ACD Advanced Equalizer™ is a professional, realtime, stand-alone, 15 band graphic equalizer product that does not require a host sound editing facility. The ACD Advanced Equalizer™ has its own, built-in, MP3 decoder engine .The Equalizer can be used with different input/output sources, such as CD Players, making it the ultimate tool for enhancing desktop audio listening pleasure. Fast Fourier Transformation (FFT) is used by the equalizer routines in the program.The longer the FFT, the more accurate a sound reproduction the equalizer produces. The length of the FFT can be varied with a slider. The ACD Advanced Equalizer™ offers two spectrum analyzers, separately for left and right channels, and one central oscilloscope as a visual means of observing and controlling the workings of the system. The only additional software needed to operate the ACD Advanced Equalizer™ is a CD Player, like the one provided as part of the Windows 95/98 Operating Systems (which you will find in the Windows Start up Menu in Accessories, Multi Media). Other CD Players can also be used.A Half Duplex, or even better, a Full Duplex Sound Card and a CD-ROM player is required. A purchaser will also receive a free CD-ROM/DVD drive performance Tester.