Amazon.com: Akai Professional MPK249 | 49-Key USB MIDI Keyboard & Drum Pad Controller with LCD Screen (16 Pads / 8 Knobs / 8 Faders), VIP Software Download Included with 4-Port USB Hub
usb hub - Shouldn't my Belkin USB hub be able to power on a USB MIDI keyboard? - Super User
Add MIDI Port to Keyboard : 15 Steps (with Pictures) - Instructables
MPC MIDI Tutorial: Connecting MIDI Controllers to the MPC One/Live/X/Key
美しい さくら機電Nektar Impact LX25 25-Key USB MIDI Keyboard Controller Bundle With On Stage Sustain Pedal And Knox Gear 4-Port USB Hub (3 Items) スマホケース、カバー | sbc-a.jp
LAUNCHKEY25-MK3_K2 Novation Launchkey 25 MK3 25-Key MIDI Keyboard with Sustain Pedal and USB Hub
Novation FLkey 37 37-Key MIDI Keyboard Controller for FL Studio Bundle with FL Studio 20 Fruity Ed., Pedal and USB Hub | Reverb
How to connect multiple USB audio devices to an iPad/iPhone - YouTube