A record of a [[well log|well-logging]] measurement of one or more specific characteristics of [[acoustic wave|acoustic waves]] propagated in and around the liquid-filled wellbore.

(1) The [[interval transit time]], usually of the [[compression wave|compressional wave]], is recorded on such logs as the [[sonic log,]] continuous velocity logs, and [[borehole compensated sonic log|borehole compensated sonic]] and Acoustilogs.

(2) The amplitude of part of the propagated acoustic wave, such as the compressional wave or [[shear wave]] is the measurement recorded on other well logs. These are the [[amplitude log]], [[cement bond log]], and [[fracture log|fracture logs]].

(3) The acoustic [[wave train]] of the propagated acoustic wave is displayed in the [[amplitude time|amplitude-time]] mode on full wave train logs such as [[signature log|signature logs]] or [[character log|character logs]]; whereas the wave train is shown in the [[intensity modulated time|intensity modulated-time]] mode on [[variable density log|variable density logs]], [[variable intensity|variable intensity logs]], 3-D Velocity Logs, or Micro-Seismogram Logs.

(4) Includes logs resulting from the measurements of [[travel time]] and amplitude of reflected [[acoustic]] energy. Tools making such measurements are the [[borehole televiewer]] and [[sonar caliper]].

(5) Also includes logs produced by devices which detect and measure the amplitude of sound waves in the audible frequency range. Audible sound might emanate from liquid or gas movements in the wellbore environment. Tools developed to make such measurements are used in audio or [[noise logging]] techniques.