Sub Box Calculator › Bass tone generator

Bass tone generator

Plug your phone or laptop into the head unit (AUX or Bluetooth), start at low volume and pick a frequency. A phone speaker can’t play deep bass — the sub has to.

How to find the tuning of a ported box

1. Connect the phone to the head unit, turn the volume down and play about 45 Hz.
2. Move the frequency down a hertz or two at a time and watch the cone (a flashlight helps) and feel the air at the port.
3. At the tuning frequency the cone almost stops moving while the port blows hardest. Write that frequency down.

Press This is my box tuning and the calculator compares it with the design: if the box came out a few hertz off, it tells you why and how much to trim the port. A sweep is a quick way to get close first; then fine-tune with the buttons. The impedance method (DATS, REW) is more accurate — see how to tune a sub box.

Check for rattles

Run a slow sweep from 20 to 80 Hz at moderate volume and listen: license plate, trunk lid, rear deck and door panels buzz at their own frequencies. Stop the sweep when you hear a rattle — the frequency stays on screen, so you can hold it while you find the panel.

Set the subsonic filter and crossover

Play a tone just below the box tuning: if the cone flaps with little sound, the subsonic filter on the amp should be set around 0.7–0.8 of the tuning. Tones from 60 to 120 Hz help you hear where the sub hands over to the door speakers.

Safety

A pure sine at full power is hard on the sub and on your ears. Keep the volume low, especially below the box tuning, and never run long tones at full gain. Turn the gain down first, then raise the volume slowly.

FAQ