Simultaneous Multi-Frequency vs Single Frequency: What's the Difference?
Simultaneous multi-frequency has become one of the most heavily promoted technologies in modern metal detecting. Look across current machines from Minelab, Nokta and XP and you'll see Multi-IQ, Multi-IQ+, FMF and other versions of the same broad idea appearing everywhere from relatively inexpensive detectors to premium machines costing well over £1,000.
It's tempting to reduce the argument to something simple: multi-frequency is newer, therefore multi-frequency is better.
The evidence from the 12 detectors we've researched doesn't support such a neat conclusion.
The Nokta Simplex Ultra operates at a fixed 15 kHz yet gives the user plenty of control over recovery, tones and discrimination. The Minelab X-Terra Pro and XP Deus 1 allow the detectorist to choose between different frequencies but still operate one at a time. At the other end of the spectrum, machines including the Nokta Legend, Minelab Equinox 900, XP Deus II and Minelab Manticore can operate in simultaneous multi-frequency while also allowing selectable single-frequency operation.
Then there are detectors such as the Minelab Vanquish 360 and 560, which use simultaneous multi-frequency but deliberately give the user relatively little control over the frequency system itself.
So the useful question isn't simply whether a detector is "multi-frequency". It's what type of frequency system it uses, what choices it gives you and whether those differences matter on the ground you actually detect. Simultaneous Multi-Frequency vs Single Frequency, let's dive in.
Three Different Types of Frequency System
Across our 12 researched detectors, the frequency systems can broadly be divided into three groups.
Frequency approach | Examples from our research | What it means |
Fixed single frequency | Nokta Simplex Ultra | Detector operates at one fixed frequency |
Selectable single frequency | Minelab X-Terra Pro, XP Deus 1 | User can choose from several frequencies, but only one operates at a time |
Simultaneous multi-frequency | Vanquish 360/560, Score, X-Terra Elite, Legend, ICON, Equinox 900, Deus II, Manticore | Detector can work with multiple frequencies simultaneously |
Several of the simultaneous multi-frequency machines also provide selectable single-frequency operation. That includes the Score, X-Terra Elite, Legend, ICON, Equinox 900, Deus II and Manticore, although the number and range of selectable frequencies varies considerably between them.
This is an important distinction because "multi-frequency detector" doesn't necessarily mean you're permanently locked into multi-frequency operation. On many more advanced machines, simultaneous multi-frequency is one option within a much broader frequency system.
What Does Frequency Actually Change?
A metal detector creates an electromagnetic field using its search coil and measures how buried conductive objects affect that field. The operating frequency is one part of that process, and changing it alters the way the detector responds to different targets and conditions.
As a broad principle, lower frequencies are commonly associated with greater response to larger and higher-conductive objects, while higher frequencies tend to increase sensitivity to smaller and lower-conductive targets. Manufacturers use this distinction when explaining why selectable-frequency detectors offer different operating frequencies.
It is useful as a principle, but it shouldn't be turned into a simplistic rule that low frequency equals deep and high frequency equals shallow. Target size, conductivity, orientation, coil size, ground mineralisation, moisture, sensitivity, recovery settings and surrounding metal can all affect what happens in the field.
Our X-Terra Pro evidence illustrates this well. Minelab provides 5, 10 and 15 kHz in Park and Field, allowing the detectorist to select a frequency appropriate to what they're trying to achieve. Beach mode, however, operates at 8 kHz rather than offering the same frequency choices.
The detector therefore gives the user frequency flexibility, but only one selected frequency is working at any particular time.
Fixed Single Frequency: The Simplex Ultra Example
The Nokta Simplex Ultra is the clearest example of fixed single-frequency technology in our 12-machine comparison. It operates at 15 kHz, so there is no choice of frequency and no simultaneous multi-frequency processing taking place.
That sounds basic compared with a detector advertising five selectable frequencies and a simultaneous multi-frequency mode, but it doesn't mean the rest of the Simplex Ultra is basic. Nokta provides six search modes, adjustable recovery speed, tone controls, notch discrimination and manual ground balance, giving the detectorist considerable influence over how the machine behaves.
This makes the Simplex Ultra useful for understanding the difference between frequency technology and overall detector capability. A machine can have a relatively simple frequency system while still providing meaningful control over target separation, audio and ground response.
Independent evidence in our research is reasonably positive about the Simplex Ultra for general inland detecting. The limitations become more apparent when conditions themselves become difficult, particularly conductive wet salt and mineralised ground.
That is where simultaneous multi-frequency becomes more interesting.
Selectable Frequency: One Detector, Several Choices
The Minelab X-Terra Pro takes a different approach. Instead of fixing the detector at one frequency, Minelab's PRO-SWITCH system lets the user choose between several.
