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Angle between body - neck? Please help

oudde - 12-12-2009 at 03:00 PM

Is it necessary to make an small angle (downwards) between the neck block and the neck, so when the strings apply their pressure will straighten the whole oud structure (like the long neck bouzoukis), and if yes, how many degrees would that be? Please help! :bowdown:

I was making arabic neys since now and i want to make my own oud

Dr. Oud - 12-13-2009 at 03:13 PM

The oud neck is much shorter than a long neck lute like bouzoikis or saz, so it does not bend with string pressure. There is negligable change in action before or after tuning the oud. The best way to check the angle of the neck is with a string through the bridge, over the top nut. There should be a clearance at the neck joint between 1/8 inch (4mm) and 3/16 inch (6mm).

oudmaker - 12-14-2009 at 06:31 AM

As far as the behavior of the neck on oud Dr.Oud is correct. But 1/8 inch=3.175mm and 3/16 inch = 4.76 mm. I would prefere 2.5 mm. max.
Dincer

Aymara - 12-14-2009 at 12:14 PM

Quote: Originally posted by oudmaker

I would prefere 2.5 mm. max.

The 3mm action I have on my oud is the maximum I would accept ... I would prefer 2mm. 6mm are an absolute no-go in my opinion, though I often read, what Richard reported.

I vaguely remember, that I read anywhere, that the neck's end at the nut should be around 3mm lower than the top of the soundboard, when no strings are attached.

Is that correct?

oudmaker - 12-15-2009 at 05:41 AM

It is wrong. Make your oud such a way that the neck will hold on its original posture under normal standard tuning. I consider to expect any movement on neck is not acceptable. That is the most important part of the oud building next to the sound of course.

Aymara - 12-15-2009 at 07:06 AM

Quote: Originally posted by oudmaker

It is wrong.

Good to know, thanks.

Dr. Oud - 12-15-2009 at 09:40 AM

Quote: Originally posted by Aymara

...I vaguely remember, that I read anywhere, that the neck's end at the nut should be around 3mm lower than the top of the soundboard, when no strings are attached. Is that correct?

Actually, the height of the strings passing through the bridge will determine the angle of of the neck relative to the body. Without any strings, the top nut end of the neck will locate between 1mm and 3mm below the plane of the face. Without this setback, the height of the strings at the bridge will result in a high action. However, that is not the best way to measure the action, as the string holes in the bridge can change the result. Use a string tied on the bridge, preferably the first string so you can check the height as well as the side edge of the fingerboard.

Aymara - 12-15-2009 at 10:03 AM

Quote: Originally posted by Dr. Oud

Without any strings, the top nut end of the neck will locate between 1mm and 3mm below the plane of the face.

I thought, this might be something like a rule of thumb, but the real action will also depend on the strings tension, which differs from one set to another.

I also read, that this neck angle is neccessary, to avoid the action rising too soon by a warping neck caused by the string's tension in combination with temperature or humidity changes.

At first sight, that sounded logical to me.

oudde - 12-16-2009 at 01:00 AM

Thanks to all for replying.
So, the ouds soundboard with the fingerboard are aligned in a perfect line.
Correct or wrong??

Dr. Oud - 12-16-2009 at 11:05 AM

Quote: Originally posted by oudde

...So, the ouds soundboard with the fingerboard are aligned in a perfect line.
Correct or wrong??

If the fingerboard and face are in a perfect line, and you wish the action to be low, the strings at the bridge will be too close to the face to allow plucking without hitting the face. Raising the strings at the bridge for plucking clearance requires a set-back of the top of the neck to align the fingerboard with the string plane.
The neck rarely warps, it is usually the body bending.

fernandraynaud - 4-6-2010 at 01:55 AM

Richard,
So we are back to the problem of how to adjust the "lean-back" of the neck, which Alfaraby says is no big deal.

