DEPTH

I've always assumed that the depth of a guitar contributed to both tone and projection. But the nylon string, thin-bodied X7 electric has me questioning that assumption.

Alistair was surprised when he first heard the 7 electric; I was astounded. The 7 is about 2" deep and yet has a very pronounced voice. It's not what I would call a thick, dark voice, not like the voicing of my Rainsong Parlor or my X20 acoustic--but very much there.

The 7E poses a variety of questions. In a recent thread on this forum a study was noted that suggested back and side materials had little effect on sound. Could that not be true with new materials?

Given the projection of the 7E, I've also been wondering if more bout width would enhance both volume and projection in a guitar with 2" of depth?

Your thoughts will be appreciated.

[kramster]

Originally Posted by EvanB

Your thoughts will be appreciated.

Good points...still thinking though

[Earl49]

Here you go making me think.... and on my day off. I work as an acoustical engineer. There are so many things going on here - size of the active vibrating part of the soundboard and its properties, body cavity dimensions and air resonances, bracing or lack thereof, sound hole location/size/ shape/orientation, etc, etc. One could get a PhD in the science of instrument vibration and musical acoustics, and still not understand the topic fully. I'm not sure there is a straightforward answer.

Although there is considerable science that could be applied, most of guitar design is - and has always been - purely trial and error. I am often asked what did they know about opera house and concert hall acoustics in the time of Mozart and Beethoven that we don't know now? Actually I personally know more about room design than anyone who was alive back then, and I am *not* a leading expert in that field. I've helped design some nice halls, but there have not been any textbooks written about my design approach.

IMO, the answer is rather simple: the rooms that worked and sounded good by pure dumb luck were kept and revered, and the ones that didn't were torn down or remodeled into something else. In the case of guitar design, until CF came along as a material there were also some serious limitations due to wood working.

[byudzai]

It's a shame we can't visualize sound. Like a 3D heatmap. Even then, it would look different for every frequency within a sound and would be nigh impossible to interpret.

[btbliatout]

I'm not ready to go and write the software, but it's entirely conceivable (at least to me) to write a program that could model a guitar and simulate what we're looking for.

I expect that inserting the correct parameters to get an accurate model would be the tricky part.

Get on it someone ;^). And build a free library of parameters we can all pull from. And keep it open source...and built for Linux.

Trial and error works, but is slow and wasteful. It would be nice to have all the variables under control and manageable, but that might be impossible. There are so many variables that even a butterfly can change the way the wind blows.

The 7Electric has moved me to thinking about some more trial and possible error. I'm wondering if the volume that comes out of big guitars is more caused by face size than depth.

Intuitively, I'm wondering if the back of a guitar should be viewed as a reflector and if increased depth should be viewed as contributing to dissipation and possible distortion of sound.

Years ago a Japanese guitar maker was having trouble with humidity in its instruments made with plywood sides and backs. The company started using a sealant on the interior of the guitars and projection was significantly enhanced. Maybe CF, a hard dense surface reflects better than wood. Maybe if the interior of CF guitars was finished to the same level as the surface projection would be further enhanced?

Lots of questions. Lots of room for trial and error.

As you might guess, I am really into this thread. Lutherie is in revolution and many of the old assumptions are going by the side.

My X7E has a short scale. that's not supposed to be good with a nylon strung guitar--supposedly not enough tension. However, high tech strings change the art and make short scales okay with nylon, even with a less daunting nut width, even with a very thin body. Remarkable stuff.

I just finished some play down in the park; two guitars, an Emerald Balor, a mandolin, a banjo, and my 7E with a small Roland amp. A professional player showed up and I gave her my 7 to play. She's a far better player than I, and loved the guitar: The weight, the balance, the intonation, the ease of play, and the quality of sound. A short scale, thin bodied guitar with a 1 7/8" nut. She was amazed. CF is leading us to a whole new way of thinking about guitar construction.

[zeeway]

Hmmmm. My experience in making guitars is tiny, but I offer this. I made a prototype travel guitar about a year ago, that sounded like a cheap ukelele, i.e., hardly any bass. I took the guitar apart and made new sides that increased the depth from 2.5 inches to 3.5 inches, and voila, more bass. My guess is that the conventional guitar wisdom goes out the window with CF guitars, and just maybe the influence of the soundboard front is much, much greater, as suggested earlier.