Larrivee volume / shaving braces

[jeremy3220]

I took this from Scott VanLinge's site, and cleaned it up a bit in P'shp.. it's his approach to re-voiceing Larrivee's... if/when Scott shows up here, i'm sure he will talk about his work far better than i ever could, but it would seem to go a fair bit beyond shaving the height of the X brace, and although i have talked to him a bit about this, i have not felt the desire to touch my OM19 ;-)



d.

This is what I'm talking about, the 'after' shape has a better stiffness to weight ratio.

"In comparison with a rectangular brace of the same width and height, a triangular cross-section brace would need to be either three times as wide or ~ 1.44 times as high to obtain the same stiffness"  David C. Hurd Ph.D.

[jimmy buffett]

Why did you remove material from there of all places? If you removed 10% of the brace height I think you lost about 20% of the stiffness of that brace. I don't know if those figures are exact but you definitely decreased the stiffness to weight ratio of the top. Those are the only two top braces with a somewhat triangular profile which provides the best stiffness to weight ratio. Have you experimented with with removing material from other braces?

To  the best of my knowledge, it's the two braces that cross the lower bout that have the most impact, given that they brace the largest area of the top.  That's where the sound comes from.  Anything in the upper bout or around the sound hole would have less of an impact on the sound because the lower bout is where the sound comes from.  It's like a set of drums, where the oomph comes from the bass drum, or the drum with the largest skin.   

Also, it's pretty hard to move your hand around in that small space, so the longer brace is where you have the best access.

I think that diagram above shows what I'm getting at pretty well.  I don't think that I was able to make this kind of impact, but this is a good example of what I'm shooting for.  When you look at it, the "after" brace isn't so much lighter that it should negatively impact the guitar.

jimmy

[leerichards]

Jimmy, you say that you have shaved the braces of your four Larris. Can you describe the differences you noticed after you'd worked them to your satisfaction? Changes of tone, balance, sustain, volume etc? And was it a significant change ie really noticeable? With thanks, Lee.   BTW I replaced all the broken top braces in a bowl backed mandolin in which the soundhole was about the size of a duck's egg. I had to drop a mirror in there and an LED light and work with a mirror and purpose-made tools - man do I have respect for dentists now.

[jeremy3220]

Are you talking about the X brace or the lower tone bars? The X is the longest brace and supports the top the most. The tone bars are already pretty triangular from what I remember so I don't see how you could do much other than lower the height.

[jwb]

OK, I can't help myself...you need to buy a Bourgeois, Collings, SCGC, (insert other fancy guitar here).  A Larrivee is built like a tank (OK, much overstated!).  They will last forever, the top won't hardly move with time (be around in 100+ years with care) and they can sound a bit subdued compared to one of the aforementioned hotrods.  But they are great guitars for what you pay.  I love mine.  Especially the OM-03MT!  They can be exceptional guitars when you match yourself to the right one.  Please, unless you just can't control yourself, don't shave the braces on your Larrivee.  No offense to those that have....the world needs tinkerers.  Just sell it to someone who will love it for what it is and save your lunch money for something that will do the job.  FWIW, my .02

Justin

[hadden]

If you want to mod I'd say what the heck, go for it. I prefer the word Sturdy though. Overbuilt and built like a tank overstate the case. I really don't want to get into this debate again, but those ways of describing Larrivees have negative connotations that don't really apply to the lively guitars they are. Just this morning I was enjoying how much pop there was to the harmonics, with also a lovely floaty bloom to the sound....

You can certainly go from excellent to more excellent, of course.

[prof_stack]

A few years I read a post (here or at AGF) that Leo Kottke used to whittle the braces of his Taylor 12-strings when he got them.  If true, I'm sure he knew where and how much to remove.

Agreed with the comment to leave them alone.  Once shaved, its too late to go back.  Maybe some medium strings will drive the top more to one's liking.

[jimmy buffett]

Jimmy, you say that you have shaved the braces of your four Larris. Can you describe the differences you noticed after you'd worked them to your satisfaction? Changes of tone, balance, sustain, volume etc? And was it a significant change ie really noticeable? With thanks, Lee.  

I would say that the changes are mostly to volume and sustain, but like so many questions about the sound of a guitar (i.e. different tone woods, scale length, body style), it can be very subjective.  I don't know if I'm up to the task  :(

My primary comment is that whatever sound your guitar was producing before, it will be enhanced after this minor mod.  Look at the illustration of the two braces, and ask yourself which one would allow the top to move more freely.  In my experience, most custom made guitars have a profile more similar to the taperred brace, while the standard Larrivee seems to have a wide flat surface at the top edge. 

Hope this helps...

jb

[magictwanger]

Hmm!I have a Collings and a Bourgeois,but I "must" say that I happen to love the sonic presentation of my Larri D-O3R.

  Sheesh,it has it's "own" sound,and if I did not really like it,I'd not have bought the thing!

  Soul search as to whether you like it,or not.That's about it really....but...