Meanwhile most of the ouds I have played in the last few months would be perfectly usable ouds if not for the neck leaning too far forward causing a > 4.5 mm action or the strings being very low above the sound board. It's a rare oud that sounds good and plays well with that kind of action! ! Something like 8 out of 10 ouds are usable only as flower pots or student demoralizers right out of the gate or within a short time! That's absurd! If anyone can tell us how to quickly adjust that neck angle, they can really do some good!

sabbassi - 4-6-2010 at 03:37 AM

Oudde,

Assuming that everything is in perfect line, soundboard, neck and neck join.
When opening the neck join (where the neck will fit), the opening must be lower at the front and higher at the back side , the difference could be between 0 and 1mm. this way when glueing the neck it will lean forward just a bit and after the strings are in place, the pressure line up everything to 0. but this always depends on many factors of courses, the wood used for the neck and neck join, is it quarter sawn? humidity etc...

fernandraynaud - 4-6-2010 at 06:34 PM

There are two subjects here. Richard is pointing out that expecting the neck to flex is wrong. He is also recommending an action height that is a bit higher than several here present members find acceptable. I too prefer 2.5 mm.

So the big question is what to do if the oud has a high action, minor adjustments are insufficient, and there's not enough clearance above the soundboard to lower the bridge holes?

Alfaraby says he adjusts the neck angle routinely, and that it's "as simple as putting a coin into a machine". Can Alfaraby please help and explain briefly how he does it, so we can all have the action we want?

Aymara - 4-6-2010 at 11:54 PM

Quote: Originally posted by fernandraynaud

So the big question is what to do if the oud has a high action, minor adjustments are insufficient, and there's not enough clearance above the soundboard to lower the bridge holes?

I thought, the standard routine would be to let a luthier exchange nut and bridge to achieve the desired action ... or am I wrong?

fernandraynaud - 4-7-2010 at 12:49 AM

Unfortunately, you are wrong. Sketch it and you will see.

I have one oud that I have been scratching my head over for months, because I don't like its 4.5 mm action.

Lowering the strings by drilling new holes in the bridge has limits, as you can't work the risha comfortably too low over the soundboard. There is a limit and I'm trying to understand the limits of the compromises. It seems like if I really wanted a 2.5 mm action, I'd have to be whippin' my Faridism a couple millimeters above the soundboard!!!

Some bridges also have other structural or geometric limits. On my Syrian, for instance, the bridge is sloped, so lowering the holes shortens the scale, thankfully not significantly in this case.

Raising the nut goes hand in hand with raising the whole fingerboard. I had found a suitable Brazilian rosewood board to glue over the existing fingerboard and then realized that long fingerboards, like on my Sukar, are mounted a special way so as not to dampen the vibration of the soundboard. I think it was Sazi who told me about his bad experience gluing on a layer of soundboard: the tone changed.

Not using a loop but just tying a knot in the string, like a ball end, drops the action a little bit, and I'm doing that on another oud where that's sufficient.

So what else can we do? Show me! What can your luthier do by swapping bridges and nuts?

So here's the pattern: 1) many ouds have a tendency to high action 2) there is no way other than re-setting the neck angle to lower the action a couple millimeters without causing other problems and 3) unless we learn how to easily loosen and re-set a neck, an adjustable neck like on a Sukar is a necessity.

Oy

Sazi - 4-7-2010 at 02:37 AM

Quote: Originally posted by fernandraynaud

Is there a pattern here?: 1) many ouds have a tendency to high action 2) there is no way other than re-setting the neck angle to lower the action a couple millimeters without causing other problems and 3) unless we learn how to easily loosen and re-set a neck, an adjustable neck like on a Sukar is a necessity.

I'll just re-arrange those first words... There is a pattern here... Which is why people like Ibrahim Sukar with his low-tech wing-nut system and Fadi Matta with his (only slightly) more complex locking system, have come up with, or utilise these solutions in the first place. Solutions that have almost become standard in guitar design over the years, and I'll stick my kneck out here... hopefully will become more common on ouds. And to those who complain about changes to the oud ...- if we were to be stuck in tradition we would all be playing 4 course gut strung ouds, there'd be no floating bridges or 7 courses , and Naseer Shamma might be out of a job!

