Professional DJs need to preview and cue tracks to make a mix flow. MegaSeg supports multiple audio outputs to do just that. Below are solutions for adding a second output to your Mac.

The Griffin iMic is an audio device with both input and output jacks. (No, it's not a funky microphone, just a USB sound in/out device). The 1/8th inch mini-jacks include a line-level output, and a mic or line-level input. The iMic will power headphones louder than your Mac's built-in output. At around $40, it's an excellent and inexpensive solution.

Roland/Edirol has some great USB and FireWire based solutions, for example the Edirol UA-1EX, with high-quality stereo RCA outputs, digital (S/PDIF) Optical outputs, and a stereo Mini-jack out with volume control for headphones! (List $95).

The ION ICJ01 is a Computer DJ Kit with a Mixer that connects via two USB plugs to give you two discrete outputs for MegaSeg. It includes everything you need to start mixing. A two-channel mixer with direct USB connect to Mac, optional line and phono inputs to connect turntables or CD players, and includes microphone, headphones, and powered speakers. (List $99)

Numark has various mixers with built-in USB audio, including the DXM01USB (List $349), and less expensive DM950USB (List $99). Simply connect them to your Mac via USB, and you have two outputs direct from MegaSeg to the mixer.

The Presonus FIREBOX is a 24-bit FireWire based output device, and one of the most professional-quality mobile interface in it's class delivering higher-quality analog to digital converters (Dynamic Range 110dB), with rugged build quality and metal chassis. (List $299)

The Rane MP 4 is a two-bus mixer with two stereo Line/Phono inputs, two stereo USB digital audio inputs and one stereo digital audio output to USB. A-bus, B-bus, Master Mix or Microphone may be assigned to the USB record channel. Ground isolation is provided between the mixer and the PC, removing a major obstacle to good quality PC sound. The MP 4 supports bit depths up to 24-bit and sample rates up to 48 kHz. (List $799)

M-Audio has an assortment of USB, FireWire, and PCI based audio devices available that are professional and reasonably priced. For example the Transit USB, FireWire Audiophile, Fast Track USB, and FireWire Solo.

The VXPocket v2 and 440 from DigiGram are high-end solutions that offer professional balanced XLR audio connectors. The 440 model has two independent outputs. The VXPocket series is a PCMCIA card that fits in the card slot of Apple's PowerBook line (the VXPocket will not work with iBooks). At around $599, the VXPocket is an excellent top of the line solution.