  Best of luck to you

[GA-ME]

My take on this kind of stuff is, if its yours and you feel you are comfortable in doing the mods, then do them. Just about anything can be "improved" if a person takes the time to learn what they are supposed to be doing. Some folks are just more curious and adventurous than others. Some folks like to learn about new things and then to try new things out. Some folks are really handy and enjoy customizing just about anything. Other folks prefer to buy things, keep them pristine, and never alter anything from stock. To each his own.

[ryler]

My take on this kind of stuff is, if its yours and you feel you are comfortable in doing the mods, then do them. Just about anything can be "improved" if a person takes the time to learn what they are supposed to be doing. Some folks are just more curious and adventurous than others. Some folks like to learn about new things and then to try new things out. Some folks are really handy and enjoy customizing just about anything. Other folks prefer to buy things, keep them pristine, and never alter anything from stock. To each his own.

Yeah, what GA-ME said. 

[Danny]

       I can't speak for others but the Forum III is the loudest Larrivee out of the eight I have owned. And that includes a D-09 and LV-03R. Because of the 12 fret design and bridge placement it is very loud, if you want it to be. I have the Mahogany with the Italian Spruce top. I just noticed today that the F-III is actually louder than my Martin OM-21.
       Of course the OM-21 is 14 fret and RW/Spruce, but it used to be louder than all of my Larrivees. And of course the OM-21 has very light bracing. So imagine what the F-III would be like if it was shaved. But I won't do it to mine.

         I agree with Mark early on in the thread, if you want to be the loudest git at a Jam, just buy a big ole J-200 or a Jumbo Guild. Personally I'm even picking up my classical more lately. I like the subtle tones much more than "driving'' jangles of sound. Unless they are brief punches that match the mood or lyrics. Otherwise I look for my earplugs.

[leerichards]

Thanks, Jimmy. The fact that you modified all four guitars shows that you felt you were onto a winner. Brave man getting into the first one though - unless you are a luthier, I'll bet you took quite a few deep breaths before taking off that very first shaving. Did you use violin makers' thumb/finger planes? I'd be interested to know more about the process but I don't suppose the forum is the place for that. If you have the time (and inclination) to email me, I'd like to find out more. Not sure I'd touch my Larri- she's my no.1, but experimenting with instrument modification is something I like to do myself - I converted a broken down old Harmony flattop into a resonator which is at present strung as a 6 string bass/baritone. Thanks again.

[Scott van Linge]

This is what I'm talking about, the 'after' shape has a better stiffness to weight ratio.

"In comparison with a rectangular brace of the same width and height, a triangular cross-section brace would need to be either three times as wide or ~ 1.44 times as high to obtain the same stiffness"  David C. Hurd Ph.D. 

Jeremy,

I don't know where you got the rectangular cross section, since I don't believe it's on my website, or this quote about a triangular cross section which seems irrelevant.   The parabolic cross section is the shape I use for all braces I reshape, as it seems to best deliver the energy from the strings into the soundboard from the X brace.  Or to resonate with the soundboard, as with the other braces. 

It's not as strong as a rectangular cross section, but lots stronger than a triangular one, all of the same height.  And both of those shapes have corners, which, IMHO, absorb energy, dampening both the volume and sustain.  A parabolic cross section also has the greatest strength-to-weight ratio of various possible cross sections.  I think.  It's been over 45 years since I took physics...

But I do remember from mechanical engineering 101 that a parabolic spanning beam (in length) is just as strong as a rectangular one of the same height and width (same height as in the middle of the parabola). 

The "before and after" cross sections you show could be from many guitars I've worked on.  Some companies cut their braces from billets that are shaped lengthwise, but as wide as 6 or more  braces.  The billets are then cut up into individual braces.  Sometimes they are just glued in with the rectangular cross section (Taylor) and sometimes they are rounded or semi-triangulated with some sander or router. 

For a company to shape braces in the careful fashion I do, graduating their height to match the string tension on them at any point would necessitate a CNC router/computer program for each brace.  Not quite mass production standards.  But it is only when I accomplish that balance that the entire surface to which the brace (all braces) is glued is able to vibrate with the rest of the soundboard.  And that adds up to a lot of dead, very expensive real estate on, yes, even your Larrivees. 

The re-voicing I do does not change the basic tone of any guitar.  That is determined by the woods and shape and size.  Minus, of course, all of the sound that braces either absorb or do not  transmit.

10% off the top?  You've got a long way to go, but go slowly...  And don't forget that the back can add a lot of reinforcement, if allowed to.

Scott

[jimmy buffett]

Thanks, Jimmy. The fact that you modified all four guitars shows that you felt you were onto a winner. Brave man getting into the first one though - unless you are a luthier,

I should have been more clear about this.  When I said that I've shaved four of my Larrivees, I should have been specific in saying that I had my friend, Tony Karol, do the planing.  Tony is superb at wood working (did I mention that he's a luthier?)  Tony's experience at working with those little thumb planes and his precision makes it a lot easier to get this done.  I did some final sanding on the braces just to smooth and shape the end result.  Besides, it always makes a nice excused to spend time in Tony's shop.  

