In a home theater, several speakers work together to provide good sound: usually five speakers and a subwoofer.
The subwoofer is responsible for the low tones (bass) – such as explosions, thunder, or the palpable pressure in music.
The following tips will help you with the proper setup.
Set volume before calibration
Before you start the automatic calibration system of your AV receiver, the active subwoofer should be properly leveled in advance:
- Set the volume directly on the subwoofer to a middle position (about 50% or 12 o’clock position).
- The volume on the AV receiver remains unchanged.
This way, the calibration system receives a neutral initial signal and can correctly integrate the subwoofer into the overall sound image.
More tips on calibration can be found under Setting up speakers & home theater.
What does the lower cutoff frequency mean?
The lower cutoff frequency describes how deep a subwoofer can play. It indicates up to which frequency a subwoofer still reproduces bass audibly and noticeably (e.g., 25 Hz or 40 Hz).
Basically:
The lower the lower cutoff frequency, the more powerful and impressive very deep bass components are – especially in movies. In other words: the lower this value, the more deep bass you hear (and feel).
For more information, we recommend our blog post on the topic:
The crossover frequency (also transition frequency)
Not every speaker can reproduce low frequencies equally well. Therefore, in a home theater, the AV receiver handles the so-called bass distribution:
- Frequencies above the crossover frequency are sent to the satellite speakers.
- Frequencies below the crossover frequency are handled by the subwoofer.
The crossover frequency thus determines from which point the subwoofer takes over the bass. The goal is a seamless transition with no audible gaps or overlaps in the sound image.
The crossover frequency setting is done in the AV receiver. The optimal value mainly depends on the bass capability of the speakers used – smaller speakers usually cannot reproduce deep frequencies cleanly and therefore need to be relieved earlier.
Proven guidelines:
- In most home theater systems, sensible: 80–120 Hz
- 80 Hz is considered the THX reference value, provided the speakers can still reproduce this frequency cleanly
- Compact center or surround speakers often require a slightly higher crossover frequency
Since ideally a subwoofer should be non-localizable, in practice the crossover frequency is usually under 160 Hz. Particularly common and proven are:
- 80–140 Hz with compact home theater speakers
- 80 Hz with more powerful satellite or floor-standing speakers
Tip: The automatic calibration of the AV receiver usually provides a good starting point. Fine adjustments can then be made depending on the room and personal listening preferences.
The phase
Phase refers to the timing of the audio signal output in relation to the subwoofer's position in the room and the listening position when watching movies. A simplified rule of thumb is as follows: If the subwoofer is in front of you, keep the phase at "zero" (degrees); if the device is behind you, set the phase to 180 (degrees).
The phase setting helps synchronize the subwoofer and speakers in time. Depending on the placement, bass components might otherwise cancel each other out.
Simple rule of thumb:
- Subwoofer is in front of the listening position → Phase 0°
- Subwoofer is behind the listening position → Phase 180°
Since room acoustics and distances play a major role, additionally:
👉 Test both settings and choose the one where the bass sounds strongest and cleanest at the listening position.
More information can be found here: