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Good day all. I just finished intonating my first SJ-200 (LMI plans). Here are all the gory details to avoid wasting anyone's time with information gaps

Used Adi top, Rosewood back and sides, sitka bracing, Cocobolo bridge and fretboard, and mohogany neck, kerfing and side braces. Top was about 0.10" and the back was just under that around 0.98. Bracing was medium height, scalloped and very close to the plans in terms of height and tapering, but if anything a little short here and there based on the top's radius. Bolt-on neck, hide glue throughout except epoxy under the fretboard. Two CF strips surrounding a two way truss rod (which I didn't have to tension). I have a 15' spherical radius on the back and I hand-carved my own solera for the top, with a flat surface from neck joint to sound hole and a ~30' radius from there down. Bridge and bridge plate were radiused to match perfectly. Oversized bone nut and saddle. Set up at the first fret is .017 at one and two, .02 at three and four and .025 at five and six. 12th fret is a little higher than I'd like, but the neck angle ended up being a little too low. I also have a bridge pin pattern that slopes away as it moves to the low e, which means the break angle at E and A are not ideal. I did ramp them inside the bridge, but I could only do so much. They are at about 40 degrees, hitting a relatively short saddle.

I had issues with spraying the finish (long story omitted) so I ended up sanding it back to a very thin "base coat" that went through in a couple areas and I'm waiting on a shipment of finish to continue the finishing process.

In the mean time I decided to just assemble the thing to see how it sounds. This is where I need some opinions.

It sounds great when played delicately with fingers, and has a nice round tone with a "deep airy low end". The concern I have is when you start to dig in with a pick. The overall sound becomes too bright and edgy. The Adi top handles the volume really well, even when pounding it, but it's just too bright. I currently have D'Add coated phospher bronze 13's on it.

My question is whether or not I should expect a full coat of finish to tone down that brightness, or if it's a side affect of a construction issue that can be mitigated, or just designed around for the next one.

Thanks in advance!

I read a long time ago where Lance McCullum strung up one in the raw to see how it sounded. He wrote that it was much as you describe, his words were uncontrolled, jangly, other adjectives pointing to too bright. He said finish brought it under control.

Thanks Glen. I've not tried to voice one "in the white" as they say, so I'm glad to hear that it's probably a side effect of having practically no finish on it. The body resonates like crazy though....

As someone who has finished a few hundred guitars.....If you are counting on a few thousandths of an inch of thermoplastic resin and the almost infinitesimal weight, stiffness etc it adds to improve your tone, you will be disappointed.

Trust me, if finish was a magic sauce the guitar world would have settled on a single type of acceptable finish long ago.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

As a general principle, top mass damps trebles and stiffness damps bass. A jumbo has extra mass due to the size, so I like to use very light tops on mine because I value an articulate voice with clear trebles. Since your guitar is pleasing when played finger style but loses definition when strummed, it sounds like it lacks headroom. If I were building a guitar intended for strumming, I would use a slightly heavier top. You didn't mention tuning, but a lower top fundamental will produce more warmth and less treble response by comparison. A top tuned to 190 Hz will have a brighter voice than the same guitar tuned to 170 Hz. Here is a video of one of mine being played in a studio setting.

https://www.youtube.com/watch?v=FKI5pR5 ... e=youtu.be

I agree with Brian, don't expect much change based on adding finish.

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It will probably be alright.

Thanks for the responses guys. I've read many of your posts in the past, and trust your experience.

Sounds like this one is just going to be what it is, if I'm hearing the input correctly that the only help is to add mass to dampen that treble response. I must have gone a little too "Somogyi" on that top for strumming purposes.

As for my tap tones on the current unbraced top, the lowest readable harmonic, using a petersen digital strobe tuner is under 100. By ear it sounds to be in the 3rd octave E-G range. Or, around 160-190. That's a little high to me, so I was going to thin it more. It's currently around .115. But, given the information in this thread, maybe I ned to leave it thicker and see how it goes.

