DIGITAL GUITAR AUTO-TUNER PROJECT

Jerry Avins wrote in news:brydnYP4-My62 snipped-for-privacy@rcn.net:

It

Sounds like fun! but I'd take the Steinway.

Al

THERE HAVE BEEN A LITTLE LESS THAN A HUNDRED REPLIES ON THIS THREAD BUT UNDOUBTLY, IT TOTALLY CLEAR THAT YOU'RE THE ONLY ASSHOLE HANGING AROUND WITH SERIOUS THINKERS. IF IT SO HAPPENED THAT ALL OF THE OTHERS RESPONDED THE WAY YOU DID, MAYBE I WOULD THINK I WAS BEING AN ASSHOLE.

GUESS WHAT? YOU'RE THE SOLE STINKING SHIT SURROUNDED BY DECENT INTELLIGENT PEOPLE.

IM GETTING THINGS QUITE FAST NOW AND I CAN SAY THAT I CAN FINISH THE PROJECT ON TIME. THANKS FOR ALL THE GREAT MINDS WHO SHARED THEIR VIEWS AND EXPERTISE. SO IM KEEPING MY JOB, IM GETTING A LOT MORE LEARNING THAN EVER BEFORE AND I FOUND NEW GREAT FRIENDS ALL OVER THE WORLD.

AS FOR YOU, SAY SORRY TO YOUR MOTHER BECAUSE YOU JUST PROVED THAT SHE DEFINITELY FAILED TO RAISE YOU WELL...

I read in sci.electronics.design that Jerry Avins wrote (in ) about 'DIGITAL GUITAR AUTO-TUNER PROJECT', on Mon, 25 Apr 2005:

An ichthyology group should be added, so that tuna experts can participate.

Tony (remove the "_" to reply by email)

That sounds fishy.

How many newts in the scale?

How many scales on a newt?

Ken

On Mon, 25 Apr 2005 15:43:53 -0400, Jerry Avins wrote:

Lower harmonics may well be locked together through the bridge interaction, though I believe that with increasing harmonic number there is less coupling at the bridge, the most coupling being at the fundamental. But there's another phenomenon in the piano having nothing to do with harmonics when several strings are sounded in unison, and this causes tje result described above, "Exact tuning makes the note loud ans it's [and its] decay rapid" and you would presumably see this in the amplitude on the oscilloscope, especially if you were looking for a perfect exponential decay of amplitude, and wonder what's going on. The decay will be quite fast in the first few seconds, then much slower in the seconds thereafter. When the hammer strikes the strings, they are all in phase, going up and down (presuming a grand piano with horizontal strings) together, and passing a lot of energy to the bridge (which goes up and down with the strings, and transferring this motion to the air), resulting in much energy being taken from the strings and a high decay rate. But due to the coupling at the bridge, one or two of the three strings will eventually change phase until one is going up while the other(s) are going down. At this point, much less energy (in relation to the amplitude of each string vibration) is transferred to the bridge (when one string goes up, its effect on the bridge is mostly canceled by the other string(s) going down, so the bridge moves up and down a lot less in relation to string motion), and since less energy is being taken out of the strings at the bridge, their decay rate is much longer. This is a part of the piano's sound (fast decay at the start of the note, slow decay after a few seconds) that cannot be made with a single-string-per-course instrument. I intentionally ignored the harmonics in the above description to simplify things, but the harmonics might also change phase in the same or a similar way. There have been three or four articles on the piano in Scientific American over the past 30 or 40 years, and I recall reading the above description of the string changing phase in one of them.

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The converse of a statement proves nothing. ;-)

...

Oh? I thought it proved the converse.

Jerry

-- Engineering is the art of making what you want from things you can get. ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

That's a good description that I omitted for brevity. You did a better job of describing it than I would have. The math, at least for two strings, is relatively simple. It is in many texts on diff-eq for engineers and physics lab demos as the "coupled pendulum" demonstration. Tuning the strings so that they just barely lock in frequency gives the longest sustain. If they slip just a bit further apart than that, the typical way-out-of-tune twang is the result. Just a touch with a quarter-inch-drive socket face up and turned with an Allen wrench can restore the lock. When three strings are involved, it is usually easy to identify the one that slipped. With two, even if you tweak the wrong string and so leave the note out of tune, it sounds so much better that you'll get laurels anyway. When you know how things work, the world is one big sandbox.

Jerry

Ok, so my optical idea wasn't taken well. What about dopler radar? I remember when police radars were calibrated using tuning forks.

Yeah, microphones are just too obvious. ;-)

No, I think you'll find that it does _not_ prove the converse. ;-)

someinteresting reading about harmonics and overtones

harmonics overtones modes inhamonicity

You mean that proving the converse doesn't prove anything? Oh, I get it!

The converse of something is nothing.

Proving the converse of something proves nothing.

Ah, so!

Jerry

I read in sci.electronics.design that Ben Bradley wrote (in ) about 'DIGITAL GUITAR AUTO-TUNER PROJECT', on Thu, 28 Apr 2005:

If one or both of the outer strings shifts phase, in such a way that the bridge can twist, the decay is different from the case where the middle string shifts (relatively).

That's funny! All the ideas are smart.

What's funny? What ideas?

Usenet messages need to stand by themselves. There is no guarantee that any older messages are available to the receipient. That is why we quote the relevant portions, and post replies after (or intermixed with) the quoted portion. The google usenet interfact is seriously broken, but you can live with it if you follow the instructins below in my sig.