Enhancing Woofer Performance with MFB and Crossover Optimization

Speaker acoustics theory states that voice coil acceleration is directly proportional to the acoustic output of a woofer in a sealed enclosure when operating in piston mode below the breakup frequency.

In the first chart, the green plot represents voice coil acceleration without MFB, while the red plot shows the improved response with MFB activated.

Additionally, close microphone measurements on the driver’s acoustic axis are known to closely approximate free-field measurements. In the second chart, the red plot shows the microphone output with a 100 Hz crossover filter, the blue plot with a 200 Hz crossover filter, and the green plot with the subwoofer’s full bandwidth.