This kind of ties in with Uncle John's Graduation discussion I guess.
I'm finding that all the time I spend on my quest for good acoustic tone and volume by leaving a space between the through neck and soundboard sometimes goes to waste. After they are strung up for a while ( years maybe?) the soundboard just bends till the bridge and soundboard are now resting on the neck.
In some cases, this has actually improved the playability by lowering the action but on others that already had low action, it results in "fretbuzz".
So it looks like I may need to "Graduate" to the advanced stuff like bracing or maybe even making my own boxes or soundboards.
Do you folks think bracing helps with tone/volume or does it just result in a strong top that no longer vibrates much due to the bracing since that adds mass and weight to the soundboard? I know it is essential on full sized guitars but on the small area of a CBG.
I wonder if a small block between the bridge and neck would be better, worse or about the same as bracing. A block or a screw or something sure is a lot easier.
Food for thought. Inside many violins (maybe all) you will find a short round dowel that runs from the top to the bottom of the instrument directly under the location of the bridge. I think the concept was to provide enough support to prevent the strings and bridge from depressing the top over time, but not so massive as to prevent the top from vibrating.
A similar concept could be applied to a neck through CBG where a piece of dowel fit under the bridge and rested on the neck. A short piece of 3/8" dowel should be enough to provide resistance to compressing the box top, but still allow the bridge to transfer string vibration.
I think you got something there, Tom. I built a 4 string git with a 10 inch by 3 inch cookie tin. The lid (top) was about 1/8th inch above the neck through at the bridge, with a small hump 1/16th inch in the neck to support the bridge. The can top depressed down to the hump and actually rattled so much that I put it in the corner for a few weeks. After reading something on the Nation, I rasped off the hump and drilled a hole through the neck at the bridge position and glued a 3/8th inch hardwood dowel (3/8 because that was the only hardwood dowel I had) in the hole that went from the top of the can to the bottom. I had to cut and sand the dowel to get the right tight fit. Actually I had to drill it out and start over once, because I took too much off. The sound is much more like I think a can git should sound. I am going to try this method from starting with the concept from very start of the build soon.
contrary to popular belief that you will get better resonation with a space under the neck , i believe gluing right to the top resos the whole guitar as one much better . most that have tried the same exact box trying both ways , say the one glued to the lid actually sounded better . many also say they can't tell the difference .
and i truly believe they last much longer also .
so going back to the " k.i.s.s " (keep it simple , silly ) method . may be all you need . instead of forward to advanced bracing , which may result in the same problems anyway . and add issues like pivot points and folding etc .
i can run over a swamp witch guitar body with a car with no damage .. and its semi hollow . ;-)
My loudest guitar was a 1/2 in thick m d f top that i thinned down t a 1/4,but i've found,a thin top,around 1/8 with some light bracing sounds pretty loud,and if good hardwood ,it sounds sweeter
Very interesting discussion. I have read a lot on this subject and there seems to be as many in one group as the other. Some say it helps to have a gap between the soundboard and the neck, others will say it is better to have solid contact on the neck. I love to experiment and thinker with new ideas so I have built them both ways. From my limited experience at building (less then a dozen builds) the ones that have the lid or soundboard setting on the neck have the best sound and most volume acoustically. Hooked up to the amp I can't tell the difference between one or the other......but that could be my hearing lol.
Shane speal has a video on how he builds his slide guitars for sale... He does dado out a gap under the lid, but he leaves about 1/4" piece to support the lid under the bridge...
Me? I made a lot with the gap, then started using no-gap building methods.. I like the latter...
Wow, this what I love about this site, the info gleaned from so many people is invaluable! Thanks guys
Thanks for the great feedback. I think I will try the dowell trick on existing builds that have "top crush" and try a full contact model next. I also have read about the gap not being needed. Mike Snowden comes to mind. I think he uses the full neck contact method and is getting national recognition with his builds. Maybe this is a use for all those bamboo chopsticks I seem to save?! In fact, I think I will try one with a dowel just between the neck and top and another with the dowel acting as a "violin sound post" and going all the way from top to back, adding support and also coupling the top and back.
I would also go with the post under the bridge method. I have messed about with making carved bracing under a cigar box lid before. I have found that having two posts under either side of the bridge is a great deal simpler, and the results are better.
I have been using a dowelstick the way banjos are constructed. I takes most of the tension off the box. My oldest build is two years old and I have 8 or 9 none of the boxes have caved so it could be a solution for you.