Vented vs Sealed subwoofer box enclosure diagrams


The graph show here is a sample of how to F3 drop-off point differs between sealed vs vented subwoofer box enclosure.

SEALED ENCLOSURES


Sealed enclosures are the simplest to build.The most important part of
building a sealed enclosure is to make sure that the enclosure is airtight.
Using glue and some type of sealant on all seams will ensure solid
construction and prevent air leaks.The box volume will directly impact
the performance of the speaker. Larger enclosures will provide flatter
response and deeper bass where smaller boxes will provide a bump in
the response curve and generally higher output for greater SPL.
Advantages of sealed enclosures:
• Small enclosures
• Linear (Flat) response
• No port noise
• High power handling at all frequencies
• Excellent for sound quality
• Extended low frequency output when compared to vented enclosures


VENTED ENCLOSURES


Vented enclosures vary only from the sealed enclosure in that a vent or
port is added to “tune” the enclosure.The enclosures recommended are
designed for great overall performance. Larger boxes tend to be easy to
tune to lower frequencies while medium and small boxes are easier to
tune to higher frequencies.The vented design is less linear in response
than the sealed box but with noticeably more output at the tuning frequency.
Advantages of vented enclosures:
• Higher average output than sealed
• Tuning frequency can be easily adjusted by changing port length
• Deep bass response with lower power requirements
• Great for high output with limited power