What are sealed loudspeakers?
Sealed loudspeakers, also known as acoustic suspension speakers, use an airtight cabinet to control bass response. They prioritise accuracy, control, and consistency over sheer bass output.
Definition: what a sealed loudspeaker is
A sealed loudspeaker is a speaker design in which the cabinet is completely airtight. The air trapped inside the enclosure acts as a spring that controls the motion of the woofer.
This air spring helps regulate cone movement, resulting in predictable, well-controlled bass response.
How sealed loudspeakers work
When the woofer moves forward, it compresses the air inside the cabinet. When it moves backward, the air expands.
This pressure change resists the woofer’s motion, keeping it under control and reducing unwanted resonance.
Why sealed designs are used
Sealed cabinets sacrifice some bass output in exchange for accuracy and consistency. Designers often choose sealed designs when precision matters more than maximum volume.
- More controlled bass response
- Gentler low-frequency roll-off
- Predictable behaviour in different rooms
Sealed vs ported loudspeakers
| Design | Main advantage | Main trade-off |
|---|---|---|
| Sealed | Tight, accurate bass | Less bass output for a given size |
| Ported | Deeper, louder bass | More sensitive to room placement |
Bass roll-off and room interaction
Sealed speakers typically roll off more gradually at low frequencies than ported designs. This often allows room gain to blend more naturally with the speaker’s bass response.
In smaller rooms, sealed speakers can sound more balanced and less boomy.
Amplifier requirements
Because sealed designs are generally less efficient, they often benefit from more amplifier power to reach the same volume levels as ported speakers.
The trade-off is cleaner bass and better control at moderate listening levels.
What sealed loudspeakers contribute to sound
- Bass accuracy: tight, well-defined low frequencies.
- Consistency: predictable sound across different rooms.
- Timing: bass that integrates smoothly with the rest of the music.
- Control: reduced overhang and resonance.
Common questions
Are sealed speakers better for music?
Many listeners prefer sealed speakers for music because of their controlled bass and natural integration, but preferences vary.
Do sealed speakers lack bass?
They typically produce less bass output than ported speakers of the same size, but the bass they do produce is often cleaner and more accurate.
Do sealed speakers need more power?
Yes. Sealed designs are usually less efficient and benefit from a capable amplifier.
Are sealed speakers easier to place?
Generally, yes. Sealed speakers tend to be less sensitive to placement near walls compared to rear-ported designs.