How hard can you drive a 2.5 m tapped horn?

Why a tapped horn here?

A tapped horn puts both faces of the cone into one path, with a single mouth. There is no box behind the driver: the path loads both sides, so the whole cabinet works as horn. That gives a lot of bass for the size of the cabinet, over a band set by the path length and the two entry points. How a tapped horn is connected.

Try the model

Every combination below was simulated when this page was built, in half space at 1 m. The working band, 25–120 Hz, is solid; the rest of the response is dashed.

Three things to notice

Power moves the curve, not the band

Going from 100 W to 400 W to 800 W lifts the peak from 123 to 129 to 132 dB. The −3 dB band stays at 39–113 Hz, because this model is linear: power scales the whole response.

The cone moves most below the band

At 100 W the cone peaks at 6.0 mm inside the band but 10.9 mm at 10 Hz, where the horn no longer loads it. Excursion grows with the square root of power, so the driver reaches its 15 mm Xmax below the band at about 190 W, long before it does inside the band at about 620 W.

A high-pass filter buys the headroom back

A 28 Hz, 4th-order Butterworth high-pass keeps the lowest octave out of the horn. At 400 W the peak below the band falls from 21.9 mm to 6.5 mm, and even at 800 W the cone stays at 10.9 mm, inside Xmax. The −3 dB band is still 39–113 Hz. Add the same filter from the EQ panel in the simulator.

Then try

• Move the front entry and watch the region above the band change. What the front entry position does.
• Stuff part of the first span to calm the peaks above the band. Stuffing.
• Check how fast the air moves at the narrowest section at your power. Diagnostics.
• Fold it into the cabinet you can build, and simulate the folded version beside it. Fold into cabinet.

Before you cut wood

• The result is only as good as the driver data. Check the T/S parameters and Xmax against the manufacturer’s sheet, or measure them.
• Excursion is one limit; heat is the other. The Max SPL tile shows the loudest the horn can play before either, whatever power you set, so compare it with SPL at your power, or open the Headroom layout.
• The model is linear and one-dimensional. It does not include power compression, bend losses or port and passage noise.
• Export the design to Hornresp to cross-check it in a second simulator. Hornresp export.

Ask your AI the same question

With 00 Simulator connected, an assistant can answer this from your own design. The numbers below come from the same runs as the explorer above.

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