Sound Blaster Live! - Design Shortcomings

Design Shortcomings

The original SB Live! had a very low noise floor for its time; however, a critical design flaw limited its application in quadraphonic audio. The two S/P-DIF channels that each provided a stereo pair differed in their Digital to Analog reconstruction. Since the AC'97 chip provided an internal 48 kHz DAC, Creative chose not to implement two identical DAC pipelines, and the front-speaker audio pair was subjected to a different reconstruction and amplification regime to that of the rear channel (as evidenced by differently valued pull-up resistors and filter-capacitors in the area forward of the AC'97 chip, in the specifications of the AC'97 itself, and in the use of different amplifier Op-Amps).

The rear channel was serviced by a separate, but arguably better Philips UDA1334 DAC, yet the Op-Amp used to boost the signal to output levels had a noticeably different frequency response envelope that was not normalized to the front channel, leaving a "thin and quiet" rear channel. To make matters worse, the rear channel Op-Amp was of the inverting variety without being treated as such, leaving the rear speakers out of phase with the front, requiring switchover. These problems were not encountered by those using the Gold editions' daughterboard 4-speaker digital-output, but the tendency of the AC'97 chip to fail when used as an input source to medium-impedance musical instruments removed the use of the front channels altogether, although the chip could be sourced from cheaper AC'97 compatible products and soldered into place. Nevertheless, simply redirecting front signal to rear output of SB Live! was for a long time a favorite trick for computer audio enthusiasts who want better sound for minimum of money.

Despite these problems, the original SB Live! can still be used well as a S/P-DIF input/output and MIDI input/output device for network-connected digital audio workstation environments.