FV15 has two port openings. With two ports open, the max extension is 18hz and the rumble filter should be set to ON/2 position. In the following is the frequency response when extension filter is set to 14hz and low damping.

Fig 1.0 - FV15 Frequency response chart in AVR/12 low pass filter setting and both ports open

To achieve lower group delay and lower bass extension at 12hz, customer can plug one of the ports and set the rumble filter position to OFF/1. In the following is the resulting frequency response with extension filter set to 14hz and low damping.

Fig 1.1 - FV15 Frequency response chart in AVR/12 low pass filter setting and one port open

The level matching between two port mode and one port mode is very good as shown in the following figure when the volume setting is unchanged and the rumble filter setting is at ON/2 and OFF/1, respectively.

Fig 1.2 - FV15HP level matching level two port and one port modes when the rumble filter is set ON/2 and OFF/1, respectively

FV15 also provides an LFE mode that extends the upper end to 200hz as shown below.

Fig 1.3 - FV15 LFE mode response with two port

Integration

One important aspect of getting a correct integration is phase alignment. We have written a guide on how to achieve a phase aligned subwoofer. More