Audio Surveillance Detection · Wired Devices
Wired Audio Device Detection
Professional detection of hardwired listening devices, series and parallel wire taps, and embedded audio surveillance systems.
Covert listening systems range from a single concealed microphone connected to a recorder in an adjacent space to a fully networked audio monitoring installation drawing power from building wiring. Wired audio devices present a particular detection challenge: because they have no RF transmission signature, standard RF detectors find nothing. These devices require non-linear junction detection (NLJD) — a specialized instrument that emits a microwave signal and detects the harmonic response of semiconductor components, identifying electronic devices regardless of whether they are powered, transmitting, or even assembled.
Empire Investigation LLC uses professional NLJD instruments as standard equipment in every sweep. This ensures that passive, hardwired, and non-transmitting devices receive the same detection thoroughness as actively transmitting equipment. No device is safe from a properly conducted professional sweep.
Wireless transmitters — the device most people think of when they think "bug" — are among the easiest for professionals to detect, because they actively broadcast an RF signal. Our spectrum analyzers, both broadband and swept-frequency, identify transmission signatures across the full RF spectrum including the sub-GHz bands commonly used by covert devices.
How Wired Audio Devices Operate
Wired audio devices draw power directly from a building's electrical infrastructure or operate on internal batteries and transmit audio through a physical wire connection rather than a wireless signal. These devices may route audio through telephone lines, power lines, dedicated wire runs, or structural conduits — making them entirely invisible to RF-based detection.
Common Placement Methods
Wired devices are typically installed during construction or renovation, during after-hours facility access, or by individuals with access to wall cavities and utility spaces. Electricians, contractors, and maintenance personnel with facility access are common vectors for hardwired device installation. Once installed, these devices can operate indefinitely without battery replacement.
What We Look For
- Series telephone taps installed on landline infrastructure
- Microphones hardwired into wall cavities and routed through conduit
- Power line carrier devices transmitting audio over electrical wiring
- Embedded audio devices connected to building security or AV systems
- Induction coils capturing phone conversations without line contact
Our Sweep Process
Physical Inspection
Systematic examination of walls, cavities, and electrical access points.
Electrical System Analysis
Testing of power lines and infrastructure for carrier-based audio transmission.
Telephone Line Testing
Electronic analysis of line characteristics for tap devices.
NLJD Detection
Identification of electronic components within walls or structural cavities.
Documentation
Formal report of all discovered devices and installation methods.
Frequently Asked Questions
Confidential Inquiry
Schedule a Confidential TSCM Sweep
If you suspect surveillance or want to verify your environment is secure, professional detection is the only way to know with certainty.
All inquiries handled with complete discretion.