This sensor is a micro lectrodynamique al (thanks a sort of pate fixed) against the soundboard of the bass. I used more than two years.
The acoustic sound reproduction is fairly good but not making direct use interface to record his (very bad sound and EQ ncessaire).
Live, use this sensor with XLR. A jack is possible, but the volume is much lower, which means that a traditional bass amp with jack, has a intrt of that small room, without battery and instrument noisy. We must therefore go through a PA system but you have to watch out for feedback. Filter around 150 Hz (which is the frquence rsonnance of the instrument) is ncessaire. Note that this filter is included in the Pramp of Shertler. Otherwise, one will be qualisation couraging to dig around the frquence of rsonnance.
The price is prohibitive limit (about 800 new). Despite the quality of the product, I do not see a justification. The ratio quality price is pretty bad.
In the end, I prfre sensor "the realist" is a piezo located between the foot of the bridge (ct E string) and the soundboard