This means that WAV files are larger, but retain more detail than MP3's, which trade audio resolution for much smaller file sizes. Your computer should automatically see the Zoom H4n as an audio input. The Zoom H4n Pro can be used as a fully portable recorder, saving audio recordings to an SD card, and running on two AA batteries. For details, see page 134 of the Operation Manual. The Zoom H4n is capable of recording in both Mp3 or WAV file formats. That’s great, but if you do have power available, you can also plug the H4n Pro into wall power via the Zoom AD-14 AC Power Supply Adapter which is not included but is only $20 on Amazon . Recording to a computer with the Zoom H4n Pro. The Zoom H4n Pro can also be used as an audio interface when connected to a Mac or PC. WAV is an uncompressed and loss-less file formal, while Mp3 is compressed and lossy. Yes. The Zoom H4n cannot record internally while being used in the USB interface mode. * However, please note that once an SD card has been used in the H4n, it can no longer be used in the H2/H4 models. Set the gain level on the right side as needed. Focusrite's second-generation Scarlett 2i2 is a portable audio interface designed specifically for use in a portable computer environment. The Zoom H4N Handheld Recorder brings high-quality, on-the-spot audio recording within easy reach with features like 90 and 120 degree selectable recording width stereo condenser mics, 24-bit/96-kHz audio quality for files that sound even better than CD, and an optional SD slot for an expansive memory. You may want to consider purchasing a basic, stand-alone audio interface. Recorded files and project data on SD cards created with the H2 or H4 can be used as is in the H4n. Toggle the correct mic input on the recorder to select using the onboard mics (MIC) or external mic/instrument inputs (1, 2). The device is class-compliant on Mac computers, meaning no additional driver software is required.