bridge height

[Br1ck]

Is there any relationship between tone or volume between a neck that sits a bit deeper in the neck pocket, and thus creates a slightly shorter bridge, and one that is a bit higher? Let's assume the same neck angle and string break over the bridge.

My fuzzy thinking is that the down force on the bridge would be equal.

[Nevin]

The angle of the stings over the bridge changes the force. If there were no angle the strings would rest on the bridge with little or no downward force. As you increase the angle you increasethe force. Thus the bridge height and neck depth are part of the geometry of the angle. One factor to consider is the playing comfort.

[sblock]

No, it's not the height of the bridge saddle that matters for tone and volume, per se. I've seen both high and low bridges on some great mandolins. It's the break angle of the strings over the bridge saddle that really matters! This angle controls the string downbearing force, and it is set by several geometric factors, including the height of the top arch, the fingerboard height, the bridge position relative to the tailpiece, and most especially the neck angle with respect to the body, along with other details of the neck set. A greater break angle leads to a greater downbearing force. F5's have great downbearing force than F4's, due to the neck set and other factors.

[fscotte]

I'm not 100% convinced that greater break angle affects tone or volume. As long as it has enough force for the bridge feet to seat properly, I don't notice much difference.

[HoGo]

The break angle has VERY LITTLE effect on tone (almost nonexistent if he change is not large) as has been shown on violins (which are MUCH more sensitive to adjustments than mandolins).
The vibrations don't "go" into the top jsut via the bridge but the anchored ends of strings also act, and when you increase the bridge break angle the bridge force increases, but the forces given by string ends decrease (in the horizontal level) so it's "you add here and lose there" game, perhaps balance is good for exact tone color for given instrument but not loudness or responsiveness.

[MediumMando5722]

I believe most every adjustment affects the tone and volume in some way. With mandolin, once you find your action height, the rest kinda is what it is. However, on my banjo, I've dorked around with everything I can adjust, from the neck angle, to bridge height, to tailpiece height, to head tension. All of them affected the tone and volume one way or another.

[HoGo]

Banjo with perfectly rigid tone-ring and rim with steel rods is as far from mandolin as it gets regarding function of bridge. On banjo pretty much 100% of energy transfer goes thru bridge into the pre stressed sensitive head, so the angle and tailpiece pressure down is critical. On mandolins huge part of the energy goes thru tailpiece and neck to create vibrations of body.

[Ivan Kelsall]

From Adrian - "..so the angle and tailpiece pressure down is critical..". Spot on !!.That's why Geoff Stelling's banjo tailpiece is fully adjustable up & down to allow the back pressure behind the bridge to be adjusted. More back pressure = a harder / tight tone.Less back pressure = a more mellow tone. The Stelling tailpiece is also moveable back & forth to allow the ''pressure point'' to be closer or further away from the bridge,allowing even greater tonal changes.

I read many years ago,a comment made by Bela Fleck in the book ''Master of The 5-string Banjo''. He uses a 1" high bridge, & stated that the higher bridge,but with a greater neck angle to bring the action back down for playability,gave him more volume.

As Chris Bowsman points out - once you've got everything set up ok regarding action & bridge position,there's little else that you can do. Anything that you DO do,will move things away from their correct position & function (IMHO).

Thinking about it,many mandolins might have benefitted from a slightly different neck angle / bridge height than they have. However,having been built to 'a design',there's very little that can be done about it other than a neck re-set. I suppose that what we all have is a well thought out 'compromise'. Maybe in the time that the great Violin builders were building,they put a lot of thought (& maybe experiment ?) into this aspect of their instruments. Relatively speaking,current mandolin design is still pretty new !.

I suppose that it would be possible for an ''adjustable mandolin neck'' / top 'mock-up' model to be made,allowing it to be strung up, with the strings running over a standard mandolin bridge, & pressure gauges to be placed under the mandolin feet in order to measure the 'down force' as the neck angle is adjusted up /down. It wouldn't be too difficult to make something like that - although in an actual mandolin build,the flexibility of the top would come into play,& as we know - they're all different. However,it could give a meaningful insight re. how neck angle / string tension & bridge height inter-react. What we need is a mandolin body (minus back),with a neck joint that will pivot up & down & which can be bolted up as hard as a glued neck joint.

Maybe it's already been done ??,
Ivan

[HoGo]

Thinking about it,many mandolins might have benefitted from a slightly different neck angle / bridge height than they have. However,having been built to 'a design',there's very little that can be done about it other than a neck re-set. I suppose that what we all have is a well thought out 'compromise'. Maybe in the time that the great Violin builders were building,they put a lot of thought (& maybe experiment ?) into this aspect of their instruments. Relatively speaking,current mandolin design is still pretty new !.

I suppose that it would be possible for an ''adjustable mandolin neck'' / top 'mock-up' model to be made,allowing it to be strung up, with the strings running over a standard mandolin bridge, & pressure gauges to be placed under the mandolin feet in order to measure the 'down force' as the neck angle is adjusted up /down. It wouldn't be too difficult to make something like that - although in an actual mandolin build,the flexibility of the top would come into play,& as we know - they're all different. However,it could give a meaningful insight re. how neck angle / string tension & bridge height inter-react. What we need is a mandolin body (minus back),with a neck joint that will pivot up & down & which can be bolted up as hard as a glued neck joint.

Maybe it's already been done ??,
Ivan

Violin makers threw the whole concept of different neck angles out of window many years ago and just use overstand (given constant) and projection (also given) as their main measures so neck angle is pretty much dictated by arch height. I believe the numbers were more or less taken from golden era instruments (after modernization) and I don't remember any serious research of how the neck angle affects tone for given instrument*... Violin bridge height is limited by access of bow (you cannot use too low bridge) and flexiblity od bridge (too high a bridge would require thick (=heavy) waist to resist bending under pressure)
On mandolns we have more freedom, but since there is so much variation of top arch height and shape that folks use it is nearly impossible to tell which angle is best for which instrument. We have seen that similar problems can have surprising counter-intuitive "solutions", like lighter strings working better on certain instruments where most folks suggested using heavier strings for "more tone". There are too many variables at play so for now we can just experiment and see what it gives... If someone is wlling to make couple dozen experimental instruments with varying top/back arches and graduations and neck angles and statistically evaluate the results we will know more...

*except one recent experiment that shows that there is surprisingly very little difference in tone of violin even if you reduce the string angle to bare minimum.

[Nevin]

Violin makers threw the whole concept of different neck angles out of window many years ago and just use overstand (given constant) and projection (also given) as their main measures so neck angle is pretty much dictated by arch height. I believe the numbers were more or less taken from golden era instruments (after modernization) and I don't remember any serious research of how the neck angle affects tone for given instrument*... Violin bridge height is limited by access of bow (you cannot use too low bridge) and flexiblity od bridge (too high a bridge would require thick (=heavy) waist to resist bending under pressure)
On mandolns we have more freedom, but since there is so much variation of top arch height and shape that folks use it is nearly impossible to tell which angle is best for which instrument. We have seen that similar problems can have surprising counter-intuitive "solutions", like lighter strings working better on certain instruments where most folks suggested using heavier strings for "more tone". There are too many variables at play so for now we can just experiment and see what it gives... If someone is wlling to make couple dozen experimental instruments with varying top/back arches and graduations and neck angles and statistically evaluate the results we will know more...

*except one recent experiment that shows that there is surprisingly very little difference in tone of violin even if you reduce the string angle to bare minimum.

Upright bass makers and players are still messing with the angle. Violin is probably the most studied instrument.