Why would you prefer "hand-carved" scalloped X bracing?

[Riverwolf]

Saw this mentioned in another thread and pondered it all day...

Assuming these are factory built and not custom shop or luthier built.
Why would you prefer or trust a human to carve out and shape these braces over a machine?
I have to assume that each individual top is not tone tested on mass assembly lines.
I also assume that CNC machines will make perfect copies all day long.
Machines don't get tired or have bad days.

So why is hand carved such a selling point?

[Mycroft]

No two pieces of wood, even from the same species, are identical.

[charles Tauber]

Originally Posted by Riverwolf

Assuming these are factory built and not custom shop or luthier built.

So why is hand carved such a selling point?

Assuming there is no deflection testing, tap testing or similar individualizations of the braced top, its marketing to appeal to one’s emotions and evoke a sense of old-world workmanship vs factory assembly line.

[Steadfastly]

Well, of course, that is true. We can also ask ourselves, does a luthier have the ability to look into each piece of wood and see how its atoms are constructed? Can he remember how each piece of wood he has hand carved over the last week, month, year and decade needed to be shaped to provide the best vibration for the guitar tops?

I don't believe they can and since that is the case, a luthier can't apply that information to the next guitar or the thousands after, that he works on. For those reasons, I will opt for the CNC machine every time. Once we figure out the best design for the bracing, the CNC machine will get it right. Humans will not.

Now, here is a little story my local luthier told me last week. He had an old Martin D-28 with non scalloped bracing and said it was a dud. When I asked him how he fixed it, he said he scalloped the bracing and it came alive. That made sense but it doesn't mean he did a better job than a CNC machine would have. It simple means he made a big difference from non scalloped to scalloped bracing.

So, to answer the OP's question about why hand carved is such a selling point is the marketing that has gone on to make this sound like some sort of magic, which it isn't. It's based on emotion and lack of knowledge.

[Paddy1951]

What you are questioning is the marketing hype. You are correct that machine made parts will be more consistent.

[guitar george]

Because individually hand-carved braces can be custom shaped to produce the best sound from the back, side and top wood being used. The sound will change depending on where the wood is being removed and how much wood is being removed from the braces. This is how a luthier built guitar could likely excel over a factory made guitar.

[ManyMartinMan]

I would trust someone who was doing a tone-tap tuning of a top to hand-scallop the top braces. Other than individually tuning a guitar I wouldn't care if the top braces were scalloped by hand or machine if the guitar sounded magnificent.

[hifivic]

Originally Posted by charles Tauber

Assuming there is no deflection testing, tap testing or similar individualizations of the braced top, its marketing to appeal to one’s emotions and evoke a sense of old-world workmanship vs factory assembly line.

B I N G O...........we have a winner folks!

[hillin]

Originally Posted by Steadfastly

Well, of course, that is true. We can also ask ourselves, does a luthier have the ability to look into each piece of wood and see how its atoms are constructed? Can he remember how each piece of wood he has hand carved over the last week, month, year and decade needed to be shaped to provide the best vibration for the guitar tops?

I don't believe they can and since that is the case, a luthier can't apply that information to the next guitar or the thousands after, that he works on. For those reasons, I will opt for the CNC machine every time. Once we figure out the best design for the bracing, the CNC machine will get it right. Humans will not.

Now, here is a little story my local luthier told me last week. He had an old Martin D-28 with non scalloped bracing and said it was a dud. When I asked him how he fixed it, he said he scalloped the bracing and it came alive. That made sense but it doesn't mean he did a better job than a CNC machine would have. It simple means he made a big difference from non scalloped to scalloped bracing.

Like Mycroft said, no two pieces of wood are identical. It means, two pieces of wood, even from the same tree, have different tonal properties.

It's needless to say that the top plate of a guitar contributes most to its sound. The top plate has to be braced to work against the string tension. How it should be braced thus becomes an eternal subject. Most guitars nowadays adopt the X bracing pattern designed by Martin, but it's only a pattern and there are some more variables. A luthier can apply a heavy, unscalloped bracing which we call "overbuild", making a strong top which can withstand any magnitude of string tension, but it's a massive drag for the top to vibrate, resulting a bad sounding guitar with small volume and short sustain.

