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jeremy3220
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« Reply #20 on: November 29, 2008, 03:28:13 PM »

The 40's post war Martin bracing looks pretty hand shaped to me. I'm not sure what machine they could have used to make the braces look like this.
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« Reply #21 on: November 29, 2008, 03:29:45 PM »

I love that pic, it looks like a very strange little room.

holly
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« Reply #22 on: November 29, 2008, 03:57:18 PM »

I love that pic, it looks like a very strange little room.

holly

Tom Thumb lives there.


And his brother use to live here...


...before the accident  ohmy
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Danny
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« Reply #23 on: November 29, 2008, 04:23:48 PM »

  Jeremy, explain a little more please. And how do you get such good pics?
                                         Danny
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« Reply #24 on: November 29, 2008, 04:54:03 PM »

  Jeremy, explain a little more please. And how do you get such good pics?
                                         Danny

Someone on the UMGF was kind enough to share those. The first pic I posted was a 1946 D-28 and the other two are a 1937 D-18.
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« Reply #25 on: November 29, 2008, 05:00:08 PM »

Someone on the UMGF was kind enough to share those. The first pic I posted was a 1946 D-28 and the other two are a 1937 D-18.
  So what was the accident? And while I got you here do you consider the D-18 to be the Martin basic sound, by that I mean it was the git used by so many Sun label artists and others, before the rosewoods became more visible in the 60's. Or is there another model Martin you would call the "Martin standard" . Just curious.
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« Reply #26 on: November 29, 2008, 05:02:26 PM »

Pfft, everyone KNOWS he was pushed. I love the last pic too, looks like a robot dog pooped in the corner. Or, how I feel off the meds... i'd love to see what non guitar people think it's a pic of.

holly
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« Reply #27 on: November 29, 2008, 05:06:12 PM »

Pfft, everyone KNOWS he was pushed. I love the last pic too, looks like a robot dog pooped in the corner. Or, how I feel off the meds... i'd love to see what non guitar people think it's a pic of.

holly
  Holly, you are just funny wacko in a cool kind a way.
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« Reply #28 on: November 29, 2008, 05:32:42 PM »

The 40's post war Martin bracing looks pretty hand shaped to me. I'm not sure what machine they could have used to make the braces look like this.



Hi Jeremy,

Actually, it looks as though several machines were used.  Although these braces are curved in profile or cross section, they also show machining.  The end of the finger brace on the left (butting against the outside of the X brace) shows a flat surface with square corners to the sides, which was ground against a power sanding belt.  The length of the center section of the tone bars, or the diagonal braces below the bridge and what we can see of the finger brace is all even in height.  Again, a machine cut this, as did another to shape the curved top profile.  Perhaps someone held the braces against a sander (or vice versa) to flow the contours together.

I have only looked inside of two pre-war Martins with a mirror to see the underside of the top, and into the sound hole of half a dozen or so.  They all (top and back) had carefully shaped, parabolic braces in length and cross section.  Gradual curves from one end to the other.  The exception was the tone bars and what I call the legs, or lower, longer parts of the X brace, as the lower photo shows, which were scalloped.  That photo shows careful shaping of the scallops and X brace profile, and the photo of the back shows the suggestion of a gradual taper toward the ends.  Too bad it doesn’t show those.

But both top photos show the ends of the braces are not rounded or gradually flowed into the main body of the brace.  And those corners are what I maintain absorb energy and contribute to die out of sustain.

Notice, also, that the lower tone bars on both photos are the same height as the upper ones.  Recall from teeter totter days that the further you sit from the fulcrum, the less weight it takes to balance the other side.  Which makes another of my points--that some braces are heavier than needed to balance string tension, and also dampen vibrations. 

Does this mean that I could maybe tweak a bit more out of a vintage Martin?  Aside from it being a sacrilege, I doubt if anyone would ever pay me to work on one.  But I suspect so.  I have re-voiced a '48 D-18, a '54 D-18 and a '56 D-21, all braced like the top photo, with amazing results.

Scott
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jeremy3220
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« Reply #29 on: November 29, 2008, 06:49:08 PM »

  So what was the accident?

that's a rattlesnake rattle, I was implying he got eaten.

