ProAudio: Setting up the Subwoofer / Setting up the Subwoofer Crossover Filters (PuTTY)

Modified on Thu, 17 Jun 2021 at 11:13 AM

Each zone has a cross over filter that can allow only high frequencies, or only low frequencies to pass, or be disabled (and allow all frequencies to pass). To enable a filter, both the filter type and the filter frequency has to be set before the filter is enabled.

For the following example, we're assuming the main stereo speakers are connected to zone 1, and the subwoofer is connected to zone 2.

Start by picking the type of filter and slope:

0 - Disabled, the filter is bypassed.

1 - Also disables the filter, but you should use 0.

2 - 12dB / Octave Low Pass Filter

3 - 12dB / Octave High Pass Filter

4 - 24dB / Octave Low Pass Filter

5 - 24 dB / Octave High Pass Filter

and then sending the command:

^FTYPE @1,5$ ; set the stereo speakers to use a 24dB / octave high pass filter
^FTYPE @2,4$ ; set the subwoofer to use a 24dB / octave low pass filter

If these don't make sense, that's fine. Use '4' (24dB / Octave Low Pass Filter) for the subwoofer zone and '5' (24dB / Octave High Pass Filter) for the main stereo speakers zone. The 12dB / 24dB is the sharpness of the filter, how fast it cuts off high or low frequencies. Experimenting with this setting and listening for what sound best, cannot hurt anything.

Now pick the crossover frequency:

0 - Disabled, the filter is bypassed.

1 = 50Hz 9 = 79Hz 17 = 126Hz 25 = 200Hz

2 = 53Hz 10 = 84Hz 18 = 133Hz 26 = 212Hz

3 = 56Hz 11 = 89Hz 19 = 141Hz 27 = 224Hz

4 = 59Hz 12 = 94Hz 20 = 150Hz 28 = 238Hz

5 = 63Hz 13 = 100Hz 21 = 159Hz 29 = 252Hz

6 = 67Hz 14 = 106Hz 22 = 168Hz 30 = 267Hz

7 = 71Hz 15 = 112Hz 23 = 178Hz 31 = 283Hz

8 = 75Hz 16 = 119Hz 24 = 189Hz 32 = 300Hz

and send the frequency command using the above table to select a frequency:

^FFREQ @1@2,16$ ; set the crossover frequency for stereo and subwoofer speakers to 119Hz

Experimenting with this setting and listening for what sounds best, is encouraged. Both the main speakers and the subwoofer should be set to the same frequency. When going up in frequency, this setting indicates the frequency the subwoofer stops working and the main speakers take over. This value is usually between 100Hz and 150Hz, but we allow values between 50 and 300Hz.

Note: Changes to this command should be backed up in case of power failure by sending the "SS" command:

^SS 512$ ; Backup zone settings