Buying the right double bass is never easy. Basses vary drastically in quality even when the cost is the same. There are quality basses out there in every price range–the challenge is where to look. What characteristics should one look for in a bass? Private teachers and knowledgeable bass dealers are incredibly valuable in answering these questions.
There are three general categories of basses: laminated, hybrid, and carved. Laminated (plywood) basses are usually the cheapest. Plywood, as you might imagine, is not the ideal construction material for a resonant wooden instrument, so these basses tend to sound the worst. The wood of the instrument cannot vibrate as freely as that of a carved bass, so these basses tend to sound pinched, nasal and small. A bass made out of plywood will generally not develop a more mature tone as it gets older. There are exceptions, of course. Many Kay basses from 50-60 years ago do have a certain maturity to them. I have a Kay bass from the 1950s. It looks terrible but sounds great.
In many musical circumstances, however, a plywood bass is actually preferable over a carved bass. Rockabilly, bluegrass, and some (although not most) jazz musicians seek out plywood basses, especially older Kay basses. Having a plywood bass is also a good idea in an elementary or middle school, or for outside gigs and rough playing situations. 1/2 and 1/4 size basses are usually plywood, so people who start young almost always start on one of these. High schools are also usually stocked with plywood basses, although this is changing as the price of starter carved basses drops. Plywood basses tend to fall apart. On my Kay I have had problems with buzzing, warping of the bridge, rattling tuning mechanisms, a terrible fingerboard (that gives you slivers when you shift!), a cheap tailpiece that broke in half soon after I got it, and more. Still, it is nice to have that plywood bass when facing 95 degree humid summer playing gigs!
Unfortunately, cheap basses are just about as expensive to fix as quality basses. Bridges, fingerboards, tail guts, nuts, and tuning mechanisms all cost good money to repair or replace. I have often found that a student who buys a $1000 plywood bass has to put in another $1000 within the first year on such repairs or replacements. For the $2000 they end up spending they could have gotten a much better instrument in the first place.
Hybrid basses have a carved top and laminated sides and back. This gives the instrument more resonance. I will often suggest hybrid basses to my beginner and intermediate students. They usually have a much better sound than a plywood bass, especially for bowed playing. They are also priced somewhere between $1000-2500, which is reasonable for a starter bass. If you are going to spend less than $3000 on a bass a hybrid model should be seriously considered.
Fully carved basses range in price from a few thousand dollars to hundreds of thousands of dollars. Professional players (with the exception of a few styles of music) play on carved basses. These instruments will continue to mature as they get older and develop rich, complex sounds. If a student can afford a carved bass it is always a good idea to get one, since these basses will almost always produce superior results. Don’t think about a carved bass until a student is ready for a 3/4 size bass (usually around the end of middle school).
We also talk about buying a bass in great detail on the Contrabass Conversations podcast, particularly in some of our luthier interview episodes like those featuring Nick Lloyd and George Martin. You can learn a great deal about what to look for in a double bass bow in our interview with Sue Lipkins.