And while I got you here do you consider the D-18 to be the Martin basic sound, by that I mean it was the git used by so many Sun label artists and others, before the rosewoods became more visible in the 60's. Or is there another model Martin you would call the "Martin standard" . Just curious.

I don't call any model the Martin standard. I'm not even sure what that means.



Hi Jeremy,

Actually, it looks as though several machines were used.  Although these braces are curved in profile or cross section, they also show machining.  The end of the finger brace on the left (butting against the outside of the X brace) shows a flat surface with square corners to the sides, which was ground against a power sanding belt.  The length of the center section of the tone bars, or the diagonal braces below the bridge and what we can see of the finger brace is all even in height.  Again, a machine cut this, as did another to shape the curved top profile.  Perhaps someone held the braces against a sander (or vice versa) to flow the contours together.

The square corners can be easily made with a chisel and I know they were still tucking braces into the sides and maybe still into the X; wouldn't it be easier with a chisel than trying to eyeball .100"(or whatever) at the ends of a brace while holding it against a belt sander?
I'm sure some sanding could have been done on a belt sander and it does look like the cross section profile of the X brace extends through the lap joint but I don't really know the construction techniques of post war Martins.

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jeremy3220
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« Reply #30 on: November 29, 2008, 07:12:23 PM »



I have only looked inside of two pre-war Martins with a mirror to see the underside of the top, and into the sound hole of half a dozen or so.  They all (top and back) had carefully shaped, parabolic braces in length and cross section.  Gradual curves from one end to the other.  The exception was the tone bars and what I call the legs, or lower, longer parts of the X brace, as the lower photo shows, which were scalloped.  That photo shows careful shaping of the scallops and X brace profile, and the photo of the back shows the suggestion of a gradual taper toward the ends.  Too bad it doesn’t show those.

Here's pics of a 39 D-18 that shows the lower legs of the X






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Scott van Linge
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« Reply #31 on: November 29, 2008, 07:33:17 PM »

Jeremy,

Way cool pictures!  Thanks.

Goes to show I shouldn't make blanket statements.  However, the tops I've seen had carefully parabolic finger braces, not the peaked ones here.  And it looks like three per side instead of the usual two.  However, the back braces show the  parabolas I've seen on all the vintage holes I've peered into.  And the "arms" of the X brace are half parabolas!

One of the two tops I've seen was on a 1912 O body Martin, or at least, a small one.  What was unique about that one was that the lower half of the lower tone bar, instead of having the usual scalloped peak, was a half parabola.  Especially interesting to me is that someone at the factory back then knew that leaving that peak off would add to the bass.  Of which this tiny box had plenty.
 
And, according to my theory of rings, that's the area where the bass is generated! 

Who nose,

Scott
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Dale_I
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« Reply #32 on: November 29, 2008, 07:37:39 PM »

Just looking at the pictures make me think that you could do a really cool guitar room with design cues from the interior of a guitar. The crown and base molding could be run through a table saw every inch and a half vertically, you could do open scalloped beams, use a large round recessed light offset to one side of the room, and the door could be made to look like the neck block. The walls could be done in 4x8 sheets of solid panel with 1x8 strips between them. You could even use 6 strip lights for the string pins coming down from the ceiling.

More stuff to do in my spare time...
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« Reply #33 on: November 29, 2008, 07:46:47 PM »

Just looking at the pictures make me think that you could do a really cool guitar room with design cues from the interior of a guitar. The crown and base molding could be run through a table saw every inch and a half vertically, you could do open scalloped beams, use a large round recessed light offset to one side of the room, and the door could be made to look like the neck block. The walls could be done in 4x8 sheets of solid panel with 1x8 strips between them. You could even use 6 strip lights for the string pins coming down from the ceiling.

More stuff to do in my spare time...

That's what I thought when she said that and that would be awesome.
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« Reply #34 on: November 29, 2008, 07:54:00 PM »

Jeremy,

Way cool pictures!  Thanks.

