new bouzouki - top droop - humidity?

[AndyPanda]

I'm posting a question for my sister - she's far away so I can't see the instrument first hand. She just bought a new bouzouki - it's been hanging in the store (humidity controlled?) and played OK. She bought it, took it home and played it for 3 days - kept it in the case when not playing it. Top has dropped to the point the strings are hitting the fretboard. (a ruler across the top, near the bridge shows the droop in the middle of the top).

The store wants her to keep a damp sponge in a humidifier tube in the sound hole and keep it in the case for a week (re-wetting the sponge as needed). It's some sort of plastic cover for the soundhole with a wet sponge in a tube inside.

Is this legit? Or should she return it?

I always associate too dry with cracking - why would dryness cause a top to sink in unless the braces and the top are drying out at a different rate?

[chilos]

Sounds like a humidity issue to me. The first instrument I made - a concert uke last year - did exactly the same thing. Top started out with a nice radius as designed, then over a few weeks sank and went convex. I didn't know anything about the importance of controlling workshop humidity at the time (in Scotland, so too humid is the usual problem), but found out the hard way. I think cracking is the next step. Does she have a particularly dry house? Or is it a seasonal thing? As for taking it back, that depends on how far she is prepared to go with keeping the humidity controlled.

[chilos]

Sorry, 'sank and went convex' - meant concave, of course.

[Nevin]

That seems excessive and very fast to have happened in three days. I would check the neck joint and if the bridge had moved.

[Tobin]

I tend to agree that 3 days is way too quick for a humidity change to cause that level of droopage. But I doubt the neck joint is at play here, especially if the OP's description of a ruler across the top is showing an obvious sag in the soundboard in front of the bridge.

My suspicion is that a brace has come loose. It definitely needs to go back to the shop for an inspection at the very least, and possibly a return. Simply putting a damp sponge in there to get humidity levels back up isn't going to correct this.

[acousticphd]

+1 on Tobin's comment. 3 days is too fast for this to have been caused top shrinkage due to lowered humidity. I would also strongly suspect a detached brace - that can happen very abruptly, with top deformation pretty quickly (days), even on an archtop.

Is this a Goldtone, perchance?

[John Kelly]

I'd go too with the loose brace as a possibility. I recently did just such a repair on one of my mandolins I had built in 2008. A brace had come unstuck and the owner had not loosened off the strings when it first showed signs of this, as he is a regular player and uses the mandolin a lot. The repair involved removing the back to get at the brace. Like Chilos I too am in Scotland so out humidity problems are not the same as you experience over in the USA, but A brace seems likeliest.

[AndyPanda]

Is this a Goldtone, perchance?

Yes it is.

[AndyPanda]

My sister reports that the strings have lifted off the fretboard now and it plays well today (after one night in the case with the damp sponge device). I've asked her to look at the top with a straight edge again. I'm pretty surprised that humidity would lift the top over night - just as the sinking after 3 days dry air seems hard to believe.

[AndyPanda]

My sister reports that putting the straight edge across the top shows even more sag than yesterday - but she says the strings are not on the fretboard now and it plays well.

Makes me think the neck is what was changing to cause the playing problem (strings hitting fingerboard) and the top sinking was there all along. She says 1/8th inch (about) that the top is below the straight edge across the top in front of the bridge.

[acousticphd]

Yes it is.

Well, I asked because there have been a couple spates of Goldtone OMs appear on ebay over the last couple years - I noticed at least a couple dozen - all with similarly sunken tops. Oftentimes the same seller would have a bunch listed at once.
A number of these had had "soundposts" installed to prop up the tops, and adjustable bridges (not a bad idea, but these were not stock - they were installed to adjust for top sink).

I can't believe this instrument played well in the store - and it is also not very convincing that it really can be playing "well" again so quickly. But if the string height was right on buzz threshold when she got it, it could be that a few days at lower humidity changed both the neck relief and string height for the worse.

By the way, if low humidity was the culprit, she can speed the recover to playability with a couple additional humidifiers. Damp sponges in perforated ziplock sandwich bags make effective and free humidifiers.
I will say this - I sure don't think your sister received a new (ie, flawless) instrument - I think she received one of the many defective or "2nd" Goldtones that have flowed into the mkt. I hope she at least got a "2nd"/used price. And if she keeps it, she is going to want to study up on how to adjust her setup, because it sounds like it will need frequent adjustment.

[Folkmusician.com]

An instrument can change within a few days of extreme humidity or lack of. Under normal circumstances, it doesn't cause drastic differences in just three days, A couple of weeks can though. It could be noticeable with some minor buzzing in three days.

The symptoms are exactly what happens when an instrument dries out. It doesn't take much. The top sinks a bit, a hump develops at the neck joint, and suddenly the action is down to an unplayable level. Again, it shouldn't be extreme in just three days under normal circumstances.

Example, the standard method to close up a crack for repair, is to over-humdifiy the guitar. This can often be done overnight in a plastic bag.

If she could check the humidity levels in the room where the instrument is stored, it would give some insight. If we are talking about coming from 50% at the store to 10% now, it could take a quick toll. If the humidity levels are not "crazy low", then it sounds like the instrument is overly sensitive for whatever reason, and it should be returned.

[acousticphd]

The above is all important instrument-maintenance information. But I maintain that the Goldtone OMs have a design problem, as evidenced by the many essentially brand-new instruments that have appeared on ebay with badly sunken tops and retrofitted soundposts. These issues can't be blamed on customers.

[Folkmusician.com]

But I maintain that the Goldtone OMs have a design problem, as evidenced by the many essentially brand-new instruments that have appeared on ebay with badly sunken tops and retrofitted soundposts. These issues can't be blamed on customers.

Agreed. Over the years, there have been a few batches sold to dealers as seconds for this very reason. I recall it happening to another brand once as well (most likely the same factory).

A wild guess, but a factory like this will be doing all sorts of flat top instruments on the same machines. Someone may not have changed the settings in regard to top thickness before doing the run of octave mandos. It makes sense, and that would result in the occasional entire run of octaves having top sinking issues.

In these cases, it does appear to happen in batches. Dealers are most likely purchasing these as seconds. What happens after that, who knows. Is someone pulling the sound post out and selling it as new on eBay? Wouldn't surprise me!

[amowry]

Yes, if the action went from acceptable to having the strings touching the fretboard, that sounds like the bridge dropped more than 1/8" in a few days. That seems to me like much more than can be explained by a humidity change.

[AndyPanda]

Well ... my sister took the instrument back to the store today to have them look at it again. They saw how far the top had sunk and said "WOW!" and took the instrument back for a full refund.

Thanks everyone for the very helpful replies - my sister thanks you as well.

[sebastiaan56]

Glad it got sorted. I hope she retains some desire for the bouzouki.