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Location: Earth·SolarSystem·LocalInterstellarCloud·Local Bub | It's Friday night. I am home alone. What else would I do but, calculate the area of the Ovation 22 sound hole design and compare it to a standard 4 inch hole
The answer-
22 sound hole area is almost precisely 12 sq in.
4 in sound hole area is a hair over 12.5 sq in.
I would have guessed that there was more area in the 22 holes.
(let the hole comparisons begin...) |
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Posts: 13996
Location: Upper Left USA | Brought this up before! there is a theory and some physics behind it as well. I just say that the multi-holed guitars swish the sound around a little more before they spit it out. |
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Location: Midland, MI | I thought it was that the sound waves had a harder time getting out of all those tiny little holes so they got all mad and agitated and just sounded louder than you'd expect when they finally burst forth.
Interesting about the area...I figured it was the same as a soundhole, just all divided up. Do you think the Tacoma with the offset teardrop soundhole was building on Ovation's innovation or is it just a design thing? |
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Posts: 11039
Location: Earth·SolarSystem·LocalInterstellarCloud·Local Bub | I just dug this out from Oct 2002 from CWK2:
--------------------The area of the holes is supposed to be the same as the area of the centre round hole, although I've never done the math. Sam's with the mini rosettes came later, an idea that didn't make it into production.
I also read through the reasoning for the design...less bracing required...the upper bout tends to contribute less vibration (read sound) so the holes make for a more responsive soundboard moved from the center of the soundboard...etc |
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Location: Upper Left USA | My second favorite guitars are the Tacomas with the single upper bout soundhole. It's just the right thing to do! |
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Location: Wooster, Ohio | When you have time to calculate the areas of that many small holes, I think you need to start looking at your life choices.
"And though the holes were rather small, they had to count them all"
Steve |
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Location: Earth·SolarSystem·LocalInterstellarCloud·Local Bub | Steve,
As if I didn't already know that... |
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Posts: 2850
Location: Midland, MI | Originally posted by MWoody:
My second favorite guitars are the Tacomas with the single upper bout soundhole. It's just the right thing to do!
When I first decided to get an AE, the only reason I was in the music store was because they said they had a Tacoma Chief (I believe that's the one with the funky soundhole). They didn't...they only had the bass. But, they did have this really cool 1868 that caught my eye...
:)
edited for typohs |
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Posts: 5750
Location: Scotland | Some of the physics involved is known as the Helmholtz principle. The purpose of a soundhole (or soundholes) is to tune the resonant frequency of the air cavity, kinda like a bass-port in a loudspeaker enclosure. Plug the soundhole with a feedback buster or set of airlocks and the volume level hardly changes at all, but the bass response diminishes significantly. |
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Posts: 6202
Location: Phoenix AZ | Paul, If you plug ALL the holes doesn't the volume drop drastically because the cavity is basically "sealed" and thus inhibits the top from vibrating? Interesting experiment would be how the PLUGGED in sound compares with no holes plugged vs. all holes plugged.
Another thing comes to mind - is there any reason the sound hole(s) has to be on the soundboard for the guitar (front of guitar)? I'm wondering because it is a "bass port" like you say, could the hole be located someplace on the side of the bowl? |
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Location: SoCal | There are several guitars that I've read about that have a bass port on the side of the guitar. Can't recall the names... |
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November 2004
Posts: 100
Location: Asheville, North Carolina | Paul is correct...sound holes are more for tuning the resonant freq. The top is a speaker cone and taking the hole out of the center is threefold..strengthens the top, places the vibrations more focused since there is all solid top with no interuptions in the bridge area where the vibrations originate. It also as someone said allows for lighter bracing....which allows greater resonance.
Click this link for a picture.
My Tacoma Custom |
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Location: Scotland | Dave there is no reason why the soundhole has to be in the top. I guess most manufacturers are following centuries of convention. Several Luthiers, mostly classical guitar makers have used single or multiple ports in various locations on the rims & at least one maker has made a side-located port with a variable-size opening via a sliding-door contrapion.
Plugging the soundhole(s) has no effect whatsoever on the efficiecy of the top as a vibrating membrane, and consequently has minimal effect on the overall SPL.
You can experiment with a "bowl soundhole" by taking the access panel of an Adamas or Elite. Not recommened! |
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Posts: 11039
Location: Earth·SolarSystem·LocalInterstellarCloud·Local Bub | If you just tap the top of your guitar in different areas on the soundboard you can hear different responses.
I wonder how the epaulets effect the vibration of the soundboard. I |
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Sound hole Comparison
