# Determining guitar balance through simple visualisation



## ixlramp (Dec 8, 2018)

I worked through the mechanics of the forces and torques and have derived a simple way to consider and perfect guitar balance through visualisation.

This is very useful to know as a large majority of guitars have poor balance, even at fairly horizontal playing angles, and balance that becomes rapidly worse at higher playing angles. On an existing guitar balance can often be perfected by moving the strap buttons.

The intention here is to equalise the forces pulling on each end of the strap while the guitar is at a particular playing angle, so that there is zero tendency for the instrument to rotate. This stops the strap pulling forward on your shoulder, which is unhealthy, with only friction stopping the guitar neckdiving.

When designing a guitar this knowledge is very helpful to create a design with good balance, it's also possible to create a design that balances perfectly over a wide range of playing angles.

First, find the 'centre of mass' (COM)
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This is often called the 'centre of gravity'.
In mechanics it is very often possible to simplify analysis by considering all the mass of an object to be concentrated at one point, the COM.

The method used is balancing the guitar on and above one hand by pinching the lower body edge between thumb and first finger, in a way that allows the guitar to pivot at that point (pivot point).
This hand is probably best resting on your knee to avoid fatigue.
The other hand shifts and stabilises the guitar until it balances, at which point it is barely touching the guitar.

1. Balance the guitar on your hand with the guitar perfectly vertical, and shift the pivot point left and right until the guitar balances vertically without falling left or right.
Now we know the COM is somewere directly above the pivot point, you could mark the pivot point or just remember where on the instrument the vertical line above the pivot point is. It will often be near the centreline of the guitar:



2. Now do the same with the guitar perfectly horizontal.

3. Where the 2 lines cross is the position of the COM:



(Continued below)


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## ixlramp (Dec 9, 2018)

Balance visualisation
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1. With the guitar at the playing angle you want to analyse, visualise 2 vertical lines passing through the strap button points B1, B2.
2. Visualise a horizontal line passing through the COM point and visualise the points E1, E2, where it crosses the vertical lines.



3. The magnitudes of the forces pulling on the strap ends will have a ratio equal to the ratio of the distances E1 - COM and E2 - COM.
The shorter the E - COM distance is, the larger the force is on that end of the strap.
If the distances E1 - COM and E2 - COM are equal the forces will be equal and the guitar perfectly balanced.

Above you can see the distance E2 - COM is roughly twice the distance E1 - COM, so the force on the horn end of the strap will be roughly twice that of the force on the rear end of the strap.
(Note i have probably incorrectly guessed the COM point for this Ibanez RG, the diagram is meant to be general not specific to this guitar.)


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## crackout (Dec 10, 2018)

ixlramp said:


> Balance visualisation
> If the distances E1 - COM and E2 - COM are equal the forces will be equal and the guitar perfectly balanced.



I would not call this 'perfectly balanced' in the understanding of a nicely hanging guitar.
If both forces are equal, you will have no 'restoring force' into the desired position, the guitar will always stay the way you put it. While technically speaking this is well-balanced, at least to me in addition to a nice hanging position a guitar should also have a tendency to move there.


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## ixlramp (Dec 10, 2018)

If you require a tendency to return to the desired playing angle, the forces on each end of the strap must be equal when at that angle, if they are not that won't be the equilibrium angle, a different angle will be.
However yes whether there is a restoring force or not is determined by stuff i haven't described yet, where the buttons are located.

I actually consider the perfect system is one that has zero restoring tendency, that is, perfect balance over a wide range of angles, otherwise you are forced to use a single playing angle, and playing angle is determined by personal taste and what techniques you are using. Fine for personal modifications or custom work, but otherwise a manufacturer should not really dictate what playing angle the player can use (but most designs do dictate this).

Almost all conventional guitar and bass designs have perfect balance only when the neck is pointing downwards to some degree. That is, friction of strap on shoulder is the only thing that keeps a guitar at the desired playing angle.

I continue with further posts.


