It is easy to think that a string fixed, or held motionless at each end will vibrate at only one frequency. This is not true. There are standing wave patterns produced on the string that vibrates the soundboard.. that are composed of the sum of all the harmonics present.

When a string of a ukulele is plucked, vibrations, that is waves travel back and forth through the medium being reflected at each fixed end. Certain sized waves can survive on the medium. These certain sized waves will not cancel each other out as they reflect back upon themselves. These certain sized waves are called harmonics. They are standing waves and produce patterns which do not move.

On a meduim such as a ukulele string several harmonically related standing wave patterns are possible.

The first pattern has the longest wavelength and is called the fundamental or first harmonic.

The second pattern, or second harmonic, has half the wavelength and twice the frequency of the first harmonic. This second harmonic is also called the first overtone.

The third harmonic has one third the wavelength and three times the frequency when compared to the first harmonic.

The other harmonics follow the obvious pattern regarding wavelengths, and frequencies.

Depending upon how a ukulele string is plucked, different harmonics can be emphasized.

It is the fundamental frequency that determines the pitch of the note that we hear. It is the sum of the total harmonic structure that determinhes the timber of the sound. When a trumpet and clarinet play the same note... they sound differently. The fundamental frequency of the tone played is the same in both instruments, but the total harmonic envelope of each instrument colors the individual sounds to give the character of the instrument being played.

Which gets me around to saying the soprano, concert, tenor and baritone ukuleles all sound differently due to their size differences.

Also, the shape of the ukulele's body, the stiffness of the soundboard, the sound absorbing or reinforcing characterics of the materials used in the ukulele, the nature of the strings themselves, all have a key effect in determining how an instrument will sound.

Ukuleles with plastic bodies and backs sound differently that ukes made of wood. Although both are sopranos, Pineapple shaped soprano instruments have a more throaty sound than regular shaped soprano instruments due to the shape of the body.

The differing woods, wood thickness, internal bracing all have a profound effect on how the instrument will sound. Instruments with thick heavy soundboards are dull sounding and do not have the sharp "bark" of instruments with the very thin soundboards. Resonance of tone is very short with heavy soundboards.

Better instruments sound better because the manufacturers have very carefully selected materials that resonate long and work well together. In addition, wood type and thickness are carefully chosen so the instrument is strong so that it will "stay together", yet resonate freely. Wood species have an effect on the sound of the instrument. Koa, Mahogany, Spruce, etc all have different sound characterics.

Many vintage instruments sound much better today that they did 70 years ago when they were built. The internal stresses in the body of the instrument have relaxed so the instrument body can resonate easily. Even relative humidity can some effect the way your uke sounds.

In my opinion all new ukuleles sound better after they have been played a year. They then began to come up to full voice. (People seek old violins because they are at their full voice.)

Buy only high quality strings. Better strings are very uniform in diameter, very resiliant, very flexible and have more "life" and have a profound effect on how a ukulele can sound. Don't buy cheap "brand x" nylon strings where the polymer was made for bristles for scrub brushes.

Remember the old song "Little Brown Jug" that said... if I had a cow that gave such milk, I'd clothe her in the finest silk.... I'd feed her on the finest hay.... and milk her 40 times per day.

Soooo... When you find the ukulele that sounds great to you, keep it as your private treasure, give it the best case, give it the best strings, AND PLAY IT 40 TIMES PER DAY! Have fun!