To emit a sound or noise means to produce it. Polly blinked and emitted a long, low whistle. to send out gas, heat, light, sound etc (emittere, from mittere )
To send forth; to throw or give out; to cause to issue; to give vent to; to eject; to discharge; as, fire emits heat and smoke; boiling water emits steam; the sun emits light
If something emits heat, light, gas, or a smell, it produces it and sends it out by means of a physical or chemical process. The new device emits a powerful circular column of light