Have either of you added braces or plates after the face to darken a jumbo? Maybe thin out the parimeter of the top?

For the next one (which I've already starting milling), anything to look out for other than just a thicker top?

Greg, excellent sound and recording. Certainly, If I would get that sound every time I'd be happy as can be. Does is sound similar when hit hard, or was it designed for that style as the target?

Thanks!

Hi Terence. I don't know how many guitars you have built,
but sounds like you are on the right track by your methods.
I can't advise you on what to do on that build.
I am different from most builders, and have built about 12 acoustics,
and about 13 electrics, so I'm not going for a particular sound.
Anyway, don't want to go any further on my stuff, just to let you know a
little about my build philosophy.
A couple of things I can tell you.
One thing is that a recorded guitar can always sound better than in real life.
Done a lot of that. I'm a decent mediocre lap steeler.
Another thing is I've built some that don't get played much,
because I didn't like the way they sounded.
Others have become my favorite guitar to play.
The last acoustic square neck I built was supposed to have less bass,
for recording purposes, and I got close to that sound, but not completely.
Another thing to consider is to use that guitar as a finger picking one,
or for strumming, or for that mojo tone, or whatever.
One last thing is, Gregs guitar sounds great, yay!
Sounds like it is in a lower open tuning, C or D?
So you can get more bass with lower tunings, yup.
Thinning the edges might work.
Good luck and keep at it my friend!
Also, keep us informed on what you do!
Alan

Hey there Alan, thanks for the encouraging comments. I will definately post back the results (whatever they are) once the piece is finished. Unfortunately, that will be a couple weeks due to the finishing delay.

My biggest concern, really, isn't this particular guitar. I didn't expect it to be a masterpiece. But, I'm not a person who likes to waste time, money or experiences. So, I'm trying to get the absolute maximum value out of this build... which is knowledge and experience.

Over the course of my not-so-short life, I've learned that people who make the most of every opportunity progress exponentally faster than those who don't. I want to be the former, not the latter.

Now, off to more learning!

Looking forward to that, Terence!
Alan

One thing I have learned is to hold off on any evaluation of how a guitar sounds until it has been together and played for a few weeks. During this time it is surprising how much the sound of an instrument can change.
If after a couple of months you decide you don't like the sound you might be able to modify it some by changing the frequencies the guitar modes resonate at by adding weight to or thinning areas of the top. A discussion of this is in Arthur Benade's " Fundamentals of Musical Acoustics". One nice thing about the method is you can hear the changes before making them permanent. It covers a lot more than vibrating plates and can add a lot to your knowledge of acoustics in general.

Great stuff Clay, thanks much. (that book you suggested is on the way)

FWIW, I've noticed some softening of tone even over the past week as the guitar settles in a bit. Good advice not to be too hastey (as Peregrin Took would say). Maybe by the time i've done the finish and let it cure things will have changed enough to balance out the tone.

Heres hoping!

My last guitar was an all-Alaskan Yellow Cedar parlor size. AYC is a Cypress. It sounded very tight and ringy on the first day it was strung up, the next day it was entirely different with the 4, 5, and 6 strings being very balanced, then it went back, then it changed again almost daily for a couple of weeks. I am a bit hard of hearing and even I could hear what it did. Don't give up yet

Ed

I had a similar situation on an OM and I switched from a macassar ebony bridge (people on here have said that is similar to rosewood) to an African ebony bridge and it helped a lot. Apparently African ebony has more damping, and that's what I was after.

Seeing as you haven't finished it yet, it would not be a big deal to try it.

Pat

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Pat

Geetings all. I have an update on this project.

I have seen a significant improvement so far, and wanted to report back (as promised) with the factors that contributed. However, it's important to keep in mind that I'm very sensitive about tone. So, when I say this guitar was "too bright" I don't mean horribly harsh or trashy. I just mean that it wasn't where I wanted to end up. So, the items listed below might not seem like dramatic changes, which is true, but together they were enough to get me within spitting distance of where I wanted to be. Anyhow, this is what happened... and now I think the guitar is just about there.

