Two or more subwoofers are the biggest single upgrade for even bass across several seats. This page covers wiring, levels and grouping with Dirac Room Correction, Bass Control and ART.
Set up multiple subs
Beginner
Give each sub its own output
Connect each subwoofer to its own subwoofer output on the receiver. Two subs on a Y-splitter look like one sub to Dirac, so it can’t adjust them separately. Bass Control’s seat-to-seat improvement depends on separate outputs.
Set each sub’s own controls
- Phase knob at 0°. Dirac corrects phase.
- Low-pass filter off or at maximum, or LFE mode if the sub has one.
- Any room EQ or bass boost in the sub’s app switched off.
- Gain set so each sub, on its own, reads a few dB above the speakers during Dirac’s level check. See Step 4.
Place them first, measure second
Dirac can’t fix a sub in a bad spot as well as a better spot can. Harman’s research on rectangular rooms found that two subs at the midpoints of opposite walls, or four subs at the midpoints of each wall or in the four corners, gave the most even bass across seats. In real rooms, try positions and check with REW before calibrating.
Which Dirac product?
| Product | What it does with several subs |
|---|---|
| Room Correction only | Corrects each sub on its own. They aren’t optimised to work together. |
| Bass Control | Treats the subs and speakers as one system, sets crossovers, and evens out bass across seats. |
| ART | Adds active cancellation of room resonances, using the subs and other speakers together. |
Next step
Bass Control setup
Once the subs are wired and placed, Bass Control makes them work together.
Multiple subs in depth
Advanced
Treat each sub as just a sub
Dirac’s advice is not to assign subs to specific duties, such as one for LFE and one for the left and right speakers. Treat each as “just a sub” and let Bass Control manage them.
Different models
Dirac doesn’t publish Bass Control guidance on mixing sealed and ported subs, or different models. With ART, Dirac recommends putting subs of different capability in their own groups so each can have its own support settings. Many users report better results with all the subs in one group, including cases where a separately grouped sub failed to fill a dip that it filled once grouped. Start with one group, then try splitting them and compare measurements.
Receiver settings
Many receivers lock subwoofer settings while a filter is on. On Denon and Marantz, subwoofer mode, layout and level adjust are locked while a Bass Control or ART filter is active, so set them before measuring. Dirac says to turn off any directional bass setting for ART. Dirac and Denon don’t publish a Standard versus Directional recommendation for Bass Control; treat any advice on that as community opinion.
Why the bass sounds lighter after Bass Control
Without Bass Control, each sub is corrected to the target on its own, so together they add up to more. Bass Control accounts for them playing together. Raise the target below 100 Hz by a few dB if you want more. See Bass Control setup.
Common questions
Questions people ask about multiple subs in Dirac user groups.
Why can’t I set a target curve for a sub in its own ART group?
In ART, target curves belong to the main channels. A subwoofer moved out of the main LFE group has no target curve of its own. Instead it helps each group it supports reach that group’s target. To change the bass it produces, adjust the curve on the groups it supports, or move it back into the LFE group.
Source: Dirac Help Centre: ART channel group and support settings.
Can I give each sub its own target or curtain?
Not with Bass Control. The subs share one bass target, and changing the low-frequency shelf in one group changes it for all. That’s by design: the subs are optimised together to reduce variation across the seats.
Source: miniDSP: Dirac Live Bass Control.
Should I turn off my subwoofer’s own room EQ?
Yes, as a rule. Switch off the sub’s own auto-EQ or app room correction, and keep its settings the same between measuring and listening. If you change them, measure again. Community practice.