The initial idea of scalloping is to reduce the mass of the braces, only keeping necessary mechanical strength. A famous luthier (I can't remember who, maybe Ervin Somogyi) believes that the best guitar is always built on the edge of collapse. Because no two pieces of wood have the same mechanical structure, the amount of brace wood to be removed varies. This can be told by experience, but factory built guitars, even hand-carved, often tend to be overbuilt to ensure a high yield rate/low repair rate.

Later luthiers found that by carving the braces, it can alter the guitar's sound, or technically speaking, equalize it. This process is called "voicing", and/or "tap tuning". The luthier listens to the response by tapping on the braced top plate, and adjust the braces accordingly (sometimes they even sand down the plate) to find the best "tap tone". Again, because plate and plate are different, this process cannot be standardized. Tap tuning is a common practice in making boutique crafted guitars, but some assembly line guitars also have it introduced. Of course the outcome highly depends the experience, skill and even talent of the luthier; but it's something a machine like CNC cannot replace - unless you can teach it to identify a good tap tone.

[stringjunky]

Originally Posted by Steadfastly

Well, of course, that is true. We can also ask ourselves, does a luthier have the ability to look into each piece of wood and see how its atoms are constructed? Can he remember how each piece of wood he has hand carved over the last week, month, year and decade needed to be shaped to provide the best vibration for the guitar tops?

I don't believe they can and since that is the case, a luthier can't apply that information to the next guitar or the thousands after, that he works on. For those reasons, I will opt for the CNC machine every time. Once we figure out the best design for the bracing, the CNC machine will get it right. Humans will not.

Now, here is a little story my local luthier told me last week. He had an old Martin D-28 with non scalloped bracing and said it was a dud. When I asked him how he fixed it, he said he scalloped the bracing and it came alive. That made sense but it doesn't mean he did a better job than a CNC machine would have. It simple means he made a big difference from non scalloped to scalloped bracing.

A luthier can tap a top to get a feel for its tone then modify it. A CNC cut top is just a random top that may sound good or not; it's a lottery.

[Steadfastly]

Originally Posted by stringjunky2

A luthier can tap a top to get a feel for its tone then modify it. A CNC cut top is just a random top that may sound good or not; it's a lottery.

He may tap the top but does he glue the braces on, finish the guitar and tap again and realize something is not right and take the guitar apart and redo the braces?

[stringjunky]

Originally Posted by Steadfastly

He may tap the top but does he glue the braces on, finish the guitar and tap again and realize something is not right and take the guitar apart and redo the braces?

No, they roughly cut the braces and stick them to the top, then they carve them to suit. Factory braces are cut, stuck on, job done.

[hillin]

Originally Posted by Steadfastly

He may tap the top but does he glue the braces on, finish the guitar and tap again and realize something is not right and take the guitar apart and redo the braces?

Tap tuning is done after the braces are glued. I guess if the guitar is finished, what's done is done. A boutique luthier may give it a bit more adjustment through the sound hole, but I highly doubt anyone would take the guitar apart just to adjust the scalloping. To an experienced luthier, tap tuning isn't something you can go too wrong.

[DownUpDave]

This seems to have gotten off track. The OP specifically said "assuming it is factory built and not custom shop or luthier built". In this scenario the top is not being tap toned so there is no benefit to hand carved over machine carved. If every brace is being made to the very same dimensions then it doesn't matter how it is carved, CNC would be better

[hillin]

Originally Posted by DownUpDave

This seems to have gotten off track. The OP specifically said "assuming it is factory built and not custom shop or luthier built". In this scenario the top is not being tap toned so there is no benefit to hand carved over machine carved. If every brace is being made to the very same dimensions then it doesn't matter how it is carved, CNC would be better

I would be amazed if they don't tap, because that will render the hand-carving totally meaningless and I will definitely agree CNC would do much better than the hand gimmick.
Would someone who took the Martin factory tour shed some light here?