[tjkurita]

From what I understand, old acoustic guitars built out of solid wood sound better than new acoustic guitars because wood is an organic material that forms over time. The sap in the wood crystalizes and becomes stiffer, which gives the guitar a more powerful, articulate sound. At the same time, continued playing loosens up the guitar, making it more responsive to a lighter touch. Also, the glue used to put the guitar together solidifies and makes the guitar resonate better. Even the finish hardening over time can have a positive effect on the tone. Older guitars also have fewer "wolf notes." These are notes that resonate in the body cavity and can cause strange, dead tone. For example, I have had a couple of OM size guitars that resonate at the "G" frequency. And up and down the fingerboard, a number of the "Gs" were either dead, too boosted or otherwise out of balance from the rest of the notes. They were both Collings guitars costing more than $3K. Needless to say I got rid of them and got a 15 year old Steve Andersen OM that does not have any wolf notes because it used to be owned by Scott Nygaard, who played it and broke it in like crazy. I have owned guitars of various ages. From weeks off the line to 50 years old. The older guitars have a very distinct "dry" sound that is more powerful, but also more sensitive and subtle. That is, it sounds better played soft and it can be pushed further before it the tone gets muddy. Bass gets tighter, highs get sweeter, similar to headphone burn-in but much more noticeable.

I don't know anything about the effects of age on electrics. If you used the exact same pickups, cables and amps, I'm not sure you could tell the difference between a 1980 Les Paul and a 2007 Les Paul. But I'm not sure.

But you sure as hell can tell the difference between a solid wood acoustic that has been played for 27 years and one that just came off the line.