Acoustic Guitar

• Acoustic guitars don't need an amplifier.Jupiterimages/Brand X Pictures/Getty Images
  
  An acoustic guitar is designed first and foremost to sound good without an amplifier. The body, the top, the way the top is braced and the style of strings are put together in a way that resonates, vibrating the air inside the sound chamber, and driving tone and volume out through the sound hole. Many acoustic guitars come with pickups and preamplifiers built into them, because the guitar is a very quiet instrument, and usually requires some kind of volume boost.
  
  

Hollow Body Guitar

• Hollow body guitars feature prominnently in jazz because of the warm tones they produce.Thinkstock/Comstock/Getty Images
  
  The archtop or hollow body guitar, used heavily in jazz, was developed as an acoustic instrument before the pickup was invented. The greater internal area of the body provides more volume in an acoustic situation. The acoustic tone also has more of a sharp edge than a standard acoustic, and these two attributes make the archtop more audible in a purely acoustic setting. However, archtops almost always come with pickups built into them, and are more often thought of as electric rather than as acoustic guitars.
  
  

Semihollow Body Electrics

• Semihollow body electrics provide more volume than solid body electrics.Jupiterimages/Brand X Pictures/Getty Images
  
  The semihollow body electric guitar is not meant to be played unplugged at all. It will provide more volume than a solid body electric, but it is very quiet and its tone is very thin. An examples of this is the Gibson ES-335. The internal air space provides what some describe as a more "airy" tone. Other opinions are that it provides nothing to the tone at all.
  
  

Feedback

• The larger the sound box, the more likely the guitar is to have feedback, that nasty shrieking squeal that comes from electric guitars when a sound is caught by the pickup and fed out through the amplifier. According to the Musician's Friend, the solid center design of the semihollow body electric makes it much less prone to feedback.