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Choose an enclosure type

00 Simulator has six enclosure types: Sealed, Vented, Passive Radiator, Bandpass 4, Bandpass 6 and Horn. Each one trades box size, how deep the bass goes, how loud it plays and which limit you meet first. This page shows the trade on real designs so you can pick one to start with.

SPL relative to each design’s own level

dB

  • Sealedfrom 62.2 Hz
  • Ventedfrom 30.3 Hz
  • Passive Radiatorfrom 63.8 Hz
  • Bandpass 438.9–92.2 Hz
  • Bandpass 629.7–56.8 Hz
  • Hornfrom 37.2 Hz
Each design at its example’s power, half space, 1 m, drawn relative to its own loudest one-octave average (0 dB). Simulated when this page was built.

The six types#

You pick the type in the Type list when you add an enclosure, and you can change it later in the enclosure panel. The graph above draws one design of each type. They use different drivers and powers, so it compares shapes, not loudness: where each one starts to roll off and how steeply it falls.

TypeHow it worksExample−3 dB
SealedThe driver in a closed box. The trapped air acts as a spring behind the cone.Dayton Audio DCS205-4, 15 Lfrom 62.2 Hz
VentedA closed box with a port. The air in the port resonates with the box at the tuning frequency and adds to the output there.Ciare 12.00SW, 55 L, tuned to 32 Hzfrom 30.3 Hz
Passive RadiatorA vented box with a second cone, with no motor, in place of the port. Its mass sets the tuning.Dayton Audio DCS165-4, 10 L, one radiatorfrom 63.8 Hz
Bandpass 4The driver between a sealed rear chamber and a ported front chamber. Only the port radiates.B&C 18SW115, 70 L sealed rear, 50 L front at 59 Hz38.9–92.2 Hz
Bandpass 6Both chambers are ported, each with its own tuning. Only the ports radiate.B&C 18SW115, 224 L rear at 30.6 Hz, 112 L front at 47.6 Hz (no example)29.7–56.8 Hz
HornA path that widens from the driver to a mouth, instead of a box. There are eight horn types, from front-loaded and tapped to multiple-entry.B&C 21SW152, tapped, 2.5 m pathfrom 37.2 Hz
−3 dB is measured the way the SPL tile measures F3: against the loudest one-octave average. Reading a response explains it.

The Bandpass 6 row has no example of its own: it is the starting point the Add enclosure dialog fills in when you choose Bandpass 6 for the B&C 18SW115. The second horn example, three B&C 10PS26 drivers on a multiple-entry horn, is −3 dB from 70.4 Hz to 366 Hz: horns are not only for subwoofers.

What each one trades#

TypeGives youCosts you
SealedA small, simple box. A gentle roll-off that room gain can fill in. The air spring holds the cone below resonance, and there is no port to fit or to make noise.Less deep bass for its size than a vented box, so the cone travels further and needs more power for the same low notes.
VentedMore output low down from the same driver. Near the tuning the port does the work and the cone barely moves. The example is −3 dB at 30.3 Hz.A steeper roll-off below the tuning, where the cone is no longer held and its travel climbs fast. A port that has to fit in the box and can chuff when the air in it moves too fast.
Passive radiatorVented-style tuning with no port noise and no long port to fit, useful in small boxes.A second cone to buy, with its own travel limit to check on the PR Excursion tile. The tuning moves with its added mass.
Bandpass 4High output over one band, with the driver hidden inside. The example covers 38.9–92.2 Hz.A narrow band, a large box for it, and one port that carries all the output, so check its air speed.
Bandpass 6A band set by two chamber tunings. The starting point above covers 29.7–56.8 Hz.Two chambers and two ports to size. Their tunings must stay apart: close together, their outputs cancel.
HornHigh efficiency and output over the band the path loads. The tapped horn example's loudest octave averages 121 dB at 1 m from 100 W.Size: the tapped horn's path is 2.5 m long, folded into a cabinet. Ripple and extra lobes from the path's own resonances: above its band this one drops to −30 dB near 221 Hz, then comes back within 3 dB up to 249 Hz. More to design.

Where to start#

When you choose a driver in the Add enclosure dialog, 00 Simulator suggests Sealed or Vented from its efficiency-bandwidth product, EBP = Fs / Qes. Above 75 it suggests Vented, otherwise Sealed, and it fills in a starting size you can accept or change.

  • The Ciare 12.00SW from the vented example has an EBP of 88. The dialog suggests Vented and starts from 82.5 L (1.5 × Vas) tuned to 26.1 Hz (0.9 × Fs).
  • The Dayton Audio DCS205-4 from the sealed example has an EBP of 81, so it too is suggested Vented. Choose Sealed anyway and the dialog starts from 10.2 L, the size for a Qtc of 0.707. The example itself uses 15 L.
  • Passive radiator and horn designs start from the app’s own defaults. For those, open an example and change it.

The suggestion is a starting point, not a verdict. Beyond the driver, choose by what you can build and where it will play:

  • Little space, or a room that adds bass of its own: start Sealed.
  • The most bass from one driver in a box you can fit: start Vented, or Passive Radiator if a port will not fit.
  • Loud over one narrow band: try Bandpass 4.
  • Output and efficiency matter more than size: open the horn examples and read the horn types.

T/S parameters in five minutes explains the driver numbers behind the suggestion, and Limits: travel, heat and air shows the limits every design runs into.

Ask your AI#

Ask your AI

Your assistant uses the same suggestion logic and solver through the 00 Simulator connector.
Using 00 Simulator, suggest a sealed and a vented enclosure for the Dayton Audio DCS205-4, add both to a new workspace, and compare their F3, box size and peak excursion at 50 W.
or open it inClaudeChatGPT

Connect your assistant so it can open your designs.

Boxes overviewHorns overviewT/S parameters in five minutesReading a responseCompare designs