The sensor measured the output signal of the woofer and compared it to the amplifier input signal.
The low frequency sound waves from the woofer are not reduced too much by the drivers in their path.
Fortunately, replacement of the edge can be done by speaker repair shops and the woofer can then continue working well.
Many designers therefore believed this made them a good match to cone midranges and woofers, allowing for superb stereo imaging.
The larger the room, the more air the woofer's movement will have to displace in order to produce the required sound power at low frequencies.
There have been good and bad woofers made with every type of cone material.
To design a high efficiency woofer with extended low frequency ability, cones are usually extremely light and flexible with very compliant suspensions.
Additionally, some loudspeakers use the woofer to handle middle frequencies, eliminating the mid-range driver.
