Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum How does an ETD work?

I mean how does it calculate the tuning curve from the inharmonicity values?

What is the mathematics behind it?

How does it fit all the intervals?
Are all fifths contracted, all fourths wide, all thirds wide etc. after an ETD tuning?

The stretch can go up to 50 or more cents at C8 in some pianos. Are the fifths are still all contracted in those octaves? How are they stretched, all 2 cents narrow or what?

I tried to make an Excel sheet using the inharmonicity values of my piano and the Fleitcher(?) equation and 2:1 octave at the temperament, 4:1 at treble and 8:4 at the bass, but could not fit a curve that satisfied all the intervals.

I know this is lots of questions, but I am a curious person.

It has an algorithm or computer program that some human or humans have developed that take what the unit is able to measure and processes it according to a formula that the humans have developed that they think does a good job of providing an output that will guide the person using the device in setting the pitch of a given string.

Thread closed!

Its far more complicated than having a single curve. None of the ETD's I've tuned with have ever shown me a literal "curve." That's why you have piano tuners in charge of the machines. Each ETD measures the piano and gives its best "curve" based on the formulas programmed into it. And an 8:4 to 4:1 stretch is a huge difference. I have a customer who prefers that exact stretch, actually, but it sounds terrible to me. I ended up tuning his piano with almost no help from my ETD at all, simply because the machine had issues with the transition.

What octave types do you suggest?
My piano is a Kawai RX-2 (5' 10")

How about 12:6 octaves instead of 8:4?

This link will give you all the technical details for the Sanderson Accu-tuner. Click on "Images" to see more. You may notice with this system there are uniform, slightly sharp by a beat/sec or so, double octaves across the range.

Hakki,
I may have missed it, and if so, I apologize. Could you please explain where you are at personally in your quest for information?
Have you ever tuned a piano? Are you really trying to learn or are you just throwing theoretical questions out there?

Wishing you the best,
--Keith

50 cts at A88 may be exceptionally rare. I only have seen that on ETD s a quarter tone high is too much for me. Also this gives a false impression, based on that last note, that there are tons of stretch to use in the treble.

It all will depend of the shape or curve you adopt in mediums, and it is not so easy to be moderated with stretch.

Strangely , in the treble I hardly ask myself about stretch, the justness is there or no. I stopped those arpeggios vs plain octave tests, probably I listen differently.

My "default" setting is 6:3 4:2. This is entirely subjective, of course. If it sounds good to you, its all good. For more information on THAT subject, look at any of the temperament forums, if you dare.

A88?

I'd like to see this keyboard. Starts at G0 apparently?

Isaac, why did you post to this thread? The original poster had very technical questions about the internal workings of the electronic tuning devices. You've answered none of those questions.

If you have nothing to contribute, why do you insist on writing? You're wasting everyone's time.

Would you please go away?

Chris

Actually Isaac has posted about his use of ETDs in the past.

He was quite complimentary about Dirk's Tuner a few months ago. That evaluates all the intervals and comes up with an optimum tuning.

Do any other ETDs do that or something equivalent?

My dear love,

I have used the Accutuner, RCT on a a Mac , a VT100, tested Tunelab (that I have yet a demo version on my cellphone)

ANd lately tested the excellent loutput of DIrk's tuning software on a PC laptop (works in Hz, BTW, which is more natural to a tuner than cts, somehow)

I used RCT and VT100 for concert tunings mostly.

Then when I talk about ETD's it is not for the tuning of winter spinets.

I was so much enthusiastic with US based piano technology in those times, taking things for granted.

There are many excellent things but they are overwhelmed by tons of less good ones, many of them stated in the intention to be a little famous, and that tend to corrupt the honesty of the thinking.

There is also a very basically different musical taste that may possibly allow for those differences in final product I had to notice.