Some of you might have seen his display at the Montreal Guitar Show:

http://www.karol-guitars.com/

When my friend asked me to help him cut a sound port into his Oscar Graff, I took him to Tony's and while we did the settting up together, I told him I wanted to do the routering.  It was worth it to see Darcy turn blue when I hit the power switch, but I wasn't able to see him stop breathing as he had to leave the room.  Much like an expectant father in the delivery room.

And I found the post by Scott van Linge to be a good read.  He did a great job of detailing what the objective is, and why going to a parabolic shape makes so much sense.  Isn't this what all of the master builders do when they build braces?  He did a nice job explaining the impact that the shape of a brace has on "delivering the energy".  The parabolic beam is just as strong, but eliminates the corners that have a dampening effect on volume and sustain.

As Scott points out, at only 10% you have a long ways to go.  I can honestly say that I don't know the precise amount that we removed, but was only trying to show that it's not like anyone is advocating running the belt sander along the brace until it's hard to find.  Thanks for your input here, Scott.  I learned something from your observations, which is largely why we belong to a Forum like this.

You can see the bracing that I built on my custom project if you follow the link on my earlier post.

jb

[jeremy3220]

Jeremy,

I don't know where you got the rectangular cross section, since I don't believe it's on my website, or this quote about a triangular cross section which seems irrelevant.   The parabolic cross section is the shape I use for all braces I reshape, as it seems to best deliver the energy from the strings into the soundboard from the X brace.  Or to resonate with the soundboard, as with the other braces. 

I got the picture of the rectangular cross section from the post above mine. The quote is totally relevant as it explains the stiffness to weight ratio of triangular braces to rectangular ones and is from the author of 'Left Brain Luthrie'. I don't know of any one that uses a true triangle or parabola, you don't want the sharp point of the triangle as it could tend to get damaged easily and parabolas are conic sections and rarely do brace sections form true parabolas, especially lengthwise.

[jeremy3220]

A parabolic cross section also has the greatest strength-to-weight ratio of various possible cross sections.  I think.  It's been over 45 years since I took physics...

Strength to weight ratio isn't that important especially considering the distance the brace spans cross wise. More important is stiffness to weight ratio and many parabolas would do poor as a brace cross section.

For instance this parabola would have a poor stiffness to weight ratio as a cross sectional shape of a brace.


The reason is increasing the height of the brace is the most effective way to improve the stiffness. If you double the width of the brace then you double the stiffness but if you double the height you get eight times the stiffness. So to get the best stiffness to weight ratio you want tall skinny braces whether they resemble tall triangles, tall parabolas or whatever you want to call them.

[GA-ME]

If anyone is interested in trying some slight modifications to the bracing, there is an easy way to dip your feet in the water. Just take some 100 grit, or thereabouts, sand paper and simply wrap it around the braces and just sand off the hard right angles of the braces left by the chiseling. Make it so everything is smooth and has even transitions. Don't try to substantially reshape the brace profile, so much as just even the hard angles out to smooth surfaces.You are removing very little material and I think most folks would be surprised by the increase in sustain, volume, and presence of the guitar following this simple, minor modification.

[hadden]

If anyone is interested in trying some slight modifications to the bracing, there is an easy way to dip your feet in the water. Just take some 100 grit, or thereabouts, sand paper and simply wrap it around the braces and just sand off the hard right angles of the braces left by the chiseling. Make it so everything is smooth and has even transitions. Don't try to substantially reshape the brace profile, so much as just even the hard angles out to smooth surfaces.You are removing very little material and I think most folks would be surprised by the increase in sustain, volume, and presence of the guitar following this simple, minor modification.

You mean the 90 degree angle of the main X Brace? Just the X Brace, and all the way to the sides the guitar. So you are suggesting just evenly shave off the hard edge all the way along.

Did you do this to one of your Larrivees, and what was the result? If I end up with any humps in the frequency response or increased bass as overhang or wolf tones it will be a problem.

This is tempting. I can do this. I like the guitar as it is, but if I can make the same flavor more intense........hmmmmmm

[Scott van Linge]

Jeremy,

You're right about the triangular quote being relevant.  Thanks!  It's such a burden to be right all the time...

In a way, a parabolic cross section is somewhere between a rectangle and a triangle, and I think, the best shape.  The wide parabola you show is not a good one for stiffness, true.  My work re-voicing limits me to what is there, and a wide parabola is better than not.  Such as the back braces.  But I agree that narrow taller parabolic cross sections are better. In fact, when I build one, I make the lower tone bar narrower than the upper one.  After all, it's farther from the high string tension area below the bridge and doesn't need to be as strong.  Of course, it can have a longer span, as they do in Larrivees, but I build with the traditional diagonal angle to the tone bars.  Although not as strong as the Larrivee double A frame, the tone bars pass through the rings (from my Sound is Round model) obliquely, and do not impact any one ring as much as do the A frame ones.  Which is why it has been my experience that the tone bars dampen the G and A strings, since they are tangent to and/or just inside these rings. 

Scott