The sound of my guitar has changed for the worse during the last year.
It is exactly 39 years old and in excellent condition. It was handmade, cedar top and cypress sides and back with French polish weighing just 1150 grams (2 1/2 lbs). I had some cosmetic work done to the top and some bracing repaired about 3 years ago. With new strings the sound was bright full and very "flamenco" although it seemed to "tire" after about an hour of playing but would sound good again the next day. Now the sound is "hollow" and "scratchy" A bit like the sound in Paco Pena's "Toques Flamencos" if you are familiar with that recording. Even with the same brand of stings that gave a great sound before, it is now unpleasant.
My other guitar which is 3 1/2 years old, spruce and cypress with pegs weighing 1420 grams is sounding better and better as time goes by just as the luthier who built it for me said it would. Rich, bright, full and sweet. In fact the luthier said it would take 10 years for that guitar to reach its peak whereas the Cedar top does not have a long breaking in period. Both guitars sit uncased on guitar stands .
Is there an easy fix to get a full sweeter sound back? A lacquer or varnish finish of some kind? Why would this happen? The only thing I know that I've changed is how I cut my nails. Does a guitar die of old age?
Ed

Unlike a violin, a guitar tends to go down hill if played regularly after many years. However an expert restorer can bring a guitar back to life sometimes better than it was original. The difference is guitars have bracing that can come loose and are more prone to crack, especially flamencos. I do not agree with the idea that in guitars the wood wears out from repeated vibrations from strumming, etc. as compared to the bowing vibrations in a violin. In my thinking it is a structural issue in guitar that can be repaired. I am interested in our forum guitar makers opinions on this.

Guitar-makers with years of experience repairing and restoring old guitars may be better qualified to comment on this than guitar players, although they could be biased by the fact that they are more apt to be asked to repair old guitars with problems than old guitars that are still in excellent physical and acoustic condition.

I don't think guitars necessarily deteriorate significantly with time. In fact, my experience has been the opposite. Though memories of sound qualities certainly fade over time, I have no doubt that guitars I purchased in the 60's and 70's sound significantly better now than during the first years after they were made.

Wood deterioration generally is due primarily to the enzymatic activities of microorganisms. The rates of enzymatic activities of microorganisms depend first on levels of exposure to the microorganisms and then following exposure, on temperature and humidity. However, physical stress also causes deterioration. Cracking is an extreme example, but even at stress levels below where cracking is obvious to a human observer, physical changes at a micro-level occur within wood following physical stress.

However, the "deterioration" of wood due to these causes is not necessarily detrimental to the sound quality or long-term physical stability of a guitar. In-fact, it may make a guitar sound better over time, as, for example, where an overly-stiff guitar top becomes more flexible. It also can cause a guitar to become more physically-stable over time, as, for example, where a guitar constructed from aged-wood (deteriorated-wood) changes less over time after construction than a guitar made of wood that has not been aged.

Of course, glues used in guitar making also tend to deteriorate over time and loose joints can adversely affect the both the sound qualities and structural-integrities of guitars. Fortunately, though, animal-hide glues generally are used in the construction of high-quality guitars and hide-glues have an important property known as "reversibility" that makes it possible to redissolve the glue after it has dried. That makes it possible to re-glue loose joints without first having to remove the old glue. Glue deterioration can be more serious in the case of cheaply constructed guitars glued-together with other adhesives that have to be scraped off, because that cannot be done without also removing part of the wood, which can result in loose-fitting joints.

I think time itself is the best indicator of future changes in a guitar. An old guitar that sounds good, is easy to play, and is structurally sound is more apt to still be that way ten years from now than is a new guitar with the same characteristics.

-Bob

Really good points, Bob. My 1970 Manuel Contreras blanca sounds even better now than when I bought it forty years ago, and that's saying something, considering that it sounded fantastic when I bought it. With respect to violins, the reason we are more likely to see a Stradivarius than say a Torres, is that the top, sides, and back of a violin are much thicker than those on a guitar, and so are prone to withstand the rigors of time and stress better than a guitar. Stradivarius also constructed guitars, and you don't see many of those around any more, though that might simply be due to the fact that he made far more violins than guitars.

Prominent Critic wrote:Stradivarius also constructed guitars, and you don't see many of those around any more, though that might simply be due to the fact that he made far more violins than guitars.

It might also be because they were not very good guitars. I have never seen or heard a Stradivarius guitar, but I read somewhere that despite the quality of his violins, his guitars were not actually very good. Violin and guitar construction is very different. It is wouldn't be surprising to learn that a maker was or is much better at making one than the other.

-Bob

None of the guitars from that era were very good by today's standards. Look at the size. The guitar has evolved drastically. The violin has not really evolved any since the days of Stradivarius and Guarnieri. Here is info on the strad guitar.

http://orgs.usd.edu/nmm/PluckedStrings/ ... uitar.html

Notice if you click on portions of the Stradivarius images to enlarge them that the tuning pegs had slots for the strings, instead of holes, and that the bridge didn't have a bone saddle. Also, notice how the strings were tied at the bridge.

-Bob

Hi Ed,

Did you ever replace the saddle bone?
It could be worn out after 40 years I immagine.....

Payul

No never replaced the saddle bone. How worn would it have to be to require changing? There is very slight notching under the base strings. I have read that different materials will produce different sounds so if I replace the saddle bone what should I look for that might help eliminate that scratchy hollow sound? Any idea?
I did have bracing work done about 3 years ago. I had been hearing a slight "buzz" on certain notes and the top just below the bridge had started to pull up after a life of full tension. Now the top is flat again. I can't say that I had noticed any deterioration in sound quality right after the repairs but I sure do now.
Ed

It seems to me that saddle bone wear wouldn't change anything enough to notice other than the amount of string space above the frets and resulting buzz if the clearance became too small. However, top bracing changes potentially could have profound affects on sound characteristics. Maybe you should have another luthier look at the repairs that were made.

-Bob