Guitar Waking Up?

Discussions relating to the classical guitar which don't fit elsewhere.
Andrew Pohlman
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Re: Guitar Waking Up?

Post by Andrew Pohlman » Tue Feb 13, 2018 10:49 pm

To answer this question with objective data is possible - if you have unlimited funds to spend. The largest barrier in my mind is getting consistent measurements over time. Even 5-10 mins between measurements can make a difference. But testing "playing in" phenomena over the span of years would be brutally difficult.

For example, my practice chair squeaks when I first sit in it. After a few minutes, the creaks stop for the session. Is my chair "waking up" ? Will the microphones "wake up" ? Will the differences in the chair or mics affect the objectivity of the recording? Can you write a calibration curve to mathematically eliminate any known change effects for consistent objectivity over time ? Yeah, but it'll cost you. And due to cost, maybe other reasons too, nobody has done comprehensive research.

On this topic, I take the humanistic approach. If you think it sounds different or better, cool! I personally hear near zero differences comparing the first few minutes of practice, to the last few. Warm weather or cold? I can feel it my hands, but no sonic differences at all from the instrument. And I think Alan Carruth said a while back - paraphrasing - you may be able to prove differences occur, but those differences may or may not affect sound or tone.
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chiral3
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Location: Philadelphia Area, PA / New York.

Re: Guitar Waking Up?

Post by chiral3 » Tue Feb 13, 2018 10:59 pm

I gave the example, without explicitly naming it, of Tartini. Here’s a combination tone that will unequivocally be measured to not exist yet unequivocally be perceived by every human, that is present, to exist (humans without hearing loss... this is also used to test for hearing loss). The boxes of the 4x4 hear / no hear / measure / no measure grid are filled with endless examples.
物の哀れ

Alan Carruth
Luthier
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Re: Guitar Waking Up?

Post by Alan Carruth » Wed Feb 14, 2018 5:30 pm

There certainly are subjective processes in hearing, such at the Tartini combination tones, that are clearly heard by most people but do not exist physically. They're something that is built into our ear/brain system. As I see it, part of the question here is whether the phenomena of 'warming up' and 'playing in', which are widely, if not universally, credited, are similarly subjective or are actual changes in the guitar, and measurable. I have enough evidence to suggest that they're physical changes, but not enough to be really sure. I don't think 'unlimited' funds and time will be needed to demonstrate either, but certainly it will require some effort. The main issue is that there is no monetary pay-off for the work: the big factories who have the wherewithal to do the experiments don't see any reason to, and individuals who might see more practical use can't afford to do the experiments.

I will say that demonstrating that either warming up or playing in actually happens will be one heck of a lot easier than figuring out why.

chiral3
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Re: Guitar Waking Up?

Post by chiral3 » Wed Feb 14, 2018 7:42 pm

Alan, I cherry-picked Tartini as an example because it is a non-linearity in the human ear. In this regard, while technically subjective, they do exist physically. Maybe not for a tree sloth, but they do exist for humans. In measurement we tend to be very good at isolating individual slices (Chladni, (x, y=0, z=0), etc.), or solving for global systems assuming they are linearized. I see the same issues and measurement arguments in audio engineering. General relativity is probably the best large scale physical example of a system that is easy to solve when linearized but impossible otherwise. In my day job part of what I do is solve PDEs and SDEs via Monte Carlo simulation on very large GPU-grids. 95% of the time I can explain most of what I am seeing and thinking with all the linear first order terms that I calculate. This isn’t disimilar to the calculations that are done in violin, guitar, audio. Where things get interesting are in the higher-order and cross terms. The non-linearities. On most days my d^nY/dX^n terms aren’t very interesting, but on the most interesting days they are. I am not saying anything that hasn’t been said, but I have millions of dollars to spend on my systems and 30 PhD level researchers to code up and tweak my math so I know “why”. Since these resources will never be applied to a guitar, and barring some really clever shortcut, I can only assume that if we think these things are there, and we have our cognitive biases roughly accounted for, then they are probably present. So I agree that it would be possible to measure in some top-down fashion. But, to your point, I like to know why, and this bottom-up analysis probably never happen, so the answer, at least to me, will never be satisfying.
物の哀れ

Alan Carruth
Luthier
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Re: Guitar Waking Up?

Post by Alan Carruth » Thu Feb 15, 2018 3:09 pm

All the best evidence I'm aware of says that the guitar is vanishingly close to linear, but it's still complex!

A few years ago I set up a simple rig to look at the forces a vibrating string puts on the saddle top. I wanted to verify the math relating the transverse force with the twice-per-cycle tension change. In the process of making the measurements I found a longitudinal compression wave in the string, which seems to be primarily driven by the off-center-of-length pluck. Naturally verifying and tightening up the quantities on this is requiring a major upgrade in my apparatus, and a bunch of time, which has to be stolen from my other, paying activities . All of the equations that describe this are linear, but when you stack them up things get 'interesting'. And the string is the simple part of the system.... ;)

John Stone
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Re: Guitar Waking Up?

Post by John Stone » Sun Feb 18, 2018 6:42 am

Alan Carruth wrote:
Wed Feb 14, 2018 5:30 pm
As I see it, part of the question here is whether the phenomena of 'warming up' and 'playing in', which are widely, if not universally, credited, are similarly subjective or are actual changes in the guitar, and measurable. I have enough evidence to suggest that they're physical changes, but not enough to be really sure.
This is fascinating to me because I've read about some of the related experiments you've done and I appreciate the ideal of objectivity that you bring to issues like this.
Bill B wrote:
Sat Feb 10, 2018 4:52 am
it seems like a more magical world sometimes. I almost wish i believed i could hear half the things so many musicians claim to hear. I have thought i could hear many of them at various points, but sadly i cannot.
Perhaps you don't hear particularly well? Seriously -- that's not intended in a snarky way.
2001 Manuel Velazquez
1977 Ramirez 1a
2014 Cordoba C10
They said, "You have a blue guitar, You do not play things as they are." The man replied, "Things as they are / Are changed upon the blue guitar."

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