Dynaudio pmn - Manual (Page 31)

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CALIBRATING THE SUBWOOFER -
with the main monitors
LFE Gain
Range: 0 to +14dB
The LFE channel can be boosted up to 18dB using this
parameter.
Polarity
Range: 0 or 180º
If the Subwoofer is correctly placed, setting the Polarity
parameter at 180º should result in a full Phase cancellation
at the set Cross -over frequency. If this is not the case - the
Phase parameter described below should be adjusted.
Phase
Range: 0 to 180º
Phase Introduction
The integration of the AIR Base subwoofer with the AIR
monitors requires on-location tuning. Apart from level
calibration and choosing a Bass Management Crossover
(X-over) frequency, the issue of phase alignment remains.
For this purpose, the AIR Base has a 0-180 degree phase
adjustment (in 5 degree steps) and a Phase Reverse
function. The optimum setting of these will depend on
several factors:
1. Room acoustics
2. Placement of monitors and listening position
3. Choice of X-over frequency
4. AIR Monitor type (6 or 15)
Phase settings are automatically saved and linked
to the currently selected Cross-over frequency.
Phase settings are Global settings and are
therefore not saved with individual presets.
Initial setting
During calibration of the AIR Base's DSP software, we
have come up with default settings that we found optimal in
our listening room. If you're placing the AIR Base at the
same distance from the listening position as your AIR
Monitors, the default phase settings can be used as initial
guidelines for setting the phase. If the distances are
significantly different, these values are not likely to be
optimal.
Adjustment
Now play repeatedly a low-frequency sweep signal that
sweeps over the X-over frequency that you have chosen.
Tracks 31-42 on the AIR Test CD may be used. Between
each sweep, change the Phase Reverse setting. Note the
difference. Ideally, with the right level calibration and phase
setting, the sound should cancel out and virtually disappear
at or near the X-over frequency, when the Phase Reverse
control is in one position. Tune Phase Adjust to get the
largest possible difference between the two Phase Reverse
settings. Then leave it in the position where no cancellation
occurs.
Iteration
You may need to iterate quite a bit, maybe readjust the
level calibration a bit too. You may even want to reconsider
your initial choice of X-over frequency and/or monitor
placement and start the process over again. Be patient:
The time spent getting this right is well spent.
Air_US_rev_111.qxd 16-12-2004 14:17 Page 29