 Ditto,
                                                  Scott , about my 00 sustain. I have a Martin OM-21 and a lot of other gits and have had many more over the years. Seven Larrivees to this point I think. I'm saying this to preface that I can only go by my experience and the Larrivee tone is very unique among gits today. If I want the Martin sound or Gibson, I just get one. The Larrivee braces are thicker and all but on the 00 I think there are other factors that create it's sustain. I am no luthier, but the bridge being positioned towards the end pin more and some other items may be what create it's differences from my other Larrivees. Just a thought. btw I wouldn't change a thing I like it.
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« Reply #35 on: November 29, 2008, 08:15:32 PM »

Scott, I have a question about the discussion Danny raised. He noted that his Larrivee has much more sustain than his OM-21 and asked why. In your response about 'think inside the box' and some of your other posts you pointed out various aspects of the pre-war Martin design that lends itself to greater sustain and how the square corners cause the die out of sustain. This has me confused because the OM-21 is basically the same design as the pre-war Martin OM's and the Larrivee has square corners on almost all of its top bracing. It has also been my experience having owned three Larrivee's(played countless others), an OM-21 and now a SCGC OM/PW (based on pre war Martins) that the Larrivee's have more sustain and I've never really thought the pre war Martins were known for having lots of sustain. Perhaps you think differently about Larrivee's having more sustain, care to comment?
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Scott van Linge
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« Reply #36 on: November 30, 2008, 01:57:41 PM »

Scott, I have a question about the discussion Danny raised. He noted that his Larrivee has much more sustain than his OM-21 and asked why. In your response about 'think inside the box' and some of your other posts you pointed out various aspects of the pre-war Martin design that lends itself to greater sustain and how the square corners cause the die out of sustain. This has me confused because the OM-21 is basically the same design as the pre-war Martin OM's and the Larrivee has square corners on almost all of its top bracing. It has also been my experience having owned three Larrivee's(played countless others), an OM-21 and now a SCGC OM/PW (based on pre war Martins) that the Larrivee's have more sustain and I've never really thought the pre war Martins were known for having lots of sustain. Perhaps you think differently about Larrivee's having more sustain, care to comment?


Jeremy, Deadpan,

I think I'm in over my head on this now.  I've given some general examples of why I think sustain is greater or lesser in any given guitar.  These comments are based on observations I've made in re-voicing about 175 guitars, and I do know that when I am through shaping braces as I've described, sustain is always increased.

Variations in the individual sound of any guitar company seem to be the result of different brace spacing, patterns, size, etc.  However, one of my own builds this summer had a problem G string--no sustain, low volume, it seemed as though the box was saying it wouldn't accept that string's input.  That was with braces smooth, flowing, etc.  I finally was able to get the G to work well, but still don't quite  understand why it was such a problem when I hadn't had that one before.

Larrivee bracing uses parabolic shapes on the X brace lengthwise profile, as well as the tone bars.  And the tone bars are not diagonal, but straight across, parallel to the bridge--a stronger design than diagonal, but can dampen the G and A strings disproportionately.  Also, the finger braces are flat and wide, like popsicle sticks, and there is little to shape with them.   

When I said to think inside the box, basically I was saying that manufacturing methods to shape braces influence sustain, and only reshaping them can improve it after all the superficial tricks are used (strings, saddles, etc.).  Yes, Larrivee braces are square cut in cross section, as are Taylor braces. 

In 2000, Bob Taylor hired me  to spend a week at his factory shaping braces on a couple of guitars, and I've seen a couple of changes in models since then.  For example, we had a discussion about back braces in which Bob said he didn't want the back to contribute to the sound, or change if held against one's body.  However, a 2001 and 2006 model I re-voiced had back braces that allowed a lot of bass end reinforcement from the back and were a very clever (of course) machined approximation of the low parabolic shapes I used there.   And you could really feel the back bounce when held close.  Good fun!

And at that time, Taylor braces were shaped lengthwise into billets made in China, which were then cut into six individual braces at the factory.  Ditto for Martin these days, although I don't know if they were from China.   Guild was getting them made in Mexico when I talked with them back then.  At Martin, braces on their lower cost models were just square cut from ripping the billets, but the higher end models also had curved cross section profiles shaped by running over a sander of some sort before scalloping, which then leaves square cut scallops, not like the curved scallops' cross section on the '39 D-18 shown above.

