Quest Tech. Inc. offer the SoundPro DLX, a powerful handheld acoustic measurement system. This hand-held acoustic measurement system is built around a digital signal processor (DSP) platform and a color graphics PDA-style user interface with backlighting for operation in dark environments, plus adjustable screen contrast for use in bright conditions. The SoundPro DLX uses real-time frequency analysis to reduce testing times for octave and 1/3 octave analysis efforts by 91 percent and 97 percent respectively. Because all spectral data is captured in real-time, test results are far more reliable ' accurate than traditional sound levels meters with sequential octave band analysis.