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Hi folks, 

I've got a 1960's Harmony Sovereign on the bench that is a new acquisition by a mutual friend of my cousin, who also owns one of these. They're great guitars with a nice "Stones" kinda' sound.  The top-loading bridges on these are really pretty cool and easy to deal with and the seem to preclude the mistakes many guitarists make in improperly seating the string ball against the bridge plate with a traditional design.  They appear to be a really smart design to me on the practical side of things, but I'm curious as to your opinions on these sorts of bridges in regard to tone, especially in comparison to the traditional style with bridge pins.  Has anyone ever used this sort of bridge design on a hand-made custom guitar?

Feel free to chime in, I'd like your thoughts on this.  Thanks! -John

Tags: bridge, bridges, loading, pins, tone, top

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Interesting. I think the high volume and also better sustain mainly comes from having a really hard surface and stiff and less springy anchoring of the strings ball end. Having a lighter bridge and a steep break angle is also a good thing at least for the volume.

I get the same effect (more volume/sustain) using hard wood plugs between the bridge plate and the underside of the bridge in a standard bridge giving the ball end a stiff anchoring. I would try a really hard wood instead of the brass though for a less shrill sound.

This bridge design is a good one  :-)

I can see the potential advantages of the lighter bridge, and the coupling of the strings to the soundboard.  Can you tell us a bit more about the construction?  Is there a traditional bridgeplate as well as the brass plate?  Do you have a photo you could share (understand if you are keeping some aspects of this to yourself....).  Also, is that some sort of hardwood plug that the keyholes are cut into?  The finishing of the holes looks very neat and tidy.  Nice idea!

i will get some pics 

I have been building stringed instruments far too long to get into an argument about what is the best way to do anything. no matter what you are trying to understand in sound from an instrument it is almost impossible to say why one guitar sounds better than the other. far too many variables.  I have built two identical guitars......in every way possible....and they sounded different. why......I do not know....... but I have taken a customers guitar.....removed the bridge....replaced it with my style of bridge and installed it on the guitar....... the difference is actually incredible. I do not know how many of these I have done but it is over 50. This has convinced me of one thing. It works. Now the difference between a pinned bridge or a string through bridge is almost impossible to determine........too many variables. So all I can say is my  system works .  ,,,,,,,,for me.  I have applied for a patent but it is not unique enough to make it applicable. So I keep making my guitars this way. I dont  care if people use this way, it is all good. 

I use a standard bridge plate under the soundboard.....I also add a thin brass plate so the strings never wear a hole into the plate.  The brass plate is a major sound transducer. You can actually buy them for a standard guitar setup that has worn big holes in the string anchorings. I also insert a small tear drop shaped piece of hardwood......usually ebony or rosewood to prevent the string from cutting through the wood. Of late my system uses a brass rod that extends to the top of the soundboard. It has one side cut open so the string can be inserted into it. The sound distribution is amazingly distributed into the top. It is hard to describe but I do have photos of it. All I can say is I get tired of builders saying they know what sounds best......it is so difficult to determine just what made that guitar sound the way it sounds. No two guitars are made exactly the same in every aspect.  But I do know what makes one guitar sound better with one change in it's construction.

I have another reply to make and should not hog this forum more than I have already done, but this is interesting.

Yes, I love the look of that bridge. I know the feeling when you find something new (or almost new) that really makes a difference. This one ticks all the boxes, it must sound as great as you say it does. It's a bit similar to the zero fret. The two jobs of the bridge, anchoring and providing a saddle bone for the strings, are separated into two entities instead of one.

Since I only restore and improve old instruments, to put on a bridge like this would alter the appearance too much. There is also the problem to cover the wound from the old glued down bridge. I have to wait for the right customer and guitar.

Don't you get a metallic shrill from the brass plate? I got that from the Stewmac plate mate the one time I tried it. A really annoying sound that went away when the plate was removed.

I have never noticed a shrill tone. But I have noticed an almost vibrato sound on many of them. Like tuning a string when it just hits that perfect tuning. The footprint issue has been a difficult one, especially on the water based tops. Nitro is never a problem. One problem is anchoring strings when the perfect spot is on top of braces. Not all guitars work. And vintage instruments I will just not alter. The biggest positive is setting the bridge in the perfect spot. That is so easy. I seldom have to do any adjustments on the saddle, and almost never on the nut to get all strings to be pitch-perfect everywhere on the neck, unless a fret is out of place. If you build just one this way you will never go back..........unless your customer demands the traditional look.

