Seismic recording hardware must be a deliberately designed system to extract and record high-resolution information faithfully. The single most critical element of this system is the detector. The detector chosen must be capable of faithfully generating the passband expected and furthermore, must be carefully coupled to the ground.Another important factor is to shape the energy passband so that it is as flat and broad as possible. This involves low-cut filtering of the data before A/D conversion so the magnitude of the low-frequency signal does not swamp the high-frequency signal. The objective is to permit boosting the magnitude of the high-frequency signals to fill a significant number of bits of the digital word. Judicious use of a low-cut filter is the main element of this step, although detector selection is also a factor because detectors have a -6 dB/octave velocity response at frequencies less than the resonant frequency of the detector.Finally, recording instrument quality must be good. Amplifiers should have low system noise, large dynamic range, and precision of 12 or more bits.