Selaam

There is no simple "coin in the slot" method (yet

) you either slice off the neck with a razor saw and adjust the face angle very slightly, and then re-drill the hole for the new angle of the dowel, yoiks! it sounds drastic!, but I have done it before and was happy with the result, it made an unplayable instrument very satisfying to play, and was done in a day.

Hmm, it doesn't have to be quite that drastic... I loosened the joint with heat and steam and only had to cut off the dowel... but if you have a dovetail joint it may be harder to loosen the neck as it would be glued right through the neck block and to the soundboard.

Or you come up with some form of adjustment, the simplest perhaps being the "knockdown" fitting of a threaded rod embedded in the neck with a corresponding bolt threaded into it from the inner face of the neck-block.

Not quite as simple as putting a coin in the slot :rolleyes:

but perhaps worth the effort on an otherwise perfect oud, THEN the adjustment would be as simple as putting a coin - allen key into a slot

Aymara - 4-7-2010 at 09:24 AM

Quote: Originally posted by Sazi

if we were to be stuck in tradition we would all be playing 4 course gut strung ouds, there'd be no floating bridges or 7 courses , and Naseer Shamma might be out of a job!

Selaam

Great argumentation :applause:

fernandraynaud - 4-7-2010 at 12:58 PM

If what traditionalists say were true, the landscape wouldn't be littered like the aftermath of Waterloo with ouds unusable only because of high action and/or bad pegs. If hiding 3 small pieces of metal in the neck joint can do so much with such discretion, I vote for it. Maybe someone cares to design an all-wood resettable neck? Like using a little sloped wedge?

And the pegs? Here too, discretion. We leave gears to robots. Planetary Invisibly-geared Perfection Pegs cost $250 for 12. Ouch!!! Gotoh pegs are friction-based (you regulate with a hex screw), use non-tapered holes (huge advantage), cost about $100 for 12. And hard to get. Beautiful rosewood or ebony violin or viola pegs can be found at $4 for 4. They have a 30:1 taper while typical oud and lute pegs aim for 16:1. It seems many modern oud makers already use 30:1 pegs. Am I mistaken? Can someone send a container full of reamers to Aleppo, Cairo, Damascus, etc?

And Aluminum Pegs?

fernandraynaud - 4-8-2010 at 12:21 AM

About the reamers I was being sarcastic, as i can't fathom why most oud pegholes don't fit their pegs at all.

We had collectively wondered about Gotoh aluminum pegs a few months ago. I just spoke to the man who was going to distribute them. These are less than half the price of Perfection Pegs, look great, and .... don't hold. By the time the Japanese had improved them the damage to their reputation was done, so the distributor gave up. I'm going to try to get a set of the latest design from Tokyo to try.

Sazi - 4-8-2010 at 03:10 AM

Just a quick 2.2 cents worth... aluminium pegs could be worse than you think ebony pegs are, unless the oud never leaves a controlled environment, as it expands and contracts quite a lot with temperature fluctuations... (the reason why you don't see aluminium tuning forks) ...if they got cold they would slip, and if they got hot... I'd hate to come home to a split pegbox.

Oh that's right y'all say aluminum, sorry, we spell it different here...

Luttgutt - 4-8-2010 at 04:24 AM

Tony, I am no oud maker. But I have lowered the action on some of my previous "performance" ouds.

p.s. That is one reason why I "converted" to Sukar

What I did is simply to sand down the finger board "AT AN ANGLE"! that is, I sand more the closer I get to the nut.

And it works PERFECTLY! I am sure you can do it better than me

Of course, there will be a limit as to how much you can do it, but with your 4,5mm, I don't think there will be a problem!

