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Recording and Mixing Tips (stereo, non-acoustic material)
Give us the earliest generation of your 24 bit stereo mix.
Every time you process digital material, you lose some clarity and image quality. It's even worse if you process your audio without adding dither at each step. Here's why: digital audio levels are described in discrete steps, and when you process digital audio, it doesn't always go back into those same discrete steps. Even when you do add dither at each processing step, processing can still cause problems. "Processing" means equalizing, compressing, limiting, changing gain, converting the sample rate, etc.
Keep it stereo.
Most of us have two eyes and two ears, and use two or more speakers... so build a solid and full stereo soundstage. While mixing, fold down to mono often to check for problems (this is a very efficient way to discover mixing mistakes). Try putting melody instruments across from each other to fill the room. Experiment. If you can create a big stereo sound stage that folds down to mono gracefully, then you're on the right
track path! Acoustic music is another topic entirely.
Careful with reverb.
Generally, the more instruments and the more rhythmic the music, the less you will want reverb in your mix. Reverb has a tendency to smear the attack of notes and percussion, and thus smear the rhythmic elements. Reverb is more effective on a cappella and minimalist arrangements. There are some really cheesy reverbs — they might work for a trashy guitar sound, but they should be avoided for mixes. Because mastering will raise the details in your mix, always use reverb sparingly.
If you want it loud, work at it.
Human hearing is most sensitive between 1,000 and 5,000 Hz, an area essential for understanding speech. This also happens to be an area where melody instruments predominate. Instruments which are outside this range will become less noticeable more rapidly as playback levels are reduced. As frequencies drop, we sense them increasingly with our bodies, especially our chest cavities. For this reason, maintain consistent and reasonable playback levels during mixing (Radio Shack sells an SPL meter for less than 50USD).
In addition, the ear-brain connection response is much faster at higher frequencies than lower frequencies. It's about 0.5 milliseconds at higher frequencies, compared with 20 milliseconds at lower frequencies. If you want your bass instrument to be more prominent, then 1) bass person needs to play with less sustain (i.e., drier), 2) bass person needs to use strings that bring out the overtones in the upper registers, and 3) bass person needs to play with more verve and attack. Mud goes nowhere in the stereo mix, and no one can fix it later. Keyboard bass is a possible workaround. Sometimes the sound of the bass instrument and the kick drum can be optimized by retarding the attack time on a compressor to preserve the leading edge of the envelope, so you can experiment some in making the stereo mix.
We also discriminate spatially - both left and right and up and down. Use reaction time, frequency response, and spatial cognition - to paint an effective picture with your music. If you want to exploit the ear-brain connection to the max, play your music and build your stereo mix with lots of transients and short-term dynamics, and put each instrument in its own place spectrally. In other words, for an instrument's loudness to be really pronounced, you should have short intervals/passages of relative quiet from that instrument, and to a certain extent, from other instruments close to its tone. The shape of a note's envelope (or attack) should be dramatic and strong. Compressors and limiters with fast attacks are not your friend here.
Usually you can't make an instrument punchy and loud if it wasn't played that way in the first place. Acoustic guitars and concert pianos sound awful when pushed with compression/limiting to get that "loud sound". Most people know what an acoustic guitar and real piano should sound like, and you can't make up for tentative playing later by smashing it with compression or limiting during mixing.
Avoid overloads, whether recording or mixing.
If you don't have accurate digital metering, just reduce the displayed levels at least 5dB below digital full scale on whatever meter you are using. Clipping (overloads) can occur anywhere in the recording or mixing chain, and a good engineer avoids this. Even momentary clipping can cause permanent damage to your music; ironically, clipping can be far more obnoxious when broadcast later on radio or television. Learn more about radio processing.