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## ixlramp (Dec 11, 2018)

The solution
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The strap buttons should be placed somewhere on vertical lines that are equidistant either side of the COM.

But with one condition: If a line is imagined between the strap buttons, the COM should be on or below this line, otherwise the COM is above the supporting axis and the guitar will be unstable and tend to flop forwards or backwards (that is, away or towards the player).

So for the guitar in the images, we need to either move one or both the strap buttons to the right, and/or move the COM towards the left.
We can't move the COM without adding weight, which is a bad idea for comfort and health.
Moving the horn button to the right is only possible with an ugly and costly horn extension.
So the remaining solution is moving the rear button to the right.

A solution i have used on several guitars is to place the rear button on the front of the body, near the top and roughly halfway along the body:


Placing the button on the body front tends to tilt the guitar towards the player slightly so that the fingerboard is more visible.

Obviously this solution is possibly not suitable for many guitar (as in, not bass guitar) players as it will shift the guitar to the right a little. However it is very helpful for a bass guitar because basses are positioned too far to the left when strapped on, when the bridge could be shifted to the right comfortably.

The result is a horizontal position closer to the position created when placing a guitar on your right thigh, which for a bass guitar is a far more ergonomic position.


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## ixlramp (Dec 12, 2018)

The 'solution' shown in the previous post will have the restoring behavour discussed earlier, because the COM is significantly below the line between the strap buttons. If the guitar angle changes the COM rapidly becomes closer to one or the other vertical lines in a way that tends to restore to the perfectly balanced angle.

The common problem
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The diagram in the post 2 is for a guitar angle of 30 degrees and the guitar is already significantly unbalanced. The diagram below is for a guitar angle of 45 degrees which is quite commonly used:


This shows the very common balance problem most guitars have. As the playing angle increases the guitar rapidly becomes extremely unbalanced as the COM moves to be almost directly below the horn strap button.
Here there is roughly 5 times as much weight on the horn end of the strap as on the other end, probably overcoming strap friction and making this angle unmaintainable.

Such a high playing angle is good for ergonomics and is popular with more technical players and metal guitarists. Bass guitars especially benefit from a high playing angle, angles even steeper than 45 degrees work very well for the arms and wrists.

When the electric guitar and bass were developed in the 50s/60s it seems they were designed to be played near-horizontally. A button was placed on each end and it just about worked with the guitar near-horizontal. The guitar was unbalanced but strap friction was enough to overcome that.

Considering how revolutionary the electric guitar and bass were at the time i can forgive not much thought being put into the mechanics of balance.
However, since the Strat and P-bass were designed, nothing has changed in the mainstream in 60 years in terms of strap button positions, body shape, ergonomics and instrument balance, apart from some brief but temporary progression in the 80s (Steinberger and headless).


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## crackout (Dec 12, 2018)

From my observations the COM always lies 'underneath' the anchor point of the strap (on your shoulder).
Moving the strap pins moves the guitar relative to the anchor point and the guitar will rotate in a way so the above statement is fulfilled.


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## ixlramp (Dec 12, 2018)

The only way the COM can be vertically below your shoulder is not connecting the other end of the strap, because the other end exerts a force on the guitar.
If you imagine hanging the guitar from a strap only connected to the horn button, the guitar will rotate such that the COM will be vertically below the horn button.

However you're somewhat correct in a way, but it's probably because almost all guitars are neck-heavy, so the COM is fairly near to being below the horn button, you can see this is the case for 30 and 45 degrees.


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## crackout (Dec 13, 2018)

I'm not saying the COM will lie underneath the horn button but the anchor point where the strap sits on your shoulder (the tip of the triangle formed by both strap segments and the imaginary line so to say). It doesn't matter where I put the anchor point on the strap (i.e. how I divide the strap), the COM always lies underneath the anchor. To achieve this, the guitar will rotate. You can easily verify this by marking the COM and hanging the guitar over your hand. The COM will lie directly underneath your hand (low friction strap recommended).

