Once the ability to reproduce all frequencies in each channel has been met (as described in the Bass Management section), the room must be calibrated. For each of the five main channels, pink noise is adjusted for 79 dB C-weighted slow. Many developers might find this level too loud, and may need to calibrate to a lower level.
The LFE channel is calibrated such that each 1/3 octave band between 20 and 80 Hz is 10 dB higher than the equivalent 1/3 octave bands for any of the full-range speakers, assuming that the full-range speaker is ideally flat. This level is read from a real-time analyzer (RTA), rather than a sound pressure level (SPL) meter.
If an RTA is not available, an SPL meter may be used to approximate the level. If an SPL meter is used with band-limited pink noise, then calibrate the subwoofer between 4 and 6 dB (C-weighted slow) higher than any of the full range speakers.
A properly calibrated room will result in mixes that will sound correct when played back in a consumer environment. An improperly tuned room will result in mixes that will sound fine in the mixing facility, but will be incorrect in other situations. Using the guidelines above will result in a properly tuned room.