Park and Field offer 5, 10 and 15 kHz, while Beach uses 8 kHz. Only one frequency operates at a time, which is why the X-Terra Pro must be described as selectable single frequency rather than multi-frequency.
The advantage is flexibility. Instead of buying a detector permanently designed around 15 kHz, the user can change the operating frequency to suit different targets or conditions. That gives the detectorist another useful setting to experiment with alongside Recovery Speed, Ground Balance, sensitivity and audio.
UK owner reports describe the X-Terra Pro as an approachable and capable machine, but they also illustrate why frequency is only one part of detector behaviour. One owner found high sensitivity at 15 kHz increasingly jittery, while deep Target IDs could become difficult to interpret. Other contributors regarded simultaneous multi-frequency machines as the more obvious upgrade path.
None of that demonstrates that selectable single frequency is ineffective. Plenty of successful detecting has been done with single-frequency machines. What it shows is that having several frequencies available isn't the same thing as using several frequencies together.
XP Deus 1 Shows How Far Selectable Frequency Can Go
The XP Deus 1 is another useful example because it demonstrates that selectable single-frequency technology isn't confined to inexpensive or simple detectors.
Deus 1 developed a strong reputation as a highly configurable, extremely lightweight detector. Its available frequencies depend on which XP coil is fitted, with X35 and HF coils providing different frequency ranges.
Like the X-Terra Pro, however, the fundamental principle is selection rather than simultaneous operation. The detectorist chooses a frequency and the machine operates using that selection.
That didn't stop Deus 1 becoming particularly well regarded for fast recovery, iron separation and detailed audio. The owner evidence in our research repeatedly highlights those characteristics, which is a useful warning against treating frequency technology as a complete measure of detector performance.
A detector's recovery behaviour, coil, audio, discrimination, ground handling and the skill of the person using it remain important. Simultaneous multi-frequency adds another tool; it doesn't make every other aspect of detector design irrelevant.
So What Does Simultaneous Multi-Frequency Do Differently?
Instead of choosing one operating frequency, simultaneous multi-frequency systems work with multiple frequencies as part of the same detection process.
The exact implementation differs between manufacturers. Minelab uses names such as Multi-IQ and Multi-IQ+, while XP uses FMF — Fast Multi Frequency. Nokta uses its own simultaneous multi-frequency systems across machines including the Score and Legend.
We shouldn't assume that these systems are technically identical simply because they fall under the same broad category. Manufacturers don't disclose every aspect of their signal processing, and the number of frequencies printed in a specification doesn't necessarily tell you exactly how a detector processes them in each search mode.
What they share is the ability to use frequency information simultaneously rather than requiring the detectorist to choose one operating frequency for the sweep.
In practical terms, that is intended to give the detector a broader response across different targets and ground conditions without asking the user to constantly decide which single frequency is most appropriate.
Vanquish Shows That SMF Doesn't Have to Be Complicated
The Minelab Vanquish range is probably the best example of simultaneous multi-frequency being used to simplify detecting rather than make it more technical.
Both the Vanquish 360 and 560 use Multi-IQ, but neither asks the detectorist to choose which frequencies should be running. The system works in the background while the user deals with a much smaller collection of settings.
The Vanquish 360 takes this furthest. It provides Park, Beach and All Metal modes, five sensitivity levels and relatively simple discrimination and audio. There is no menu full of selectable frequencies to understand because Minelab has deliberately kept the frequency technology away from the user.
The Vanquish 560 adds considerably more control over things such as Iron Bias, ferrous volume and discrimination while retaining the same basic Multi-IQ philosophy.
This is worth noting because simultaneous multi-frequency is sometimes associated with advanced detectors and complicated menus. It doesn't have to be. A manufacturer can use sophisticated frequency processing underneath a deliberately simple interface.
Score Makes the Same Point in a Different Way
Nokta's Score provides another useful comparison. It uses simultaneous multi-frequency and offers M1, M2 and M3 multi-frequency selections, while Park and Field can also operate at a selectable 15 kHz. Beach uses simultaneous multi-frequency only.
Yet the basic Score deliberately omits several controls found on Nokta's fixed-frequency Simplex Ultra. Recovery speed isn't adjustable, for example, and tone and discrimination options are more restricted.
This produces an unusual comparison. At the same researched price of £299.95, the Simplex Ultra gives the user more manual adjustment around a fixed 15 kHz platform, while the Score provides simultaneous multi-frequency but makes more of the decisions internally.
Again, frequency technology and overall detector complexity are separate things.
The Score gives you the more sophisticated frequency system. The Simplex Ultra gives you more control over several other aspects of detector behaviour.
Why Does SMF Get So Much Attention for Beach Detecting?
