Bracing Overview of the Acoustic Guitar
My invention, the novel Indirect Bracing Structure (IBS) system, has revolutionized the acoustic guitar. The IBS System is a whole new real concept in tonal design for the acoustic guitar.
For the past 35 years while working on guitars in my stringed instrument repair business, I listened to many musicians expressing dissatisfaction about the tonal problems they have with their acoustic guitars. Most of the often animated discussions would focus around the same old issues and what could or could not be done to fix it.
Customers, who complained about their acoustic guitar, often had the following comments:
"The guitar has too many dead notes especially in the high range, towards the body end of the neck". A dead note, is a note that fades away very quickly when it is sounded. "The treble range sounds tinny but the bass seems somewhat booming"; while others would complain that, "the notes don't sound clean, they sound dirty or muddy", and some would use terms like "cloudy".
All of these negative terms used to describe the sound of the acoustic guitars that are available on the market currently, are valid. With understanding and consideration as to the source of these problems I have successfully resolved most of the issues. In the Tech Info section (of the menu bar) I have attempted to shed some light, on the complexities of the sound created by the acoustic guitar and what factors, influences theses tonal problems.
Another common frustration that customers have expressed surrounds the subject, of a well balanced string range. A well balanced string range is what you would normally hear from an electric guitar but not usually from an acoustic guitar. A well balanced string range implies that all the strings have near even volume levels, with equal values of sustain. The electric guitar with its solid wooden body and neck is able to support the string load tension, so, it has no sustain or string range balance problems. This is because the strings are held firmly and are thus able to vibrate for a long period of time, producing sustain. String range balance for an electric guitar, is simply adjusted by varying the magnetic field of the pickup poles closer or further away from the vibrating strings, to achieve even volume levels. Easy! But don't forget you will have to plug it in.
For the acoustic guitar however, the fact is that it is not probable to expect that you can achieve a well balanced string range from an industry standard x-braced acoustic guitar. Why? Because it does not directly support the string load tension, in any way what so ever. The arms of the x-brace end on the very thin sidewalls of the guitar body and poorly supports the soundboard. As strange as it may sound, the x-brace system is intentionally made not to support the string load tension.
The x-brace's principle function, is to stop the very thin soundboard from buckling under the force of the sting load tension. Not only is the string load tension not well supported by any structure of the x-brace - guitar, but also the soundboard is forced into a state of extreme tension. This tension in the soundboard can be seen as a pronounced rising up, of the soundboard behind the bridge and dipping down in front of the bridge.
Tone and Sustain
There are some very important reasons as to why the soundboard, should be left in an initial stress free state; so as to be able to vibrate uniformly, for one. Some of the problems and frustrations expressed by the musicians mentioned above relate directly, to this tension that is created in the soundboard by the x-brace system! Which interacts with the standing wave patterns of a vibrating string. Information on how a soundboard will vibrate in either, a stress-free state and or in a state of tension, may be found in the text of Fig 1, and or in Tech Info.
Past Attempts at Building a Direct String Load Support System. So why can't we just support the acoustic guitar like the electric guitar, to obtain an even well balanced string range? The answer to this question, has been a long standing dilemma among many inventors who have tried to do just that. Some, have attempted to extend the neck through the body, either ending at the tail-block-end of the body or ending at the bridge; to support the strings load tension. While others, have even tried to use adjustable threaded steel rods to pretension the soundboard, as a means to counteract the string load tension.
You see the dilemma, is once you directly support the string load tension, you also create a locked up loop of acoustic wave vibrations. These vibrations reflect back and forth within the direct supporting brace (the neck through the body ending at the bridge, etc). The result is a great loss in sound volume levels takes place, this occurs simply because there are fewer vibrations transmitting into the soundboard. Also the weaker you make the neck or brace through the body that supports the string load, in an attempt to vibrate the soundboard more strongly, the less time the strings will be able to vibrate for. Therefore, loosing sustain, the very thing we are after!
There you have it, a huge dilemma for any direct string load support structure. In conclusion, the train of thought has been along the lines of; in order to obtain a reasonable amount of sound volume levels, soundboards are only braced to prevent them from buckling up to much, against the string load tension. The x-braced soundboard has been a compromise!
For a general understanding of how my novel "INDIRECT BRACING STRUCTURE" IBS system works and is able to overcome all of the above, long time standing problems as discussed see Fig 1 and Fig 2. For those of you who are looking for a bit more technical information about my IBS System see Tech info found on the menu bar, where I also go over some well established theory on acoustics and vibrations, which includes:
Sine Waves -- are the Building Blocks of Tone;
String Vibration -- how Standing Waves form -- for an ideal Fixed Fixed String;
Tone -- a Complex Wave form, for a Fixed Oscillating String -- changes;
Projection of Sound Waves from the Sound Hole -- how it happens;
Tap Tone -- Selection of Soundboards -- what's it all about; and other relevant topics.
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.
Musicians' who play my acoustic guitars (unplugged) with the IBS system inside, make the same comments and remark: "sounds very clean and clear, crisp"; "has lots of sustain";"sounds pretty-much as loud around the twelfth fret as it does on the low end"; "there's something about it that sounds like an electric guitar"? (a well balanced string range); "sounds louder over here when you play it"? (The sound waves are actually propagating outwardly from the soundhole not defusing into a cloud of sound, around the person playing the guitar). "Great tone, warm and bright, has depth".
IBS System Acoustic guitar models available at the moment are: Suonavera and Belvoce, both of which are your regular large body type steel string acoustic guitars. Other models using the same IBS System but made from different timber species, are also available as listed on the MODELS menu page. A Classical nylon string guitar, presently in its final stages of development will also be shortly available, along with a small body steel stringed acoustic guitar.
FOR BUILDERS:
Full size detailed acoustic guitar plans with a comprehensive detailed book manual, are now available for private guitar builders, but strictly only for their own use. Professional Luthiers who may want to build and sell these acoustic guitars are also welcomed to purchase plans, providing a licensing contract is undertaken involving a small royalty fee. For larger Guitar Manufacturers who may be interested in my new IBS System, please feel free to contact me by e-mail here
IBS System Next-->
GOTO:
Levels (shows period of sustain:
IBS System vs X-brace).