Input Monitoring using Meters
We've all been told that the key to great digital recordings (or analog for that matter) is getting the hottest signal possible to the hard drive (or tape) without clipping. Since virtually everyone is using some form of outboard gear (preamps, compressors, etc.) with an input meter on it, there are often numerous meters displaying very different results.
So if your preamp has a meter and your DAW has a meter, which one should you look at as a reference? Well, theoretically, you should keep an eye on both meters, but pay extra attention to the outboard gear meters. Pushing the preamp or compressor too hard will evidence itself on the meter on that piece of gear, but may still look fine on the input meter of the DAW. Pushing a preamp or compressor too hard can cause the recording to be distorted or over-compressed, or both, but the input meter of the DAW will still be bouncing happily at -3dB. The pitfall of not accurately monitoring the outboard gear's monitors is that distorted vocals or squashed tracks can't be undone. With gear that has multiple monitoring modes, like a compressor that can switch between Gain Reduction and Output, it's a good idea to keep an eye on both functions to get the truest picture of what's going to the input of your DAW.