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Location: Yokohama, Japan | My Celebrity CC247 has been seeing more action of late, and it's always a pleasure to use an instrument that has been salvaged from destruction. Although my re-assembled and upgraded Asian O sounds okay, it's always been a little too bright for my taste. My assumption has been that the laminated sound board was hard and rang too much in the high frequency range. Some time ago "Tap-tone" was discussed on one of my other threads; and so, I've gotten into a habit of tapping my guitars a lot. As I was doing so on my CC247, I noticed a dead-spot on the bass side of the sound board. Weird! Opened up the manhole cover to see what was going on and found that all the bracings were finished the same way at the ends. The bracings were basically the same heights too - something you would expect from an Asian mass production facility... 
Notice how all the tips are finished the same. There are only two variations in brace heights. Interesting. As I tapped the dead-spot, it was very obvious that the dead-spot was directly over the 3 braces on the bass side of the sound board. Not sure why this would happen. Since the sound board is laminated, it could be some inconsistencies with lamination thickness or adhesive application. In any case, the sound board was a dud in this area. Although the bracing was obviously re-glued to the sound board at some point there was no bracing/sound board adhesion problems per se... So, I thought working with the bracing themselves would loosen up the sound board. Took out my chisels and files and carved and shaved down the 3-braces that were directly under the dead-spot. 
As I carved the bracings down, I tested the dead-spot and voila, the dead-spot began to resonate! Cool! The cross beam under the bridge was shaved down a bit as well, and... 
...after finishing up with some filing and sanding, the dead-spot was gone, and the bass response drastically improved. Now, I would never do this to a New Hartford USA O, but for the Asian made Celebrity, especially the ones with the laminated sound boards, this may be a viable way to improve and/or fine-tune the resonance and overall voicing of these mass-produced budget guitars. Of course, if your Celebrity ain't broke, don' fix it! For me, it was a great, but non-time consuming lesson in bracing and guitar voicing! Hope this is helpful to some one out there struggling with their Celebrity.
Edited by arumako 2016-08-12 12:27 PM
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Location: Pueblo West, CO | Nicely done, Ken.
Wood density can, often does, vary across the grain. Stiffness is directly related to density. Also, denser wood is heavier. (naturally) It sounds to me like the part of the sound board that was dead was denser than the surrounding area.
When I was building model airplanes, I would candle the balsa wood before using it to make sure that I only used sections of the balsa sheets that had consistent density. I did this mainly to keep the model lighter, but also so that it would be easier to bend, shape, sand, etc.
Getting back to your guitar, if a part of the soundboard is more dense than the surrounding area, it won't vibrate as easily which would result in a dead spot.
Shaving the brace over the denser part of the soundboard would remove some of the stiffness and allow it to vibrate more freely.
That's my story and I'm sticking to it.
Keep up the good work.
Dan
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Location: Thredbo, NSW, Australia | Really interesting! More gold from BFLG.
Thanks Ken. |
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Location: Canada | Interesting, you are very brave and must be please that you improved the bass? I assume that working like this results in quit a bit of sawdust and debris - did you use some kind of small vacuum cleaner to get rid off this? |
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Location: Pacific Northwest Inland Empire | Gotta be a trick, working upside-down & backwards, with a mirror, too! |
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Location: Pittsburgh | Nice job, Ken! Your experience gives me hope for improving the sound of the next bargain O I pick up. Thanks! |
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Location: Yokohama, Japan | DanSavage - 2016-08-12 6:24 AM
Wood density can, often does, vary across the grain. Stiffness is directly related to density. Also, denser wood is heavier. (naturally) It sounds to me like the part of the sound board that was dead was denser than the surrounding area.
When I was building model airplanes, I would candle the balsa wood before using it to make sure that I only used sections of the balsa sheets that had consistent density. I did this mainly to keep the model lighter, but also so that it would be easier to bend, shape, sand, etc. ...
That's my story and I'm sticking to it.
Thanks Dan. Yes! Density that makes sense. Either because of the wood itself or (although less likely) the adhesives between the laminates, the density had to be the reason for the dead spot. Even if the thickness is the same, all lumbers vary in density across a broad area like a sound board! "Candling" balsa for consistent density is a cool trick that would work on torrefied spruce as well (won't it?). All of my vintage USA Os: 1117, 1861 and 1868 have translucent sound boards. When I put a flash light behind the sound board, I can see the light on the other side. Very very consistent density. My '06 Asturias and '67 S. Nogami concert tenor classical guitars also have translucent sound boards with killer tone. However, my '08 iDea (which is still quite new as far as lumber goes), and all of my laminated top guitars are completely opaque. Interesting! Your stories are always worth sticking too!