And of course, you will have a big problem if the fingerboard has inlay. But luckily for me, I love SIMPLE ouds

What do you think?

fernandraynaud - 4-9-2010 at 12:14 AM

Sazi: the aluminum pegs have their own friction mechanism. They look like normal pegs but sit in untapered holes. You drill out the tapered holes with a normal drill (I think 10 mm), and insert the bushings with the pegs. An allen screw adjusts the pressure on each peg's slip-clutch. Nothing moves against the pegbox walls. The Perfection Pegs use a planetary gear mechanisms hidden in what looks like ebony pegs, and the Gotohs use an adjustable slipclutch (and are much cheaper). I am in touch with the manufacturer and hope to test some soon.

Luttgutt, you sneaky oudomaniac! That's probably a VERY good way to gain a millimeter or two if we have the "spare neck material". There are two ouds on which I would like to lower the action, one has inlays and edging, I can't imagine a way to shave the neck without ruining it. The other has a veneer fingerboard that likely I can unglue and then put back on, or glue on a new one. Let me do the sketches and look into it. Adjustable necks seem better, we agree, but this fix is definitely worth knowing about! Did you do this best with sandpaper, a file, a plane, a sanding block, what?

Sazi - 4-9-2010 at 03:05 AM

Ahh, ok, thanks, that sounds really interesting, are they 1:1 ratio?. I'd be keen to hear your opinion of them, they sound like a Good Thing!

fernandraynaud - 4-9-2010 at 03:44 AM

No question the Perfection Pegs with their 4:1 invisible gears are nicer, but they cost $80+ for 4. A luthier quoted me $600 to upgrade an oud. Apparently many high end violin-makers are adopting them.

The Gotohs are 1:1 but 12 (3 sets of 4) should cost under $100 and they are easier to install. They have recently redesigned them. I'll let you know if/when they reply, I'm luring them with a big new market.

fernandraynaud - 4-9-2010 at 05:51 AM

Luttgutt you saved my Syrian Sleeper! It is so happy it is jumping up and down making Ajam ! :bounce:

Luttgutt - 4-9-2010 at 06:35 AM

Hey Toni Glad to hear!

That went fast :applause:

I tald you you'll do it better then me.

What did you use? I used everything you mentioned. Tried at least...

fernandraynaud - 4-9-2010 at 03:44 PM

Oh, no Geko, nobody works not THAT fast.

I just meant that the poor Damascus oud was so sad and neglected, I never play him, but he has a plain fingerboard and a neck like a Syrian wine merchant, so I WILL be able to shave it down. I'll get you some pictures when I actually complete the job. This apparently not so obvious trick is maybe what DrOud once mysteriously alluded to in mentioning preferably making a fingerboard thicker at the back, but I'm amazed nobody else did. Did you find this trick somewhere or just come up with it out of desperation?

Luttgutt - 4-10-2010 at 03:38 AM

I see :-)

No, not heard of it been done before...

True I am no oud maker, but I am a matematition, so it was not that difficult for me to "visualize" the effect of the angle shift and the result rather fast actually.

But the actual work took long time. I had to resting and tune at least 20 times before I got the result that I wanted!!
That is why I was shocked when I thought you did it already

And I still think you can do it faster then me

Good luck
and just ask if you need info..

Sazi - 4-10-2010 at 03:38 AM

A good 'quick and dirty' fix if you have a thick enough neck, but I tried it on an El Cheapo Turkish oud with a neck of average kind of thickness and over the next few weeks it started bending up from the nut for a couple of inches.

Luttgutt - 4-10-2010 at 03:41 AM

Hmm strange!

Why would it bend just by loosing a mm or so!?

How much did you take off it?

Sazi - 4-10-2010 at 03:44 AM

Probably about 1.5 mm, but obviously it was too much! It was a veneered neck with a spruce core.

Luttgutt - 4-10-2010 at 03:47 AM

I see!!

I thought that spruce should NOT be used on the neck!?!

