Metal detector frequencies explained

What kHz means on a metal detector

Frequency is the rate at which a continuous-wave detector's transmitted field cycles. A detector operating at 15 kHz transmits 15,000 cycles per second. The number describes part of the electromagnetic system; it does not tell you how deep every target will be detected.

Minelab's detector technology overview describes lower frequencies as tending toward larger, higher-conductive objects and higher frequencies as tending toward small or thin targets. Treat those as tendencies. A small silver coin on edge, a corroded bronze object beside iron and foil close to the surface do not follow a simple chart.

Low, middle and high frequencies in practice

Lower frequencies are often associated with larger conductors such as copper and silver coins. They may provide a calmer response to some small foil, but can miss the emphasis a higher frequency gives to tiny or low-conductive targets.

Middle frequencies around the common general-purpose range balance target sizes and conductivities. They are used by many affordable field detectors because they work capably across ordinary coins, relics and modern rubbish.

Higher frequencies can improve sensitivity to very small, thin or low-conductive metal. That is useful for tiny hammered coins and specialist natural-gold detecting, but it can also make small foil and ground effects more obvious. More responses are not automatically more useful responses.

Fixed frequency

A fixed-frequency detector operates at the frequency chosen by its design. This keeps controls simple and cost down. The Nokta SIMPLEX Lite uses 15 kHz, while the Garrett ACE 300i operates at 8 kHz. Either can be effective on suitable inland ground when the operator maintains a level, overlapping sweep.

Fixed frequency becomes limiting when regular wet salt sand or severe electrical interference is central to the plan. It is not obsolete: stability, ergonomics and understandable audio often matter more to a beginner than a long feature list.

Selectable frequency

A selectable machine provides several frequencies but operates the chosen one. The X-TERRA PRO offers inland choices and a separate beach frequency. A detectorist can move frequency to reduce interference or change target emphasis, but needs to understand why the change is being made.

Do not call this simultaneous multi-frequency. Retail copy sometimes shortens both technologies to “multi-frequency”, which hides a meaningful distinction. Check the manufacturer's technical specification.

Simultaneous multi-frequency

A simultaneous system transmits and processes information from multiple frequencies together. This is particularly useful across changing ground and conductive wet salt sand. It can also support steadier target classification across a wider target range, although no system turns target ID into certainty.

The X-TERRA ELITE is one simultaneous Multi-IQ example with inland and beach profiles. It also offers a 15 kHz option, showing that a multi-frequency detector may include a separate single-frequency mode for a specific task.

Our multi-frequency versus single-frequency comparison covers the buying decision in more detail.

Frequency does not work alone

Coil diameter and shape change ground coverage, separation and sensitivity. Recovery processing affects whether two close objects become distinct signals. Ground balance reduces the response from soil minerals, while sensitivity controls how readily weak changes become audio. Search profiles can alter several of these behaviours together.

This is why two 15 kHz detectors may behave differently. The frequency label cannot describe the coil, filtering, target scale, waterproofing, weight or interface.

A practical way to choose

For dry inland permissions and a limited budget, a well-made fixed-frequency detector can be enough. For someone who enjoys adjusting controls and faces varied interference, selectable frequency offers useful flexibility. For regular transitions between field, park, dry beach and wet salt sand, simultaneous multi-frequency is the strongest general option.

Pulse induction is a different technology rather than the next frequency tier. Read VLF versus pulse induction if severe mineralisation or specialist beach work is the real problem.

Learn one stable profile first

Use the factory profile that matches the ground, run noise cancel where available and test ordinary coins, foil and iron. Change only one setting, then repeat the same sweeps. If a different frequency helps, note the target, ground and interference conditions. That field record is more useful than memorising that one kHz number is “for coins”.