Conductive wet salt is one of the clearest situations where frequency technology becomes particularly relevant.
Salt water itself is conductive, which means a detector isn't simply trying to identify a metal target against neutral sand. It also has to deal with a conductive background that can produce unwanted responses and instability.
Single-frequency detectors can be designed with dedicated beach modes and can certainly find targets on beaches. The Simplex Ultra has a Beach mode, while the X-Terra Pro uses a dedicated 8 kHz Beach frequency.
The important point is that successful beach use and optimum wet-salt behaviour aren't necessarily the same thing.
Within our dataset, several manufacturers specifically use simultaneous multi-frequency in their beach modes. The Nokta Score operates Beach in SMF only, the X-Terra Elite uses Multi-IQ in Beach, and Minelab's higher Multi-IQ machines also use multi-frequency processing for salt conditions.
This provides a strong technological reason why regular wet-salt detectorists tend to pay particular attention to SMF machines.
What our research doesn't provide is a controlled UK beach test across all 12 detectors. We therefore shouldn't turn that technological advantage into a fabricated ranking showing how much better one detector performs than another.
Does SMF Automatically Mean Better on Inland Fields?
This is where the argument becomes much less clear-cut.
Most UK inland detecting isn't conducted on wet salt. Pasture, cultivated fields, woodland and stubble present their own challenges, including mineralisation, iron contamination and closely spaced targets, but frequency is only one part of how a detector deals with them.
The Deus 1 evidence is a useful example. It is not an SMF detector, yet owners repeatedly value its recovery speed and performance around iron. Likewise, the Simplex Ultra gives the user adjustable recovery speed despite operating at one fixed frequency.
By contrast, the basic Nokta Score has simultaneous multi-frequency but doesn't allow the user to adjust recovery speed.
If the problem on a particular field is separating a small non-ferrous target sitting very close to iron, recovery behaviour, coil size, discrimination and audio may be every bit as important as whether several frequencies are being transmitted.
SMF gives the detector more frequency information to work with. It doesn't automatically solve every other detecting problem.
What About Mineralised Ground?
Mineralisation is another area where manufacturers promote simultaneous multi-frequency systems, and there are sound reasons for wanting a detector capable of handling changing ground conditions without relying on one operating frequency.
The difficulty is proving how large the advantage is in real UK detecting.
Our evidence contains reports of SMF detectors operating successfully in difficult ground, but the conditions aren't sufficiently controlled across the 12 machines to produce a reliable numerical comparison. Mineralisation itself varies enormously, as do targets, coils and settings.
The safest conclusion is therefore a practical one. SMF gives the detector another way of dealing with difficult ground and can reduce the need to choose a single frequency around those conditions, but it doesn't remove the need for sensible Ground Balance, sensitivity and recovery settings where those controls are available.
A badly configured multi-frequency detector can still be noisy and difficult to interpret.
Why Do Advanced SMF Detectors Still Offer Single Frequencies?
This is perhaps the strongest evidence that single-frequency operation hasn't simply become obsolete.
The Nokta Legend provides simultaneous multi-frequency but also allows selectable 4, 10, 15, 20 and 40 kHz operation. The Minelab Equinox 900 combines Multi-IQ with selectable 4, 5, 10, 15, 20 and 40 kHz. Manticore provides Multi-IQ+ alongside selectable 5, 10, 15, 20 and 40 kHz, while XP Deus II combines FMF with selectable mono-frequency operation.
If simultaneous multi-frequency were universally superior in every situation, there would be little reason for manufacturers to retain those options on their more advanced detectors.
Selectable single frequencies give an experienced operator another tool. A particular frequency may be useful when concentrating on certain targets, investigating interference or deliberately changing the detector's response.
The difference is that these machines don't force you to choose between owning an SMF detector and owning a selectable-frequency detector. They provide both approaches in one platform.
X-Terra Pro and X-Terra Elite Show the Difference Particularly Well
Few comparisons illustrate the technology change more clearly than Minelab's X-Terra Pro and X-Terra Elite.
Physically, the machines are closely related. Both weigh around 1.3 kg, are waterproof to 5 metres and normally use the V12X 12 × 9-inch coil. Both provide Park, Field and Beach modes along with adjustable Ground Balance and Recovery Speed.
The Pro uses selectable single frequencies: 5, 10 or 15 kHz in Park and Field, and 8 kHz in Beach.
The Elite adds Multi-IQ. Park and Field can operate in simultaneous multi-frequency or selectable 15 kHz, while Beach uses Multi-IQ.
This means the move from Pro to Elite isn't simply about gaining more settings. The Elite changes the underlying frequency system while retaining the more adjustable X-Terra approach.