I can brake spruce with my bare hands

Sazi - 4-10-2010 at 03:59 AM

Well I have pulled apart a few necks now and have found that it is quite common to use spruce, (well quartered with tight grain), covered with veneer, (the combination of veneer and fingerboard strengthens them) at least on Turkish ouds anyway, I believe lutes are made the same way. All my Iraqi ouds have had solid rosewood or walnut necks.

jdowning - 4-10-2010 at 05:40 AM

For information.
Surviving lutes from the 16th/17th C have necks with a core of light but strong and stable wood (usually Poplar but also Lime wood, Spruce or Fir) veneered with a hard wood such as Ebony. As far as I know ouds were once made the same way. A solid neck is of course easier and cheaper to make so is likely to be the modern standard among many oud makers.
Lutes were also made with the fingerboard thicker at the nut end than at the neck joint - to allow the fingerboard to be shaved down for action adjustments. This adjustment can also be achieved by removing the finger board, shaving down the neck and then re-fitting the fingerboard. I have used both methods.

The attached images show the neck construction of an old Egyptian oud (late 19th/ early 20th C?) that I own. The neck core is a softwood - Spruce or Fir (?) - veneered with the same woods used for the bowl. Veneer thickness is about
2 mm +. The fingerboard thickness tapers from about 2.5 mm at the neck joint to about 1.5 mm at the nut - indicating that at one time in the past the action may have been adjusted by shaving down the fingerboard.

Old Egyptian Oud neck comp (515 x 739).jpg - 83kB

Luttgutt - 4-10-2010 at 08:22 AM

Thanks for the info, jdowning!

So Tony, it seems that I m not the first to do that

fernandraynaud - 4-10-2010 at 07:58 PM

Ah, seems it was John and not Richard who was mentioning the thicker fingerboard at the nut?

I can visualize the issues better now. It's funny but my wife who has no math background can immediately see it, and me (who has had to work with partial derivatives and such), it takes me a sketch and algebra to fully grasp it.

If you need to lower the action by say 2 mm, you need to shave the neck down by MORE than 2 mm, namely 2mm * 1.5 = 3 mm (because the neck-body junction, the Tiz Neva Point, is at 1/3 the scale length). My wife immediately said 3mm - how did she know?. That's not "a little". Certainly if the neck is not solid wood all sorts of problems can develop. If we limit the shave to 1.5mm, the action will drop by only 1 mm. The rule is 1 mm change at Neck-Body = 1.5 mm change at nut.

So maybe combining a drop at the bridge by drilling lower string holes, AND a fingerboard tapered shave?

How much do we need to drop the bridge holes? The 1.5 leverage is reversed at the bridge. For a drop of 2mm at the Tiz Neva Point, we need a bridge-side drop of 2mm * 3 = 6mm ! That's generally out of the question. The rule is 1 mm change at Neck-Body = 3 mm change at bridge.

Assuming the strings are 1 cm above the raqma to start with, we can afford a 3 mm drop. I would say 7 mm is a minimum string height above the soundboard, I have one oud that's about 7 mm and it's OK but darned tight.

So we can achieve the desired 2 mm action drop by drilling new bridge holes 3 mm lower AND shaving the neck so the fingerboard is 1.5 mm lower at the nut (and with the fingerboard perfectly tapered). The hardest thing probably will be sanding/filing/planing the neck so it is really flat. Maybe once I look at the neck construction I can decide how much of a shave I can do.

That leaves raising the fingerboard as a contributing solution to consider - maybe not adding a flat board, but as the very ramp we wanted to shave out of the neck? The 1:1.5 rule still holds as long as the other end of the string is the "hinge", so first let's consider adding a 3 mm thick level fingerboard. That raises the strings at the nut 3 mm so at the Neck-Body junction they rise 3 / 1.5 = 2 mm, but that's over a 3 mm higher fingerboard, i.e. in effect we have lowered the action by 1 mm at the neck-body junction. Now if the fingerboard is 3 mm thick at the neck-body junction, but in addition we taper it down to 1.5 mm at the nut, we are dropping the strings 1.5 mm at the nut, so the strings are dropping 1 mm at the neck-body junction (towards the fingerboard). Adding that to the 1 mm we gained with the untapered fingerboard, and we have met the target 2 mm drop. Is that right? Can someone pls. check this?