With neck-heavy guitars, the COM lies further to the headstock while your anchor point on your shoulder remains more or less in the middle of the guitar body.




SGs are a prime example for neck-heavy guitars. The thin body combined with the bad button placement and the fact that these necks do not protrude into the body at all moves the center of mass almost on the heel. The resulting torque is large enough to overcome the static friction of the strap (because SGs are very light guitars) resulting in dive.




By diving down the COM will reach its desired position underneath the anchor point.

With a "proper" design and good weight balance between body and neck, you can push the COM into the body whilst moving the upper button further out and thus move the guitar body as well. This helps moving the COM underneath your anchor.




I don't see why the fundamental principle should be different depending on the number of the fixture points (1 or 2). There will always be a net torque as long as the COM is not directly underneath the anchor.


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## crackout (Dec 15, 2018)

Of course, above behaviour only applies if the anchor point lies _between_ both button points.
If it lies outside this range (e.g. a SG with a super light body and a COM even further oriented to the headstock), the headstock will dive all the way down.


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## AeroSigma (Dec 17, 2018)

One of the problems with moving the body button up is that the loop between the strap mounts is thin, and uncomfortable around the shoulders. While this might not be an actual issue, I would expect this is the reason that the current way of doing it became standard. 

Consider that many acoustic guitar straps anchor on a button on the end of the body, but then wrap around the neck above the nut, which avoids the neck dive issue. You could solve this issue by using that type of strap: https://i.ytimg.com/vi/BqLnrT_fu2A/maxresdefault.jpg

Another thing to consider is adding an extension to the upper horn to move that button further from the CoG. Perhaps similar to the way Anygig does it: https://i.ebayimg.com/images/g/7JQAAOSwrh5bcTXR/s-l640.jpg


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## ixlramp (Dec 18, 2018)

crackout, i see what you mean now thanks.
So far i have assumed the strap ends are vertically above the strap buttons, but i need to address a general case where the strap ends are at any angle.
In a way the strap doesn't form a triangle because one end of the strap comes around the right side of your body so approaches the rear button from roughly above. When a player wears a guitar the horn end of the strap tends to be near-vertical up to the shoulder.


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## ixlramp (Dec 18, 2018)

Balancing the Hohner B2(A)V
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My first 2 basses were a Hohner B2V and a Hohner B2AV. These are shifted well to the left when strapped on and are fairly unbalanced despite being headless. I was interested in 2-hand tapping and needed a higher playing angle.
I intuitively decided having the COM horizontally equidistant between the buttons would help. On both i added a new button on the body front halfway between the pickups:



'B' shows the buttons i used, 'BO' is the original rear button.
This works out very well because at a playing angle of roughly 22.5 degrees: It is perfectly balanced, but also, the buttons are level and the COM only a small distance below.
This maximises the range of playing angles usable, it can go from horizontal to 45 degrees and never be more than slightly unbalanced.

The moved rear button also pulls the bass to the right which was much needed.
It was very comfortable, much more than before.

Conventional guitars and basses start out already neck-heavy when horizontal and this only gets worse at higher angles, so the range of usable playing angles is much reduced.


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## ixlramp (Dec 23, 2018)

Perfect balance at multiple playing angles
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If the COM is halfway along a line drawn between the strap buttons it will always be horizontally equidistant from vertical lines drawn through the buttons. Resulting in perfect balance at multiple playing angles.

Ideally the line between the strap buttons should be as close as possible to being horizontal when the guitar is at an angle halfway between the most extreme playing angles used. This maximises the horizontal distance between the strap buttons over the playing angles used.
Below is a suggestion for a headless guitar with perfect balance at multiple playing angles. I have guessed the location of the COM.
(This body shape i consider one of the most ergonomic designs, the guitar is by Rick Toone).




This design helps because:
The COM is horizontally closer to the middle of the guitar.
The COM is above the centreline of the strings.
The singlecut design allows a strap button low and close to the neck near the 12th fret.

