Bizarre resonance

[Dbone]

This RainSong I have here seems to have some sort of weird resonance going on related to an open G string. I don’t believe it was doing it when I first got it...I don’t think so anyway...

It’s almost as if the G string is louder than any other string, and it’s all you hear.

I’ve never experienced this before with my current Aria guitar or past Seagull...or any other guitar for that matter...

This guitar is going back to RainSong to be replaced for other reasons, but it still has me curious...

It’s quite annoying. Any thoughts?

[BlueStarfish]

Can you say if you also get the resonance when you play that same G, on another string? Stay, on fifth fret D string?

[btbliatout]

I'm probably going to be a broken record here, but my Rainsong doesn't seem to have any such issues.

Being primarily a nylon player, I can tell you the G string for nylon guitars are laughably notorious for being wonky. I don't know the physics behind it, but hearing that a G string is weird doesn't even phase me until I hear that someone's tried multiple types. In classical circles, it's not uncommon to use completely different types for the bass and the treble strings too, so you could try replacing JUST the G string, and trying out various strings, and see if the issue simmers down.

I'm no guitar tech though, so try this at your own risk, and don't yell at me if things don't work out. All I can say is I use D'addario Silk and Steel strings on my Rainsong, and love them. The low E string is obnoxiously mellow, but when plugged in the EQ makes up for it.

[penny]

Does your Rainsong have a pickup with a built in preamp?

[Dbone]

Originally Posted by BlueStarfish

Can you say if you also get the resonance when you play that same G, on another string? Stay, on fifth fret D string?

It does not seem to have the same problem as an open G. The open G is “offensive” in comparison, for lack of a better word.

[Dbone]

Originally Posted by btbliatout

I'm probably going to be a broken record here, but my Rainsong doesn't seem to have any such issues.

Being primarily a nylon player, I can tell you the G string for nylon guitars are laughably notorious for being wonky. I don't know the physics behind it, but hearing that a G string is weird doesn't even phase me until I hear that someone's tried multiple types. In classical circles, it's not uncommon to use completely different types for the bass and the treble strings too, so you could try replacing JUST the G string, and trying out various strings, and see if the issue simmers down.

I'm no guitar tech though, so try this at your own risk, and don't yell at me if things don't work out. All I can say is I use D'addario Silk and Steel strings on my Rainsong, and love them. The low E string is obnoxiously mellow, but when plugged in the EQ makes up for it.

All good...broken record away ;-0

The more info the better...I certainly didn’t rip and tear and try different strings. As I said, this guitar is going back and is getting replaced by RainSong, so that would be silly...

Thanks for the suggestion though. With any luck the replacement will not have the same issue ;-0

[Dbone]

Originally Posted by penny

Does your Rainsong have a pickup with a built in preamp?

It has an LR Baggs Stagepro Element fitted

[BlueStarfish]

One possibility is that you have a so-called “wolf tone” on open G (~196 hz).

What is wolf tone? Well, every guitar has a number of natural resonance frequencies. The two strongest are typically somewhere between F to G on the lower E string, and then also somewhere on the G string. These two resonances relate to the natural vibration frequency of the body chamber itself (for the lower one), and the soundboard alone (for the upper one).

If one of these natural resonances corresponds closely to a note you want to play, then the guitar will acoustically feed back with itself while playing that note. On the lower resonance, this comes across as the so-called “thuddy G” (or F# if it’s on F#). The note sounds louder, but quickly plays itself out and so sustains much less than the other notes on that string. “Thud.”

On the higher resonance, it can sound like a more traditional feedback scenario, with that note playing much louder than the others. That’s the obnoxious sound. The guitar is indeed acoustically feeding back on itself via the soundboard, generating higher volume.

I’ve read that wolf notes are particularly likely to manifest with high quality instruments (because lower quality ones don’t sustain as well or as clearly, and therefore mask the wolf notes). I also have read that wolf notes are even more problematic on cello (because of the bowing action, as opposed to picking or strumming).

My understanding is that there are a large number of variables that affect the resonance frequencies, and getting it right is part of the magic of lutherie. Right meaning, it’s best if the resonance frequencies fall exactly between two notes (so they are least likely to cause a wolf note). Once the guitar is built, it’s too late to change most of the variables. That said, it’s possible to marginally modify the upper resonance frequency by adding mass to the soundboard. Making the soundboard slightly heavier will reduce the resonance frequency.

I had this issue sounding on the G# (208 hz) of one of my guitars. That guitar is carbon and very lightly built. The resonance made G# on the G string sound very odd. Made playing an open E chord in particular sound weird — it wasn’t quite as noticeable if playing single note lines. The effect was also there, though weaker if G# was played on the D or A strings.

I was able to mitigate the problem enough to not mind by swapping in some brass bridge pins (and hence adding mass). For my guitar, 4 or 5 brass pins seemed to be the sweet spot. If I went to 6 brass pins, the resonance moved all the way down to G and that note got obnoxious.