BanjoJ - 2016-08-12 6:45 AM
Really interesting! More gold from BFLG.
Thanks BanjoJ. You're comments are always so encouraging. Glad to share what I'm learning!
d'ovation - 2016-08-12 7:14 AM
Interesting, you are very brave and must be please that you improved the bass? I assume that working like this results in quit a bit of sawdust and debris - did you use some kind of small vacuum cleaner to get rid off this?
Yes, really pleased with the bass response. There is even added depth and breadth when I play the 1st through 3rd strings too. The dynamics just sound more consistent all around. I didn't shave a whole lot off (it really doesn't take too much) so the sawdust was minimal, but I did use this PC vacuum attachment;
Cool thing is, because this attachment is for PCs, the brushes on the ends are all made of non-conductive materials. That means that I don't have to worry about static electricity possibly blowing out electronic parts in the pre-amp as I'm cleaning. Just attach it to a standard vacuum cleaner and go, go, go! seesquare - 2016-08-12 9:34 AM
Gotta be a trick, working upside-down & backwards, with a mirror, too! LOL! You're joking right? I don't think I could pull that off in my dreams! Being an Elite style Celebrity, all I had to do was take off the manhole cover and set-up a really nice flat area on my work table. I used two 3mm foam sheets and cut rectangular spaces for the bridge, and flipped the guitar over, and reached into the manhole cover... 
Fortunately, I have some smaller size chisels (everything in Japan is a bit smaller!), and files that make working in tight spaces a bit easier! ovie26 - 2016-08-12 10:20 AM
Nice job, Ken! Your experience gives me hope for improving the sound of the next bargain O I pick up. Thanks! Thanks ovie26! Hope you find a great bargain out there! By the way, you'll notice that the brace that is on the extreme bass side is slightly scalloped. The braces are really sensitive, and you'll want to make sure that you shave a little bit at a time. Even "where" you shave along the length of the brace will affect the resonance and hence the voicing of your guitar. You probably know this already, but the direction your chisel moves and the side you cut with, all make a huge difference. Be really really careful. If you chisel with the flat side down, you'll make a deep cut into the brace and it could splinter which will require the replacement of the entire brace...ooh no fun! Great fun, this BFLG stuff! Thanks for being so encouraging folks!
Edited by arumako 2016-08-13 3:35 AM
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Location: Pueblo West, CO | arumako - 2016-08-13 1:27 AM Thanks Dan. Yes! Density that makes sense. Either because of the wood itself or (although less likely ) the adhesives between the laminates, the density had to be the reason for the dead spot. Even if the thickness is the same, all lumbers vary in density across a broad area like a sound board! "Candling" balsa for consistent density is a cool trick that would work on torrefied spruce as well (won't it? ). All of my vintage USA Os: 1117, 1861 and 1868 have translucent sound boards. When I put a flash light behind the sound board, I can see the light on the other side. Very very consistent density. My '06 Asturias and '67 S. Nogami concert tenor classical guitars also have translucent sound boards with killer tone. However, my '08 iDea (which is still quite new as far as lumber goes ), and all of my laminated top guitars are completely opaque. Interesting! Your stories are always worth sticking too! Yeah, I would suspect the glue between layers is pretty consistent because they use high-pressure to clamp it which would squeeze out most of the glue. Actually, you can't candle most torrefied wood because it's completely opaque. As wood ages it loses its translucence. After about 100 years or so, the wood become completely opaque. That's how the experts detect forgery in violins. Martin Guitars have two levels of torrefaction; M1 and M2. The M1 is what they use on their VTS guitars and it's partially opaque because they're trying to match the characteristics of 60 to 70-year-old wood. Their M2 torrefaction takes it to the limit so the wood has the characteristics of 200 to 300-year-old wood and is completely opaque. That's about the same as the torrefied wood we buy from the tonewood supplies, such as Stewmac, RC Tonewoods, etc. WRT to plywood tops, they may be more opaque due to the glue that was used to laminate them. I just candled a piece of 1/8" solid basswood and 1/8" 5-ply birch plywood and they both have about the same level of opacity. (not much, but I can see a faint amount of light coming through them) |
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Location: When?? | I really enjoy reading the stuff in this forum. I've learned 100x more here in just 6 months than I could have through an entire lifetime of simply pondering and poking in experimentation. Thanks guys! |
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Location: Yokohama, Japan | DanSavage - 2016-08-13 12:16 AM
Actually, you can't candle most torrefied wood because it's completely opaque. As wood ages it loses its translucence. After about 100 years or so, the wood become completely opaque. That's how the experts detect forgery in violins. Martin Guitars have two levels of torrefaction; M1 and M2. The M1 is what they use on their VTS guitars and it's partially opaque because they're trying to match the characteristics of 60 to 70-year-old wood. Their M2 torrefaction takes it to the limit so the wood has the characteristics of 200 to 300-year-old wood and is completely opaque. That's about the same as the torrefied wood we buy from the tonewood supplies, such as Stewmac, RC Tonewoods, etc. WRT to plywood tops, they may be more opaque due to the glue that was used to laminate them. I just candled a piece of 1/8" solid basswood and 1/8" 5-ply birch plywood and they both have about the same level of opacity. (not much, but I can see a faint amount of light coming through them)
Okay...Wow! I think I have my understanding of aging wood and opacity/translucency completely backwards! Thanks for clarifying this Dan! I kept thinking older woods become more translucent! Yikes! Thank God for the BFLG!