It's not ideal as the line between the strap buttons is near-horizontal, and slightly back-angled, when the guitar is horizontal, which isn't the middle playing angle.


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## gunch (Dec 23, 2018)

so is the TDLR that RGs are the most comfortable shapes outside of purposefully ergo designs like kleins and breadwinners?


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## LiveOVErdrive (Dec 23, 2018)

silverabyss said:


> so is the TDLR that RGs are the most comfortable shapes outside of purposefully ergo designs like kleins and breadwinners?


As usual, the answer is "just get a used Ibanez prestige".


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## ixlramp (Dec 24, 2018)

silverabyss said:


> so is the TDLR that RGs are the most comfortable shapes outside of purposefully ergo designs like kleins and breadwinners?


No, the opposite, maybe you DR?

I criticise the RG / superstrat / strat design as being inherently poorly balanced, especially at higher angles.
Having no development for 60 years, stagnated by '1960's rock band fashion' (which perhaps needs to finally go out of fashion).
The basic shape is an acoustic guitar from several hundred years ago plus 2 cutouts added by Fender. Fender did little to advance design, but as stated i can forgive that as the electric guitar was a revolution at the time.
This is all without considering ergonomics while sitting which are far worse and cause unhealthy posture, back twisting.


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## ixlramp (Dec 30, 2018)

Multi-angle perfect balance for bass guitar and touch guitar
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These instruments are playable over a wider range of angles than guitar, between 0 degrees (horizontal) and around 80 degrees (near-vertical).
The bridges of these instruments are more right-shifted, relative to the player, than guitar.
Together these allow a different approach to strap button placement.

Warr Guitars
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The first time i encountered this innovative strap button placement was seeing the 'Warr Guitar' touch guitars.
These instruments are designed to be played either near-vertical like a Chapman Stick, when using 2-handed tapping, but also designed to be played at lower angles when using conventional guitar and bass techniques.




The horn button has been moved to the back of the lower horn. The rear button has been moved to the upper body 'waist'.
The buttons are level with each other at a typical playing angle (60 degrees).
The COM is likely to be roughly midway between the 2 buttons.
This geometry is now also used by 'Touch Guitars' http://www.touchguitars.com/models-specs/.

From the mechanics of earlier posts in this thread, it can be seen why this works so well, as it is close to the geometry that creates perfect balance at multiple playing angles.
The geometry helps to shift the instrument to the right, for horizontal position closer to that when resting the instrument on your leg. Ideal for a touch guitar but also good for bass guitar, as most bass guitars are shifted too far to the left when on a strap: The nut is uncomfortably far away but the bridge can comfortably move to the right.

Below is Trey Gunn (played in King Crimson at one point) and his signature Warr Guitar perfectly balanced at a high angle.




Applying the Warr Guitar geometry to bass guitar
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Here i will use a Hohner The Jack 4 string as the example, which helps this geometry due to being headless and therefore having a COM that is a little more central to the body. I also own one so i know where the COM is.
However, this example is meant to represent any bass guitar, and this geometry can be used for headed bass guitars.

Bass guitars are playable from 0 to 80 degrees, so i take 40 degrees as the mid angle and rotate the image of the bass to this angle. (Bass guitars may not often be played at 80 degrees but that's because their poor design makes that almost impossible, bass guitar is actually very comfortable and healthy played at very high angles).
I then try to keep the line between the strap buttons as horizontal as possible, and make sure the COM is halfway between the strap buttons.




One button would be placed on the back of the lower horn (alternatively it could be placed on the side of the lower horn at the same position, to allow placing the instrument in a hardcase), the other on the body front.

Note that placing buttons on the front or back of the body results in a safe and secure strap connection at any playing angle, unlike conventional horn button placement where the strap wants to pull off the button at high angles. (This is something i like about the Ibanez BTB design, see my avatar, the horn button is angled downwards).


