Not all metal detectors work the same way, and picking the wrong type can cost you time and treasure. You might walk right past a deep coin, get confused by constant false signals, or spend hours digging up bottle caps instead of real finds. The technology inside your detector decides how well it finds targets and how clearly it tells you what they are. Three main technologies power most detectors on the market today: VLF, PI, and Multi-Frequency.
Each of these technologies was built to solve different problems. VLF shines at telling metals apart, PI digs deep through tough ground, and Multi-Frequency tries to give you the best of both. These differences matter whether you are coin shooting in a park, prospecting for gold in the mountains, or combing a saltwater beach. In this article, our team at Garrett explains how each technology works, where it performs best, and how to match a detector to your specific goals.
| Detector Type | Pros | Cons | Best For |
| VLF (Very Low Frequency) | Strong discrimination, lightweight, sensitive to small targets, low battery use | Struggles in mineralized soil and saltwater | Coin shooting, relic hunting, dry-land detecting |
| PI (Pulse Induction) | Excellent depth, unaffected by mineralized ground or black sand | Less discrimination, higher battery drain | Gold prospecting, deep treasure hunting, saltwater beaches |
| Multi-Frequency | Handles mixed terrain and ground interference well | More controls, settings to learn | All-terrain hunting, beach detecting |
Every metal detector relies on the same basic idea. The detector’s search coil sends a magnetic field into the ground. When that field encounters a metal object, the metal disrupts the field and sends back a signal. The detector reads that signal and alerts you with a tone, a number, or both, depending on the model.
What separates VLF, PI, and Multi-Frequency is not the basic idea but the method each one uses to create and read that magnetic field. Some technologies are better at reading subtle differences between metals. Others are better at pushing the signal deeper into the ground. The way each detector generates and interprets its field is the real source of its strengths and weaknesses.
The technology inside your detector shapes nearly every part of your hunting experience. It affects how deep you can detect, how well the machine tells valuable metal from junk, and how it performs in tricky ground conditions like mineralized soil or saltwater sand. It also affects how sensitive the detector is to tiny targets and how long the battery lasts during a long day in the field. The table below breaks down the main factors that change depending on which technology your detector uses.
| Factor | Why It Matters |
| Detection depth | Determines how far underground a target can be and still be detected |
| Discrimination | Helps you tell valuable targets apart from iron and trash |
| Performance in mineralized soil, sand, or saltwater | Some technologies struggle with false signals in these conditions |
| Sensitivity to small targets | Affects whether tiny coins, nuggets, or jewelry get picked up at all |
| Battery life and weight | Impacts comfort and detecting time during long sessions |
VLF detectors send out a steady, continuous sine wave through the search coil. This wave is what creates the magnetic field that interacts with metal targets in the ground. Because the wave is constant rather than pulsed, the detector can closely study how it changes when it hits something metal.
When a target disturbs the wave, the detector studies a shift in the timing of the signal, known as a phase shift. This phase-shift analysis lets the machine make an educated guess about what kind of metal is in the ground before you ever dig. That is why VLF detectors are known for giving helpful clues about target identity right on the display.
VLF detectors are a favorite for coin shooting because they can tell a clad coin from a piece of foil or a pull tab with good accuracy. They also perform well for relic hunting, where knowing the likely target type can save a lot of digging in old fields and farmland. VLF technology shines across several everyday detecting scenarios, including:
VLF technology also shows up in light security screening, especially in settings where identifying the type of object matters as much as finding it. Because the discrimination is strong, operators can filter out everyday metal items and focus on items that need closer attention. This makes VLF a flexible choice for both hobby and light professional use.
The biggest strength of VLF technology is its ability to tell the difference between valuable targets and junk like iron and foil. This saves time and effort by helping you decide what is actually worth digging up. Strong discrimination is one of the main reasons VLF remains the most popular detector type for hobbyists.
VLF detectors are also highly sensitive to small targets. This makes them excellent at finding tiny rings, thin coins, and small jewelry that other technologies might overlook. For anyone hunting in areas already searched by others, this sensitivity can uncover finds that were missed before.
Ready to put VLF technology to work for your next hunt? Garrett offers an industry-leading selection of VLF detectors built for coin shooting, relic hunting, and everyday detecting on dry land – browse our Vortex series lineup today!
