A device for measuring the sound pressure level created by an audio source.

a good idea to get the levels perfect but you should be able to get it close by ear

a pre-requisit for balancing your setup levels

a Sound Pressure Level meter

Device used to measure sound loudness; often used to measure and balance the loudness of each speaker in a home theater system to "tune" a room.

ound ressure evel Meter Used to measure ambient sound levels: required for setting-up high quality echo cancellers.