Here a guitar maker demos his negra and blanca guitars to show differences in sustain, etc.

Nice video, Sam. Correction, if I may. Brian Burns is based in Fort Bragg, California, not Portland, Oregon. The masking tape over the strings idea is interesting. Although, along with the sustain, it seems to take out a lot of color out of the guitar as well.

Thanks for correction Peter. I knew Brian was in California but for some reason was confusing him with Clarence Burnett. I agree on the tape and didn't think it gave an accurate idea what the old Spanish flamencos sounded like. Definitely affected the response and color as you pointed out.

A few years ago I bought a factory made (Yamaha) flamenco guitar that had that sound. No brightness and short sustain. I didn't like it and got rid of it after a few months and got a handmade Blanca from a respected luthier. Perhaps I would appreciate it more now if it was just one of several that I owned.
Peter, the word "color" you used is a good one. I think that describes one of the things missing from that guitar. I sometimes use the tape trick and it does sound OK when playing a siguiriya but overall I don't think a long sustain is a bad thing even in a flamenco guitar.

Ecwriter,

Sustain is an interesting animal in its own right. If you don't mind, I'll interject a few of my observations on this issue. From my perspective, the word sustain seems to be tossed about in a rather broad sense.

As a luthier, I've come to realize that there are many facets to sustain. Some guitars tend to sustain along the fundamental note, and do not break down into harmonics very readily. Such instruments can have a relatively long sustain. Yet, their sound is likely to be rather dry and unappealing (lacking harmonic content). In most cases, such instruments are rather over-built. The guitar box finds itself unable (or at least severely restricted) to amplify the strings' harmonic content. Think about a solid-body electric. Hit the strings, and they will keep on ringing (oscillating) for a long time. Significantly longer, in fact, than they would on most acoustic guitars. The quality of the ringing, however, is nothing to relish, until the guitar is hooked-up to an amp.

In the case of the acoustic guitars, the body of the guitar, along with its enclosed air, are the amp, and these amps are not all created equal. Some do a better job of emphasizing higher frequency harmonics. Others lean in the direction of a stronger bass response. To make an instrument balanced, and capable of reaching into the highs and the lows, is one of the balancing acts luthiers must contend with. In many good flamenco guitars I've come across, there is plenty of sustain. The quality of that sustain is a bit more diffused among the harmonic series than on many classicals. I believe the primary reason for this is due to a flamenco guitar's lighter structure, bridge, as well as the players' technique, driving the strings closer to the bridge.

Happy spring!

Peter,
I'm interested in pursuing your last point a bit. So, if we imagine the flamenco guitar and its note with its harmonics on either side in a chart, are you saying that you think that the tone will last pretty much the same as in a classical but that we will see a pattern of distribution of amplitudes across a larger number of harmonics? Does that mean that they will be at lower amplitudes than with the classical? And do you mean that we might see fewer harmonics with higher amplitudes in the classical?

In other words, is the classical characterized by a primary tone and a smaller number of "higher" amplitude harmonics through the sustain period, as compared to a primary tone and a greater number of harmonics ringing at lower comparative amplitudes, but for the same sustain period?

Byron

Byron,

I must preface these additional thoughts by saying first that I am not scientist trained in the field of acoustics, or even physics. For that reason, my observations may lack technical jargon and that "authoritative" feel. However, intuition and observation have always been strong assets in any scientific inquiry, and are the ones I frequently rely on in my work as a luthier. Now to your question.

Lighter-braced tops seem to sap the energy out of stings faster (or maybe I should say, diffuse the string energy). In fact, I've observed that lightly-built guitars can get away with significantly lower action, and yet not be too buzzy. Somehow the string oscillation can be affected by varying the degree of stiffness in the soundboard/neck. Lower amplitude harmonics, I believe, are more strongly reflected in a flamenco guitar (mid-range). Classical guitars seem to squeeze out a bit more from the very upper partials of the guitar, but not always. High partials are like the tweeters in speakers. Yes, they project reasonably well across distances, but sure aren't interesting to listen to without a decent mid-range and bass. In flamenco, especially, I feel that good, solid mid-range is critical. And, the lighter soundboard/bracing sustain those partials better. It does take more energy to "drive" those mids, thought. Hence, shorter string oscillation time, as the soundboard takes the energy out of the string to accelerate mid-range.

My observations.

Thanks, Peter, that's a good expansion on where I thought you were heading with your observation.

Byron