All ETD tuners pretend to tune aurally under the scrutinity of the ETD.
Rare ones are as honest to state they just tune note by note an check the result at the end, knowing the pianists are all but exigent when it comes to temperament and mediums in the piano.
Progressiveness o intervals is checked rapidly

When tuning under the scrutiny of ETD you leave the ETD aside, generally after some time, for the reasons that you do not agree totally with it but when you make a lot of checks the ETD is OK with itself , which is not so surprising as the software follows its own logic .

Just opening the ETD and entering the good tuning file, the piano have yet begin to be tuned.
Waiting for the display to be stable to tune, robs also a few fractions of seconds at each note.
Looking at something while you need to listen in a concentrated way is not ideal, also.

I find no ETD able to put some DNA in intervals, this is the job of the tuner. This sounded surprizing but the generated intervals sound somehow cold or non natural, while certainly this can only be perceived by some tuners.

AS is repeating ALfredo Capurso often, the original ET model is flawed, and what ETD's are able to do is a lot of compromising.

I leave aside that the display, as precise it can be, does not reflect the tone, only pitches, those ct level of precision is a joke. A single string have yet a larger leeway than that, pitch wise, so what is tuned is a sort of stabilized version of piano tone, ue to the need to have a quiet display

That make those tools interesting, even fascinating, but they have no soul.

THe terrible thing is that they modify your tuning without you realizing it. A friend I know was a fine tuner, today his tunings are somehow cold and miss "life" , and he do not realize that, he is just bored of tuning.

The two persons that developed ETD software I exchanged with (and that did not had to be defensive about the precision of their tool) also witnessed me of imprecision due to the signal processing and the inconsistencies in piano strings spectra.

The other solution is to tune to a predefined acoustical shape that is in tune with itself.


As a trained acoustical technician you may be able to understand that probably.

Hz relate to tuning lever motion, cts is intellectual.

Indeed the higher you go, the faster the display, but the same happens with the lever.

Display in Hz oblige to really tune, even if I do not find it so comfortable, it obliged me to use my "tuner's ear" while cts display have no musical meaning or relation when I look at the display.

Sorry to promote something that is sold as "tune your piano yourself",something I am opposed to unless the piano is so old and in bad condition it would be difficult to find a professional tuner to tune it.

The fact is the algorithm used is particularly efficient, using late research done on tuning, possibly, or derived by a lot of work with a professional tuner, looking for an optimal set of rules.
May be the fact that those rules where based on the way pianos are tuned in Europe did change something, I dont know.
But the result differs with other ETD I tested by a better congruence for basses and (high) treble particularely.

You can use the free version of the software to check roughly an aural tuning, and look for the mistakes aurally where you will see the peaks.

The fact is when you know how to produce the perfect tuning, you feel allowed to slightly depart from it if you feel the desire to.

Hakki,

If you are interested in the mathematical computer algorithms that are taking place inside the various electronic tuning devices, Chris' advice is good. Searching the patents reveals extensive information.

You can do a search of Google patents for the authors and their devices. You'll find more than you ever wanted to know about how the devices work. And like Wikipedia, one patent search will lead you to another patent, and so on. The algorithms making up the RCT, for example, appear to be protected under several different patents.

Sanderson Accu-tuner (SAT)- authored by Albert E. Sanderson
Reyburn Cyber Tuner (RCT) - Authored by Dean Laurence Reyburn
Verituner - authored by David J. Carpenter.

You're on your own with Tunelab, OnlyPure, and Dirk's... Can't help you there.

Good luck! You've asked a very difficult question. Reading all the patent information is going to be like drinking from a fire hose.

Hope I've helped,

Great !!

That was what I was looking for thank you very much.

Looks nice, thanks!

btw easier download here

http://www.google.com/patents/US5285711.pdf

The Reyburn patent is here

http://www.google.com/patents/EP1775713B1.pdf

and

http://www.google.com/patents/US20070079688.pdf

and the reyburn program manual is here

http://web.archive.org/web/20010605111511/www.reyburn.com/pub/reyburn/rct_demo/rct3man.pdf

Thank you wouter for the links.

And here is the Verituner patent:

https://www.google.com/patents/US6613971.pdf