an orchestra. Other than the strings, brass, reed instruments, and pitched percussion don't have the same scale. Trying to resolve "in tune" chords between piano and an orchestra is an exercise in futility.

[Joe Muscara]

There are numerous ways to do a stretch tuning on a piano, as well. Some might sound better than others to you, and for the particular piano.

[dfcas]

One problem with pianos and pipe organs in churches is they go out of tune in opposite directions summer and winter. Pianos go flat in the dry air of winter, and cooler temps make the pipe organ go sharp. In the summer, the piano tends to go sharp, and the pipes tend to go flat. These problems are greater than the stretch/non stretch issues when they are both on A440.

 

Some older pipe organs were made for a lower pitch. A=435 is pretty common around here, and if you tune the piano with the organ, then wind instruments can't tune to the piano.

[cassdad]

Thank you, all, for the informative answers, greatly appreciated!

[Tom Williams]

A=435 is pretty common around here, and if you tune the piano with the organ, then wind instruments can't tune to the piano.

What wind instrument can't pull out a piece here or there (or in the case of a flute, move the aperture down a couple of degrees) to lower the pitch? The only instrument family that I can think of that would be really messed up would be mallet percussion.

[Theo Verelst]

The chorusing of the tones in a chord depends on the multiplicity of the tone generators at work, as well as the detuning of the harmonics that make up the sound. On an organ, there's a very set number of tones and overtones (harmonics) that have pre-set relations, approximating the equal temperament tuning with a frequency relation between the tones that repeats pretty soon. Also, tone development changes the chorusing of the frequencies produced by an instrument, especially through the reverberation, which in the case of pipe organs or amplifies acoustic piano is more pronounced because of the feedback of the reverberation having effect on the tones themselves.

 

Piano tones can be pressed louder and softer, but also in combinations where for instance octaves can be used to bring out overtones or cancel them, which can create difference in perceived tuning of the notes, so that normally a acoustic and an electronic organ should be playable simultaneously without real problems, as long as the players understand what they're doing and the tunings aren't off to far. There are many examples of this, I've done that myself, too, but you need a basic understanding of the acoustics and instrument use.

 

T.

[dfcas]

A=435 is pretty common around here, and if you tune the piano with the organ, then wind instruments can't tune to the piano.

What wind instrument can't pull out a piece here or there (or in the case of a flute, move the aperture down a couple of degrees) to lower the pitch? The only instrument family that I can think of that would be really messed up would be mallet percussion.

 

I'm no wind expert, but several players have told me that the low and high registers of their instrument has tuning problems when they pull a slide and causes them problems. They much prefer A440. Just reporting what I've been told.

[elif]

What wind instrument can't pull out a piece here or there (or in the case of a flute, move the aperture down a couple of degrees) to lower the pitch? The only instrument family that I can think of that would be really messed up would be mallet percussion.

I have a relative with a set of vibraphones tuned to A442. i guess this is a standard. He told me they can be retuned to A440. The resonators generally do not have to be tuned. It's not crazy expensive to have it done.

Gary Burton posting to the Vibes Workshop forum on retuning.

 

You can intonate saxophone to a non-standard tuning note at one fingering. However, it throws out the intonation for the other fingerings. Otherwise, it would be possible to create a bari sax by putting a really long neck pipe on an alto sax. It would be perfectly in tune at one note.

[KuruPrionz]

Since the bass strings on a piano are shorter and overwound to provide lower pitches in a relatively compact space, when struck briskly they go sharp. All strings do this to some extent, a wider arc of vibration will increase the tension of the string, which sharpens the pitch. Heavily wound strings that are at lower tension like bass piano strings will show more effect of this than the trebles, which are able to be tuned correctly for their gauge and often are just the core wire itself, reducing the weight of the string.

 

To make the initial note the correct pitch, the bass strings must be tuned flat. When struck, they will go sharp at that moment and sound in tune. Sustained tones are not so flat as to create a noticeable "beating", it's more of a "detuning" effect with a slow, sonorous modulation.

