Sound Holes

Glenn Reither July 26, 2010 at 9:16am

I've used side ports on 3 guitars. Two of them had F holes in the top as well. Side ports work just fine and give the player some acoustic oomph.

Alan Roberts said:

I've seen CBG where the top looked like a county road sign after a big sale on shotgun shells -- ie, shot full of holes. The physics is complicated, but a cliff notes version says that a soundboard can't vibrate if it looks like swiss cheese. Adding a second 1" hole couldn't hurt, but don't get carried away.

You might think about putting a second hole in the SIDE. That would direct the sound at the player, and not compromise the top. Just a stupid thought; I'm not sure if I'd try it on MINE, heh heh. But I've seen them on custom acoustic guitars.

I built a lyre once that had NO sound holes at all (see my photo section). A second lyre had a few small holes. both based on 1,000 year old examples. But Not much difference in volumn.

Wade April 6, 2010 at 11:16pm

It's a lot of work, but I've had success thinning the lids with a sander- got good volume out of a thinner top.

Wade

Iggy said:

I think I know the CBG you are talking about. That particular box has a lid that is somewhat thicker than the normal box, which is typically (roughly) 1/8 inch thick. Because the lid is a little thicker, it may not vibrate as easily, thus not create as much resonance as you might like.

You could possibly get more volume with more holes in the lid, but my understanding is that the more holes you drill, the more treble the sound is, and the less holes you drill, the more bassy the sound is.

You could also get one of those little battery powered amps and plug it in and crank the volume up!!! LOL

Tracy Tomlinson April 6, 2010 at 9:15pm

My first build I just finished has two holes each the size of an egg and the volume is good. My wife can hear it from the bedroom at the other side of the house when I play in the livingroom. My 2 high strings sound banjoish and the lower pitched ones sound very guitarish. What blows me away is how it sustains a note for so long.

Sam Williams April 5, 2010 at 9:53pm

I like that idea Iggy!!!

Iggy said:

I think I know the CBG you are talking about. That particular box has a lid that is somewhat thicker than the normal box, which is typically (roughly) 1/8 inch thick. Because the lid is a little thicker, it may not vibrate as easily, thus not create as much resonance as you might like.

You could possibly get more volume with more holes in the lid, but my understanding is that the more holes you drill, the more treble the sound is, and the less holes you drill, the more bassy the sound is.

You could also get one of those little battery powered amps and plug it in and crank the volume up!!! LOL

Dan Sleep April 5, 2010 at 9:03pm

I think I know the CBG you are talking about. That particular box has a lid that is somewhat thicker than the normal box, which is typically (roughly) 1/8 inch thick. Because the lid is a little thicker, it may not vibrate as easily, thus not create as much resonance as you might like.

You could possibly get more volume with more holes in the lid, but my understanding is that the more holes you drill, the more treble the sound is, and the less holes you drill, the more bassy the sound is.

You could also get one of those little battery powered amps and plug it in and crank the volume up!!! LOL

Wade April 5, 2010 at 10:31am

I have only a small quarter size hole on the side of my indian box- points towards me and has good volume.

Alan Roberts said:

I've seen CBG where the top looked like a county road sign after a big sale on shotgun shells -- ie, shot full of holes. The physics is complicated, but a cliff notes version says that a soundboard can't vibrate if it looks like swiss cheese. Adding a second 1" hole couldn't hurt, but don't get carried away.

You might think about putting a second hole in the SIDE. That would direct the sound at the player, and not compromise the top. Just a stupid thought; I'm not sure if I'd try it on MINE, heh heh. But I've seen them on custom acoustic guitars.

I built a lyre once that had NO sound holes at all (see my photo section). A second lyre had a few small holes. both based on 1,000 year old examples. But Not much difference in volumn.

Keni Lee Burgess April 5, 2010 at 8:41am

How did you construct your cbg? Is the sounding board (top of box) free to vibrate? Did you glue the top down to the neck running through the box? (Not a good idea when building acoustically) The sound hole is essential for developing the tone inside the box. Certainly holes effect the tone/sound. The size of the box and it's ability to vibrate and create soundwaves are key to volume. I hope this helps. Enjoy

Diane in Chicago April 5, 2010 at 8:19am

Back in the Yahoo group days, someone who had actual math and physics background referred to the work of Hermann von Helmholtz (same guy who came up with the music notation system of D d d', etc) and the consensus was that your average cigar box needs a sound hole the size of a quarter. Any more compromises what little bit of surface area you have to work with.

Here! Har! http://en.wikipedia.org/wiki/Helmholtz_resonance

But you have to do the math yourself.

Sam Williams April 4, 2010 at 9:48pm

"I've seen CBG where the top looked like a county road sign after a big sale on shotgun shells -- ie, shot full of holes. The physics is complicated, but a cliff notes version says that a soundboard can't vibrate if it looks like swiss cheese. Adding a second 1" hole couldn't hurt, but don't get carried away."
HA! Mine's too pretty for the shotgun treatment!

Alan Roberts said:

I've seen CBG where the top looked like a county road sign after a big sale on shotgun shells -- ie, shot full of holes. The physics is complicated, but a cliff notes version says that a soundboard can't vibrate if it looks like swiss cheese. Adding a second 1" hole couldn't hurt, but don't get carried away.

You might think about putting a second hole in the SIDE. That would direct the sound at the player, and not compromise the top. Just a stupid thought; I'm not sure if I'd try it on MINE, heh heh. But I've seen them on custom acoustic guitars.

I built a lyre once that had NO sound holes at all (see my photo section). A second lyre had a few small holes. both based on 1,000 year old examples. But Not much difference in volumn.

Alan Roberts April 4, 2010 at 9:27am

I've seen CBG where the top looked like a county road sign after a big sale on shotgun shells -- ie, shot full of holes. The physics is complicated, but a cliff notes version says that a soundboard can't vibrate if it looks like swiss cheese. Adding a second 1" hole couldn't hurt, but don't get carried away.

You might think about putting a second hole in the SIDE. That would direct the sound at the player, and not compromise the top. Just a stupid thought; I'm not sure if I'd try it on MINE, heh heh. But I've seen them on custom acoustic guitars.

I built a lyre once that had NO sound holes at all (see my photo section). A second lyre had a few small holes. both based on 1,000 year old examples. But Not much difference in volumn.

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Sound Holes

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