In one embodiment, an improved-customizability digital sound relaxation system having a sound card receiving port and a collectable sound card are cooperative to play prerecorded natural or other sounds by depressing one of a plurality of sound selector switches and a sound card selector switch. The system includes a first receiver section for receiving the signal, which has a desired signal component and an interference component. This allocation also may be performed using an apparatus having a processing unit coupled with a memory, and instructions that are storable in the memory and executable by the processing unit. This design increases utilization of electronics and minimizes the effect of spindle startstop time. Thus, assembling operability is better as compared to a case where these three are prepared separate.