AIM Dental Marketing® provides a complete turn-key package that works seamlessly with your existing phone system. Simply review our extensive library of dental on hold messages, then select up to 6 messages, adding any practice-specific information you would like. Our professional script writers review your input, and further customize the messages to your specifications. Once you approve your final message, our studio engineers create a customized recording for your exclusive use. We upload your approved audio file for easy download to your telephone system.
For those still using analogue or digital phone systems, voice on ISDN circuits has a bandwidth of around 4000Hz. The audio from an analogue phone is sampled at 8000Hz, and because of the nyquist theorem, must be low-pass filtered to 4000Hz. So any frequencies in the audio beyond 4000Hz are lost. Interestingly, the human ear and mind are good at recognising human speech, so this is considered "toll-quality" voice, i.e. good enough to pay for. This is the reason why certain vocalised letters are difficult or impossible to tell apart on the phone. For example, the differences between B, P, T, C, etc. are almost entirely above 4000Hz.

Website: https://blog.accentonit.com/how-to-professional-on-hold-recording-business-phone-system
Probably a lot less than you think! There are variety of affordable on hold message plans & pricing, and typically a small monthly fee starting at around $59 can be all it takes to get a professional sound for your brand, enhance the caller on hold experience and drive revenues.