Larger sound hole petite bouche models

Frank Wekenmann

Not a conversion, but Daniel Lehmann builds this interesting guitar:
dlgypsyguitars.com/index.php/en/guitars/od-en

Craig Bumgarner

There isn't much you could reasonably do to make it a true conversion and look like a petite bouche, but sound holes can be reduced for sonic improvement in such a way as to be not too noticeable. The way this is usually done in other guitars is with a piece of ~3mm top spruce cut to the right shape including the new sound hole. Spray paint the part of the spruce that will show flat black, then break it in half along the grain. Move the two halves inside the guitar and glue together and to the underside of the top. These pieces should be no bigger than they have to be, but need to be well supported. It is not a perfect solution and will be visible to close inspection, but it will get the job done sonically. If neatly done, it should not show too bad. If glued with hide glue, it could be removed if there was a change of mind.

Buco

There's this:
Gruen guitars
http://www.hotclub.co.uk/html/gruen.html

Unusual looking but works and sounds awesome. Tried it at DIJ 2013. Some of the instructors there tried it, they couldn't put it down.

The reason I'm posting it here is that the combined surface area of the small holes is supposed to equal petite bouche. And you get a couple of plugs with which you can close one or two of the holes to change the sound and it really works.
Such a neat instrument, I loved it.

Craig Bumgarner

Buco wrote: »

.... the combined surface area of the small holes is supposed to equal petite bouche.

Looks like the holes add up to good bit more than a petite bouche, but the point that you can put the holes in any number of places and can plug some for experimentation is well taken. Sound ports in the sides work this way too. There is kinda fun for a while be the novelty wears off fairly quickly as the player settles into the sound he/she likes. Don't know what you do with the extra holes in the long run, corks forever?

Most of us have seen guitars with the sound holes off to the side in the upper bout. This is being done to involve more of the top in sound production. With a center hole, most of the tops sound production stops at the bottom of sound hole. Course, some sound comes out of the hole, but the top surrounding and above the hole is pretty dead because of the structural reinforcements around the hole and for supporting the fingerboard & neck. By putting the hole higher and off to the side(s), more of the top can be put into sound production, for better or worse. F hole guitars are after the same real estate in a slightly different way.

Keep in mind what you hear as a player is not always what the audience hears. Some frequencies and resonant modes stay close by and circle the player, while others project out away from the top. It is human nature to believe what we hear is what everyone else hears, but in this respect, not so. Me thinks it best if guitar imparts to the player what the audience hears.

Buco

It's true about settling to one sound the player likes. I definitely preferred a combination of only one of the holes being closed, forgot if it was upper or lower. But it's a nice way to somewhat personalize the sound to your liking.