Hello
Paul - yes, 16 GB of storage is quite limiting on an iPad these days. First, tell us what types of music you own and want to listen to on your iPad and where the music is currently stored, e.g. iTunes purchases, Amazon music, ripped CDs, etc? Second, have you looked at
Apple's iCloud Options where you can stream music using
iTunes Match and/or
Apple Music - can cost and requires a Wi-Fi network. Third, have you explored other streaming choices, e.g. on my iPad Air 2, I have the following apps,
Spotify, Pandora, & Amazon Music; the latter allows me to stream any of my purchases made on Amazon over the years (thus, the first question above).
NOW, if you do not always have a Wi-Fi network available to you, then there are many wireless devices that can stream music over their own created wireless network. Let me describe two that I own, but there are other more recent devices (just do some googling on Amazon). I own the
AirStash &
RavPower File Hub - both are shown below - storage is provided by removable SD cards (and LARGE capacities can be used); both establish their own 'private' wireless networks that the iPad can join using its Wi-Fi settings - also, both have their own iOS apps that allows you to play the music files on the storage card.
The next two images show my
AirStash connected to my iPad and playing a Diana Krall song; the last three images (after I put the same SD card in the other device) shows the
RavPower Hub w/ the same song playing. Again since I've purchased these two devices, other brands & models have emerged, so do some research if you want to go this route. Dave

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