SpeakerDraft for iPad performs the basic task of modeling the low-frequency response (bass response) of a single-woofer (or subwoofer) loudspeaker design. In SpeakerDraft, a design consists of a single enclosure (a box) and a single driver.
SpeakerDraft allows you to select a sealed or ported box for your driver. With either type of box, the width, height, and depth of the box can be specified by direct text entry, or by adjusting the position of a slider control with your finger. With a ported box, port diameter and length may be specified in the same manner.
When box parameters are adjusted, a bass-response plot in the top half of the screen immediately reflects the low-frequency response of your current loudspeaker design. This is also true when a different driver is selected.
The upper frequency limit of the frequency response curve provides a quick visual indication of the first resonance frequency of the box (the lowest frequency at which the box will resonate).