Hi Norm,

I've been following this tread for a bit and it seems that I am lacking knowledge in some areas that don't get addressed in my learnings.   I'm a little unclear how a well made, geometrically correct pinned bridge differs significantly from a similar string through (acoustic top mounted) bridge or your own version of the string through top.   

Firstly, and please correct me as we go along: break angles over the nut are a function of what angle is needed to stop the string moving across the saddle and thereby transferring the sting energy fully to the saddle which in turn drives the top as a transducer/soundboard.    You obviously do this with an extreme  30 degree break angle and so it appears to discount any string energy moving past the saddle to the string anchors.   So I'm a little confused as to how the tone is improved by your anchoring the string further down the guitar top.  Also, as we in the high sound pressure world know from brutal and very evident experience, un-dampened free air string length after the nut or saddle introduces residual inharmonic content to the mix. 

Similarly, a  floating 1/32 brass block along with brass tubes/ hardwood plugs must have some inertial which works inharmonic or dampened wrt the energy already imparted to the soundboard by the complete energy transfer achieved by a 30 saddle break angle.  The string length after the saddle will determine the frequency and phase of the imparted post saddle string energy sent to the ball ends and top.   

Saddle weight makes a difference, it must due to inertia.   But I note that lighter and heavier bridges are part of the span used to enhance certain tonal qualities and are chosen accordingly - obviously, the top thickness combined with the bridge inertia is also a vital factor for achieving a tone set.  A lighter bridge, it follows,  is not necessarily a panacea or absolute requirement, as I understand it.   

I also note your use of a 30 foot radius to the soundboard - an arch in engineering terms.   Arches are stressed structures and in a soundboard/transducer function with the driver (the bridge) exciting the top would seem to introduce an asymmetric response in the vertical (in and out) plane due to their resistance to pressure being concentrated in one direction only (as is the purpose of an arch).   

In practice the asymmetrical amplitude response would be evened out around a displaced "normal" so there would be nothing to see/hear there.   The strength of the top in compression would be improved but apart from a little more beamwidth and dispersal (which in practice decreased the volume of the instrument due to spherical spreading loss) I see no real benefit in terms of tonal response or loudness, particularly with such a small deviation from flat.

I do not offer opinions here, I am just seeking clarification of the physics/sonics involved in your conclusions. I have no doubt that a well made instrument made over time with good material and hardware and great care will have a greater chance of sounding better than a "standard instrument".

However, as I have politely said before I will need some convincing of what causes what other than an opinion or self generated accolades not supported by A/B data.   HD recording is sufficient to break out and discern the tonal spectrum we deal with - its not rocket science - and it is readily available these days and should be used as a first response.

With regards. 

Rusty.       

hi, rusty. Your understanding and definitions of building procedures goes far beyond mine. I just say "it bugs me when i glue a bridge on and it is out of place my a small fraction.....so i got rid of that problem",  but in doing so found many other positives. it works for me. 

If all things are equal on two guitars.....(and I doubt that would ever be possible) and one had a standard bridge the other a string through style, i really doubt the human ear could tell the difference, The both work fine. They both are at risk to lifting off from string tension. The string through much more so. They can both creep, unless hide glue is used. 

I liked what you said about the the string length behind the saddle. The longer that distance is the less sustain you will have. The break angle also can have an impact on sustain. 30 degrees is a lot and  less than 12 degrees you will start to loose sound transfer to the top. I have seen some as low as 5 degrees......just from wear  and tension on the neck. That will usually require a neck reset. 

Sound variances on a guitar is a tricky thing. It is almost impossible to determine what has impacted a particular guitar to sound the way it dose. When a guitar is built with an arched top it sounds very bright because of the tension in the top. Similar to a carved top. But as the guitar ages and is played the tension slowly goes away to the point of having no tension at all other that the tension from the strings. Old guitars almost always sound warmer than new ones. The glues dry out....the wood dries out.....and the entire unit actually starts to relax. Then the top starts to pull up with humps behind the bridge and dips in front of it. The life of a guitar is forever a changing one. To build one that can relax and not explode is a fine art and the last thing I want is the bridge to loosen up, because it can be lifting for years, loosing tone all the time.. I am not much for words and typing......just give me a piece of wood and I wood show you. maybe too old for this.

"I am not much for words and typing......just give me a piece of wood and I wood show you. maybe too old for this."

This sounds like the lyrics to a great song.  Maybe the "luthiery blues" (played on an old L-00) or a Hank Williams style country lament (D-28).  Where poetry meets science, a bit of DIY adventuring, and power tools.  What I like about luthiery.......

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