Thumscrews? #we don't need no stinking...

[Bernie Daniel]

Ok now not to be sacreligious here - in all seriousness.

I have long been aware of the work of Red Henry on one-piece (non-adjustable) bridges. #

Red's bridge (http://www.murphymethod.com/redbridge.html)

Usually he used maple but he has made them out of many other kinds of woods as well. #I was interested in these but always just kind of assumed I needed a "new style" adjustable bridge. #

Then last week #I was looking at Steve Tourtellotte's web site
Steve's Bridges (http://www.mandolinbridge.com/bridges.htm)

I started to rethink this issue. #How often to I actually adjust the height of my mandolin strings? #Answer, rarely or almost never. #I pretty much know the set up I like and I stay with it.

So I took a precision scale down to the shop and started weighing mandolin bridges -- I had 6 of the adjustable bridges (both rosewood and ebony) from various mandolins laying around and they weighed in a about 0.4 to 0.5 ounces. One rosewood bridge that was the original bridge on a 1952 F12 (with the large thumbscrews) was a clunky 0.6 oz. #

Then I weighed a couple of old-style Gibson one piece bridges that had come off of some 1920' A-models -- 0.25 to 0.28 oz.

That is a heck of a difference in mass. #It means the stings have a LOT less inertia to overcome in transmitting vibration to the sound board. #I would guess the treble strings would benefit most from the lighter bridge.

I think I am going to try cutting out some maple bridges out of 3/16 inch stock (the one-piece Gibson bridges are that thickness). #Most to of the newer one-piece bridges seem to be made out of slightly thicker material. #

Anyone think 3/16" stock is too narrow? #I am going for a very light bridge.

[MikeEdgerton]

I didn't think I needed an adjustable bridge either until I was tuning up for a gig and noticed a buzz that wasn't there two days before. A quarter turn of a wheel and I was able to play the set and then figure out what had happened. For what it's worth, I'll take the wheels. YMMV.

[Bernie Daniel]

For what it's worth, I'll take the wheels.

In your case you were well served by the adjustment. #

But I guess there are also some "middle grounds" in this topic -- e.g., the Weber Brekke bridge uses two small set screws to raise and lower the bridge. #I do not know what they weight however.

Red Henry's site is a treasure trove of information on fixed height bridge and fasinating reading.

[MikeEdgerton]

I've spent some time on Red's site. Interesting stuff. Have you seen this (http://www.frets.com/FRETSPages/Musician/Mandolin/LtMandoBr/ltmandobr.html) article on frets.com (http://www.frets.com)?

[mandroid]

its a thumb wheel, ie. a nut thats round . thumbscrew is a bolt with a handle.
MHO, thinner Brekke insert may not have the intonation offsets you need.

a set of Titanium or Aluminum Thumbwheels and 'allthread' would be lighter than Brass.

[Ivan Kelsall]

In another post,i mentioned having a recent visit from a Mandolin playing friend who's lived in Ireland for quite a few years. He brought over his 1920 Gibson F-4,a Mandolin he bought from Gruhn's Guitars in Nashville quite a while back - the bridge,which i assume was the original one,was massive !.I compared it to the bridge on my Weber & there must have been enough wood in the Gibson one to make 3 Weber bridges.
I wasn't exactly overawed by the Gibson. It was in good condition,the frets were minute & the action low. I struggled to get any tone or volume out of it,so did it's owner. I think it's just a case of a super instrument needing a few adjustments,not least the huge bridge,which i'm certain isn't helping any. This is in no way a criticism of Gibson,i just wish that Mandolin was mine to spend some time on,sorting it out to get the max.potential out of it,
Saska

[jim_n_virginia]

I have knothing to go by but my own experimentation but I have studied the solid, adjustable and the Brekke bride a lot. I had all three on 3 different mandolins for a while. Sanded the feet to fit the top of all ther madolins I had at the time and after much study and listening I decided the adjustable bridge was ther only way I could go.

While in theory the solid bridge is supposed to sound better getting to that place is the most difficult. The only way I could find that perfect spot was starting out tall and little by little bringing the bridge down to where I liked it. But everytime I didn't know when is enough and I would susequently sand down just a hair past where it was at it's best. Took me 3 tried (and 3 bridges) to get what I wanted as I am very picky about the tone and action.

Then once I had the bridge set all was fine until the weather started doing the hot one day and then cold the next day that Virginia is famous for. I had my action set low as it could be without buxzzing and when it was hot the D string (found out later the nut slot was cut too deep)would buzz so I was forced to take it off and put an adjustable bridge back on it.

In retrospect I should have set the solid bridge at a medium level that would account for expansion in high humidity.

I'll try again one day knowing what I know. I guess this is why Weber shipps mandolins with two bridge, one short and one high for when you need to make adjustments.

Oh yeah the Brekke bridge gave my mandolin great clarity but robbed me of volume so it was history.

For now I am stuck with thumbscrews.

[Ivan Kelsall]

Jim,is that true re.Weber shipping out 2 bridges with each Mandolin ?. I take it that you mean just the top part (makes sense) & is that for the Brekke bridge or the standard type. The reason i ask, is that i only got one bridge saddle with my Weber Mandolin.But it does seem like there is a heck of an adjustment possible with the one that's on (standard type). Maybe with the standard bridge,they've built in as much potential adjustment as you'd realistically need.

[Dave Cohen]

I'm used to grams, so I'll share some measurements in those units.

