there's a dearth of geophones available right now, unless you want to go with used from ... eastern europe. there is one brand that is available, and it is $60-

there's a dearth of geophones available right now, unless you want to go with used from ... eastern europe. there is one brand that is available, and it is $60-$70. A geophone is a metal canister; and in a simple form, a magnet is suspended by two springs and encircled by an electromagnet inside that canister, with wire leads as output. The more tuned the magnets and springs are, the lower the frequency they can detect. Also, a sound card can be used as the ADC, we're talking about sub 200hz for every commercial geophone, and ideally sub 10hz. think of the decimation! There's no reason for used and oxidized stuff to go for $40, and "new" $70. Someone want to explain what happened to all the $30 geophones that were on amazon, adafruit(and digikey, etc) and ebay a couple of years ago?