Our linearized velocitimeters SS-10/05/02 and 01 are manufactured with the geophone cell with an eigen-frequency of 4.5 or 2 Hz. The signal is equalized by a electronic circuit board with the Lippmann method that is used since few decades.
In spite of some limitation that this technique gives, is it possible to have a flat band wider than the natural band of the geophone, moving the eigen-frequency at lower value. This method is effective for the noise survey (HVSR) because the sensors can bear better the tilting. The high value of amplification (400 V/m/s) helps if you are using a very cheap (low signal-to-noise ratio) or an old digitiser.
Is it possible, before the manufacture, to choose a different level of sensibility (800, 1200 or 2400 V/m/s).
The 1 and 0.5Hz use the 4.5Hz cell; the 0.2 and 0.1Hz use the 2 Hz sensor. Those last have a physical blocking system for the sensor to preserve the integrity of the cell while moving the sensor.
In relation on what digitiser is used with them, it is possible to use those sensors in a very wide range of applications from Nakamura (HVSR), seismic or engineering monitoring (Seismic monitoring Oil & Gas reservoir monitoring, Early Warning, structural monitoring and modal analysis of a building).