So what can we do to avoid inflicting further musical misery on our own customers while they’re patiently sitting on hold? We could just go back to playing a ringing sound, or an intermittent beep just to let people know they’re still connected, but that would be awfully dull. The best compromise is relatively simple electronic music that doesn't have too much going on as the ideal choice for hold music as it requires far less refined sound quality to get a decent rendition down a telephone connection.
at two sites wherever you have a phone system for your business that places people on hold and you want to take the opportunity to sell to a captive audience.

For the average 4-minute on hold message, we recommend no more than 2 music tracks. Having too much variation in music can distract your audience. Longer programs can accommodate more music themes. To sample our music, please visit our production music library.
OnSIP’s enhanced music on hold allows each user to select their own hold music, so each caller gets different tunes depending on who put them on hold or which menu they came in through. (You can even change your hold music for the holidays or for a special event!) You can also record a customized hold message to engage your callers while they’re waiting on the line. This presents a great opportunity to advertise additional features of your business or inform your audience of a special sale or promotion.