Classical guitar music is typically played on guitars specially built for the purpose. Classical guitars have smaller bodies than steel-string acoustic (and steel-string electric) guitars; they have shorter1 and wider2 necks; and they use nylon strings instead of steel strings (see Wikipedia for a description of guitar construction). The changes in the neck make fingering somewhat easier (the strings are farther apart, meaning that while the fingers must stretch farther, it's less likely that a finger will accidentally hit multiple strings), and the nylon strings change both the sound (it's mellower) and the pain coefficient (the strings are much easier to hold down without causing pain)3.
So, buying a classical guitar has been on my to-do list since last summer. Regular readers may recall my joyful experience buying my first guitar online. To summarize, I ended up having to return two different guitars, and even the guitar I eventually kept had been slightly damaged. It wasn't a pleasant experience, and it drove home the point that online music stores don't seem to quality-check their merchandise before selling it (or, at least, the two stores I purchased from didn't). Additionally, finding comparable sound samples of guitars online is nearly impossible, making comparison shopping difficult. Given that when I started shopping I was considering spending at least $500 on a classical guitar, I didn't want to take the risk of buying it online.
Shopping advice I found for buying a classical guitar can be summed up as: "Check the guitar for mechanical flaws (buzzing strings, odd noises when playing, cracks, etc.), play a few guitars, and then buy whichever guitar sounds the best to you." Oh, and "bring an experienced player with you if you're a novice." Unfortunately, I didn't have any experienced players who were willing to go shopping with me, and the advice to "buy whichever guitar sounds best" meant very little to me at first, as I had no clue what to listen for. So, that advice wasn't terribly helpful.
To make a long story short, my SO and I made about a dozen trips to different guitar stores over the past six months, and at each store I played as many classical guitars as I could (often about 5-10 different models at each store, until I started narrowing the field). Playing (and more importantly, listening to) all of these different guitars was excellent experience: by the end of the six months my SO and I had both developed better ears, and we felt confident distinguishing different guitars in my price range.
Over this time we figured out a few things that might help someone else shopping for a new guitar:
- If you're not great at tuning by ear, bring an electronic tuner and use it to tune every guitar you play. Even at specialty stores, we found that most of the guitars were out of tune4, and even the best guitars sounded awful out of tune. I felt a bit embarrassed about bringing a tuner at first, but it was well worth it.
- If possible, find specialty guitar stores in your area. We went to one of the chain retailers, and were disappointed by the quality of their classical guitars (the guitars tended to be horribly out of tune, some had very old/damaged strings on them, and a surprisingly high fraction had mechanical problems, something we didn't find nearly as often at specialty stores). The specialty stores also tended to have a better ambiance (they were quieter and calmer, which is important when the entire point of the excursion is to listen to the guitar you're playing).
- Play as wide a range of guitars as you can. Even though I knew I couldn't afford the $4,000 guitars, I still played them, and it was by comparing the sound of $4,000 guitars to $200 guitars that my SO and I started learning what to listen for.
- Bring someone with you who can listen to the guitars as you play, even if that person isn't an experienced guitar player. Even though both my SO and I were novice listeners (and my SO doesn't play the guitar), we found it educational to be able to discuss the sound of the guitars (as together we heard more than either one of us individually).
1 The neck of my new classical guitar is 32.5cm long (from the nut to the joint with the body), while my steel-string's neck is 35.5cm long. On a classical guitar the neck joins the body at the twelfth fret, while on my steel-string acoustic the neck joins the body at the fourteenth fret.
2 The width of the neck at the first fret on my new classical guitar is 53mm, while my steel-string acoustic is 44mm wide at the same point.
3 Acoustic steel strings are like little razor blades: they require a lot of force to push down at the frets, and they're so thin that they jab into your fingertips as you do that. When I first started playing on my steel-string acoustic, I couldn't play for more than 15 minutes a day before my fingers started killing me; after a few weeks I built up calluses, but even so it's still mildly painful to play for more than a few hours a day. Nylon strings make fretting much easier - they're thicker and they're plastic, so they don't cut into the fingers nearly as much.
4 While many guitars were just awfully out of tune (and even a simple relative-tuning check would discover the problem), some guitars were relatively in tune (i.e. the strings were in tune relative to each other) but were way off from standard tuning (e.g., the B string was actually playing B-flat). Thus, just checking the guitar by ear to determine if it's relatively in tune wouldn't be sufficient to compare all the guitars on an even footing.