Check the listing for details. DOD SR231QXLR Stereo Graphic Equalizer - Precision Sonic Sculpting. Condition: Used, Made in United States. Listed at 64.99 USD. The DOD SR231QXLR Stereo Graphic Equalizer is a high-quality rack-mountable signal processor designed for precision sonic sculpting in audio applications. With two channels and XLR input/output ports, this analog equalizer offers precise control over the frequency response of audio signals. Made in the United States by DOD, a trusted brand in pro audio equipment, the SR231QXLR model is ideal for musicians, sound engineers, and producers looking to achieve a professional sound with detailed graphic equalization capabilities.