Shaving X bracing

[ajh]

On my Kala tenor guitar the x bracing is square cut...no radius or taper to the sides. (The bracing on the back is rather tall but is tapered and radiused.) What would be the expectation in tone change for going in and adding taper and radius to the x bracing? Is it worth the bother?

Thanks
Tony

[Ken]

Inexpensive instruments sometimes don't have sharp edges of the braces relieved. I don't think it would make much difference to the tone to simply soften that sharp corner, so why bother unless it would be fun to do. If you remove significant amounts of wood from the braces it could change the tone, but that could be either bad or good ( maybe a fuller tone, but maybe lose your treble response), and removing too much wood from the braces could damage the structural integrity of the guitar top. So go with caution.

[sunburst]

I would expect no real difference in sound from shaving the braces, but I would expect a high percentage of people who did such brace shaving to hear a difference after doing the work.

[Bill McCall]

I would expect no real difference in sound from shaving the braces, but I would expect a high percentage of people who did such brace shaving to hear a difference after doing the work.

I think the instrument would have to open up again to fully hear the tonal change.

Unless, of course, you used a Blue Chip pick.

[ajh]

Thanks everyone. I appreciate the replies.

I won't bother messing with it.

We do stuff like that.......because we can.

[HoGo]

I've done this, and I've experimented with quite a few instruments.
I got nice Cort E200 guitar (solid sitka top and mahogany back Korea made - better quality than recent Chinese) and took measurements. It sounded nice, perhaps a bit tight and trebly. Top wood is excellent quality and thickness just exactly like typical Martin. Major difference from Martin D-18 was bracing that was quite a bit taller and only little rounded at top. It has a rosewood bridge plate, but smaller than some Martins from 70's. The upper block has L shape much like some of the "A-frame" Martins but I consider it better for stability than normal block.
SO I took my fingerplanes and shaved the bracing (both top and back) down to size corresponding to average Martin (covered the x joint with spruce cap as I removed the glue saturated cloth) and the sound transformed hugely (my friend and my brother have same guitars that sound very similarly to mine so I have comparison). I did it in several steps and the last was adding scalloped bracing. The sound is now really completely different and the guitar has very loud and responsive tone and clear fat trebles and crisp low end with good separation like nice "hog". I'm thinking about changing the bridge to more traditional (these have bridge thinned under pins) and reshaping the neck which is a bit fatter and wider.
I wouldn't advice anyone doing this unless they can accept possible failure.
I once shaved overly tall tonebars of Capek mandolin (they were over 1/2" high) but the result was just slight - problem was also very weird arch and mile-thick lacquer. Back was likely quite thick as well deadening the response.
Work like this requires judgement based upon examination of many many instruments.

[peter.coombe]

A guitar is a different animal from an arch top mandolin. A flat top guitar top has very little in the way of stiffness without any bracing. Most of the stiffness is in the bracing, so shaving the braces is likely to make a significant difference to the stiffness of the top and hance to the sound. On the other hand, an arch top mandolin top is already quite stiff, so small changes to the braces is not likely to make any where near as much difference as a guitar.

[j. condino]

Ahhhhhhhhh.... another half deaf old geezer thread about tone... You kids get off my lawn....!

Some people can't hear any difference in modifications to an instrument, no matter how small or large- materials, brace sizes, ALL of the fittings like bridges, tuning machines, fretwire, nuts, and tailpieces and they will deny that anything makes a difference and claim if it isn't exactly the same as it was done back in the end of the Pleistocene by one now unrealistically mythical factory worker then it is a whole lotta nothin'.

Other folks have very good hearing and can detect very subtle differences to almost any modification or changes that are made.

A cheap heavily built instrument constructed of mediocre materials will usually respond far less to changes. A lightly built instrument made from excellent materials will generally respond much greater to small changes. Your personal ability to hear and detect those changes is a separate conversation.