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## LiveOVErdrive (Dec 31, 2018)

Cool stuff. I'd be concerned about the strap getting in the way of my hand on the neck though, when it is on the lower horn like that.


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## ixlramp (Dec 31, 2018)

Yes that is something to be careful of, the Warr geometry tries to keep the button near the base of the lower horn, and i have tried to do this on the The Jack example too.

I discovered this issue when i modified my Crafter Cruiser RG600 (i added quartertone frets), an Explorer type shape with no top horn. I placed the button on the tip of the lower horn, and noticed that at high playing angles the strap would slightly get in the way of my fretting arm.
Balance and comfort is excellent though at any angle. It's interesting how much more comfortable it is when the strap is not trying to pull forward over your shoulder, which happens on most guitars.
Here you can see the button locations:




The Warr geometry is useful for balancing guitars which have no top horn and therefore even worse balance issues.


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## ixlramp (Jan 19, 2019)

I realised i can state the balance visualisation in a simpler way.

Determining guitar balance using visualisation
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Find the Centre Of Mass (COM) using the method described in the first post of this thread.

With the guitar at the playing angle you want to analyse, visualise 2 vertical lines passing through the strap buttons B1, B2.




Consider the horizontal positioning of the COM relative to the lines.
If the COM is halfway between the lines the guitar will be 'perfectly balanced': The weights on the ends of the strap will be equal, the strap will not want to pull forward or backward over your shoulder, the guitar will not want to rotate away from this playing angle.

If the COM is closer to one line than the other, as shown in the image: The weights on the ends of the strap will be unequal, there will be more weight on the strap end corresponding to the closer line, the strap will want to pull forward or backward over your shoulder, the guitar will want to rotate away from this playing angle. However, if the imbalance is not extreme, sufficient friction between the strap and your body will prevent the guitar from rotating.
If the COM is on one of the lines: The entire weight of the guitar will be on that end of the strap, there will be zero weight on the other end of the strap, the guitar will probably rotate.
The ratio of the weights on the ends of the strap is equal to the ratio of the distances from COM to the lines. For example in this image: The distance from COM to the B2 line is roughly double the distance from COM to the B1 line. So the weight on the B1 end of the strap will be roughly double the weight on the B2 end of the strap.


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## vilk (Jan 20, 2019)

I noticed when I've moved a couple of strap buttons from the upper horn to the back of the neck heel that the guitar gets more neckdive but also it takes less force to move it up into a high angle playing position (which also feels more comfortable). Do there might be less neck dive with the button on the upper horn, but if you want to push the neck up into a high angle it feels like lifting almost the whole weight if the guitar, as opposed to with more neck dive, yes you'll have to push it up but it's like gotta be like only a fraction of the foot/lbs that you'd have been using with the button on the horn.

Does that make sense?


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## ixlramp (Jan 20, 2019)

It possibly does actually, due to the angle of a line from COM to B1: With the button on the neck heel this angle is lower, which is something that helps. It's related to how having the horn button low and close to the fretboard helps (as on a singlecut like the Abasi design). Something i'm about to address.

With the button high up on the horn, as you move to higher angles, B1 is almost above the COM, which causes problems.


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## ixlramp (Jan 20, 2019)

The advantage of a singlecut or low horn button design
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For the same body blank length, having the 'top horn' button as low and close as possible to the fretboard helps balance at any playing angle above horizontal.





The vertical line through the button is shifted away from the COM. This advantage increases at higher playing angles.

As playing angle increases, the vertical line through the button doesn't move towards the COM as rapidly, allowing higher playing angles.

This is closer to the 'perfectly balanced at all angles' geometry described in earlier posts (the COM being halfway along a line between the buttons).
This is the advantage of a singlecut design, but can also be done by using a claw shaped top horn like the extremely well designed Basslab STD guitar:




The advantage of using a horn is less mass is added on the neck side of the COM, helping balance.


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## ixlramp (Jan 20, 2019)

'High on the butt' doesn't help
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Moving the rear strap button upwards slightly on the rear of a guitar is often recommended to help balance, but actually makes it worse.