No need to wreck the existing neck? All the tricky wood-working is done off-oud (in vitro) on a disposable board? No need to lower the strings at the bridge?! Wow, that sure is appealing as long as the glued-on fingerboard doesn't kill the tone.

Need to see how much acoustic damping occurs vs. how long a board I can afford to glue on. One could even shave/undercut the fingerboard a millimeter and let it "float" over the body portion of its length instead of gluing it down, flying it a little like a violin fingerboard? That sounds doable!

BTW I'm enclosing a translated Turkish document that is a goldmine of oud construction details, including recommended dimensions.

Attachment: TECHNICAL_STRUCTURE_OF_THE_OUD_AND_ITS_FEATURES.rtf (54kB)
This file has been downloaded 615 times

Luttgutt - 4-11-2010 at 07:14 AM

Tony,

1- the "flying" finger board is doable.. I have seen it on oud.

2- I don't see why you need to lower your action so much! 3mm is more then good enough!! What hight are you seeking?

3- Your calculations assume that everything is leveld! But it is not always the case. It is almost NEVER the case on cheep, and old ouds (and i dare say on ALL ouds)
A litle twist on the bridge would make a big angle difference, and "ruin" your calculations.
The finger board on most old ouds is NOT level. It is curved a litle on perpous (on old syrian ouds the nut is LEVELD with the finger boars. So the later HAS to be curved).

So I suggest you do the same as I did:
Shave off a little, tighten the strings (the dd strings to begin with) and TRY and see what change you produced.
Repeat the process to the level requierd.

P.s. I don't think it is practical or feasable to aim at 2mm action

fernandraynaud - 4-11-2010 at 07:41 AM

No, no, I am aiming to lower the action by 2 mm, not TO 2mm.

The action is now almost 5 mm, i want it down to 3 mm. So I need to drop it 2 mm.

I went into too much detail (as I often do), because I was thinking it through as I wrote it. So I confused you. Sorry.

What i finally came to (much to my surprise) is that I can drop the action 2 mm (down to 3 mm) by making a little fingerboard starting from a brazilian rosewood board that is 3 mm thick, and tapering it down 1.5 mm (to about 1.75 mm) at the nut. What the calculations show is that gluing such a fingerboard on top of the neck (and raising the nut of course), the effective action drops 2 mm. Without having to shave the existing neck at all! If you have a moment see if my reasoning is correct: a) I gain 1 mm just by adding a level 3 mm fingerboard and b) I can gain another 1mm from tapering it towards the nut by 1.5 mm.

Luttgutt - 4-11-2010 at 08:35 AM

This sounds sound to me...

Will it be a short finger board? Or are you going for the "flying" type?

A question on the side:
I read the "turkish" attachment. This is a sentance that is confusing me

"Due to the same reason, the bridge is glued on the board so that the higher tip is 1 mm closer to the bottom side and not parallel, for all the string lengths to be equal."

What does that mean??

Where is the "higher tip"? and what is the "bottom side"? of what?? :shrug:

fernandraynaud - 4-11-2010 at 09:35 AM

Yes that was my favorite sentence too. That's in the same league as Sukar's "horse". I pondered until I came to this hypothesis: maybe he means the bridge is crooked, not perpendicular to the oud's midline, the same way a guitar saddle is compensated? I have seen a number of bridges built with scientific obedience to this principle, in all three axes, and with all sorts of ideas as to what is parallel to what and what this sentence means ;-) This goes with the "Oud as chicken coop ornament and fern planter" school of woodworking.

Sazi - 4-14-2010 at 04:31 PM

Translating things sure can be really confusing!

In reference to the oud, at least in the Arabic articles I have read, "horse" means bridge (as we know it) whereas "bridge" actually means brace.

Haven't got a clue what the Turks mean though, but there is a discussion around here somewhere on that bridge/compensation thing.

supasoul20 - 6-14-2011 at 11:20 AM

Quote: Originally posted by Sazi

...aluminium pegs could be worse than you think ebony pegs are, unless the oud never leaves a controlled environment, as it expands and contracts quite a lot with temperature fluctuations... (the reason why you don't see aluminium tuning forks) ...

