At an addition to basic watermarking, Promo.ly can provide an indestructible and inaudible watermarking. We've developed our own software that places an inaudible and indestructible watermark into the waveform of the audio. To the human ear it cannot be heard and will not affect the audio quality. If you are interested in this service please raise a support ticket and we will provide you with a quote. This service is labour-intensive and is provided on a individual basis.