Official Luthiers Forum!

Hey Hesh, how about this for your L-00?   That my early '30's L-00. Square
and simple with a nice re-curve on the wings!



And here's one of mine...

[IMG] http://www.freilicherguitars.com/OLF/bridge/mybridgeprofile. jpg[/
IMG]

Louis

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- Louis Freilicher

Oh No! Not another learning experience!

Thanks Hesh!!   

I'm not sure why the other photo is not loading. I think the system hates
me!

My L-00 is from 1932-1934 and all original except for the neck block has
been slipped to correct a low neck angle. The repair is functional but a
bit ugly of you look close. On the plus side it dropped the price about
$400 when I bought it! I'll post some more pics in a new thred for you.



Louis

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- Louis Freilicher

Oh No! Not another learning experience!

Hesh,

I wanted to get back to your question about bridge mass. I think it might be hard to build one that is too light without running into structural deficiencies, first. Meaning that I think there needs to be enough to hold it all together, and no/not much more.

On the other hand, I think that too much mass will certainly be a stumbling block to getting the energy through the bridge and into the guitar. More mass = more inertia to overcome = slower response due to longer transient time to get it moving. More work, too.

I once received a Larrivee for re-voicing that had a Martin bridge from hell. It was about 1/3 again as big (tall) as your normal Martin bridge, and looked massive. While test playing it with a flat pick, I noticed that my thumb hurt. I had a skin crack on it due to low humidity and not enough omega oils in my diet. I would glue such cracks with thin super glue (after all, I read it was developed in the Korean War for gluing soldiers back together) and was surprised it still hurt.

The harder I would strum, the more it hurt my thumb. It seemed (OK, guys, this is very subjective, I know) as though the bridge was saying: "Go ahead, just try to get through me!!"

I got out my ol' D-28 with my first streamlined bridge, and found that strumming it did not hurt my thumb, and took much less work to get sound.

As a test, I reshaped the bridge before I stuck my arm inside the Larrivee, just to compare, and found an amazing improvement in response time and ease of strumming. But by then, my thumb had healed...

I wonder if this is where the expression "Rule of Thumb" comes from?????

Scott

I've been following this fantastic thread with great interest.

As to bridge mass considerations, I'm no expert, but have had long discussions with my father-in-law. He's a retired physics professor, violinist, and taught acoustics for musical instruments. He also took a class or two from Carleen Hutchins. His focus was on violins, but we've talked at length about stuff that applies to stringed instruments in general. What I have to say here is mostly what I've learned from him, and I'm not taking the importance of shape into consideration. I've done no scientific research or testing.

As related to this discussion, the mass of the bridge is yet another of those things with instrument design that can't be effectively examined by itself. As has been said many times, it has to be taken in the context of where it's being used,

My father-in-law talked about how vibrating energy is transferred from a string to the bridge and into the top. The part that I found most interesting in what he said had to do with the interplay of vibration between the string and the bridge. To illustrate, if we were to have a bridge and nut with infinite mass in a vacuum, and could eliminate internal friction losses inside the string, nut and bridge, then plucked the string, we'd get infinite sustain. He said the energy of the string vibrations would not sink into the nut or bridge, nor would they vibrate the bridge or nut, but would be reflected back into the string, theoretically giving us infinite sustain. We would, of course get no sound since the energy would stay in the string. Sort of like a solid body electric. The bridge has no movement so the string's energy stays in the string, giving lots of sustain. The artificial scenario I've just described is of course impossible and impractical, and is just for illustration.

Now, if we reduce the mass of the bridge, at some point the string's vibration will be able to get the bridge moving. If its mass becomes small enough, the transfer of energy from the vibrating string would be so efficient that response would be near-instantaneous and there would be little or no sustain. At some point, we can arrive at a mass with which some energy moves the bridge and some is reflected back into the string. Now we have a bridge that can move yet can reflect back enough energy into the string so that we get some sustain which is where we want to be with our acoustic guitars. But not so with a violin. Being bowed, there's not as much concern about sustain, so they're built light, which makes them loud for their size, and responsive. Lots of energy moves through the instrument in a very short period of time, where it's used up almost immediately when it becomes sound, and is then replenished with the next wave of energy which is generated by the bow/string interaction.

In the acoustic guitar world with the bridge mass question, we need to look at the whole top (well the whole guitar, really). Seems that a light guitar, light top, bracing, b&s, etc, would act a bit like a violin, dissipating sound energy quickly, providing fast response and little sustain, perhaps with a harsh or barky tone. More mass in the guitar might keep more energy in the vibrating string, perhap giving more sustain, a smoother tone, less barky. Of course there are lots of examples that run counter to this idea, but I think it's a reasonable statement.

So, it seems to me that we can talk about bridge mass but it's not an entity unto itself. It's connected to the top, braces, etc, and that makes me think that some of the things we hope to accomplish with changes in bridge mass can be done (or undone) on other areas of the top, such as the mass of the bridge plate, bridge pins, bracing, and so on. With an already-built guitar, we might change to lighter bridge pins, reshape the bridge, shave the braces a bit, maybe even reduce the mass of the bridge plate. Of course, (this is where a prof might say, "indeed" or "clearly") some of these changes might affect tone due to changes in stiffness rather than changes in mass, but I sill wonder if changes made with the intention of changing bridge mass might give similar results if they were made in other places besides the bridge. I can't help but believe this to be the case, tough it is certainly as grey as grey areas get.

Just some more stuff to ruminate on.

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now known around here as Pat Foster
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http://www.patfosterguitars.com

Here's mine, with addition of the dove inlays on the bridge wings. I have also done several bridges shaped as the dove descending in the soundboard, but can't seem top find a photo of them. They ended up on guitars used in the music ministry at several churches.

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Hank Mauel

Oooh, Oooh, I found the dove bridge. Not a good pic, but you get the idea.

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Hank Mauel

Sorry but it looks like a seagull to me.

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"It's a Tone Faerie thing"
"Da goal is to sharpen ur wit as well as ye Sgian Dubh"
"Sippin Loch Dhu @Black lake" ,Kirby O...

Kickin' it old school! Classical-inspired rectangular design with rounded over wings. The top of the bridge is slightly "radiused" like the fingerboard with the pinholes parallel to the slant of the saddle.



Warren

Pretentious artsy shot:

Of course the saddle has not been shaped in this pic, but here is my new bridge design.



Greg

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Gwaltney Guitars