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So, which bridge should I use for this classical?
http://luthiersforum.com/forum/viewtopic.php?f=10101&t=33445		 Page 1 of 1
Author:  Phillip Patton [ Mon Sep 05, 2011 6:32 pm ]
Post subject:  So, which bridge should I use for this classical?
I'm not considering the one on the left. It's desert ironwood, and it's too heavy, and doesn't match the guitar.

The middle one is ebony, and weighs 32 grams (I expect it to lose another gram or so before it's finished), the third is rosewood, and weighs 24 grams.

The rosewood bridge doesn't fit the color scheme either, but if it would be better acoustically, then I'm willing to use it.

The ebony bridge sounds brighter than the rosewood one when tapped, which makes me think it would be fine. Am I wrong?

Image

Thanks,
Phillip
Author:  alan stassforth [ Mon Sep 05, 2011 6:45 pm ]
Post subject:  Re: So, which bridge should I use for this classical?
I think looks are more important than sound,
so, I'd go with the ebony.
Author:  TonyKarol [ Mon Sep 05, 2011 6:49 pm ]
Post subject:  Re: So, which bridge should I use for this classical?
I'd go for tone .. ebony on classical is too heavy, it will likely kill volume and sustain ... use the rosewood and stain it darker if need be ...
Author:  Jim Watts [ Mon Sep 05, 2011 7:13 pm ]
Post subject:  Re: So, which bridge should I use for this classical?
use the rosewood bridge.
Author:  johnparchem [ Mon Sep 05, 2011 7:16 pm ]
Post subject:  Re: So, which bridge should I use for this classical?
I would go with the rosewood because the ebony bridge is 30% heavier. It has the effect of stiffening the top as the strings has to drive the extra weight.
Author:  Phillip Patton [ Mon Sep 05, 2011 7:18 pm ]
Post subject:  Re: So, which bridge should I use for this classical?
What's the maximum weight for a classical bridge?
Author:  WaddyThomson [ Mon Sep 05, 2011 9:17 pm ]
Post subject:  Re: So, which bridge should I use for this classical?
The Rosewood bridge is close to the max. I've put some on a guitar as much as 28 grams, but it really kills the headroom.
Author:  Phillip Patton [ Mon Sep 05, 2011 9:19 pm ]
Post subject:  Re: So, which bridge should I use for this classical?
WaddyThomson wrote:
The Rosewood bridge is close to the max. I've put some on a guitar as much as 28 grams, but it really kills the headroom.


Rosewood it is then. Thanks guys!
Author:  jfmckenna [ Tue Sep 06, 2011 9:42 am ]
Post subject:  Re: So, which bridge should I use for this classical?
I have built very nice sounding guitars with ebony bridges. I still don't understand why people claim it's a bad wood to use for Spanish guitars. I mean, I understand the principal behind it, but it's been my experience that ebony works well. I've never replaced a bridge with rosewood to see if I can tell of an improvement. So...
Author:  Shawn [ Tue Sep 06, 2011 10:23 am ]
Post subject:  Re: So, which bridge should I use for this classical?
You did not mention if when you used Ebony bridges if it was a classical guitar but in general Ebony has much higher dampening than Rosewood so even if the weights were the same the rosewood would be more resonant. The exception is ebonies such as macassar ebony which can be less dense and also does not have the high dampening that other ebonies would have.

When you consider that Smallman in his classical looking guitars with paper thin tops uses padauk as the bridge as it is lighter than rosewood, it speaks to the choice of less mass being better for most classical guitars.

I dont know that I have ever seen a concert classical guitar that had an ebony bridge.
Author:  Colin S [ Tue Sep 06, 2011 10:33 am ]
Post subject:  Re: So, which bridge should I use for this classical?
Of all the woods that we tested in our lab at my University, where we passed standardised wave forms through standard sized samples of woods (the equipment is really designed for testing rock samples but produced good results with wood) the one with by far the highest internal impedence to the wave forms was ebony. The full data is somewhere here on the archives, but you know how easy it is to search those!

The maximum bridge weight I'll use on my classicals is 25gm, many I use are in the 19-20gm area, and all are BRW. BRW was with Madrose and Macassar the least impeding of the 20 or so woods we tested.

