The following examples are merely suggested settings, but they can help you to get started if you are new to compression or need help finding a particular sound.

Vocal Limiting

Vocalists tend to be one of the most dynamic recording challenges in any studio or stage. Even though a singer may go from a whisper to a scream during the course of a song, it's the engineer's job to keep the vocal's level in line with the rest of the ensemble. You can do this by setting the compressor with a high ratio and a high threshold. This way, softer sections will go by uncompressed, and louder peaks will be kept under control.

• Threshold set so that the loudest sections get around -6 of reduction(usually around 3 o'clock)
• Ratio set for 6:1
• Knee set for Soft
• Peak/RMS set for RMS
  

Vocal Compression and Spoken Word

In other cases, you may want to compress the entire dynamic range of a vocal. This is typical of sung vocals and voiceovers for radio commercials. Whenever there is signal, there is some compression taking place; just barely on the soft passages, and up to 12 dB of reduction during loud passages.

Threshold set so that one REDUCTION LED (-1 dB) lights during the softest passages with signal (usually around 11 o'clock)

• Ratio set for 2:1
• Peak/RMS set to Peak
• Attack set to 0.1 ms (7 o'clock)
• Release set between 10 and 12 o'clock (100 ms.)
• Raise output to compensate for gain reduction

Touch sensitive triggered percussion samples

Engineers often compress percussion tracks just to get a nice punchy sound in the mix. The settings below sound good on a snare sample:

• Threshold set so that all hits are compressed (around -3dB)
• Ratio set for 4:1
• Knee set for Soft
• Peak/RMS set for Peak
• Attack set around 8 o'clock
• Release set around 9 o'clock
  

By turning the Threshold down even more, you can "squash" the sample as much as you want. Turn the attack up (longer) to get more attack out of the sample, and down for a synthetic slap effect.

Bass samples

Since bass samples form the foundation of most electronic music, it's important that the levels don't jump around in the mix. By all means zero all velocity sensitive expression parameters on either your sequencer or sound source, but by adding compression to bass tracks (or almost anything else) you can make them punchier.

• Threshold set so only the peaks are compressed (around 0dB)
• Ratio set for 4:1
• Knee set for Hard
• Peak/RMS set for Peak
• Attack set around 9 o'clock
• Release set around 10 o'clock

Occasionally when recording vocals, the letter "s" seems to jump out louder than the rest of the part. This is because sibilant letters, especially the letter s, have more high frequency energy than other letters. This can cause tape recorders or other components to distort, even though the level may not seem very loud. This "sibilance" can sometimes be eliminated by moving the microphone, but often a de-esser is required.

Many compressors allow you to perform de-essing on a track by using a sidechain. By placing an equalizer in the sidechain, you can set the compressor so that only certain frequency ranges trigger the unit to start compressing.

The trick is to set the EQ to cut all frequencies except for the sibilant range, between 3-6kHz. Then set the compressor like this:

• Threshold set around 0dB
• Ratio set for 6:1
• Knee set for Hard
• Peak/RMS set for Peak
• Attack set at minimum (0.1ms)
• Release set around 8 o'clock
  

The Threshold should be set so that an "s" triggers about -3 to -6 dB of compression. If other sounds are triggering the compressor, you might need to adjust the EQ cutoff frequencies.

Go here to get back to the Studio Help subject index.

electronicmusic.com/features/siu/studiohelp/about/compsettings.html