If you don’t have a set of brass pins laying around, you could try taping 4 or 5 quarters just behind the bridge using some masking tape, to see if that mitigates the problem. If yes then you have your answer on what to do.

Another way to add mass, would be to install a soundhole mag pickup. If you have one laying around unused, that’s another cheap way to test to see if it solves the problem.

I don’t know if this is what is troubling your guitar or not, but on the chance it is, I share this experience with you. Best of luck sorting it out.

[Dbone]

Originally Posted by BlueStarfish

One possibility is that you have a so-called “wolf tone” on open G (~196 hz).

What is wolf tone? Well, every guitar has a number of natural resonance frequencies. The two strongest are typically somewhere between F to G on the lower E string, and then also somewhere on the G string. These two resonances relate to the natural vibration frequency of the body chamber itself (for the lower one), and the soundboard alone (for the upper one).

If one of these natural resonances corresponds closely to a note you want to play, then the guitar will acoustically feed back with itself while playing that note. On the lower resonance, this comes across as the so-called “thuddy G” (or F# if it’s on F#). The note sounds louder, but quickly plays itself out and so sustains much less than the other notes on that string. “Thud.”

On the higher resonance, it can sound like a more traditional feedback scenario, with that note playing much louder than the others. That’s the obnoxious sound. The guitar is indeed acoustically feeding back on itself via the soundboard, generating higher volume.

I’ve read that wolf notes are particularly likely to manifest with high quality instruments (because lower quality ones don’t sustain as well or as clearly, and therefore mask the wolf notes). I also have read that wolf notes are even more problematic on cello (because of the bowing action, as opposed to picking or strumming).

My understanding is that there are a large number of variables that affect the resonance frequencies, and getting it right is part of the magic of lutherie. Right meaning, it’s best if the resonance frequencies fall exactly between two notes (so they are least likely to cause a wolf note). Once the guitar is built, it’s too late to change most of the variables. That said, it’s possible to marginally modify the upper resonance frequency by adding mass to the soundboard. Making the soundboard slightly heavier will reduce the resonance frequency.

I had this issue sounding on the G# (208 hz) of one of my guitars. That guitar is carbon and very lightly built. The resonance made G# on the G string sound very odd. Made playing an open E chord in particular sound weird — it wasn’t quite as noticeable if playing single note lines. The effect was also there, though weaker if G# was played on the D or A strings.

I was able to mitigate the problem enough to not mind by swapping in some brass bridge pins (and hence adding mass). For my guitar, 4 or 5 brass pins seemed to be the sweet spot. If I went to 6 brass pins, the resonance moved all the way down to G and that note got obnoxious.

If you don’t have a set of brass pins laying around, you could try taping 4 or 5 quarters just behind the bridge using some masking tape, to see if that mitigates the problem. If yes then you have your answer on what to do.

Another way to add mass, would be to install a soundhole mag pickup. If you have one laying around unused, that’s another cheap way to test to see if it solves the problem.

I don’t know if this is what is troubling your guitar or not, but on the chance it is, I share this experience with you. Best of luck sorting it out.

Wow, this is a great post my friend...

If it happens on my replacement I’ll have some things to consider. With any luck it won’t.

Your use of the word “obnoxious” describes well the experience that I tried to explain I think...

The weird thing is, I’m not sure it was there right from the beginning. I could be wrong, but I don’t think it was...which makes it more confusing...lol

I wonder if a pick guard would tame the wolf?

[Dbone]

Originally Posted by EvanB

I wonder if a pick guard would tame the wolf?

Perhaps? Probably a good suggestion. I actually have a removable Taylor pick guard that I could try on there...

How common is this stuff? Like, what is the likelihood that the replacement guitar they send me will have the same or similar issues?

I had heard of this wolf tone stuff, but it was never anything that I experienced directly until now.

[jonfields45]

Twice in the past I thought a heard an open string on a new guitar sound louder than the rest. Once I started thinking about it, it was hard not to hear it. In both cases it went away in a few weeks, which I think was my perception changing or the string aging, but not the guitar.

I would expect RainSongs to be very consistent from guitar to guitar because of the way they are constructed with prepreg CF.

You might try a different set of strings, like phosphor bronze or monel to give the sound of the guitar enough of a jolt to reset what you are hearing. You might also try cleaning out the G-string nut slot.

[SpruceTop]

Originally Posted by Dbone

It does not seem to have the same problem as an open G. The open G is “offensive” in comparison, for lack of a better word.

Do you get the resonance when you fret the G-string? Is it a pinging and tinny overtone-like sound you hear along with the open-G note, and do you hear it along with other notes when you fret that string?

Spruce;

You're leading the witness. Probably a good thing. These wolves are crafty.

[SpruceTop]

Originally Posted by EvanB

Spruce;

You're leading the witness. Probably a good thing. These wolves are crafty.

Evan, I think you know where I'm going with this ... Yes, it's the old "string-ping/sitar-zing" ... hmmm ... but will he bite?