I can see a case (just) for using ebony on a steel string if you wanted to reduce the treble end or a tendency to overbrightness, but not on the much lower energy systemm of a classical.

Colin
Author:  Ti-Roux [ Tue Sep 06, 2011 11:37 am ]
Post subject:  Re: So, which bridge should I use for this classical?
Colin S wrote:
The full data is somewhere here on the archives, but you know how easy it is to search those!


Seriously, I searched a lot, in every way possible, and I just can't find. Is there a way I could see these results, i'm really interested!
Author:  Alexandru Marian [ Tue Sep 06, 2011 1:04 pm ]
Post subject:  Re: So, which bridge should I use for this classical?
I too believe a CG bridge should not exceed 25 grams. A heavy bridge is not the end of the world, as I have noticed from adding weights on completed guitars, not worse sounding, but definitely slower. It always sounds better overall with the weights taken off.

Colin, did you test several different Macassar samples? Did it sound glassy to the tap? I am asking because the two Macassar sets I have are quite dull, same as what i read from numerous other builders. I had the same experience with ABW, dull dull dull, although for this wood there are many many people claiming it taps divine.

I wonder if they are simply very variable woods (Indian is pretty variable ime) or maybe there is some difference between perceived taptone quality and actual damping, scientifically measured.

Can wood tap like wet cardboard and yet allow excellent transmission of vibration, even higher frequencies?!
Author:  WaddyThomson [ Tue Sep 06, 2011 2:35 pm ]
Post subject:  Re: So, which bridge should I use for this classical?
This is only a small sampling, but I have made guitars with Mad Rose, BRW, Cocobolo, and Indian Rosewood bridges. My best ones had BRW, and Indian bridges weighing in at less than 20 grams. The difference is staggering in volume and projection, between heavy and light bridges. The heavy bridge guitars sounded great, but just didn't have the oomph (Headroom as Paul at Dream Guitars put it). My best sounding and loudest to date, is my #8, Mad Rose B&S/ Italian Spruce top, EIR bridge weighing about 19 g. The top was so floppy across the grain that I actually left it thicker in the wings of the LB than it is in the center, where the bridge is. It's about 2.5 in the center, and about 2.8 - 3.0 in the wings. I did thin it to about 2.2 - 2.3 in the tail. The owner of this guitar is a bit miffed, because it's louder than his double top classical. Probably just luck on my part. I don't have a good sound clip of it, just the You Tube of the Luthier Showcase from GFA 2011, which is an OK representation, but not recorded under the best conditions. I'm hoping the owner will do a couple of clips for me so i can post them on my website.
Author:  billrayner [ Tue Sep 06, 2011 3:16 pm ]
Post subject:  Re: So, which bridge should I use for this classical?
I go with the majority - rosewood. I made a classical guitar with a 32g. ebony bridge last year, and another with a 22g. EI rosewood bridge. The guitar with rosewood just sings and has a profound bass. The one with ebony, although it has a very nice well-balanced tone, is lacking that extra "something" in both the treble and bass ranges. (In fairness, the guitar with the ebony bridge was made of black walnut, which is probably damping some sound, while the other guitar has a thin soundboard and light bracing. Etc.)

This is a very interesting subject. The bridge is part of a mini-structure that includes the soundboard and its bracing. I would love to see a document that explained the mechanics of bridge operation, including things such as any rocking motion, optimal stiffness / flexibility of the whole bridge and of the wings, etc. Your point about the damping quality of the wood was enlightening, Colin S. I hadn't thought about that.
Author:  johnparchem [ Tue Sep 06, 2011 3:39 pm ]
Post subject:  Re: So, which bridge should I use for this classical?
billrayner wrote:
... This is a very interesting subject. The bridge is part of a mini-structure that includes the soundboard and its bracing. I would love to see a document that explained the mechanics of bridge operation, including things such as any rocking motion, optimal stiffness / flexibility of the whole bridge and of the wings, etc. Your point about the damping quality of the wood was enlightening, Colin S. I hadn't thought about that.


Referencing to another current thread in this forum, the first book of Contemporary Acoustic Guitar Design and Build by Trevor Gore has an in depth analysis of all of the point you list to explain bridge design considerations. I just read that section last night.
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