Major third chords less dissonant with the third note lowered

[rick-slo]

Originally Posted by PiousDevil

I think during most chords in which the 3rd is fretted we unconsciously make minute adjustments with our finger pressure to get the sweetest sounding note that we can.

Hard to counteract a note sounding sharp unfortunately.

[charles Tauber]

Originally Posted by vindibona1

The system of equal temperament is off by design...The thing is that the intonation issue is most clear when playing triads or chords.

Those are two different, unrelated things. The first is temperament, which determines the target pitches. The second is intonation, which is how closely or accurately an instrument is able to achieve the target pitches.

By design, nearly all guitars are fretted to produce pitches belonging to equal temperament. If a guitar had "perfect" intonation - was able to sound exactly the target pitches of equal temperament - it would still sound out of tune. It sounds out of tune, not because of a failure of the instrument to accurately produce the target pitches, but because the target pitches are off. Intonation is a separate issue from temperament. (It's also a different issue that many, many guitars have poor intonation and many buyers either don't expect better or can't tell the difference.)

Since you can't, on most guitars, move the frets around so that they do not produce equal temperament pitches, the best you can do is decide how you want adjust string tensions to have specific notes, at specific frets, sound "better" and deviate from the pitches of equal temperament. As others have pointed out, it moves the out-of-tuneness around, possibly to a place that is temporarily less objectionable for that specific key or piece of music.

[Stomp]

Shifting the tuning around to suit the situation is common practise, but you need to be familiar with the flaws in Equal temperament and how Just Intonation works.

Take a bluegrass band as an example, the fiddler will often tune the open G straight and stack perfect fifths on that G (701.9 cent intervals instead of Equally tempered 700 cents), making the open E string sharp of ET by 5.7 cents.
Out of tune? Not really, as fiddlers say "better sharp than out of tune" (Sweetener FDL).
A concert violinist will tune differently with the A string tuned "straight" and the others tuned in perfect fifths above and below the A (Sweetener VLN).

The Dobro player will invariably lower the B strings by the full 13.7 cents to get a pure beatless third (Sweetener DB0).
Does he worry about "blending in"? No, it's about sounding good - he just watches when he plays what, those sweet triads are worth it.

The banjo player will also lower the B string a smidge (about halfway between an Equally tempered third and a Just intoned third - Sweetener BJO).

Then there's pedal steel, with three different pitches for F# etc. (Sweeteners SE9, SC6 etc.)

It's all about having your instrument sound as good as possible within itself while being aware of the general tonal center of what's being played.
Equal temperament is a distant object in the rearview mirror at that stage...it's a good basis, sure, but trust your ears.
What sounds good to you is probably going to sound good to others too, just be aware of how tuning works.

Our tuners are just the programmable assistants which can show you visually how to get to what your ears want to hear, when your ears can't hear (e.g. on stage).
Purely IMHO of course .

[DesertTwang]

Originally Posted by PiousDevil

I think during most chords in which the 3rd is fretted we unconsciously make minute adjustments with our finger pressure to get the sweetest sounding note that we can.

An intriguing thought. I'll try to pay attention to this from now on.

[PiousDevil]

Originally Posted by rick-slo

Hard to counteract a note sounding sharp unfortunately.

You’re right that there is very little you can do in regards to pressure to flatten the actual third, but I guess what I mean is you can sharpen the other notes around it (except the open root, in the case of the D shape obviously)

[ljguitar]

Originally Posted by rick-slo

Hard to counteract a note sounding sharp unfortunately.

Hi r-s

It's why I squeeze other notes in the chord a bit sharp too. It's more in tune with itself.

Not everyone hears out-of-tuneness unless it's extreme.

One observation I made early on is when you play a guitar your not only hear out of tune notes, you feel them when playing particularly resonant instruments.