The following is the audio signal of a sample obtained at a restaurant with less crowd. Prominent background noise sources include tapping feet (stationary), footsteps (moving around at intervals), distant (approximately around a 5 feet radius) chatter at low volumes, music from a player, and noise from the kitchen (around 30 feet from the point of recording).
The frequency analysis spectrum, obtained with the help of audacity:
The cepstrum for the above sample:
Below is the signal of a sample taken in the same location, a few minutes apart. This sample includes noise from a nearby (around 2-3 feet away) conversation, along with the rest of the above events occurring in addition:
The frequency spectrum:
Frequency cepstrum:
Judging by the audio signals alone, the two seem to differ visibly. The sample with the conversation has sharp, visible spikes in it that occur along the duration of the sample. The amplitude of the signals of the conversation are quite large compared to that of the rest of the signal. Factors such as the proximity of the source might have an effect over the signal as well.
