The Seaboard RISE 2 is an MPE-ready MIDI controller. It does not generate any sound by itself and will need to be connected to a computer running a software instrument - such as Equator2 - or via USB/MIDI DIN to an external sound source, such as an analog synthesiser or sound module.
Getting started with the RISE 2 is explained in this video, and below it you can find some common misconceptions about the RISE 2.
"I've connected headphones to the RISE 2 and all I hear is a buzzing sound"
It sounds like some headphones have been plugged into the MIDI OUT port. This is not an audio output, it is only intended for attaching to an external synth or keyboard using the included MIDI dongle.
The port is a 3.5mm jack which is the same as the headphone jack on computers and phones, so this could be mistaken for an audio jack. As mentioned above, the Seaboard does not produce sound and this port will output raw MIDI data (note the 'MIDI OUT' label below the port) which would only produce a distorted static sound.
"I'm not getting any sound from ROLI Dashboard"
ROLI Dashboard does not produce any sound - it is an app for configuring MIDI settings and touch sensitivity on the RISE 2. You can use a software instrument such as Equator2 or ROLI Studio Player to play music with your RISE 2.
"I opened Equator2/ROLI Studio Player and I'm getting no sound"
Ensure that in the Audio & MIDI Settings, 'Seaboard RISE 2' is selected as the MIDI input and your desired speakers/headphones/interface is selected in the Audio Output section.
"Some notes are not coming out when I play them"
This is usually due to the RISE being in the wrong MIDI mode. When the RISE is in MPE mode, it sends data down all 16 MIDI channels. If the plugin is mono-timbral (uses one MIDI channel), a lot of notes will be lost to the ether as the plugin isn't listening to them!
If using an MPE-ready plugin like Equator2, make sure the RISE 2 is in MPE mode. If using a non-MPE plugin, use Single-Channel mode. More information on multi-timbral and mono-timbral MIDI can be found here.