Guides · Measure, share and build
Calculators
Six free calculators each answer one box question in the browser, with no account: a port length, a box volume, sealed or ported. They run the simulator’s own model, so their numbers match the app’s closely. Open the simulator when the design needs more than one answer.
The six calculators#
| Calculator | What it answers | Needs a driver | Into the simulator |
|---|---|---|---|
| Bass-reflex port calculator | How long to cut a port for a box and a tuning (Port length), or the tuning a port you have gives (Tuning). Round or Slot, one port or several, drawn to scale. | No | Simulate it with a driver |
| Port velocity calculator | How fast the air moves in a port across the bass range, with a real driver, power and an optional high-pass, and the cone excursion alongside. | Yes | Open in the simulator |
| Speaker box volume and dimensions calculator | Net volume from a box’s Outside or Inside sizes (Volume), the depth for the volume you need (Depth), or a whole box in good proportions (Box size), allowing for the panels and what sits inside, with a cut list. | No | Tune a port for this box takes the volume to the port calculator |
| Sealed box calculator | The box volume for the Qtc you want (Box volume), or the Qtc of a box you have (Qtc), with the response, F3 and cone excursion. | Yes | Open in the simulator |
| Ported box calculator | A box volume and tuning that suit the driver, with the port to build, the response against the same driver sealed, cone excursion and port air speed. | Yes | Open in the simulator |
| Subwoofer box calculator | Sealed or ported? Starting boxes for the driver side by side, by size, extension, level at your power and the most each can play, with a pick for Compact, Balanced or Deep. | Yes | Open the pick in the simulator, or Simulator on any box |
All six are listed together at Calculators. Each links to the others that pick up where it stops: the box volume calculator’s Sealed or ported? leads to the subwoofer box calculator, for example.
What they share#
- A driver. The calculators that need one start on an illustrative 12-inch woofer marked Example. Search the driver library by brand or model, Paste T/S values from a spec sheet, or Edit T/S to type them in.
- Units. The switch at the top reads mm · L or in · ft³.
- A link. Copy link copies an address that reopens the calculator with your numbers. Reset to the example starts again.
- The model. The calculators with a driver run the simulator’s model in half space at 1 m, with one simplification: they leave out the driver’s voice coil inductance, which only rolls off the top of the range. The simulator includes it.
The same model as the simulator#
The vented example is a 55 L box tuned to 32 Hz with one 100 mm port. The port calculator cuts that port to 355.6 mm, and the simulator’s Port length reads the same.
Bass-reflex port calculator
- Net volume
- 55 L
- Tuning
- 32 Hz
- Port
- Ø 100 mm
- Length
- 355.6 mm
Enclosure
TypeVented
Volume55.0L
Tuning32.0Hz
Port length355.6mm
The port calculator shows more about the port itself: the effective length the air behaves as, other port sizes for the same tuning, a guide to trimming a port to tune it, and a check that it fits a box of a given depth. Ports and end correction explains the effective length.
Take a design into the simulator#
- 1
Press the button
At the foot of a calculator, Open in the simulator (or Simulate it with a driver on the port calculator) opens the simulator with the design in the address. - 2
Check it
A dialog shows what will be added: Inspect this vented design or Inspect this sealed design, with the driver, box and power. The port calculator has no driver, so Check this port with your driver asks for one first. - 3
Add it
Create vented design or Create sealed design adds it as a new enclosure beside the ones already there, and saves its driver to your own drivers if it is not there yet.
When to open the simulator instead#
The calculators cover sealed and vented boxes with one driver, in half space at 1 m. Open the simulator when you need:
- Other box types. Passive radiators, fourth- and sixth-order bandpass boxes and eight kinds of horn: Choose an enclosure type.
- Several boxes on one graph. Every enclosure in a workspace draws its own curve: Compare designs.
- More graphs. Impedance, group delay, phase and the most each design can play before it reaches a limit: All tiles.
- The rest of the system. Several drivers and their wiring, series resistance, full EQ, the radiation space and listening distance: Power and limits and EQ and filters.
- To keep and share it. Signed in, workspaces save as you go, and any design can be shared as a link: Share and publish.
- To check a build. Import a measurement and compare it with the simulation: Measured traces and notes.
Ask your AI#
Ask your AI
Your assistant can size, add and simulate boxes through the 00 Simulator connector, with the same model the calculators use.
Using 00 Simulator, suggest a sealed and a vented box for the Ciare 12.00SW, add both to my open workspace, and compare their F3, peak cone excursion and peak port air speed at 200 W.
Connect your assistant so it can open your designs.