FORMING A SUITABLE SOUNDBOARD BRACING SYSTEM
What immediately comes to mind is to use a brace in the area between the bridge and the neck, to form a ridged support system directly in line with the strings (shown in Fig 10 below as the wide orange line). This arrangement would largely stop the rocking motion of the bridge wavering back and forth in line with the string length direction of x and would also provide extra sustain. As an added benefit, the soundboard would also be alleviated from string load tension, allowing it to vibrate freely and therefore uniformly.
The list goes on; sustained string vibration would cause longer periods of reverberation, for air waves inside the body of the guitar, giving rise to a build up of resonance. More importantly, Nodal migration dx of the overtones is greatly reduced keeping the overtones closer to their natural frequency with their amplitudes maintained for a longer period of time, and therefore able to produce a rich full tone. The benefits' are seemingly numerous!
However, in order to make the soundboard vibrate, some of the string wave energy has to pass through the bridge saddle in to the soundboard. Should the bridge be held in a direct fashion, as said above practically all of the wave motion incident onto the bridge (seen as the blue line in Fig 10) will be reflected backward (seen as the red line in Fig 10). Why, well for one important reason the bridge as a boundary is set at 90⁰ perpendicular to the brace holding the strings. This backward reflection occurs naturally for any type of wave striking a boundary at 90⁰... the wave will just reflect back on its self.
If however, we were to move one end of the brace by an angle θa to a secondary reflection boundary (as shown in Fig 10), the string load tension could be supported indirectly. Placed at an angle θa the bridge supporting brace takes up the static string load tension and therefore, has to reflect the wave motion of the vibrating string(s); within the brace in the direction indicated by the arrowhead of angle θa. As a result acoustic pressure waves are now also travelling through the plane of the soundboard as indicated by angle θb, an opposite but identical angle of vibration takes place.
Consequently, the string load tension has now been put onto or loaded in two different places, at the bridge and at the new reflection area. At the new area, the Reflection Boundary is a well constructed solid mass, fixed to the supporting block work of the neck (as shown in grey Fig 10). Essentially the end of each brace attached to the reflection block work, is mass loaded by the 3 strings (~ 37kg) and is well supported, while the string load tension at the bridge area is now a controllable vibrating quantity by points (A), as discussed in Fig 1. IBS System. The string wave motions θi incident on to the bridge will now largely vibrate the bridge to move in the y direction , as an up and down motion (perpendicular to the soundboard), as indicated along the zero deg line in Fig 9. The bridge is also able to vibrate side to side in the z direction . With the bridge rocking motion in the x direction now largely removed, the seemingly numerous benefits previously mentioned, become a realization.
But a straight brace, set at any angle from any location nearby the outer strings to a secondary reflection area simply, just won't do!
While taking the above approach to solve our string boundary problems may be heard to work to some degree, it is only a basic idea that needs a lot of fine tuning, using some mathematical formulation and understanding of the parameters. Referring back to Fig 1. IBS System, it's seen that the angle that is taken is not just a simple straight brace set at any angle away from the string line. But instead is a block and brace involving two parts, with a dynamic response. The Trans Lobe numbered 5 in Fig 1, also contributes to combine the two sides Treble and Bass, with a calculated action. It also serves to transmit vibrations through the soundboard transmitting braces, and which are appropriately set at calculated angles. A fully detailed approach to the construction of a workable IBS System Soundboard, is clearly shown on the plan, and is explained in an easy to read format with lots of illustrations in the Book Manual, package. The performance of the IBS System Guitar is clearly illustrated in the Specifications link below.
SPECIFICATIONS: IBS System vs X-brace: dB graphs compare both systems over a period of time, to show Sound-Intensity-Levels.
Benefits or functions of this design are given in the text for Fig 1 and from all the above it should now be somewhat clearer as to how these functions can take place. However not all the functions have been covered and so the following explanations may be of interest.