I have found that Gibson adjustable bridges have masses from about 13 g to about 18 g, depending on the density of the wood and the size of the thumb wheels. I did weigh one Brekke set-screw adjustable bridge, and found it to have a mass of about 13 grams. I haven't weighed any of the old Gibson one-piece bridges yet, but will do so when I get the opportunity.

I have weighed a couple of Red Henry's one-piece bridges which he kindly provided for some experiments that Jim Rae and I were doing on bridge admittance. A maple Henry bridge had a mass of about 6 g iirc. And an ebony Henry bridge had a mass of about 8 g. I weighed one Randy Wood bridge, and it had a mass of about 18 g.

I have also been making adjustable bridges for my own instruments using aluminum hardware. I carve them much differently than the usual Gibson shape. In ebony, my adjustable bridges typically have a mass of about 9 g. I made a few in maple that had masses of ca 5 g. Rosewood bridges fall somewhere in between, ca 7-8 g. The surprising thing about the admittance measurements was that there weren't any features that stood out and hit us over the head. The one-piece Henry bridges were not that different from the two-piece Cohen and Gibson bridges. I don't hear enormous differences in sound, but then I haven't made a lot of measurements either. I made a lightweight replacement bridge for one customer's Fraley F5, and he claimed that it really woke his mandolin up. I dunno. I have put conventional Gibson bridges on my mandolins, then replaced them w/ my own bridges, and I didn't hear much difference, if any. The bridge admittance measurements sorta corroborated that. My assessment for the moment is that we aren't there yet. I have to first find something that makes a measureable difference, then understand it, and only then might we be able to come up with some kind of improved bridge design.

[mandopete]

Ok now not to be sacreligious here - in all seriousness.

I have long been aware of the work of Red Henry on one-piece (non-adjustable) bridges. #

Red's bridge (http://www.murphymethod.com/redbridge.html)
Holy smokes, thanks for posting this! I have been thinking about this off and on for years. I have a Flatiron mandolin that just does not have enough volume and I've often thought about swapping out the bridge. I have tried a few things such as a fossil ivory saddle (thanks Kurt!) and a graphite saddle (thanks Greg!), but neither has gotten the result I wanted.

My problem is that I would need someone to set it up as I'm just no good when it comes to fitting the bridge to the top of the mandolin.

Now you got me thinking again. . . . .

[Bernie Daniel]

Dave Cohen: My assessment for the moment is that we aren't there yet. #I have to first find something that makes a measureable difference, then understand it, and only then might we be able to come up with some kind of improved bridge design.

Very interesting view. #Personally, I find that I am not particularily sensitive or preceptive on sound and as a result I am always amazed by those who tell me that they hear this difference or that difference between two mandolins. #

This situation with bridges is a good example -- there are those who claim to hear differences between two identical bridges made of different woods. #

I am not making a judgement here just noting what others have claimed. #

I just assume that they can hear it and I can't. #It is also possible, in some cases, that these individuals only imagine they can hear these differences? -- who knows?

Still I was impressed by the arguement that a 6 gram bridge would have less inertia than an 18 gram bridge and thus in theory should move the sound energy from the strings to the tone plate better.

But in reading your post I had a thought #-- maybe the ability of the bridge material to transmit sound (the molecular structure) is more important then the total weight of the bridge? #

It might be nice to find some way to do a test where in the volume is recorded on using an objective insturmental method and the string is struck by a precision controlled insturmental method to give exactly the same input of energy each time. #Then one could generate some statistics on the process and assess different bridges.

[Dave Cohen]

First, a bridge (for any instrument, for that matter) doesn't literally transmit "sound". Sound gets transmitted by the propagation of travelling waves in a fluid (usually air for us). Sound does propagate through solids, but at a much higher velocity. The velocity of sound in solids is up around 3000 m/s or more, compared to 343 m/s in air at room temperature. So the frequencies for sound transmission in ordinary sized solids are much higher than the upper limits of human hearing.

An instrument bridge does transmit mechanical vibration from the strings to the instrument top plate. And it has an impedance, which is kinda like a frequency dependent resistance, and the impedance does depend on mass. So a heavy bridge is OK for low frequency motions, but not so good for high frequency motions. The catch is, how do we define "high" frequency for musical instruments. For bowed stringed instruments, the stuff at 3 or even 4 kHz is important, and you will notice that violin bridges are really light for good reason. But plucked stringed instruments tend to be dominated by their low frequency motions. So where does a mandolin fit in all this? I'm still trying to sort that out.

Jim Rae and I did better than what you have described. We used a "shaker", i.e., a calibrated accererance head, and bypassed the strings altogether. We damped the strings and drove the bridge top directly with the shaker, and compared that to driving the top plate directly with the shaker. As I said, nothing in the results hit us over the head.

If you just want to compare loudness with a constant initial "plucking" force, there is a low-tech way to do that. Get some very fine coil winding wire and cut, say, 6" long pieces of it. Thread a piece of the wire behind the string to be plucked, hold both ends of the wire, and pull until the wire breaks. As the breaking tension is quite consistent, you will be displacing the string by the same distance each time by the time the wire breaks. Have someone help you initiate the sound recording as the wire breaks. Probably best to have some sound editing software. One program that you can download for free is Wavesurfer, from the Swedish Royal Institute of Technology. Google "KTH" and look for the Wavesurfer links. All you need in addition to that is your computer sound card and microphone.