 

If they tuned the bass strings to correct pitch it would drive you insane. The high strings would all sound flat, even if they were correct - as we tend to "map" our pitches in our head from the bottom up.

[The Real MC]

There's a limit to overwound bass strings. The Yamaha CP-70/80 illustrated this. The bass strings are short enough that the inharmonics won't resolve to a fundamental pitch and the bass strings are hard to tune. Once you reach that point the strings sound slightly clangorous.

[cassdad]

Wow, some impressive technical comments here! These comments trigger one more thought for me: These issues of inharmonics, pitch change on the strike of a piano key, bass wound strings, etc..... these all must pose quite a challenge for sampled digital pianos! I don't know how Yamaha does it, but the thing I most love about my MOXF8 piano is how amazingly in tune it is, throughout the entire range. [in fact, I have been extensively comparing it to the Pianoteq 7 trial-version pianos, and to my ears, albeit I understand they are "modeled", to my ears, tuning on my Yamaha MOXF8 is better than some of their pianos].

 

As a kid, my parents couldn't afford to get my acoustic piano tuned, thus I grew up learning on an always out-of-tune piano. I fell in love when I played my first digital sampled piano - hearing, for the first time, the wonderful sounds of all the notes being in tune! In fact, every time I play an acoustic (I don't get to play concert hall pianos or the like) - I'm immediately struck by how out-of-tune at least some of the notes are, and I frankly can't stand it. The tuning (and all the other required physical maintenance) of an acoustic piano keeps me away from acoustics and drives me to digital pianos. Just my 2 cents.

[The Real MC]

The tuning (and all the other required physical maintenance) of an acoustic piano keeps me away from acoustics and drives me to digital pianos. Just my 2 cents.

 

Some pianos hold their tuning really well so don't give up on them. When our parents had to be placed in long term care, I had their Kawai piano moved to my house. It was the piano I learned to play on and they bought it new for my piano lessons when I was a kid. After it was moved, the piano was STILL in tune.

 

I can appreciate the low maintenance of DPs but I haven't been happy with the stiff action on many of them, bought and sold three of them in the last ten years. When I got the parents' piano I had forgotten how good a real piano action feels and sounds. Also it's nice to play an instrument that doesn't need electricity and doesn't cost money to operate.

[Tom Williams]

You can intonate saxophone to a non-standard tuning note at one fingering. However, it throws out the intonation for the other fingerings. Otherwise, it would be possible to create a bari sax by putting a really long neck pipe on an alto sax. It would be perfectly in tune at one note.

Wonderful point! But then why is the mouthpiece moveable? Answer: to adjust to whatever pitch standard is in effect. Since A435 is only 20 cents lower, or a pipe-length difference of about 1%, I think that that slight down-tuning on a sax would be doable. Not perfect, but even-tempered ain't perfect anyway.

 

Flutes shouldn't have much trouble, since some of the adjustment is made at the mouthpiece aperture.

 

Brasses would have no trouble at all.

 

Retuning an A442 marimba to A435 would stink, especially if the next gig required A440 or 442 (preferred by mallets so they stick out a bit). Probably better to just have an extra set of marimba/xylophone/vibes/whatnot that are tuned to A435 if it comes up that often.

 

Another poignant reminder that we electronic keyboardists have really got it good! If you want Werckmeister, with F as tonic, tuned to A435, go to this menu and hit Enter twice. :-)

[jazzpiano88]

I've been stretch tuning the organ since the Pandemic. It's gotten me lowered, but not sure the Hertz are worth it.

[Tom Williams]

I've been stretch tuning the organ since the Pandemic. It's gotten me lowered, but not sure the Hertz are worth it.

Bravo!

[bourniplus]

I've been stretch tuning the organ since the Pandemic. It's gotten me lowered, but not sure the Hertz are worth it.