You can hear low frequency sounds with a CI, but they're different. First off, they're higher pitched than you would expect, due to the fact that a good portion of what we perceive as low frequency sound is due to the basilar membrane itself resonating (up to 1000 Hz, which allows sound perception up to about 300 Hz). CIs don't fake sound in that manner -- they only simulate tonotopic neural firing. That's a major reason bass doesn't sound right with CIs, as the fundamental frequency of many sound waves are only partially encoded via tonotopic mapping and missing the base note makes it much harder for the brain to pull everything together. Another reason is just that the tonotopic firing region only extends as far as the implant electrodes themselves -- which isn't the whole length of the cochlea. AB implants only go about one and half turns into the cochlea, or 60% of the way in. MedEl has some longer implants so they should simulate deeper frequencies of the cochlea but there is less resolution as there are less electrodes and they are further apart. Everything in the CI world is a trade off.
But really, ecp, as hard as "music" is for CI recipients to enjoy, singing is something else. The less complex something is, the easier it is to enjoy with a CI and I'm happy to tell you that even when rock music sounded like mush to me, singing was very clear. I can enjoy much more complex music now than I could a year ago and singing has always been great, it's mostly instruments that were lacking in definition. This makes sense since CIs are tuned pretty specifically to encode vocal ranges.
