If you're having any difficulty with the setup of an external MIDI device with Studio One, check out the following guide and video:
PreSonus Knowledge Base: http://support.presonus.com/entries/21728493-how-do-i-set-up-my-midi-device-in-studio-one
Additionally, you'll want to examine section 4.4 of the latest Studio One 2 manual. You can access it from within Studio One by clicking Help -> Contents.
If your keyboard is the type that contains its own internal sounds, such as a workstation keyboard or synthesizer, you would need to connect its audio outputs to the audio inputs on your recording interface's line-level input and record audio files.
Additional MIDI Information.
To setup Midi sync so that the transport (Stop, Play, Record functions) engage another external device's sequencer you will need to setup your external midi sequencer as an external device and select the midi sync options.
Here are the steps:
* Go to the Studio One >> Options (Mac: "Preferences") >> External Devices page.
* Click the "Add" button to show the "Add Device" menu.
* Select "New Instrument" on the left hand list of items.
* Name your new instrument in the "Device Name" field. Name it the actual name of your device.
* Now set the "Send To" field to the midi port where your external midi instrument is connected. This could be the audio interface's midi port where you have connected midi cables or if your device connects via USB, it could have the actual name of the device.
* Set Midi channels to "All" so that each of the numbered boxes is lit blue.
* Here is where you set the way that Studio One will sync with your external midi device. Select "Send Midi Clock" as well as "Use Midi Clock Start". If you are familiar with midi syncing you may select Timecode if you choose, but only if you know that your device uses Timecode instead of Midi Clock. For most instances Midi Clock is sufficient.
* Click "Ok" to save your device and then click "Ok" to exit the "External Devices" menu.
* Now, on your external midi device, you must ensure the following:
** The device is setup for "external sync"
** The device is set to receive midi clock or midi timecode information
** You have turned "Local Off" mode on. This is important so that you don't hear your sounds triggered twice.
** If your device has a "Midi Thru" option make sure it is turned off. This will result in a midi loop sometimes which may crash the program.
After you have done these steps you will be able to engage play mode in Studio One and it should send a signal to start your external midi instruments sequencer.
You can now record into Studio One using this method and your tracks will stay in sync.