Inharmonics.

[XW-Addict]

This function in the PX5S  Stretch tune, has not been covered yet. It sounds like a very deep part to the piano part.

I know now it has to do with tuning , doubling of frequency and the human ear hears flat. And imperfect 

in tune piano strings something.  

 

 

[Jokeyman123]

It is related to upper register-upper octaves on the piano. Our ears tend to hear those pitches in particular as "flat". I'd have to look it up, but i think it affects only the top 2 octaves in an 88-note keyboard with digitals but i could be wrong. I'm not sure if this digital stretch tuning stretches the lower octaves too. In an acoustic piano, this also has to be done to make the lower register sound in tune to our ears, even though mathematically it is changing the actual exact ratios theoretically needed to keep each octave in tune. This it what made tuning an acoustic piano a brutal proposition only for someone with a good strobe tuner and great hearing, since one needs both to get a piano tuned properly. And all instruments have to be adjusted in some way to sound in tune as a solo instrument which will now make certain notes on that instrument out of tune with other instruments! I had to know all this unfortunately  

to conduct and rehearse groups. and why you often would see certain instruments played only in  a solo context-it is easier to get instruments to sound in tune together, if the difficult instrument is set in a solo part. iI's.....unfortunately complicated.  Just ask any guitar player and keyboard player in a band how they are getting along with each other............!

[mike71]

Another reason is that higher octave strings are short, so their diameter to lenght ratio is lower thah middle strings.

So their harmonic content stars to have  more harmonics at odd ratios, so to make them to sound better with lower octaves they have to be stretched.

[XW-Addict]

This function helps the keyboard player to set a setting to play well with other musician instrument in tune if not else basically.

[Jokeyman123]

And this is  why 1) piano tuners used to make alot of money-some still do I guess-and 2) why digital pianos were invented (well partially).

[Joe Muscara]

17 hours ago, Jokeyman123 said:

This it what made tuning an acoustic piano a brutal proposition only for someone with a good strobe tuner and great hearing, since one needs both to get a piano tuned properly.

Not true. There have been and still are people that can tune a piano completely by ear! Well, they usually do use a tuning fork to tune one note (A above middle C, 440 Hz), but then they tune everything else on ratios above and below that.

 

Ratios of what, you ask? Counting beats. If you've ever tuned a guitar, you know that when two strings are playing the exact same note, there's no "beating" between them, it's perfectly smooth. If one string is slightly out of tune with the other, you'll hear the two waves going in and out of sync with each other. That's the beating I'm talking about. You an also hear this when one of the strings for single note on a piano is out of tune with the others. In order to tune one of the other notes to that A that I mentioned above, you have to know the ratio of that note to the A. It's mostly that simple when it comes to notes around the middle of the piano, which are tuned as you might expect.

 

 

But here's the trick. Even though we think of a note being A=440, 220, 110, 880, etc., no note is purely one frequency. There are actually multiple frequencies generated by each string or whatever the instrument uses to make a note. This is what gives it its timbre. If every note was just that one pure frequency, it would be a sine wave, and if every instrument did that, they would all sound the same and music and life would be pretty boring. Instead, each note has overtones or partials which are usually whole multiples of the fundamental frequency. But what happens is, various factors can cause the overtones to deviate from this ideal. This is inharmonicity. Stretch tuning accounts for this by tuning to one of the partials instead of the fundamental frequency. Different ratios can be chosen as well to provide different amounts of stretch.

 

There's some good stuff on Wikipedia about this with much more detail than I have provided here.

 

Inharmonicity

Piano tuning  - particularly, see the section on Stretch

 

I would be interested to know what the different Stretch options are on the PX-5S. I just took a quick look at the manual PDFs I have but besides listing their names, they didn't describe what the differences are.

[Brad Saucier]

Storytime.  Growing up, our town had a piano tuner everyone knew was the best around.  Anyone who needed a tuning called him.  He was born with no eyesight.  Mr. Buddy showed up with his small bag of basic tuning tools, felt his way around the piano and worked his magic. I still remember that day as a kid watching him tune moms upright piano.  Sadly he passed away before I could really know him.  