These production short cuts contribute to differences in sustain and string volume balance, and no doubt give the individual company's "sound".  And then, there's the magic factor...

Scott
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« Reply #37 on: November 30, 2008, 09:06:09 PM »

Hey Scott - This is some fascinating info - and I love the pics. Do you have drawings that would illustrate the differences in bracing shapes and contours? And do you have any feelings about riven vs. sawn braces? I remember reading that riven were stronger and could be made smaller while maintaining better vibrating characteristics. But thats REALLY old school - Tad
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« Reply #38 on: December 01, 2008, 01:23:47 AM »


Jeremy, Deadpan,

I think I'm in over my head on this now.  I've given some general examples of why I think sustain is greater or lesser in any given guitar.  These comments are based on observations I've made in re-voicing about 175 guitars, and I do know that when I am through shaping braces as I've described, sustain is always increased.

Variations in the individual sound of any guitar company seem to be the result of different brace spacing, patterns, size, etc.  However, one of my own builds this summer had a problem G string--no sustain, low volume, it seemed as though the box was saying it wouldn't accept that string's input.  That was with braces smooth, flowing, etc.  I finally was able to get the G to work well, but still don't quite  understand why it was such a problem when I hadn't had that one before.

Larrivee bracing uses parabolic shapes on the X brace lengthwise profile, as well as the tone bars.  And the tone bars are not diagonal, but straight across, parallel to the bridge--a stronger design than diagonal, but can dampen the G and A strings disproportionately.  Also, the finger braces are flat and wide, like popsicle sticks, and there is little to shape with them.   

When I said to think inside the box, basically I was saying that manufacturing methods to shape braces influence sustain, and only reshaping them can improve it after all the superficial tricks are used (strings, saddles, etc.).  Yes, Larrivee braces are square cut in cross section, as are Taylor braces. 

In 2000, Bob Taylor hired me  to spend a week at his factory shaping braces on a couple of guitars, and I've seen a couple of changes in models since then.  For example, we had a discussion about back braces in which Bob said he didn't want the back to contribute to the sound, or change if held against one's body.  However, a 2001 and 2006 model I re-voiced had back braces that allowed a lot of bass end reinforcement from the back and were a very clever (of course) machined approximation of the low parabolic shapes I used there.   And you could really feel the back bounce when held close.  Good fun!

And at that time, Taylor braces were shaped lengthwise into billets made in China, which were then cut into six individual braces at the factory.  Ditto for Martin these days, although I don't know if they were from China.   Guild was getting them made in Mexico when I talked with them back then.  At Martin, braces on their lower cost models were just square cut from ripping the billets, but the higher end models also had curved cross section profiles shaped by running over a sander of some sort before scalloping, which then leaves square cut scallops, not like the curved scallops' cross section on the '39 D-18 shown above.

These production short cuts contribute to differences in sustain and string volume balance, and no doubt give the individual company's "sound".  And then, there's the magic factor...

Scott
  Thanks for the reply Scoot,                   "deadpan" Danny
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« Reply #39 on: December 01, 2008, 02:56:15 AM »

Hey Scott - This is some fascinating info - and I love the pics. Do you have drawings that would illustrate the differences in bracing shapes and contours? And do you have any feelings about riven vs. sawn braces? I remember reading that riven were stronger and could be made smaller while maintaining better vibrating characteristics. But thats REALLY old school - Tad


Yo Tad,

I'm totally unable to post stuff like pictures, but there is an interesting thread on a luthiers' forum I just hope to have finished up recently.  It starts out with a question about mid range, and morphs into a near battle over scalloped vs.  parabolic bracing.  Lots of pictures from other luthiers, and one of a top I built with my comments. 

Here's the link:  http://www.luthiercom.org/phpBB3/viewtopic.php?f=32&t=482&st=0&sk=t&sd=a&sid=d241e4eabe7b759a1464081ada843467

It goes on for five pages.


  Thanks for the reply Scoot,                   "deadpan" Danny


Deadpan Danny,

I like it!!

Scoot
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