What immediately comes to mind is to use a brace in the area between the bridge and the neck, to form a ridged support system directly in line with the strings (shown in Fig 10 below as the wide orange line). This arrangement would largely stop the rocking motion of the bridge wavering back and forth in line with the string length direction of x and would also provide extra sustain. As an added benefit, the soundboard would also be alleviated from string load tension, allowing it to vibrate freely and therefore uniformly.
The list goes on; sustained string vibration would cause longer periods of reverberation, for air waves inside the body of the guitar, giving rise to a build up of resonance. More importantly, Nodal migration dx of the overtones is greatly reduced keeping the overtones closer to their natural frequency with their amplitudes maintained for a longer period of time, and therefore able to produce a rich full tone. The benefits' are seemingly numerous!
However, in order to make the soundboard vibrate, some of the string wave energy has to pass through the bridge saddle in to the soundboard. Should the bridge be held in a direct fashion, as said above practically all of the wave motion incident onto the bridge (seen as the blue line in Fig 10) will be reflected backward (seen as the red line in Fig 10). Why, well for one important reason the bridge as a boundary is set at 90⁰ perpendicular to the brace holding the strings. This backward reflection occurs naturally for any type of wave striking a boundary at 90⁰... the wave will just reflect back on its self.If however, we were to move one end of the brace by an angle θa to a secondary reflection boundary (as shown in Fig 10), the string load tension could be supported indirectly. Placed at an angle θa the bridge supporting brace takes up the static string load tension and therefore, has to reflect the wave motion of the vibrating string(s); within the brace in the direction indicated by the arrowhead of angle θa. As a result acoustic pressure waves are now also travelling through the plane of the soundboard as indicated by angle θb, an opposite but identical angle of vibration takes place.
Consequently, the string load tension has now been put onto or loaded in two different places, at the bridge and at the new reflection area. At the new area, the Reflection Boundary is a well constructed solid mass, fixed to the supporting block work of the neck (as shown in grey Fig 10). Essentially the end of each brace attached to the reflection block work, is mass loaded by the 3 strings (~ 37kg) and is well supported, while the string load tension at the bridge area is now a controllable vibrating quantity by points (A), as discussed in Fig 1. IBS System. The string wave motions θi incident on to the bridge will now largely vibrate the bridge to move in the y direction , as an up and down motion (perpendicular to the soundboard), as indicated along the zero deg line in Fig 9. The bridge is also able to vibrate side to side in the z direction . With the bridge rocking motion in the x direction now largely removed, the seemingly numerous benefits previously mentioned, become a realization.
But a straight brace, set at any angle from any location nearby the outer strings to a secondary reflection area simply, just won't do!
While taking the above approach to solve our string boundary problems may be heard to work to some degree, it is only a basic idea that needs a lot of fine tuning, using some mathematical formulation and understanding of the parameters. Referring back to Fig 1. IBS System, it's seen that the angle that is taken is not just a simple straight brace set at any angle away from the string line. But instead is a block and brace involving two parts, with a dynamic response. The Trans Lobe numbered 5 in Fig 1, also contributes to combine the two sides Treble and Bass, with a calculated action. It also serves to transmit vibrations through the soundboard transmitting braces, and which are appropriately set at calculated angles. A fully detailed approach to the construction of a workable IBS System Soundboard, is clearly shown on the plan, and is explained in an easy to read format with lots of illustrations in the Book Manual, package. The performance of the IBS System Guitar is clearly illustrated in the Specifications link below.
SPECIFICATIONS: IBS System vs X-brace: dB graphs compare both systems over a period of time, to show Sound-Intensity-Levels.
Benefits or functions of this design are given in the text for Fig 1 and from all the above it should now be somewhat clearer as to how these functions can take place. However not all the functions have been covered and so the following explanations may be of interest.
- A well balanced string range, extending all the way up the neck.
- An appreciable reduction in sympathetic string vibration, due to the in-built buffing action.
- A 3 x simultaneous string note mixing action smoothes out and combines the overall sound, of the complex musical tone.