Cookbook

Cookbook · Tapped horn

Tapped horn subwoofer

How hard can you drive the 2.5 m tapped-horn example? Use its B&C 21SW152, increase power and compare a high-pass filter while reading SPL and excursion together.
Path
2.5 m tapped horn
Starting drive
100 W, half space at 1 m
Driver travel limit
15 mm Xmax

The path loads both sides of the cone#

A tapped horn couples both faces of the driver into one path at different positions. Their outputs combine at the mouth, with the path length and entry positions shaping the useful band. How the tapped horn is connected.

At 100 W the lower and upper −3 dB points within this example’s working band are 39 Hz and 113 Hz. Those are response markers, not recommended crossover settings.

Try the model#

Amplifier power
High-pass filter
Tapped Horn · B&C 21SW152SPL · Half Space · 1.0 m · 100 W
Cone excursionmm · Xmax 15 mm
−3 dB band
39–113Hz
Peak, 25–120 Hz
123dB
Excursion, 25–120 Hz
6.0mm
Excursion below 25 Hz
10.9mm

At 100 W the cone peaks at 10.9 mm at 10 Hz, inside its 15 mm Xmax across the graph.

Open this example in the simulator
Every combination was simulated when this page was built, in half space at 1 m. The 25–120 Hz working band is solid on SPL; the response outside it is dashed.

Three things to notice#

  1. 1

    Power changes level

    From 100 W to 400 W to 800 W, the in-band peak rises from 123 to 129 to 132 dB. The linear model scales the response instead of compressing it.
  2. 2

    Check below the working band

    At 100 W, peak cone travel is 6.0 mm inside the band and 10.9 mm below it. The unfiltered model reaches Xmax at about 190 W below the band, compared with 620 W inside it. These are excursion-only comparisons over the simulated ranges.
  3. 3

    Compare the high-pass

    With the 28 Hz, 4th-order Butterworth high-pass, peak travel below the band at 400 W changes from 21.9 to 6.5 mm. At 800 W, peak travel across the explorer’s graph is 10.9 mm. Read that against 15 mm Xmax and check the filtered SPL too.

Then try#

Change an entry positionCompare the upper response and the useful band before accepting the change.Try stuffingDamp a selected part of the path and compare what changes inside and outside the band.Inspect the pathCheck pressure, impedance and particle velocity through the horn.Fold the designFit the path into a cabinet and simulate the folded version beside the original.

Before you cut wood#

  • Check the exact driver data and excursion definition against the manufacturer’s sheet or your own measurements.
  • Select the working band, filters and amplifier drive together. Useful in-band output does not prevent over-excursion below the band.
  • The one-dimensional model follows the acoustic path. It does not calculate bend turbulence, cabinet vibration or large-signal compression.
  • Cross-check an export in Hornresp, then measure the finished cabinet before setting an operating limit.
Open the tapped-horn exampleStart with the unfiltered design at 100 W.

Ask your assistant the same question#

Your assistant
00 Simulator connected

You: Using 00 Simulator, how much power can my tapped horn take before the driver passes Xmax? Show me the excursion.

Tools used: get_workspace, get_driver, simulate_workspace, render_simulation_graphs.

Assistant: At 100 W the cone peaks at 6.0 mm between 25 and 120 Hz, well inside its 15 mm Xmax, but reaches 10.9 mm below 25 Hz, where the horn stops loading it. Excursion grows with the square root of power, so the driver reaches Xmax in the band at about 620 W and below it at about 190 W. A 28 Hz, 4th-order Butterworth high-pass protects the low end: at 400 W the peak below the band falls from 21.9 mm to 6.5 mm.

Open the workspace
The conversation above is illustrative. The tool names are the server’s own, and the curve and numbers are solver output from when this page was built.

Ask your AI

Using 00 Simulator, inspect my selected tapped horn and compare the power it can take before the driver passes Xmax, with and without a 28 Hz, 4th-order Butterworth high-pass. Do not save changes. Show the excursion inside and below the working band, and state the frequency range used.
or open it inClaudeChatGPT

Connect your assistant so it can open your designs.

TappedHornresp exportMax SPL (dB)Model and limits