1) Each day the guitar mellows a bit as it settles in. This isn't a surprise, but normally a finishing process gives the guitar time to settle, plus a waiting period that this unit didn't have.
2) There were a couple high frets that I didn't catch during the prep that I believe were causing some slight buzz when the guitar was played hard. Not the whole issue, but I think it contributed.
3) Next, I've been playing "shorter scaled" guitars for years, and I usually struggle to get the bite I want out of them. Because of this I have been playing fresh .13's as a SOP. In fact, every time I play in front of people, I put on a fresh set. This Jumbo was a longer scale (25.312") than what I've been playing, which had a significant affect on the sound of my "standard" strings on this instrument. The increased string tension made my usual strings too bright when played hard, particularly at the tension required to get 13's up to pitch. I chnged to a more mellow string (Martin Retro) at a lighter gauge (.12) and it made a big difference.
4) Finally, I resorted to evaluating the X braces and their thickness toward the edges. Since the soundbox was closed, there wasn't a lot of room for carving the braces differently. But, determination overcame and I managed to reduce the thickness of the last few inches of the lower bought scalloping. This made a noticable difference in the lows, and will be something I incorporate into the next build. It's cool to see how, with a very sensitive soundbox, the smallest chagnes are noticable.

The last thing I think I need (besides a longer wating period and more playing) is the finish. I understand that a professional finish at 3-4 thousanths of an inch won't make much difference... but lets be honest. I don't spray finish on acoustics for a living, and even if I did, the finish must have some affect on the tone. Just a touch more mellow will get me to where I want to be!

If you are interested in the rest of this guitar's story, check my new post. I ran into a pesky problem now that the sound is close to where I wanted it.

Thanks!

Thanks Terrence. I try to build my guitars with some headroom, meaning they can take a pick without losing definition. I voice and tune primarily for finger playing. The guitar in the video sounded great when played with a pick, but more balanced and articulate than a factory jumbo. I built it in 2011 and it is still one of my wife's favorites. The guy playing it in the video bought it.

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It will probably be alright.

Appreciate that Greg. If you would be willing to share some of your parameters for top, bottom and braces I'd be interested to compare them with what I did. I'd like to take what you did and beef it up a little to handle agressive picking in an amplified autidorium environment.

I'm going to start the next one tomorrow while the finish is drying on this one. The first one took me 10 weeks (mostly making jigs and templates) so I'm hoping the next one will be half of that. Maybe less if I don't second guess too much!

I select and thin my tops based on individual material properties including modulus. The Sitka top on that guitar was .105, mass per square inch of .641 grams and a total top mass of 160 grams. The IRW back was .110. Top fundamental on completed guitar was 189 Hz.

My Sitka braces are tapered, not scalloped. X braces are .312 x .700 tall before carving. Four back braces are also .312 x .700 before carving. I glue braces on and then carve as part of the voicing and tuning process.

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It will probably be alright.

Thanks for that. Doesn't seem too far off what I did on the one in this thread... however, your braces definitely started a good bit taller than mine and more narrow. That probably suggests they were stiffer at the X than mine, but with less mass. That would imply similar response on that alone, but your top was also thicker and likely less responsive to the highs. So, we probably have a difference in the tapering toward the outside edges that is making the low end profile different. The back is much thicker than the one I did. What radius do you use for the back?

I use a 20' radius for the back. My top was .105 so a bit thinner than yours. Less mass = less treble damping.

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It will probably be alright.

I might have had a typo in my original post. My top was .10 so very close to yours. You have a back with less radius than mine was, so that might equal out the difference in our back thicknesses.

Looking forward to seeing how the next one sounds with a few minor changes!

Good luck, its a journey for sure!

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It will probably be alright.