Wolf tone/dead note question?

[gordon]

Recently I've been noticing that when I play a "G" on the high "E" string that it sounds like it's quieter and maybe a little fuzzy compared to the other notes. Oddly enough the "F" note on the treble string sounds very clear and louder than other notes.
I checked the action, relief and looked for a high fret and all is spot on. Then it occurred to me to check the "F" and "G" in other areas of the guitar on different strings and low and behold the "G" is quieter and the "F" is louder.
I assume it has something to do with the frequency inherent in this guitar or something like that.
The open "G" sounds fine which I don't understand.
BTW It's a cedar topped Kevin Ryan guitar.
Anyone here ever encounter this and have an explanation?

[Bob Webster]

The F note is at around 349Hz and is probably benefitting from the support of one of the T(1,2) vibrational modes of the top. This is exceedingly common. The frequency of the mode is probably not exactly at 349Hz but somewhat higher. What does the F# sound like relative to both the F and the G? It's also common for the note just higher in frequency than the vibrational mode to be somewhat lower in intensity.

The G note from the open G is at 196Hz, almost 2-fold lower and it's top amplitude is more influenced by the drum like T(0,0) mode and the corresponding air mode and should be well supported.

Does the F note on the E string have the same sustain as adjacent notes? Two hallmarks of a wold tone are much greater intensity than adjacent notes and lower sustain. The reason is that vibration of the top is most efficient at frequencies corresponding to natural vibrational modes of either the top or the air in the guitar. This leads to a real "dumping" of energy very fast.

Cheers,
Bob

[gordon]

Hi Bob,
I tried to analyze the notes as indicated in your response.

I'm not sure if I hear a difference in the F# or not but I can hear the same muted sound of the G# as I hear on the G and it seems to dissipate as you move up the scale.

I would say that the F does not sustain as long but it's a subtle thing.

I tuned to a few open/alternate tunings and the same thing happens just at a different fret.

[Bob Webster]

Sounds like a pretty normal guitar to me. I've done extensive analytical recordings of guitars of all qualities and can tell you that there is no such thing as a perfectly even response. It's the nature of the beast that there can be a range of up to 15dB (that's 32-fold linear difference) among the fundamental frequencies of the notes in an E scale on the treble E string. Why, and what else is happening with the guitar and our ears to make it sound like less variance, is a BIG book.

Cheers,
Bob

[gordon]

Something occurred to me Bob.

It seems to me that this same thing "appeared" last winter. Is there some correlation between the change in humidity and temperature and the body frequencies of the guitar?

The guitar is always cased when not played and the instruments are kept in a humidity controlled room at between 45%-50% humidity.

[Bob Webster]

Yeah, I think everyone has some experience at how their instrument responds when the temps or humidity is unusual. As the humidity goes up and the wood gains moisture, it also gains weight. One outcome is that the frequencies of all the modes shift downward subtly. The converse is also true.

Also, the actual moisture content of air is different for 45-50% humidity at low vs high temperature. As I have time, I'll look that up again and pass on what the actual numbers are. The point is that the wood is presented with difference water content in the air as the temperature varies but the relative humidity stays the same.

Bob

[gordon]

That's a good and interesting point Bob. In the winter the RH may be at 45-50% but the room temperature is usually around 65 degrees as opposed to the summer months being around 70 degrees.

[FRANK]

wow

[gordon]

Thanks for the help Bob.

[Tim Mace]

I think this could be due to the tap tone of your sound/board/box...you mentioned inherent.If your instrument taps out at an F the F will be more pronounced when struck. Believe me I'm no authority
but i have experienced what you're saying.Overtones sympathetic to F. It could be another note on a different instrument,Then again, it could be none of the above explanations.Is it properly compensated?

[gordon]

Hi Tim,
I think what you're saying is the same theory as the resonant frequency of the guitar being the F note and the same applies to canceling out the G & G#, therefore, causing the quieter/fuzzy notes as well. Does that make sense?

As far as intonation. None of the notes are out of tune. The intonation is good.

How would poor intonation cause what I'm experiencing?

Thanks

[Tim Mace]

beats me...just grasping at strings! The tone freq. idea sounds pliable but how would you adjust it? Different
string gauge?
could it be a defective string?I've had bends in strings that caused weird tonal flaws.For example if the string gets moved from its original placement due to adjusting.Crooked so to speak like if at one time where it sat in the nut slot and was brought forward into the playing field now there's a kink.I'm running out of steam..........

[Bob Webster]

Hi, Tim and Gordon. The top frequency is a consequence of how the guitar is built. Specifically, the top bracing and thickness primarily, and the body shape, dimensions, and construction secondarily, all conspire to produce a guitar with a specific set of resonant frequencies. When you tap the top of the guitar, what you hear is the output from the first six or so resonant frequencies.

If you want to change these at all, then one needs to selectively thin braces or the top in a fashion that will target the specific resonant frequency that is giving the wolf tone. This is a bit risky and has to be undertaken with a very light hand because making a change in one vibrational mode most often also changes others to some extent.

Changing that wolf tone won't, however, can't be achieved by changing strings; that wolf tone is an intrinsic property of the instrument as it was built.

Bob