Love O Fair - 2016-08-13 12:30 PM
I really enjoy reading the stuff in this forum. I've learned 100x more here in just 6 months than I could have through an entire lifetime of simply pondering and poking in experimentation. Thanks guys!
I know exactly what you mean Love O Fair. The folks here at the BFLG selflessly share their expertise. I've learned so much here too! |
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Location: Tuscany, Italy | Very interesting. Thanks guys for your inputs...  |
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Location: SoCal | Regarding torrefied wood, the top Dan put on my 1113 is torrefied addirondack spruce. Dan shaved it a little thinner than Ovation would have. I've been playing it for 2 months (every day), and am amazed at how fast it has found its voice.
A really wonderful instrument.... |
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Location: Pacific Northwest Inland Empire | So, if this is truly the BFLG:
What are the chances you could put a set of book-matched top pieces, sealed into a large metal drum, and put it in the sun, in 100-degree temperatures, for 2 weeks? Do you have to have the increased atmospheric pressure of an autoclave, to achieve torrefication? Might rule out this method in Minnesota, or other lower-temperature locales, I suppose.......Arizona, Central California, & my bailiwick, come to mind. "Thinking outside the box", so-to-speak. |
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Location: Pueblo West, CO | seesquare - 2016-08-15 3:15 PM
So, if this is truly the BFLG:
What are the chances you could put a set of book-matched top pieces, sealed into a large metal drum, and put it in the sun, in 100-degree temperatures, for 2 weeks? Do you have to have the increased atmospheric pressure of an autoclave, to achieve torrefication? Might rule out this method in Minnesota, or other lower-temperature locales, I suppose.......Arizona, Central California, & my bailiwick, come to mind. "Thinking outside the box", so-to-speak.
In theory there are two ways to torrefy wood: dry and moist.
The 'dry' method is to simply put wood into an oven. The 'moist' method is to use an autoclave.
See: Characteristics of aged wood and Japanese traditional coating technology for wood protectionYamaha uses the 'moist' method for their A.R.E tops, as does Martin for their VTS guitars. Similiarly, Stewmac, and others also use autoclaves to torrefy their tonewood. As near as I can tell, Taylor is one of the few to use the 'dry' method. As to which one is best, wet or dry, I couldn't say as I've only used tonewood that has been put into an autoclave. |
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Location: Pacific Northwest Inland Empire | Thanks, Dan!
The article is a bit esoteric, & will take some effort to wade through, but I see some possibilities. After I get some familiarity with the process, I have some top sets I can use for experimentation. 180-degrees Celsius, for 1-to-120 hours. Well, it does not get THAT hot around here, so the week-in-the-barrel scenario might not be sufficient.
Cheers! |
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Location: Yokohama, Japan | seesquare - 2016-08-15 7:15 AM
So, if this is truly the BFLG:
What are the chances you could put a set of book-matched top pieces, sealed into a large metal drum, and put it in the sun, in 100-degree temperatures, for 2 weeks? Do you have to have the increased atmospheric pressure of an autoclave, to achieve torrefication? Might rule out this method in Minnesota, or other lower-temperature locales, I suppose.......Arizona, Central California, & my bailiwick, come to mind. "Thinking outside the box", so-to-speak.
