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Permalink Reply by Taffy Evans on October 4, 2018 at 11:34pm

Hi, The tops of resonator guitars, "Dobro" or National styles, have stiff tops as some have a reinforcing rim sandwiched between the back and the top, looks like a tambourine. So the contribution of the vibrating effect of the top and back is very low.

It could be the size of the box or size of soundholes. A look at the instrument may help identify a cause.

Taff

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Permalink Reply by Taffy Evans on October 5, 2018 at 6:29pm

Hi again, I just reread your post. Depending on the thickness a maple top could be too stiff for an acoustic guitar. Flexibility is the key so thinning it and a brace may have rectified the problem. Providing the soundhole/s are good size.

Taff

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Permalink Reply by frank learman on October 5, 2018 at 6:44pm

 The top is 1/8 th. in. thick and I thought it was just too stiff to properly vibrate as an acoustic that was the reason I cut in the thunder cone. I guess I was just expecting more punch out of the cone. I mean it's better than it was just doesn't sound like the videos of reso's I've heard. This is build number 10 and I've built all my own boxes. All the previous ones I used cedar and they are very loud to say the least. lesson learned function over form. I fell into the pretty wood trap.

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Permalink Reply by Blind Doughboy on October 5, 2018 at 7:15pm

a 1/8-inch top isn't really thick - no matter the wood - so I suspect there are other issues going on.

I build traditional resonator guitars - incorporating a tone ring or soundwell,  a 9 or 9.5-inch biscuit cone, etc. For such instruments, it's not unusual to see 3/16-inch tops (or thin steel - maybe 24 gauge - backed with wood). Thickness is necessary, as down-string pressure for a biscuit cone is often around 30 pounds or more.

You could zap up the volume on a CBG with a traditional biscuit cone, if the body size will allow, but looking at your photo, it doesn't appear to have the needed height, width, and length to make a cone viable

I see a lot of these "cones" that are screwed to the top of the box. They may give you a somewhat twangy, imitation reso sound,, but they really won't increase your volume. To do that, a cone has to float; it never touches the top of the instrument (let alone be glued or screwed) and is in fact inset into the body an inch or some via the tone ring or soundwell

Also, the instrument has to have some resonating volume inside. I wouldn't want to spend the money on cones - or the time building soundwells - unless the body was at least 12" wide x 18" long by 4" deep.

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Permalink Reply by Blind Doughboy on October 5, 2018 at 9:20pm

Maybe this will help (wasn't sure I had a photo). This is a steel top, backed with wood. The tone ring is attached to the bottom side of the guitar's top with 3M marine epoxy (can handle the string pressure, and never comes loose). You'll see the lip at the bottom of the tone ring.  That's where the cone rests. It touches neither the sides nor the top . . . it just "floats."

To vastly simplify (this is not totally accurate, but will give you a mental image) think of the reso body as a speaker box. The top should maybe flex a tiny bit . . . but mostly you want it to be sturdy

Hope that helps

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