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## ixlramp (Jan 27, 2019)

Dingwall rear-mounted straplock
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Some Dingwall basses have a straplock connector mounted somewhat forward on the body back.
This is usually discussed as helping to shift the bass to the right, to help with reach on the extended scale length.
However it can be seen that a vertical line through this connector is much closer to the Centre Of Mass compared to one through the conventional strap button. So balance is also improved.

At a playing angle of 45 degrees the positioning shown is equivalent to (and is as effective as) placing a strap button at the top of the body front about halfway along the length of the body, something i suggested earlier in the thread.


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## budda (Jan 27, 2019)

I have a tele with traditional button locations, but I experience slight neck dive. I dont know if my headstock is thicker than an actual Fender, but I do have a fairly thick neck. Would repositioning the top button like an SG (behind upper bout) alleviate this?


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## ixlramp (Jan 27, 2019)

I'm looking at a photo of the back of a Telecaster now. I can't see anywhere the front strap button can be moved to that would improve balance. At playing angle the button cannot be moved horizontally leftwards (leftwards as seen from the player).
If you move it to body back, behind the upper bout, just above the neck joint plate, it gets shifted away from the headstock, so i suspect the advantage of having the button lower will be more than cancelled out.
As far as i can judge i don't think it will help and could even be slightly worse.


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## budda (Jan 27, 2019)

Thank you for looking into it! I don't know what my locking tuners weigh, but I don't know how much that would contribute to dive.


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## ixlramp (Feb 9, 2019)

Determining guitar balance using visualisation, general case, strap ends not vertical
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Find the Centre Of Mass (COM) using the method described in the first post of this thread.

With the guitar at the playing angle you want to analyse, visualise 2 force lines, parallel to the strap ends and passing through the strap buttons B1, B2. These represent the forces F1, F2 applied to the strap buttons by the strap ends.

For each force line visualise a perpendicular line that passes through the COM. These lines are shown as LE1, LE2.





Consider the lengths of LE1, LE2.

If the lengths of LE1 and LE2 are equal the guitar will be 'perfectly balanced': The forces on the ends of the strap will be equal, the strap will not want to pull forward or backward over your shoulder, the guitar will not want to rotate away from this playing angle.

If the lengths of LE1 and LE2 are unequal: The forces on the ends of the strap will be unequal, there will be more force on the strap end corresponding to the shortest of LE1 and LE2, the strap will want to pull forward or backward over your shoulder, the guitar will want to rotate away from this playing angle. However, if the imbalance is not extreme, sufficient friction between the strap and your body will prevent the guitar from rotating.

The ratio of the forces on the ends of the strap is inversely equal to the ratio of the lengths LE1, LE2. For example: If LE2 was twice the length of LE1 there would be twice as much force on the B1 end of the strap than the B2 end.


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## ixlramp (Feb 27, 2019)

Another in-practice example. This is my self-converted 8 string (4x2) quartertone-fretted bass, with 8 bass tuners on the headstock and a Hohner/Steinberger-copy flip-down legrest. It started as a second hand Dean Metalman V.

The Centre Of Mass (COM) is located on the fretboard at 2.5cms from the end of the fretboard.
The rear strap button i added is clearly seen on the body front halfway between the pickup and the fretboard. The front strap button is as stock and is on the back of the neck joint plate and mounted on one of the neck joint screws, i added an arrow to point to it.

So the COM is near-halfway between the strap buttons, the rear strap button should be even closer to the neck joint but i was concerned about a strap end touching the strings.

It balances very well and is very comfortable, despite these strap button positions looking crazy. Not having the strap pulling forward on your shoulder improves comfort.
The right end of a strap wraps around the right side of your body and so pulls the bass to the right, putting it in a very ergonomic left-right position with both 1st fret and bridge comfortably reachable.


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## ixlramp (Mar 3, 2019)

When a guitar is supported on one leg, it will balance when the Centre Of Mass (COM) is vertically above the point in the leg cutout where the body edge is horizontal.

