Loose bracing

I don't have this issue, but I'm curious.
On a Uke Talk thread, the consensus seems to be that a loose brace will deaden the sound of a uke.
Can anyone tell me how this is possible? Am I just ig'nant?

I'm not sure about deadening the sound but it's likely to introduce a rattle at certain frequencies
Miguel

A loose brace is all bad, and will certainly be causing issues. Rattles, buzzes are the first thing you'd probably notice. Then possibly distortion of the soundboard as it's not being braced as intended. Deadening the sound is the least of your problems.

Anything can cause a loose brace. Time, temperature, not enough or too much humidity, any unseen issue during the build process.

And actually, you might not hear a buzz or rattle with a loose brace; at least that is what my luthier told me when I took an acoustic guitar to his shop last week.

Here is my story:
Recently, I bought a used guitar off the internet and even with a string change I was getting a slight buzz, the guitar sounded unresponsive and there was a lack of volume as well.
I told my luthier that the guitar was on a UPS truck in Texas over the weekend and it had been a hot couple of days; so I thought the heat might have loosened something inside. He said that is possible.

His first thought was that it was a loose brace and he needed to get his hands and a camera, inside and feel/look around.
I left the guitar with him for one day and when I returned the guitar sounded perfect.
When I asked him what he did, he said the buzz was coming from the 9 volt battery was vibrating in it's housing and the guitar top and body are so responsive that it was picking up that vibration and causing it to increase. A little tape around the battery solved that problem,
But what about the lack of volume?
Well, that came from the factory installed "JLD bridge doctor" not being adjusted correctly. Once he had the bridge doctor set right the guitar was in perfect working order.
While I was there we talked about bracing and what can happen with a loose brace and that is how I know what I know about loose braces. =)

A loose brace can do many things - it can rattle, it can make the instrument louder (the soundboard can move more, allowing more volume), it can make the instrument quieter (by vibrating weirdly and absorbing energy from the soundboard), and it can just alter the tone. It depends on which brace is loose, and where that brace is loose, and how much it is loose, and how much space there is between the brace and the soundboard.

@johnson430, so I'm guessing that guitar is a Breedlove? What model and how do you like it? I have a C20/SMYe on the way.

First thing I do with a new used guitar after tuning it up and trying it out for a few days, is take off the strings, blow out the dust etc. and put my phone in with the flashlight app on to make an HD video. I get as far in as possible and get the top and bottom too. I can zoom and everything. I also generally narrate which side and angle of view. I'm looking for any issues that might be in there. Then I do a video and pics of the exterior. So far I've not seemed to have an issue with any of my ukes as far as braces, except for one that still buzzes and which I'd like to get looked at. With guitars only a couple that needed a neck reset or were overheated and dry so the neck bowed.

I've had a guitar with a loose truss rod vibrate in a way that it was hard to pinpoint. I finally tracked it to the headstock thinking it was a tuner, they were sealed so I picked the side that when pressed would stop the vibration, replaced those tuners, then could feel it in the neck. Putting a tool on the truss rod just spun it, so it was broken or loose at the sealed end. Bummer, but it was a $40 Olympia I'd gotten just for the scale length as a test.

Teek said:

@johnson430, so I'm guessing that guitar is a Breedlove? What model and how do you like it? I have a C20/SMYe on the way.

First thing I do with a new used guitar after tuning it up and trying it out for a few days, is take off the strings, blow out the dust etc. and put my phone in with the flashlight app on to make an HD video. I get as far in as possible and get the top and bottom too. I can zoom and everything. I also generally narrate which side and angle of view. I'm looking for any issues that might be in there. Then I do a video and pics of the exterior. So far I've not seemed to have an issue with any of my ukes as far as braces, except for one that still buzzes and which I'd like to get looked at. With guitars only a couple that needed a neck reset or were overheated and dry so the neck bowed.

Click to expand...

Teek, Yes, it is a Breedlove Passport PLUS C250/SBe.
http://breedlovemusic.com/acoustic-guitars/plus-c250-sbe
I love it. Actually, I bought a Breedlove prototype tenor made in Bend, OR. here on the UU marketplace and as soon as I played it I started looking for a reasonably priced Breedlove acoustic guitar.
They make great instruments.
Thanks for sharing the idea about getting in there with a flashlight and phone to take photos so I know how things look when everything is working properly.