You can make large audible differences in archtop mandolins from just the bracing, as covered in this thread:

https://www.mandolincafe.com/forum/s...hlight=condino

[Tom Haywood]

Not sure what the OP means by putting a "radius" on the braces. It being a guitar, it is likely that altering the braces will change the sound to some noticeable extent (think "voicing" the instrument). What to expect is a different matter without hearing another Kala tenor that has been similarly voiced. My advice is to go slow, do a little at a time and listen. Sanding the square corners off the braces a little bit probably will not diminish the strength. I'm not familiar with their tenor guitars, but I have a Kala UBass that is sturdy but very lightly constructed. I wouldn't alter any of it's structural design. You may be the first pioneer with this on the Kala, and of course any warranty will be history.

[ajh]

Not sure what the OP means by putting a "radius" on the braces. It being a guitar, it is likely that altering the braces will change the sound to some noticeable extent (think "voicing" the instrument). What to expect is a different matter without hearing another Kala tenor that has been similarly voiced. My advice is to go slow, do a little at a time and listen. Sanding the square corners off the braces a little bit probably will not diminish the strength. I'm not familiar with their tenor guitars, but I have a Kala UBass that is sturdy but very lightly constructed. I wouldn't alter any of it's structural design. You may be the first pioneer with this on the Kala, and of course any warranty will be history.

Tom, To clarify. Looking at a section view through the braces, they have vertical walls (basically a rectangular box). I was referring to sanding both sides to bring the sides in at an angle resembling a truncated triangle...then adding a radius to the top edges.

Actually, the Kala tenor is not a bad instrument, especially for a couple hundred dollars. Very nicely made with a light box and a thin satin finish. I was really surprised by it.

The reason I was looking at reaching inside and sanding (carefully) is that because the box is so lightly made there might be room for improvement. On an overbuilt instrument I wouldn't even think about it.

I had sent out a carved top mandolin for "mandovoodoo" a few years back just to check it out (a major component of that is shaving braces). It did make a noticeable difference (to me....and I agree about the subjectivity issue) so thought it might be worthwhile to try it here. (Note that we don't have to re-open the opinions and analysis tangent of the voodoo process.)

Hmmm. And I am not half-deaf...although I am an old geezer. A grumpy one too this time of the morning, James.

[fscotte]

Radiusing the ends of the braces will loosen up the top. I know the uke builders do this. Some will also taper down the thickness of the top at the edges.

[Willie Poole]

I knew Mike Longworth quite well when he was with Martin and he gave me the plans of how the Martin Herringbone braces were shaped and I have carved quite a few guitar braces to those specs, the ones I could reach through the sound hole, and using a finger plane it did the job quite well...Every one that I ever altered did sound better and the owners were all satisfied with the tonal change....I will admit that some people hear a change because they want to hear it....I own a $100 guitar that sounds as good as any Martin and I did those braces as soon as I bought it 30+ years ago and it has no top cave in...and as stated above they seem to get better the more they are played...

Willie

[Tom Haywood]

Shaping the braces to seek a completely unknown result in a completed guitar seems a little backwards to me, especially since the trade-off is potential structural failure. Most dreadnought guitars on the market, including Martin, are overbuilt. Shaping the braces to Martin herringbone dimensions brings fairly predictable results. One of the main goals is to increase the bass response so that the guitar can be the cannon that some folks want. Tone-wise it can end up being a bit out of balance. That can be desirable or not. Since a tenor guitar is not designed to do what a dreadnought is designed to do, I'm not clear what the goal would be - i.e. what would be considered an improvement. At the price the Kalas sell for, maybe the exploration outweighs the risk. I would love to hear the before and after if you proceed.

As a builder, I'll add that freeing the top is not necessarily a good thing. A lot of thought goes in to designing the bracing to not only support the top but also to make it less free so that the vibrations are controlled. A surprising result is that more bracing sometimes produces a "better" sound in a given design.

[ajh]

Shaping the braces to seek a completely unknown result in a completed guitar seems a little backwards to me, especially since the trade-off is potential structural failure. Most dreadnought guitars on the market, including Martin, are overbuilt. Shaping the braces to Martin herringbone dimensions brings fairly predictable results. One of the main goals is to increase the bass response so that the guitar can be the cannon that some folks want. Tone-wise it can end up being a bit out of balance. That can be desirable or not. Since a tenor guitar is not designed to do what a dreadnought is designed to do, I'm not clear what the goal would be - i.e. what would be considered an improvement. At the price the Kalas sell for, maybe the exploration outweighs the risk. I would love to hear the before and after if you proceed.