[Jokeyman123]

I had to maintain 3 rather shop-worn uprights in my school music program-and the best tuner in all North Jersey still used the strobe tuner-it was faster and after about 3-4 hours on a very bad piano-acoustic ear fatigue can bedevil even the best. Consider -3 strings per notes on the lower register-2 on the others and it can get very difficult getting everything just right. Unless one has about 2-3 or more days to bring up a badly neglected piano, a strobe makes it alot easier. it can be done of course it can be done strictly by ear-preferably 2 ears, but  would you want to? Not me, and I used to tune them myself without the strobe-really rough. And if you are tuning for someone else who tells you its still not right, even if you are sure it is-you can always fall back on showing them the strobe!

[Tom Williams]

Back to stretch tuning.  Yes, it covers the entire range of a string piano.  The counterintuitive reason is that the strings' overtones are not perfect multiples as e would expect; something about the realities of metal elasticity.  Anyway, the end result is that the piano just sounds better when each octave is a few cents wider than a pure 2-to-1 ratio.

 

Another weird example of that is Tympani, whose harmonics are quite sharp of the fundamental, which makes them seriously difficult to tune even for a one-note-at-a-time drum.

 

The fun comes in with pipe organs and orchestras, which do not need to be stretch tuned.  When a piano interacts with other instruments it is necessary to make compromises.  Usually the alterations are made in the piano, because retuning a pipe organ is a big task.

 

So now we have ROMplers which provide a little bit of everything, including built-in incompatibility between this set of samples and that set of samples.   On my Kurzweil keyboards, there are pianos, and then there are "440" pianos which have had the stretch tuning turned off to make them play better with other instruments.

 

 

[Joe Muscara]

BTW, I tune my acoustic piano myself, but I do it 100% with a tuning app that real tuners use (there are several, I use TuneLab, which is available on several platforms). I wish I could do it by ear. I just use my ears to make sure it sounds good as I do it and when I'm done.

 

I know tuners that do it by tuning the area around A=440 with a tuning app, and the rest of the piano by ear from that. I have also had a guy who is completely blind do my previous piano all by ear. I'd have him do it again, but the part that I didn't like is that he touches the strings with his bare fingers, which I've had other tuners tell me is a no-no. I already have some tarnishing on my strings from a cat who walked across it when I wasn't in the room.

 

I still wish Casio would tell us the various stretches available on the PX-5S. Also, do any other models offer this? I haven't checked the manual for my PX-S3000 yet.

[XW-Addict]

Wow you guys I've learned much from this, This changed my perspective and made me more curious about the extend of the PX5S piano tones.

I can only second guess the piano sample complexity and if stretch doubles or reduce the tuning effect.

[Jokeyman123]

On the PX560 at least, it "sounds like" only the upper 2 octaves are being raised a tiny amount proportionately, but lower octaves are harder to "hear" since  lowest bass tones on the piano are a little harder for me to hear pitch. I don't "hear" much change in the middle registers, but my hearing can play tricks on perception of pitch, so not sure what is happening with stretch tuning on the 560 but it sounds better to me. Not related in this post I guess, but I have trouble getting the G string on guitars just right in relation to other strings. If I don't tune to octaves all over the fingerboard, I find it very difficult to get a sound that sounds right with chords, even with a digital tuner. Add piano chords and it's murder!

 

Timpani-trick was always have a tuning fork in your pocket, hold it to your temple-with ambient noise, this was the only way to hear the pitch loudly enough on the fork-or on the head of the timpani which would amplify the fork's pitch. To graduate from college, I had to play a piece on 5 timps-one etude in an hour recital full of other solo and ensemble pieces (yeah) all tuned differently for each "movement" of the etude, and with different mallets, sometimes in the same phrase-took months to perfect it. I think i still have the score somewhere, my sanity lost that a long time ago! 

                                                               

                                                                                                                           yours truly, Stretch Armstrong

[Vcombo]

Hi,

sorry for reviving this old thread, but I 'discovered' PX5s stretch tuning just now.
hard (for me) to hear it 'absolutely' (one doubt if it's real or just 'imagined' - eventually influenced by the psychological effect of touching the +/- buttons )
So the idea was: layer 2 Grands, switch st off on the 1st and change st on the 2nd - and voila: there's massive beats ('saloon type' piano) in all octaves with the center around B4 (H4).
The nuances between st 'Piano1-5' are subtile (one can hear the differrence when layering e.g. st Piano1 with Piano2) and E.Piano2 is the largest 'stretch'

Edited January 15 by Vcombo