JBL CINEMA SB400 – SB350 Powered sound bar with powered, wireless 8” Subwoofer. Schematic diagram

Power:
3.3v supply pins are provided on either side of the module. These pins are all internally connected inside of the SiP and are provided for convenience so that Ginseng can be powered from either the left or right sides to make routing a PCB convenient for various applications. It is generally recommended to power the 3.3V bus from only one side of the SiP. The pins on the other side should be shunted to ground through a 0.1uF and 1uF set of capacitors.

XPD:

The XPD port is a SPI bus used for loading module firmware during development and mass production and also for debugging. One of the following two styles of XPD port connectors should be included on all motherboard designs that use Ginseng to ensure that loading code and debugging can be done easily. The XPD port interfaces to the XPD module which provides an interface to a host computer via RS-232 or USB. The XPD port operates from the VCC bus. To ensure proper functionality of the XPD interface, be sure to minimize the amount of capacitance on the XPD lines. Note: the XPD_RESET / EXT_RST pin is tolerant up to 1.8V MAX -- if control of the Reset pin is desired, a series diode must be used to guarantee the input voltage does not exceed the 1.8V max.

Digital IO:

Ginseng has general purpose digital IO (“GPIO”) pins available for use by the application firmware. GPIO pins use the same logic voltage as the 3.3V pin and have the following software configurable features: IO direction, drive strength (for output only), Schmitt Trigger (for input only), pull up (input only), pull down (input only), slew rate (output only). Ginseng is also capable of active-high and active-low configuration of LEDs.

Circuit diagram [Click on the schematics to magnify]

Subwoofer Level control:

Use this control to balance the subwoofer’s volume with that of the soundbar. Turn the knob clockwise to increase the subwoofer’s volume; turn it counterclockwise to decrease the subwoofer’s volume.  Crossover control: This knob adjusts the subwoofer’s cutoff between 40Hz and 200Hz.The higher you set the Cutoff control, the higher in frequency the subwoofer will operate and the more its bass will “overlap” that of the soundbar. This adjustment helps achieve a smooth transition of bass frequencies between the subwoofer and the soundbar for a variety of different rooms and subwoofer locations. See Subwoofer Crossover control, on page 8, for more information.  Phase switch: This switch determines whether the subwoofer driver’s piston-like action moves in and out in phase with the speakers in the soundbar. If the subwoofer were to play out of phase with the soundbar speakers, some of the sound waves produced by the subwoofer or soundbar could be canceled, reducing bass performance and sonic impact. This phenomenon depends in part on the relative placement of the speakers in the room.