As a builder, I'll add that freeing the top is not necessarily a good thing. A lot of thought goes in to designing the bracing to not only support the top but also to make it less free so that the vibrations are controlled. A surprising result is that more bracing sometimes produces a "better" sound in a given design.

That is the interesting thing to me...where is the balance. And why I asked the question in the first place.

It surprised me that the xbracing was not tapered and shaved in the first place considering how nicely the instrument is made. That leads me to think it is the (minimal) cost addition....but then why were the back braces tapered and radiused? For an instrument that only cost 200...a light box with a rosewood back (pretty sure it is laminate back...but still?) I just don't see it being analyzed that closely..to me it seems that the designer found really good materials and a fantastic assembler. They tried something and it worked fairly well. But then the bean counters got in the way and they let it go at that because of the market size. That kind of thing has been my direct experience, but I may be completely out of line here.

From a structural point of view, the rectangular section does give you a bit...just a bit...more strength than a truncated triangle with radiused upper corners. But given how much effort folks put into the analysis of (the mirrored) mandolin bridge structure (taper, material, density, mass, geometry) and how touchy that is...it begs the question. Granted the respective tapers of the xbrace and the bridge are doing two seperate functions, but they are still transmitting vibrations through a geometric structure. To me, yes, it will make a difference..........but how much? And for better or worse ? And at what point does the return diminish? That is why I brought it up for an honest discussion.

I have an upper grade (flamed mahog back and sides with solid spruce top) late 20's Regal that is like a feather....with only a really light lateral brace behind the soundhole instead of the xbracing. Comparing the Regal to the Kala is night and day. But they both sound good in their own realm. But the Kala doesn't touch the Regal.

The Regal rarely leaves the house and is what I typically play to learn things and for my own enjoyment. When I play "out", the Kala is what I take out. So I am giving some effort to making the Kala as good as I can make it.

After the first couple responses I was just going to let things be and move on. We all know how that is going to wind up now.

Once I start playing with shaving things I am then stuck with having to put new strings on every time I make a change to get a true comparison. And I detest new, zingy strings. Part of the deal I guess. I will make comparative base recordings if/when I get to doing it. But for right now it is Minnesota in springtime....and it has been a long, nasty winter.

I do appreciate all of the responses and very much respect all points of view.
Thanks!

[sunburst]

A couple of anecdotes (to add to those already here).
I can think of at least twice (maybe 3 times?) that I had early 1970's Martin guitars in the shop for significant repairs. I asked the owners if they were OK with me removing some material from the top braces of these overbuilt, heavy guitars. They enthusiastically said yes, so I shaved away enough spruce shavings to fill gallon pails from each top. How did they sound after the repairs and the work? About the same as they sounded before.

A friend had a guitar that was made by a well known (at the time) mandolin maker. He asked me what I thought of it, and I said it felt kind of heavy and sounded kind of tight, and that it might be a candidate for brace shaving. He immediately brightened up and asked if I would be interested in shaving the braces. I said that first I would have to take a good look inside to see what the braces were like, so I did. The braces were so small as to be nearly worthless for structure. There was nothing there to remove. The owner then told me about a well known guitar player (who had aspirations as a luthier) who played the guitar and told him exactly which braces needed to be cut down and how much! He obviously didn't look inside the guitar, yet he "knew" what he was hearing.

...and one more.
I once had a 1974 Martin D-18 in the shop for significant repair. I don't remember exactly what was wrong with it when it came in, but it was unplayable (I think the bridge was off, among other things). I worked on it over the course of several days or a week or so, and the whole time I kept thinking; what a lousy guitar! Klunky neck, big braces, mediocre workmanship, not even a good example of 70s Martins. Finally, I finished all of the repairs and rather unenthusiastically strung it up and set it up. When I strummed the first chord I could have sworn I had a '40s D-18 in my hands. If I had shaved the braces in that guitar, would I have attributed the sound to the lighter braces? I'd like to think I would not have, but I might have...