realtime bending of strings to bring classical guitar in tune [closed]

Question

While talking with a friend, I mentioned that the width of a classical guitar neck is quite large, to allow a player room to slightly and subtly bend a string (or strings) by moving fingers parallel to frets to bring chords more accurately in tune while playing. Although this is arguably an advanced technique, it surely is used, particularly on held chords where this “pushing” of strings on frets will really help land a chord in better tune.

Two questions:

1. Any suggested pieces where unless this done, the equal temperament of the guitar is really noticeably out of tune? (I expect there are some trickster composers out there who have written music specifically to exploit this requirement for satisfactory performances).

2. Any link to a particular youtube clip where it is clear that the performer is doing this bending to bring chords into better tune?

I’d like to show my friend this being done, on a piece of classical guitar music.

Thanks.

— edit amendment:

Thanks for the interesting comments. I would really like a youtube clip of a competent performer playing an established work from the standard repertoire, that shows this kind of bending going on. I’ve done some dives down youtube rabbit holes, and found some that it looks like this is what’s going on, but I’d really love to have one where it’s really obvious, in case someone knows of one.

All in good fun, I’m not in an (ill-tempered) argument with anyone or anything, it’s just interesting to me.

Answer 1

Perhaps the equal temperament interval that has the highest potential to sound out of tune is major third (or tenth or seventeenth...). However the top note in equal temperament sounds sharp with respect to just temperament, so in order to "fix" it one would need to lower the top note, not bend it. Trying to bend the bottom note would likely make the whole chord sound out of tune.

Classical guitars often have issues with intonation, especially at the higher frets. Part of the issue is that the bridge doesn't allow for easy adjustment, most classical guitars also don't have truss rod.

Indeed some people sometimes bend some notes in some chords, or adjust tuning to make sure the most critical chords sound well. But I would say it depends more on specific instrument.

Classical guitar is built with equal temperament in mind. Older instruments, like lutes or baroque guitars had often gut frets which you could slide along the neck to adjust intonation. But that of course meant compromises (by adjusting one note you made another out of tune), and possibly required adjustments whenever you played piece in another key.

Answer 2

Two things: A fixed, straight fret guitar won’t really be ET anyway, because the tuning depends on more things than just the distance. Basically when you press down the string the tension changes, and depending on the diameter of the string the geometry might be a bit different.

That being said, a decent guitar will be quite well in tune.

The other thing is that with plucked instruments you do not have a fixed intonation. When the intonation of the string will depend on the amplitude, thus starting higher and dropping. As a result of this the brain cannot really detect tuning differences as well as on let’s say a bowed instrument (because there never is any constant pitch).

This means that on a sufficiently well intonated instrument the difference to pure intervals are less noticeable than on other instruments.