Geofón
- High sensitivity contact microphone
- Omnidirectional vibration pickup
- Usable frequency range 20 Hz – 1 kHz, naturally flat above 20 Hz
- Professional XLR-3M output
- Balanced gold-plated Neutrik connector
- Includes neodymium magnet, spike and suction cup for mounting
| Parameter | Value |
|---|---|
| Type | Omnidirectional geophone |
| Open-circuit sensitivity | 88 V/(m/s) |
| Natural frequency | 20 Hz |
| Coil DC resistance | 3500 Ω |
| Recommended recorder input impedance | 2 kΩ (for flat response; higher values can be compensated — see damping compensation) |
| Spurious frequency | > 400 Hz |
| Usable frequency range | 20 Hz – 1 kHz (12 dB/oct rolloff below 20 Hz; diminishing fidelity above 400 Hz) |
| Output | XLR-3M balanced gold-plated Neutrik |
| Dimensions | 52.5 mm × ⌀36.5 mm |
| Weight | 190 g (with cable and magnet) |
| Operating Temperature | -10 to +55°C |
| Storage Temperature | -25 to +70°C |
Read this before first use
- Neodymium magnets may cause interference with credit cards (magnetic stripes), cardiac pacemakers and ICDs.
- Geofón is weather-resistant, but not waterproof. Do not submerge it, and keep sustained water away from the XLR connector and cable gland.
- Avoid hard drops. The geophone element is a coil suspended on thin springs — drops onto hard surfaces from waist height or higher can damage the suspension. See what if I drop it?
- Due to the nature of the geophone sensor, you may experience electromagnetic interference in specific urban areas and places with strong electromagnetic fields.
Will it work with my recorder?
Yes, if it has a balanced XLR microphone input. Geofón is a fully passive transducer — no phantom power, no batteries, no electronics. Its output level is comparable to a sensitive dynamic microphone, which any field recorder's preamp handles without difficulty. Do not use phantom power — it will not damage the Geofón, but it provides no benefit. For perfectly flat response the element wants a ~2 kΩ input impedance; on higher-impedance recorders the 20 Hz resonance is more pronounced — see which recorders match and the optional damping compensation.
Quick start
- Mount the Geofón: the bottom of the case has an M4 thread for the provided neodymium magnet, suction cup, or spike (via the extender).
- Connect a standard balanced XLR cable from the Geofón to your recorder's mic input.
- Set the gain, and enable your recorder's high-pass filter if you don't want the infrasonic content — Geofón has genuine output well below 20 Hz.
- Experiment with placement. Mounting is part of the signal path: rigid contact transmits faithfully, loose contact loses highs and rattles. Different spots on the same structure can sound dramatically different. Taping the cable to a rigid structure will reduce the cable noise transmission.
Mounting options
- Magnet — for ferrous surfaces: steel beams, fences, machinery, vehicle bodies. Excellent coupling, very repeatable.
- Spike (via extender) — for soil, soft wood, snow, sand. Works best firmly seated.
- Suction cup — for truly smooth surfaces: glass, polished stone, lacquered wood. Won't work on textured surfaces.
- None of the above? Firm contact under the Geofón's own weight works on rough surfaces — a heavy weight on top improves coupling. Gaffer tape or museum putty also work.
- For sensitive measurements, unscrew the bottom plastic part to expose the element and attach it directly with poster-hanging adhesive putty.
Good to know
- A clinking sound when shaking the Geofón is normal and expected. It is the inner coil suspended on springs.
- Orientation doesn't matter. The omni-tilt element works vertically, horizontally, upside-down, or at any angle.
Geofón hears the structural side of the world — not airborne sound, but the motion of the surfaces it touches. It shines on large structures (bridges, walls, scaffolding, fences, metal poles), tree trunks and root systems, ice on lakes and rivers, the ground itself — footsteps, traffic, distant machinery felt through soil — and heavy machinery, tunnels, and drainage pipes. Two Geofóns on the same structure make a compelling stereo pair. Less suited: small light objects (the geophone's mass loads them) and bright, stiff surfaces like glass, where a piezo's high-frequency emphasis serves better — see how it compares.
Cleaning. Wipe the housing with a slightly damp cloth. Avoid solvents — they can attack the polyurethane cable jacket and the cable gland seal.
Moisture. Keep moisture away from the XLR connector. Splashes, light rain, dust, and cold are fine for short sessions; for extended outdoor placement in unpredictable weather, add protection.
Handling. Avoid drops onto hard surfaces — the element's spring suspension is the one fragile thing inside. Casual handling is fine.
Storage. Store between −25 °C and +70 °C. Mind where the magnet ends up — keep it away from cards and medical implants.
- Low-frequency peak or boom in the recording → the element's undamped 20 Hz resonance, more pronounced on high-impedance inputs. By design and reversible — see why and the damping compensation.
- Ringing after impacts → same resonance, excited by impulses. See why it rings.
- Something moves inside when I shake it → normal — that's the suspended coil. See is it broken?
- Dropped it? → check for harsh rattle or lost sensitivity. See what to look for.
- Hum or buzz in the recording → likely electromagnetic interference; try a different location or reposition the cable.
Manual PDF download coming soon
Warranty. LOM products are covered by a two-year guarantee beginning on the date of purchase. Keep your proof of purchase — it is required for any claim. Within the guarantee period we will, at our discretion, repair or replace products with defects in materials or workmanship. The guarantee does not cover damage caused by misuse, mechanical damage, moisture, unauthorized modification, or use with third-party cables or power sources outside the published specifications. Destructive opening of certain parts of the product voids the warranty.
Repairs. Before sending anything back, contact us with a description of the problem and your proof of purchase — many issues can be resolved without shipping.
Declaration of conformity. This product complies with the applicable European directives, including EMC Directive 2014/30/EU, when used with cables and accessories supplied by LOM.
Disposal. Do not dispose of the product in household waste. Like all electrical and electronic equipment, it must be handed in at a WEEE collection point at the end of its life.
Manufacturer: LOM s.r.o., Jelenia 10, 811 05 Bratislava, Slovakia · store.lom.audio