. . . must i need cables or speakers?

Speakers are optional.  If you want to play without headphones, you'll need them.  For headphones, you plug them into the Scarlett 2i2.

Cables are required.    As follows:

Cable from the keyboard to the computer.  If the keyboard has a USB jack, you'll need a "USB printer cable" (or USB-A to USB-B cable, same thing).

. . . The keyboard may come with its own cable.

If the keyboard just has 5-pin MIDI jacks, you'll need a MIDI-to-USB converter.  "M-Audio" makes some at reasonable prices, I think.  There are lots of others.

Cable from the computer to the Scarlett -- also "USB printer cable".

.    Charles

i recently turned to keyboard from acoustic pianos and would like to know if i lack any material to play correctly. here's the list of what i bought:

- sl-990 pro keyboard
- scarlet ts i2i audio interface
- m-audio sp2 pedal
(waiting for delivery)

- sennheiser hd 598 headphones
- iMac
(own them already)

must i need cables or speakers?

thanks in advance!

sjk