M-Audio has a large range of inexpensive keyboard MIDI controllers on the consumer market, and the O2 Keyboard Controller offers perhaps their best combination of features and quality.
First, a quick explanation of the features. The most attractive aspect of the M-Audio O2 Keyboard MIDI Controller is the USB port. A recent trend in MIDI controllers is developing the product to include a USB port, so the input from the keyboard controller can go directly into a computer. The O2 controller is both Mac and PC compatible, and is bundled with the next best feature: free audio software. Depending on where you purchase the controller, you receive either Ableton Live Lite 5 or Propellerhead Software Reason Adapted. Ableton Live is more geared for live performance, while Reason is designed exclusively for recording. Both programs have Mac and PC versions and both are highly regarded among musicians and producers for their quality. The M-Audio 02 Keyboard MIDI Controller features 25 velocity sensitive keys (meaning the volume is impacted by how hard you hit the key), pedal input, MIDI output, 8 programmable buttons, 8 programmable knobs, a volume slider, a modulation switch, a pitch changing switch, on/off switch, and an octave changing switch.
There are some drawbacks that become apparent rather quickly. For starters, the directions provided with the M-Audio O2 Keyboard MIDI Controller are very lacking and confusing, making programming those buttons and knobs very difficult. Also, while there is an external power adapter available for the keyboard controller, it does not come with the purchase itself. Power can only be supplied out of the package by connecting the controller to the USB port on your computer. This means that unless you spend more money for the adapter, you have to include a computer in your MIDI set-up. Additionally, there are only 25 keys, limiting what you can play at any given time.
There are some pretty strong advantages to the device as well. The small size makes for easy portability between studio, rehearsal space, performance space, and your home. Also, the latency (delayed reaction time) is almost unnoticeable, meaning if you run your M-Audio O2 Keyboard MIDI Controller through your computer as opposed to a hardware module, the sounds will be perfectly in time with everything else going on around you. Another great feature is the octave changing switch, which expands the full range of this little wonder by nine full octaves.
A quick note: this is not a keyboard. This is not a synthesizer. This is a keyboard MIDI controller. This means that the M-Audio O2 Keyboard MIDI Controller cannot produce sound on its own. You will need either a computer and software or an external hardware sound module to actually produce sounds with the controller.
The M-Audio O2 Keyboard MIDI Controller is a great entry level product for someone just beginning to experiment with MIDI and electronic music. While there are a few drawbacks, this controller is easily the best you will find for under $100.