What to use for music video playback?
 

What are the best ways to playback music when shooting a music video?

It depends on whether your cameras and editing system can utilize external timecode.
If the answer is no, then the easiest way is to use a CD player with skip protection and a large amp or capable powered PA speakers. You've got to have it loud enough for the drummer and everyone else to hear it over the live drums. Everyone else on instruments can fake it. Singers should really sing.
You can segment the song into sections (with overlap or clicks) ahead of time and have these as tracks on your playback CD.
If the timecode answer is yes, then you must use a device that can generate and output timecode while playing back the song.

Jay: No external timecode. I'll use the other method you suggested. Thanks a lot for the help.

You're welcome. I forgot to mention that if it's a portable CD player, it should be one that has a line-level output in addition to the headphone out they all have. This line-level out is the correct match for a mixer or amp input. They seem to be harder and harder to find on portable CD players lately.
If you're working indoors this situation can be very loud, especially for the hours that it can take to get all the coverage that's needed. I wear Hearos earplugs. If you don't want to look uncool, you can find a pair of closed-back headphones and pretend you're monitoring something. This by itself gives some reduction in sound volume.
If you have a sub-woofer you can get the beat without having to have the entire song at full volume.
As always, record camera audio for sync later. Using the on-camera mics is usually easiest since there will be lots of camera movement. Sometimes this requires setting the MicAtt switch to prevent overloading so you can still cleanly distinguish the lyrics.

CD playback problems
 

I did a music video recently using this method and in post we found that there was drift between the player and the camera.
Now it could have been the cheap portable, the camera was a DVX100, not a likely candidate.
I thought hard about this and wondered if on the next project whether a system whereby the CD player output was fed to the camera and the PA would overcome the problem, but maybe not.
The sync problem was a real pain and we never really cracked it.
Any thoughts??
Rob Dunford
UK

Do you mean sync instead of drift? The DVX has a known sync error between sound and picture due to the processing time for video. Did the error get larger over time or was it a constant error between sound and video during each take?
There are lots of places in post where a drift error can occur, but drift can't really occur between the camera and playback, only between the recorded footage and the music track within your editor. Sync errors can occur live, like with the DVX, or if you're shooting at a great distance.
How long were your takes, were you doing the entire song in one run?
How did you put the polished music track into your editor?
Did you shoot and edit in 24p? All audio settings matched during all phases of production?
How did you record live audio into the camera when shooting?

Depending on your NLE, you can also run into a tiny lil' problem of sample rate.
If you shoot the vid while monitoring playback from the CD player, obviously everything is in sync. Then when you import those clips to the timeline, everything from the tape is still in sync.
But, when you rip the CD to use for your master audio, you lose sync.

This is because CD's are sampled at 44.1, and DV is sampled at 48K. Over a few seconds, the drift becomes painfully obvious. Vegas and a couple other NLE's resample to 48 on the fly, making this a moot issue, but if your NLE doesn't....you'll need to use a resampling application before importing the CD to the timeline.