There actually are aluminum tuning forks, and they sound much better than steel ones (higher stiffness-to-mass ratio, see for example: http://www.petesummers.com/tools2.html ) Aluminum does not have a high temperature expansion coefficient. The reason why, correctly, you would not want to use an aluminum peg, is that the expansion/contraction of the wood is orders of magnitude higher than that of aluminum (or any other metal like steel or copper).

supasoul20 - 6-14-2011 at 11:34 AM

I would like to consider the following citation: Lets vary the angle of the neck and keep the action fixed at, say, 2mm. To do this, we would need to adjust the bridge height, in the case of a floating bridge.

What is the impact on the instrument's sound if the bridge were raised or lowered significantly? I observe that a higher bridge means more normal force on the resonator, which can amplify or dampen the certain frequencies. The violin has a very high bridge, and a raised/angled fingerboard. Has anyone experimented with such designs, or perhaps only changing the bridge height a few millimeters?

This topic also relates to this discussion http://www.mikeouds.com/messageboard/viewthread.php?tid=9959#pid664...

aytayfun - 6-19-2011 at 10:37 AM

Quote: Originally posted by oudmaker

It is wrong. Make your oud such a way that the neck will hold on its original posture under normal standard tuning. I consider to expect any movement on neck is not acceptable. That is the most important part of the oud building next to the sound of course.

Iam with you master. Luthier must give an angle that will be in in correct position after tunning.

bulerias1981 - 2-16-2012 at 11:03 AM

This conversation seemed to deviate at times, but I want to return to the core of the topic.
So there are several variables one must consider when working with the fingerboard to achieve a good action across the plane of the fingerboard and avoid slapping or buzzing of the strings.

*Angle of the bridge platform to the neckjoint.
*Height of the string holes in bridge
*Off set of neck angle at the nut end
*Height/thickness of fingerboard (which alters the angle)

I have seen a few types of configurations of neck angles, off sets, and string heights at the bridge contribute to good actions.

What I want to do is have a formula for the ideal proportions in order to render a good action without buzzing... very consistently.
I have a lot of measurements, but its hard to formulate a single standard, since there are many variables. But lets say even in the case of a bowl that is concave and has a "scoop" for example, it shouldn't matter I believe. Why? Consider the bridge platform, and the neck joint area as your first or main point of reference. That should be a straight line, even if the face dips down in that area.

So if that area is a straight line, what should the ideal neck angle be?

Please note, this is obviously not to scale!

SamirCanada - 2-16-2012 at 01:11 PM

I like this subject very much. I am willing to pitch in my 2 cents.

I think there will be a range of acceptable combinations here. We can discuss their theorical feasability but in the end we also need to use our experince in playing this instrument and rule out the combinations that, yes may work on paper, but wouldnt be comfortable to play or would put to much stress on the materials used ( a 10cm high bridge is out of the question, right? RIGHT?)

Some questions remain though,
- What is the ideal string height on the bridge? Here again there is a range of acceptal combinations (between 0.7 cm to 2 cm)???
Of these potential string heights on the bridge what height provides the optimal playability and optimal sound production? I am not a physician but I think the tension / torque on the soundboard goes up as we move the strings higher on the bridge.

With that ideal bridge height a constant, we can determine the rest of the ideal configurations for the string scale we are using say (60 cm) we know the neck is 30 cm and we can then determine the combination of angles on the neck which will give us a neck action between (2mm to 4mm)

Now who is good in trigonometry?

bulerias1981 - 2-19-2012 at 06:17 PM

By the way. I have come across ouds in which the necks bend under tension. This depends on neck thickness and the grain orientation.

bulerias1981 - 2-20-2012 at 10:45 AM

Also, another factor that changes the angle aspect is the bridge platform lifting due to string pressure (mostly in fixed bridges).

The top can lift up maybe as much as 1mm-2.5mm as far as I've seen.