You can use this fact to roughly judge where the COM of a guitar is from a photo of someone playing one.


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## cynicown (Mar 4, 2019)

Cheers for such useful info! Going off of what you've stated above, where do you think the ideal strap positions would be on the Ibanez xiphos? I've tried them in a number of positions and never really found the magic formula.


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## Konfyouzd (Mar 4, 2019)

LiveOVErdrive said:


> As usual, the answer is "just get a used Ibanez prestige".


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## ixlramp (Mar 4, 2019)

cynicown please post a front-on photo with the centre of mass marked (you can find it using the method in the first post). Or if you can precisely describe where the COM is that's ok too.
What playing angle (or what range of playing angles) do you use? 24 or 27 frets? 6 or 7 strings?
Xiphos will be tricky as it has a short top horn.


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## ixlramp (Mar 5, 2019)

The technical stuff
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This is so anyone good at mechanics can check this, i hope it is checked.

My results come from a torque analysis of a guitar on a strap and therefore affected by 3 forces:
The 2 upward forces 'F1', 'F2' of the strap ends, applied to the strap buttons 'B1', 'B2'.
The downward weight force 'mg' that is applied to the centre of mass 'COM' ('mg' is mass * acceleration of gravity).




'Torque' is a twisting force at a pivot, or axis.
In this torque analysis i choose an axis on the guitar and calculate the 3 torques created at that axis by the 3 forces.
The trick is to choose the axis to be 'COM'. The torque of force 'mg' is therefore zero as it passes through this axis, so i now only have to consider 2 forces and 2 torques. It's also intuitive to consider the guitar rotating around it's centre of mass, objects tend to do this.
/////////////////

Now i consider the general case of how to calculate the torque at axis 'COM' created by a force 'F' applied to point 'B' which is distance 'L' from the chosen axis 'COM'.




Torque is calculated by multiplying the length 'L' by the perpendicular force 'FP' applied to 'B'.
Torque = FP * L
'FP' is the component of force 'F' perpendicular to 'L' (Force 'F' can be considered equivalent to the 2 components 'FP' and 'FL', where 'FL' is parallel to 'L'.)
FP = F * cos(A)
Where 'A' is an angle
Torque = F * cos(A) * L

I have marked 2 angles on the diagram, both called 'A', they are equal angles.
'LE' is a line perpendicular to force 'F'.
Notice that
LE = L * cos(A)
So the torque equation above can be written
Torque = F * LE
This proves that torque can be calculated by multiplying force 'F' by the distance 'LE' measured along a line perpendicular to 'F', as if the force 'F' is being applied to point 'BE' instead of 'B'.




/////////////////////

Since the guitar is not rotationally accelerating around axis 'COM' i know that the torques created by 'F1' and 'F2' are equal and opposite, cancelling each other out.




So
F1 * LE1 = F2 * LE2
Re-arrange to
F1 / F2 = LE2 / LE1
"The ratio of F1 and F2 is equal to the ratio of LE2 and LE1."

When the guitar is perfectly balanced, the forces on the ends of the strap are equal, so
F1 = F2
So
F1 / F2 = 1
So
LE2 / LE1 = 1
So
LE2 = LE1


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## KVNTZ (Mar 12, 2020)

ixlramp said:


> View attachment 67371
> 
> 
> Another in-practice example. This is my self-converted 8 string (4x2) quartertone-fretted bass, with 8 bass tuners on the headstock and a Hohner/Steinberger-copy flip-down legrest. It started as a second hand Dean Metalman V.
> ...



I've got absolutely no clue how this position works, the distance between the strap points is small small your strap must wrap around your stomach. What does it look like on your body when you play it?


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## KVNTZ (Mar 12, 2020)

Additionally how do you determine the end point of F1? Is that basically the length of the strap from button to the tip of the shoulder?


