A resonator guitar is an electric guitar that produces sound via the steel bridge to a single or several spinning metal cones rather than directly to the guitar's soundboard. The bridge allows the sound to resonate around it and travel to the rest of the strings, and the metal cone allows the vibration to resonate around it. This process is called resonance and can be heard in jazz, blues, classical music, reggae, folk, and even new-age music. In a nutshell, a resonator is a tool used to vary the pitch and quality of sound from one string to another. The bridge is what connects the tuning head and the body of the guitar.
As mentioned above, some people choose to build their own resonator guitars. They can be bought from your local music store or online. But if you're not the type who likes working with your hands, then you can buy an already made resonator. Acoustic steel string resonators are available from online retailers and online music stores. However, you should first make sure that the model you choose is compatible with your acoustic guitar's specifications.
When it comes to making your own resonator guitars, you have a couple of different options. The most common method involves the shaping of a hollowed piece of wood into a frame. Another method involves attaching nylon strings to wooden spindles and tuning pegs using a tuning fork. There's really nothing special about the resonators you'll find at any music store - they're basically a variation on the basic strumming guitar.
The main difference between pre-made and resonator guitars is the size and shape of the cones. Acoustic guitars with larger cones are typically made for much larger ensembles and, therefore, more suitable for playing in band situations. The larger cones are also more efficient at producing sound, so they produce a more powerful tone. Pre-made instruments may also feature diaphragm-shaped cones instead of flat ones. If you're playing live, you'll need a larger diaphragm to produce a deep bass note, and the same goes for tingling.
Resonator guitars have always been used as accompaniment instruments in classic rock and blues songs, country and western music, even jazz. Since the late 70s, however, they've become increasingly popular as solo instruments in their own right and many other genres. One of the most popular types of resonator guitars is the bluegrass blues guitar. It's a very simple guitar, very much like a classical acoustic guitar, but it features a wooden body (bluegrass being a darkish shade of mahogany). Most acoustic blues guitars are also fitted with a thin steel neck.
There are many versions of bluegrass or blues resonator guitars, each featuring its own distinctive sound. Some have only a shallow truss-thru and a shallow humbucker at the bridge, while others have elaborate truss-thru designs and humbucker pickups behind the neck. Many guitarists who play both the blues and the acoustic blues prefer to use a resonator with a deep bass tone.
Another popular model for a resonator acoustic guitar is the tremolo. It can be very striking! On a resonator, the instrument's neck is curved, so there's more room for the strings to vibrate. When the strings are struck, these vibrations travel through the tremolo to the instrument's body, creating a vibrato effect. Some resonators, called "twangy" tremolo instruments, have a vibrato wound into the metal of the instrument's frame. They have a flatter tone than the regular rocking tremolo.
The final type of resonator I'll mention is the doped resonator. These are the ones that sound as if you're talking to someone who is sitting directly in front of you. The cones are very thin - about one-eighth of an inch - and the sound they make is similar to a diaphragm producing a wind call. The doped model of resonator guitars is usually equipped with three to five miniature aluminum cones rather than the usual one to two inches. It produces a much more detailed sound than the ducked model.