1st Guitar - Starting in Texas

Thanks for the info. If I had heard about that I might not have gone down the path I have ... or maybe I'd try it anyway. I've never had the opportunity to play a guitar that is side ported, so it is something novel to try.

If I get to the end of this road and don't like the sound ... I'll just nail it to the wall and have a pretty remind of what not to do next time (who am I kidding, I'll blame the port for the sound quality and forget about the other "issues" I had along the way).

Or you could spackle over the soundport and hope for the best................
-tommy

[Ben-Had]

Welcome to the madness!

In theory you are correct to reduce the size of the soundhole when adding a port. Many don't though... I think you may have reduced it a tad too far (depends on the size of your port!) but chances are you'll never know the difference.

How does the rosette look now? did you replace the purflings?

This is actually a VERY technical concept and interesting. Because a guitar is essentially an air pump, as is a loud speaker, any change in the interior volume combined with the size of the opening (whether you call it a sound hole or sound port it is still changing the opening) will change the "ideal" area the opening should be to have the sounds bouncing around inside stay in phase with each other. That means as you are building the guitar if you sand the sides heights, top and back thicknesses to different specs the size of the opening should change as well but no one ever (that I know of) changes the sound hole size to account for these differences and in fact they are probably so slight you would be unable to tell the difference. Hence, it doesn't matter much if you don't change the size of the sound hole when adding a port, within reason.

[Darryl Young]

Welcome!

Only my opinion but I doubt adding a small soundhole in the widest part of the upper bout would drop the main air resonance enough to notice. However, reducing the size of your soundhole from 4" to 3.5" will have a significant impact. Why?, you reduced the area of the sound hole by roughly 25% so the main air resonance pitch will drop quite a bit. When the main air pitch drops, it also drops the pitch of the top and back resonant modes which also changes the sound. You get to decide if it changes it for the better or for worse. Debatable, but this may reduce volume of the guitar as well. My best guess is it will be warmer/mellower and quieter.

The other, bigger issue is that now it will be difficult for your to get you hand in the soundhole! <smile>

No one is right.
No one is wrong.
That's the great thing about this lutherie voodoo......

-tommy

[Kevin Sjostrand]

Hi Kris and welcome to the forum. It looks like you are well on your way to building a guitar. Good for you.
On the rosette purfling..did you have to force it in your slot, perhaps not get it deep enough? Did you thin the top quite a bit after installing the rosette?
Also, can you get your hand through that sound hole? You may need to down the road.
It is looking good though. Keep the pics coming, and we will all help where we can.

Kevin

[Kris42]

Thanks.

After the discussion above, I'm considering finding a way to increase the diameter of the sound hole. I'm guessing it won't be straight forward, since I have bracing in place, and the top is no longer flat.

The side port is an oval roughly 1 3/8" by 1" (I'll put pictures up later); so if I want to get close to total hole area of the plans, I need to increase it anyway.

To give the pictures a little scale, the inner black line of the interior BWB purfling forms a diameter of exactly 4". So I can't go all the way back to the plans. Maybe increase the diameter of the sound hole by 1/4" (total 3.75")?

I'll see what I can think up.

Thanks again.

[Kris42]

To answer the question about the purfling. Yes, I had to force it into the slot I made ... most likely it did not make it all the way in.

I didn't thin the top very much after installing the rosette, because I didn't have much room to work with. I had the top almost at final thickness when I installed the rosette (which caused everything to stick up fairly high, until I sanded it down).

[Kris42]

Ok, over thinking again.

Using this to provide some back support.


Old rosette:


New rosette:

[Kris42]

Final diameter of the sound hole was 3.92"

Back
The back went together a little easier (probably because I didn't have to worry about the sound hole).

Indian Rosewood with a maple strip down the middle.





And finally with braces glued in place ...


thickness of back: 0.090"

[Kris42]

OK, bending the sides is less straightforward than it appears. I stared with an iron and some sample sides, thinned to about 0.075".

Bending took significantly longer than I thought, and I'm still not certain how to bend the cutout with an iron.
This is as close as I was able to come.


The side popped on me. I assume I could have helped prevent that if I had used stainless steel to back the wood, but I' still don't understand how to make the tight turn needed for the cutout. So, time for a change.

I decided to go a different route.

(thank you BluesCreek Guitars)

I still had an issue with the tight cutout turns; but by touching them up a little with the iron, I was able to get close enough. Should I have been able to bend closer to the true shape without needing the iron?

What should I have tired ...

• Use a different caul to press into that section of the form?
  Pressed the side multiple times?
  (something else?)