ProAudio: Setting Up a Subwoofer & Crossover Filters (Control4)


Each zone has a crossover filter that can pass only low frequencies, only high frequencies, or be disabled entirely. This is what lets a subwoofer handle the bass while the main speakers handle everything else, without either one straining or distorting. This is set on the same zone parameters panel used for other per-zone settings on the Properties tab.

Setting up a subwoofer zone? It should usually also be locked to its paired speaker zone so it follows the same source and volume changes — see Locking Two (or More) Zones Together (Control4).

Setting the Sub Filter Type

Both the filter type and the crossover frequency have to be set before the crossover filter is enabled. Start with the filter type and slope, using the Sub Filter field:

Sub Filter options on the zone parameters panel.

If you're unsure, use 4 - 24dB/oct Low Pass Filter on the subwoofer zone and 5 - 24dB/oct High Pass Filter on the main stereo speakers zone. The 12 dB vs. 24 dB choice controls how sharply the filter cuts off frequencies beyond the crossover point — it's safe to experiment and listen for what sounds best.


Setting the Sub Freq

Next, set the crossover frequency using the Sub Freq field — this is the point where the subwoofer hands off to the main speakers:

Sub Freq options range from 50 Hz to 300 Hz.

Both the subwoofer and the main speaker zone should be set to the same frequency. It's typically somewhere between 100 Hz and 150 Hz, though the full range runs from 50 Hz to 300 Hz — this one is also open to listening tests, so experiment for what sounds best.

Both Sub Filter and Sub Freq must be set for the filter to actually engage. If either one is left at "Disabled," the crossover filter stays off — even if the other one has a value selected. There's no warning for this, so if a filter doesn't seem to be doing anything, check that both fields are set.

Backing Up the Filter Settings

Back up after every change. On Composer's Action tab, press Backup Audio Settings (except volume). Skipping this means a power outage can silently revert your filter settings.

Related Articles

Need help with your subwoofer setup?

Our support team can help troubleshoot Control4 driver or crossover filter issues.

UK: 01202 413 610 | US: (858) 748-8250 | support@pulse-eight.com