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## ixlramp (Mar 13, 2020)

Heh, yes that is quite an extreme conversion. The right side strap end wraps around your body a little, and depending on how high the instrument is it can be uncomfortable having the strap digging into your side (this is a possible problem with some of the 'solutions' i describe). However, the balance itself is pleasant. Also, this pulls the bass guitar to the right quite a lot, which i find comfortable.

The length of the line labelled with F1 is irrelevant and unused in the maths, the F1 value in the maths is a force value, the amount of force pulling upwards on button B1. In fact you never need to know what F1 or F2 are, because the result of all this is that, for perfect balance, the distances LE1 and LE2 must be equal.


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## ixlramp (Mar 13, 2020)

I might have misunderstood, perhaps you were not asking about the length of that line but how to choose its angle?
The correct angle of the F1 or F2 force line is simply the angle of the strap end close to the button.
A strap will change its angle as it passes over the players body but that is irrelevant.


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## jco5055 (Jun 3, 2022)

ixlramp said:


> I might have misunderstood, perhaps you were not asking about the length of that line but how to choose its angle?
> The correct angle of the F1 or F2 force line is simply the angle of the strap end close to the button.
> A strap will change its angle as it passes over the players body but that is irrelevant.



Hey man, I don't have a question about this quote specifically but figured this was the best way for you to get notified of a response-

So in general, there really is no superstrat shape that works, because the key (in a very dumbed-down explanation) is that the strap button needs to be as close to the fretboard as possible? and the placement on the upper horn is quite the opposite? and by saying "works" I mean having that ideal classical guitar-ish much more vertical neck angle?


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## ixlramp (Jun 4, 2022)

@jco5055 Yeah the superstrat horn strap button position makes it harder to create a design with good balance at a high playing angle, and also makes balance change a lot when changing playing angle.

The horn strap button does not absolutely have to be close to the fretboard, another way to improve balance at a high playing angle would be a very long top horn, but that might then shift the guitar too far to the right.

A superstrat design could balance well at a high playing angle if the Centre Of Mass is significantly shifted towards the bridge. Looking at the Ibanez RG, the COM would have to be at the bridge pickup for perfect balance at a 45 degrees playing angle.
This would require a headless design, but would probably also require more than that to shift the COM that far back.

One approximately 'superstrat' design concept i have seen that would balance well at a high playing angle is that of the Basslab STD Guitar. It is headless. It has a long top horn reaching to the 11th fret, but the horn also curves down towards the fretboard so that the strap button is close to the fretboard. See image below.


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## jco5055 (Jun 5, 2022)

ixlramp said:


> @jco5055 Yeah the superstrat horn strap button position makes it harder to create a design with good balance at a high playing angle, and also makes balance change a lot when changing playing angle.
> 
> The horn strap button does not absolutely have to be close to the fretboard, another way to improve balance at a high playing angle would be a very long top horn, but that might then shift the guitar too far to the right.
> 
> ...



Thank you! Any thoughts on how the EQ Accipter would work? It’s a unique shape I can’t say for sure….the button is of course on the upper horn as usual. I'm still struggling to figure it out with these more unique shapes. I assume the Tucci Shelly I included at the end would pretty easily be like other superstrats/RG, but just thought I'd ask also.


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## ixlramp (Jun 6, 2022)

@jco5055 this thread gives you all you need to judge balance.

Firstly use post 32 https://www.sevenstring.org/threads...ough-simple-visualisation.333311/post-4979060 to judge where the COM is.
Try to find a photo of someone balancing the guitar on a leg without using a strap, the approximate COM position will be vertically above the centre of the leg and on the guitar centreline.
If you cannot find such a photo, you can assume a typical balancing angle of 10-20 degrees and imagine a leg in the cutout.

Secondly, use post 21 https://www.sevenstring.org/threads...ough-simple-visualisation.333311/post-4961062 to judge balance.

The EQ has fairly conventional geometry but does have a long horn which will help a little.


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## dmlinger (Jun 6, 2022)

This is a strange thread.


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