PI detectors take a different approach than VLF machines. Instead of a steady wave, they send rapid bursts of high-voltage current through the coil. Each burst creates a brief but powerful magnetic field that reaches into the ground.
After each burst, the detector measures how quickly the reflected signal decays, or fades away. Metal targets cause that decay to happen differently than the surrounding soil does. By reading this decay rate, PI detectors can sense metal even through soil conditions that would confuse other technologies.
PI detectors are widely used for deep treasure hunting and in mineralized grounds, since their design allows the signal to push further into the ground than VLF technology typically allows. Gold prospectors also rely heavily on PI machines, especially in areas with mineral-rich soil that would overwhelm a VLF detector with false signals.
Saltwater beach detecting is another strong use case, since PI technology is not thrown off by salt and moisture the way VLF is. Outdoor security sweeps in mineral-rich or wet terrain also benefit from PI detectors, since they can maintain reliable performance where other technologies would struggle.
The standout advantage of PI detectors is depth in challenging, mineralized environments. They can often detect targets buried deeper than VLF machines can reach, which makes them valuable for serious treasure hunters and prospectors. This added depth can mean the difference between finding a deeply buried relic and walking right over it. PI technology delivers reliable performance across some of the toughest hunting conditions, including:
PI detectors are also less affected by mineralized soil or black sand. While these conditions cause problems for VLF machines, PI technology reads the ground in a way that ignores most of this interference. This reliability is a major reason PI detectors are the standard choice for gold prospecting.
Ready to chase depth most detectors can’t reach? Garrett’s lineup of PI detectors is built for exactly that. Take a look and find your perfect match.
Multi-Frequency detectors send out several frequencies at the same time, a method often called Simultaneous Multi-Frequency, or SMF. Rather than relying on just one frequency like a typical VLF detector, the machine processes multiple signals at once.
This approach effectively runs a low-frequency detector and a high-frequency detector at the same time inside one machine. Low frequencies tend to perform better at depth and in finding highly conductive metal targets, while high frequencies are better at picking up small or delicate targets with lower conductivity. Combining them allows the detector to cover more ground conditions and target types without switching settings.
Multi-Frequency detectors are well suited for all-terrain hobby detecting, especially for people who hunt in parks, beaches, and mixed sites without wanting to switch machines. Saltwater beach hunting is another strong fit, since the combined frequencies help the detector handle salt interference better than a single-frequency VLF machine. Multi-Frequency technology holds up well across a wide range of detecting conditions, including:
These detectors also perform well in iron-heavy or mineral-rich ground, where a typical VLF unit might struggle. Simultaneous multi-frequency detectors have the ability to maintain better Target ID analysis in soils that are more mineralized.
Multi-Frequency technology combines strong Target ID performance with sensitivity to small targets, something that is hard to achieve with a single-frequency machine. This balance makes it a strong all-around choice for detectorists who hunt in more than one type of environment.
These detectors generally ignore ground interference better than single-frequency machines. Because multiple frequencies are being processed at once, the detector can filter out mineral noise more effectively, leading to cleaner signals and fewer false alarms.
Want one detector that handles it all? Garrett’s lineup of Multi-Frequency detectors is built for exactly that. Take a look and see which one fits the way you hunt.
Each technology has clear strengths and weaknesses once you compare them directly. The table below lines up the most important factors so you can see exactly where each type stands out and where it falls short.
| Factor | VLF | PI | Multi-Frequency |
| Discrimination | Strong | Weak | Strong |
| Detection depth | Moderate to strong in mild soils | Strong | Strong |
| Mineralized ground/saltwater performance | Weak | Strongest | Strong |
| Power consumption | Low | High | Moderate |
| Typical cost | Low to moderate | Moderate to high | Moderate to high |
This comparison shows why no single technology is the automatic best choice for everyone. The right pick depends heavily on where you plan to hunt and what kind of targets matter most to you.
At the end of the day, there is no single best metal detector, only the right detector for how and where you hunt. VLF technology rewards precision on dry land, PI technology rewards depth in tough ground and saltwater, and Multi-Frequency technology rewards versatility across mixed terrain. Once you know your primary activity and hunting environment, the right technology becomes obvious rather than a guessing game.
Reposted from Garrett.com with permission as a licensed dealer.
