Installation guide

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There are a number of different ways to incorporate a subwoofer. However, one method is as

follows:

1. Measure and Correct your speakers (see Measuring a Loudspeaker and Correcting a

Loudspeaker). When correcting the speakers, window in order to eliminate the first reflection.

This will typically make the speaker correction less than ideally accurate below about 150 Hz, but

the intention is that the subwoofer(s) will be taking over below that frequency, so the low

frequency performance of the main speakers is not so important.

2. Measure and Correct your subwoofer(s) (again, see Measuring a Loudspeaker and Correcting

a Loudspeaker). Measure the subwoofer(s) at 15cm – this provides essentially anechoic

measurements of the subwoofer. Alternately, each subwoofer’s output can be measured

INCLUDING room reflections (locate the sub at its intended room location), by measuring the

subwoofer at the listening position sweet spot, or over a wider area by holding (still) then moving

the microphone in between sweeps. Move the mic (quickly) between one or two sweeps, then

move quickly to a new position, and so on. The number of sweeps can be set to say 16 to all

quickly, sweep then move etc – don't move continuously) – while keeping the distance from the

mic to the subwoofer as constant as possible. At subwoofer frequencies the wavelength is

several metres long, allowing manual movement of the microphone. Measuring midrange drivers

and tweeters however requires the microphone to be a consistently exact distance from the

drivers. When correcting the subwoofer(s), window at about 20ms or more and use limits of 20

Hz and 300Hz and set smoothing to 100%, but experimenting down to zero smoothing can also

provide good results in some rooms.

3. Connect up your system and set the speakers and subwoofer(s) in their intended final locations.

4. Configure the PDC to match your setup (see Configuring the PDC). Use low pass filter(s) for

the subwoofer(s) and matching high pass filters for the main speakers. The crossover frequency

should be set to 150 Hz or higher (depending on where the main speakers were windowed in

step 1. If you were able to make measurements of your main speakers with a longer time to the

first reflection, then a larger window can be used for correction and they will be more accurate

lower down, allowing a lower crossover frequency.)

5. Measure your room, using the profile in which you configured the speakers and subwoofer(s)

(see Measuring a Room). Measure at the listening position, measure the drivers concurrently.

6. Load the room measurements into the PDC Control Panel's Parametric EQ (Or the Viewer).

Refer to DEQX Viewer and Response Charts in the Reference section, which explains how to

move, sum and manipulate plots. You will need this knowledge to carry out the steps below.

7. Normalise the measurements to 0dB and smooth them to 100% if they are not already so

smoothed.

8. If the left and right speaker measurements are not equal above 150 Hz (or your chosen

crossover frequency), move one of them to get them as close as possible, by adjusting the figure

in the 'Scale' column. This should only be necessary if your room is not symmetrical from left to

right.