# Losses and damping

> The losses 00 Simulator assumes in every box: leakage, absorption and port loss, where each applies, and how much they change a design.

Source: https://simulator.00aud.io/docs/boxes/losses

Every real box loses a little energy: air leaks through joints, the air inside is damped, and the air in the port rubs on its walls. 00 Simulator models these as three fixed losses, the same in every box, with no setting to change them. This page says what they are, where they apply and how much they matter.

## The three losses

Each loss is a Q value: the higher the Q, the smaller the loss. Leakage and absorption are set against the chamber’s own tuning, so the same Q damps a small box as much as a big one.

| Loss | Q | Where | What it stands for |
| --- | --- | --- | --- |
| Leakage, Ql | 10 | Every chamber: sealed, vented, passive radiator and both bandpass chambers | Air escaping through joints, gaskets and the driver. It is set against the chamber’s tuning; in a sealed box, against its resonance with the driver. |
| Absorption, Qa | 100 | Chambers with a port | Damping of the air inside the chamber as it is squeezed and let go. |
| Port loss, Qp | 100 | Ports with the **Lumped** port model | Friction in the port. A port with the **Distributed** model uses its **Duct loss** instead: see [Ports and end correction](https://simulator.00aud.io/docs/boxes/ports#port-model). |

- There is no control for them in the enclosure panel, and the 00 Simulator connector cannot change them for boxes either.
- Air that leaks from a sealed or vented box is added to what the box radiates. A passive radiator box leaves it out.
- Boxes have no stuffing or lining setting: damping material in a box is not modelled beyond these fixed losses.

## How much they matter

Leakage matters most, and most near the tuning, where the port does the work. To show it, the figures run the vented example through the same solver with a leakier and a tighter box. You cannot set these in the app; they show how far a real box could sit from the model.

_Figure: The vented example's SPL with a leakage Q of 5, 10 and 20: the leakier the box, the less output near the 32 Hz tuning._

Ciare 12.00SW in the 55 L vented example tuned to 32 Hz, at 100 W, half space, 1 m. Only the leakage Q differs; the app always uses Ql 10. Simulated when this page was built.

| Design | F3 | At 32 Hz |
| --- | --- | --- |
| Ql 5, leakier | 33.5 Hz | 104.2 dB |
| Ql 10, as the app models it | 30.3 Hz | 106.1 dB |
| Ql 20, tighter | 29.4 Hz | 107.3 dB |

From Ql 5 to Ql 20 the level at 32 Hz rises from 104.2 dB to 107.3 dB, and F3 falls from 33.5 Hz to 29.4 Hz. The air in the port speeds up with it: 16.2 to 22.8 m/s at 100 W. With next to no losses at all (every Q at 1,000) the example would play 3.0 dB louder at the tuning; the leakage alone accounts for 2.5 dB of that.

_Figure: The vented example's impedance with a leakage Q of 5, 10 and 20: the leakier the box, the lower its two peaks._

Ciare 12.00SW in the 55 L vented example tuned to 32 Hz, at 100 W, half space, 1 m. Only the leakage Q differs; the app always uses Ql 10. Simulated when this page was built.

| Design | Peaks | Dip |
| --- | --- | --- |
| Ql 5, leakier | 20.3 Ω and 18.2 Ω | 5.6 Ω at 31.6 Hz |
| Ql 10, as the app models it | 22.8 Ω and 21.0 Ω | 4.6 Ω at 31.6 Hz |
| Ql 20, tighter | 24.4 Ω and 22.8 Ω | 4.1 Ω at 31.6 Hz |

Impedance shows losses most clearly. A vented box has two peaks either side of the tuning and a dip between them; the leakier the box, the lower the peaks and the shallower the dip. The example’s peaks are 22.8 Ω and 21.0 Ω.

A sealed box feels its leak too. Without it, the sealed example’s F3 at 50 W would fall from 62.2 Hz to 59.7 Hz, and its impedance peak would rise from 40.4 Ω to 63.7 Ω.

## Check it against your box

Measure the impedance of the box you built and import it as a measured trace: it draws over the **Impedance** tile beside the simulation. Peaks taller than the simulated ones point to a tighter box than Ql 10, lower ones to a leakier box or more damping. Expect the response near the tuning to differ the same way.

- [Measured traces and notes](https://simulator.00aud.io/docs/guides/measurements): Import a measurement and compare it with a design.
- [Impedance](https://simulator.00aud.io/docs/reference/tiles/impedance): How to read the Impedance tile.

## Horns and the air

- Horns work differently: their paths can be stuffed segment by segment. See [Stuffing](https://simulator.00aud.io/docs/horns/stuffing).
- The air in every design is at 20 °C: sound travels at 343 m/s and its density is 1.201 kg/m³.

## Ask your AI

**Ask your AI**

Your assistant runs the same solver on your own designs through the 00 Simulator connector.

> Using 00 Simulator, compare the measured impedance trace in my open workspace with the enclosure it belongs to, and tell me where the measured peaks and the dip between them differ from the simulation.