I just built my first CBG and am quite amazed by the sound that comes out of the simple design I used. It is a neck through the box, fretless design. I cut 4 1/2" f-holes near the top (neck end) of the box. I've been making modifications trying to increase the resonance.
First thing I did was to move the bridge from the junction of the box and the tailpiece to the body of the box. The second thing I tried was to remove 1/8" of the neck inside the box so the box top had room to vibrate.
These two things made a huge difference!
Another thing I tried was to turn the box upside down so the f-holes were closer to the tail than the neck. That also put the bridge between those holes. That seemed to help some but not enough to keep it that way, mostly for cosmetic appearances.
Does anyone have any opinions on how the size, shape, and location of the sound holes will affect the resonance? I'm looking for ways to improve the acoustic qualities.
Also, I have a nice sized cigar box. It is made of the typical Spanish cedar but the face of the box has a paper cover. Does anyone know how the paper will affect the resonance? Does anyone have any tips for removing that paper?
Thanks for any insight that anyone can give me!
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I just did an experiment. After reading some of the threads that Swamp Witch posted, I decided to try installing a dowel between the neck and the lid (soundboard). Some had claimed that improved the sound and I thought that would be in between having a gap between the lid and neck and having the neck tough the lid through out the box.
When I installed the dowel, it dampened the sound tremendously. I mean day and night difference!
I took a video to show the difference... https://www.youtube.com/watch?v=F31SJo9Xd70&feature=youtu.be
hummmm. you should post this in the other thread also .. my make for some good convo .
Good idea, will do.
wait ... did you put the dowel between the neck and the lid ? or from the back cover to the lid ?
it seems most were saying the back and front .
I'm wondering if I'm off track with the dowel thing. It might make more sense if the dowel went from the front to the back in body with an attached neck instead of a neck through body.
Another thing to experiment with.
This is like the differences between Hollow Body guitars and Semi-Hollow Body guitars.
Hollow bodies don't have a block under the bridge and allows the top to vibrate freely which lessens the instruments sustain because the tops vibration interrupts the string vibrations duration, but has a louder acoustic volume.
Semi-Hollow body has a block under the bridge from top to back which lessens/dampens the top's vibration which increases sustain, but also lessens/dampens acoustic sound waves resulting in loss of acoustic volume. Which is why most Semi-hollow instruments have pickups of some kind.
Soundholes: There is a mathematical calculation for this on acoustic guitars. If you do a Goggle search you'll find the right answer. I lost that link.
Soundhole & Bridge location is usually best near the center of the sound board which also happens to be the best place for the bridge. Think about this in relation to a acoustic guitar.
I think that the typical location for sound holes and bridge on CBG's is part of the CBG instrument's sound and charm. When I was building my CBG, I looked over several CBG instruments and went with what I was seeing. 2 - 3/4" soundholes near the neck on each side of the strings and bridge close to the edge of the box. If you follow the Acoustic Guitar build & sound principles it will work better acoustically, but going too far in that direction will move you away from CBG territory. Have to watch out for that fine line.
Sorry for the long post, hope it helps.
Well I put the dowel from the neck to the lid but I had to add some support to the neck and that is touching the back of the box so in essence, it is solid from the the back of the box to the lid.
you say ...*** "First thing I did was to move the bridge from the junction of the box and the tailpiece to the body of the box. The second thing I tried was to remove 1/8" of the neck inside the box so the box top had room to vibrate. These two things made a huge difference!""'***
i'm willing to bet only the first part made the difference .
contrary to popular belief , ( in my opinion ) , gluing the neck right to the box lid makes the entire body and guitar resonate much better .
some long time builders that used to swear by leaving a space , have now changed their tune .. after playing and / or building one glued right to the neck .
( pardon the pun :-)
Hmmm.... That's interesting. To be accurate, I didn't make both those moves at once, I did one (moved the bridge), evaluated it then did the other (make a space between the neck and the lid) and then evaluated that.
The creation of the space between the neck and the lid made the biggest difference.
It would be some way I could quantify the difference in sound. Maybe I need to make a video playing the same song every time I make a modification.
Anyway, you've given me more food for thought. Thanks!
humm indeed, .. i didn't take into account the f holes .. which sometimes act as a sound tongue .. and heck . sometimes many things work together . and all guits are different . there are many variables . anywho ...
heres some more chatter on this very topic ;-)
http://www.cigarboxnation.com/forum/topics/neck-touching-inside-of-...
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