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  #1  
Old 05-17-2018, 03:03 PM
Foughe Foughe is offline
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Default 3,81" soundhole diameter > 4" diameter?

Hello,

I read that all Martin dreads have a 4 " soundhole diameter.

I have a fantastic sounding made in Japan seventies D45 copy that is not so loud... I did some measurements and to my surprise the diameter is smaller than normal (3,81 inch or 9,68 cm). I have other Japanese brand guitars (from that era) and these are all in the 4" ballpark.

I'm thinking about enlarging the soundhole to normal specs.
Can anyone tell me if this could and would deteriorate the sound?
I'm hoping the guitar would retain it's full bass (or most of it) and gain some volume. The difference is diameter is only slight....

Last edited by Foughe; 05-17-2018 at 11:45 PM.
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  #2  
Old 05-17-2018, 03:04 PM
Foughe Foughe is offline
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Here 's a link to this guitar and it's sound:

https://www.youtube.com/watch?v=pdOew7OEFDM
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  #3  
Old 05-17-2018, 05:16 PM
mirwa mirwa is online now
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Sound hole size is only one of many things that work together to create a sound.

That is, top thickness, brace shapes and sizes, side strength, bridge thickness and so much more contribute to the sound, just changing one thing may do nothing or may imbalance what you already have.

Just thoughts before you proceed.

Steve
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Old 05-17-2018, 11:57 PM
Foughe Foughe is offline
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Quote:
Originally Posted by mirwa View Post
Sound hole size is only one of many things that work together to create a sound.

That is, top thickness, brace shapes and sizes, side strength, bridge thickness and so much more contribute to the sound, just changing one thing may do nothing or may imbalance what you already have.

Just thoughts before you proceed.

Steve
What was remarkable about this guitar too, was it's top thickness (0,108") and a smaller scale length (25 2/17). I've got two of these guitars and this one sounds much better than the other one (0,118 inch top thickness).

I'm only wondering if slightly enlarging the soundhole up to Martin spec would have a negative effect (or any effect at all). Maybe someone has done this same experiment here?
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Old 05-18-2018, 05:06 AM
runamuck runamuck is offline
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I can only tell you that I've read that enlarging a soundhole, like you're considering, may very well reduce the lower frequency response.
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  #6  
Old 05-18-2018, 05:18 AM
Mooh Mooh is offline
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Isn't there a Clarence White or Tony Rice model Martin with an enlarged soundhole? Maybe a search for that would yield some research.
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  #7  
Old 05-18-2018, 05:35 AM
JDaniel JDaniel is offline
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Quote:
Originally Posted by Foughe View Post
Hello,

I read that all Martin dreads have a 4 " soundhole diameter.

I have a fantastic sounding made in Japan seventies D45 copy that is not so loud... I did some measurements and to my surprise the diameter is smaller than normal (3,81 inch or 9,68 cm). I have other Japanese brand guitars (from that era) and these are all in the 4" ballpark.

I'm thinking about enlarging the soundhole to normal specs.
Can anyone tell me if this could and would deteriorate the sound?
I'm hoping the guitar would retain it's full bass (or most of it) and gain some volume. The difference is diameter is only slight....
Regarding your question on sound quality deterioration resulting for a 0.19" enlargement of the sound hole to the Martin standard of 4.0", probably not. You might be underwhelmed by the result though. This will however deteriorate the value of your instrument. I listened to your youtube post, very nice. In my opinion, enjoy your guitar for what it is and leave it in the form that its creator made. Sound quality is a complex mix of wood, sound chamber size and acoustics, design, bracing shapes and materials. If you are looking for a different sound profile, perhaps increasing your guitar collection might be the next step to take.
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  #8  
Old 05-18-2018, 05:46 AM
JDaniel JDaniel is offline
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Quote:
Originally Posted by Mooh View Post
Isn't there a Clarence White or Tony Rice model Martin with an enlarged soundhole? Maybe a search for that would yield some research.
Yes, the D-28CW (Clarence White), but this is not currently in production. Other custom guitarmakers also produce or have produced commemorative Clarence White/Tony Rice models with the enlarged soundhole.
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  #9  
Old 05-18-2018, 07:32 AM
printer2 printer2 is offline
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There are three resonances that work together at the low end of the guitar spectrum. The top, back and hole resonance. The three interact and cause the resultant resonances to be in different positions than they started. One goal is to place these resonances in between the scale tones. Decreasing the stiffness, adding and removing mass and increasing the hole size can be used to nudge the resonances off a scale tone if needed. The change you are contemplating will move the sound hole resonance slightly up in frequency. I doubt it will have much effect in volume, it may place a resonance on a scale tone and produce a wolf note.

I will let you figure out what my thoughts are on modifying the guitar if you like the way it sounds.
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  #10  
Old 05-21-2018, 12:33 PM
Foughe Foughe is offline
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Hi,

thanks for all the replies and the opinions...

I will trust your experience and will not mess with the soundhole, but leave it as the maker apparently intended it to be.

As a maker of Martin style guitar (or outright copies) I was just wonderin' why they didn't choose for the standard 4" diameter.
Again, thanks. Interesting opinions and insights here.
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  #11  
Old 05-21-2018, 12:46 PM
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Quote:
Originally Posted by Foughe View Post
...As a maker of Martin style guitar (or outright copies) I was just wonderin' why they didn't choose for the standard 4" diameter.
There were no true "copies" of Martin guitars during that period. Look inside and you'll find all sorts of things that aren't exact copies of Martin construction. The sound hole diameter is easily measured, so it's obvious. It could as simple as whatever tooling they had available was used and that produced a slightly smaller hole.
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