If an audio file is cropped it means a certain part of the audio clip has been selected and then removed. Different effects can also be added to the clip, (fade in, fade out, etc..). An echo can be added to the clip, just like an effect, making the sound repeat from the reflection of the sound waves. Reversing the audio clip is when the whole clip is played backwards. Changing the volume on the clip will either increase or decrease the loudness..
Lossy Compression; when an audio file some of the quality of the file is lost.. Sampling Depth/Resolution(bytes); when an audio file is sampled, the sampling depth is how many bits is needed to store the information.. Sampling Frequency(Hz, KHz); the amount of samples per second that is taken from the audio signal.. Sound Time(s); the length of time that the sample has been taken for.