Abstract: A downhole acoustic logging tool having a random access memory for storing acoustic waveforms in digital format. The waveforms being transmitted from a surface logging system to the random access memory in the downhole logging tool. The logging tool playing back the stored waveforms by converting the stored digital format into an analog signal that is amplified sufficiently for driving an acoustic transmitter. A received pilot signal is used to determine the signal attenuation of the logging cable and a correction is made therefrom to the actual received acoustic signal. Complex waveform types may be programmed into the random access memory for specific formation characteristics. Tapered turn-on and turn-off of the signal waveform amplitudes reduce higher frequency spectral noise that may interfere when correlating the received acoustic signal with the transmitted acoustic signal.