Great question seesquare! and WoW! Dan, that is some great information thanks for sharing! Man, that is originally a Japanese document translated into English! You truly are a man of diverse resources! Very cool! |
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Location: Pueblo West, CO | Thanks, Ken.
I didn't translate the doc, but I do possess highly refined Google search skills. (LOL!)
As long as we're talking about technical documents, here's a link to Yamaha's patent for their A.R.E. process which describes the 'moist' method of torrefaction. See: US Patent 6,667,429 (Method for manufacturing modified wood) |
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Location: Yokohama, Japan | moody, p.i. - 2016-08-15 12:41 AM
Regarding torrefied wood, the top Dan put on my 1113 is torrefied addirondack spruce. Dan shaved it a little thinner than Ovation would have. I've been playing it for 2 months (every day), and am amazed at how fast it has found its voice.
A really wonderful instrument....
Thanks for the update moody, p.i.! That 1113 is really special. I've always found that the Celebrity nylon strings, just never seem to get the clarity of voicing that one would imagine. Just kinda assumed a lyrachord bowl was not really suitable for that kind of application, but I'm beginning to guess that I'm wrong about that assessment too. It sounds like your 1113 and perhaps the Country Artsist (6773) would hold its own against any nylon string. My Asturius and S. Nogami concert tenor classicals have really killer tone. It would be so cool to do a head-to-head comparison.
More cool info Dan. It's gonna take me awhile to digest the information, and I'm bound to suffer from substantial mental indigestion; but some of the information seems to relate to how the top of my 1868 straightened out with added moisture and drying. Completely different scenarios; but perhaps minimally applicable?! Very cool! |
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Location: Texas | Arumako, I have had several different Ovation classicals and all of them lacked the tonal response that a pure classical guitar offers. I always felt that nylon wasn’t a fit for the design. My Ramirez is the only non-Ovation acoustic I own. I also am interested in Paul’s 1113 to see if the different top provides for the rich resonance that the true classical guitar offers. Don't get me wrong...plugged in, Ovation nylons will exude that richness...but acoustically, they have always been a little thin to me. |
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Location: Boise, Idaho | I haven't played too many classical guitars, although I did spend a few minutes with a nice custom in Barcelona. I never really liked the sound. I don't know how to describe it other than my 1713 sounds bigger. The 1713 seems to have more bass than a traditional classical guitar. I just think size matters and the 1713 or 1113 Ovations are just bigger and sound like it. Classical or Flamenco guitars are made to sound the way they do and I've heard a lot of little Flamenco guitars that cut through the pounding of heals on wood floors without amplification. I just don't know if I could describe it as rich or poor, thin or fat, just different. |
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Location: Boise, Idaho | I looked up some information on the differences between classical and Flamenco guitars that I had read before, but forgotten. I shouldn't have even placed them in the same category because they are intended to play and sound so much different from the other. An Ovation Classic should probably be compared with a regular classical guitar, not a Flamenco. For that comparison to be somewhat valid, you'd have to make sure the action on the Ovation was high for starters. I don't think my 1713 action is close to the height of most regular classicals. |
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Location: Boise, Idaho | Edit: deleted double post
Edited by Mark in Boise 2016-08-17 6:59 PM
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Location: Yokohama, Japan | Interesting discussion about the classicals, flamencos and nylon strings. I guess "technically" an O could not be called a classical or a flamenco, and would have to be referred to as a nylon string. The flamencos were more for the common guitar player and were made from lighter and less expensive materials making the tone a bit brighter. The pegged head stock tuners and super lightweight were basic characteristics. The classicals usually featured Brazilian Rosewood back and sides with cedar or spruce tops and were much fuller in tone and much heavier in weight.
Mark in Boise's comment about Ovations sounding bigger with more bass and moody, p.i.'s review of his 1113, seems to indicate that the bowl design of the O might be highly suited for nylon stringed instruments! My 2006 Asturias and 1967 Nogami classicals both use the same (a slight variation on the 1943 Hauser) bracing pattern (interesting that different companies from completely different time periods chose to use the same bracing pattern). Moody, p.i.'s Dan Savage special 1113 used Ovation's fan bracing design. I wonder if O used that bracing pattern exclusively for all their nylon stringed instruments? Man, it would be really cool to see what an O nylon with other bracing patterns would sound like. Since Mr. Kaman was a musician/scientist/inventor at heart, I suspect the fan bracing design was finalized after much research. Would be neat to find out how they came to that final design decision.
Edited by arumako 2016-08-19 9:30 AM
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Sound board "dead-spot" Fix