UK owner evidence for the Elite includes positive reports around small targets, iron separation and Target ID information at depth. What we don't have is a controlled Pro-versus-Elite test proving that Multi-IQ adds a particular amount of depth or a specific percentage improvement.
The technology difference is clear. Quantifying the real-world advantage isn't.
Legend, Equinox 900 and Deus II: SMF Plus Choice
Machines such as the Nokta Legend, Minelab Equinox 900 and XP Deus II represent the more flexible end of the argument because they don't really ask the detectorist to choose a side.
All three provide simultaneous multi-frequency operation alongside selectable single-frequency options. They then add extensive control over other parts of the detector, including recovery behaviour, discrimination, ground settings and audio.
That changes the role of frequency selection. On a simpler selectable-frequency detector, choosing a frequency is fundamental because the detector can't operate several simultaneously. On an advanced SMF machine, switching into a single frequency becomes an optional tool rather than a necessity.
For a detectorist who simply wants a capable general-purpose programme, SMF can do much of the frequency decision-making in the background. Someone who wants to experiment or address a particular problem can move into a selectable frequency and see whether the detector behaves differently.
This flexibility is one reason advanced detectors can take longer to learn. They don't just give you better technology; they give you more ways to decide how that technology should be used.
Is Multi-IQ+ Better Than Multi-IQ? Is FMF Better Than Both?
These names belong to different manufacturers and shouldn't be treated as directly comparable specifications.
Minelab describes Manticore's Multi-IQ+ as its more powerful development of Multi-IQ, while XP's FMF system is designed around XP's own wireless coil architecture and programme structure. Nokta's simultaneous multi-frequency implementation operates within yet another detector platform.
There isn't enough controlled evidence across our 12-machine research to declare one manufacturer's SMF system universally superior to another.
Nor would comparing the number of selectable frequencies settle the question. A detector listing six frequencies isn't automatically better than one listing five, because frequency choice is only one part of the complete signal-processing system.
Real detector performance depends on the entire machine: coil, software, recovery behaviour, ground handling, discrimination, audio, settings and the operator interpreting the response.
Brand names for frequency technology don't replace field evidence.
Does Simultaneous Multi-Frequency Detect Deeper?
Not automatically, and our research doesn't support a simple SMF-versus-single-frequency depth table.
Depth comparisons are particularly difficult because apparently small differences in testing can change the result. Soil condition, target size, orientation, conductivity, moisture, mineralisation, coil size, sensitivity and recovery settings all matter.
Our X-Terra Pro evidence, for example, contains owner estimates of deep targets but explicitly warns against treating those figures as verified measurements because the conditions weren't controlled. The same problem appears elsewhere in the dataset.
Likewise, moving to a more expensive SMF machine doesn't guarantee a dramatic increase in maximum depth. Our Vanquish 560 evidence found improvements in Target ID stability and response to faint or small targets without establishing a major depth improvement over its predecessor.
SMF may contribute to better target information, stability or versatility without producing a headline increase in centimetres.
That is why "how deep does it go?" is often the wrong question when comparing frequency systems.
What Does Frequency Mean for Small Targets?
Higher frequencies are generally associated with increased sensitivity to smaller and lower-conductive targets, which is one reason advanced selectable-frequency machines extend well above the frequencies used by general-purpose detectors.
The Nokta Legend reaches selectable 40 kHz, as does the Equinox 900, while XP's coil-dependent frequency systems can extend considerably higher depending on the equipment being used.
That doesn't mean selecting the highest available frequency is automatically the best choice for every small target. Ground conditions, target composition and the rest of the detector's settings still matter.
SMF systems approach the problem differently by using a spread of frequency information rather than asking the operator to select one frequency and accept its particular characteristics.
For general detecting where the next target could be a tiny hammered coin, a larger copper object or modern rubbish, that broad approach is one of the attractions of simultaneous multi-frequency.
Does Single Frequency Still Have a Place?
Absolutely, and the current detector market itself demonstrates that.
The X-Terra Pro exists specifically as an adjustable selectable-frequency detector. Deus 1 remains widely used despite predating XP's FMF platform, while advanced machines such as Legend, Equinox 900, Deus II and Manticore deliberately retain selectable single-frequency operation alongside their SMF systems.
The important change isn't that single frequency has stopped working. It is that detectorists no longer necessarily have to commit to one frequency for every target and every condition.
A fixed-frequency detector such as the Simplex Ultra keeps the technology straightforward and can still provide plenty of useful adjustment elsewhere.
A selectable-frequency detector such as X-Terra Pro or Deus 1 allows the operator to choose which single frequency suits the job.
An SMF detector such as Vanquish or Score lets the machine work with several frequencies together.
An advanced detector such as Legend, Equinox 900, Deus II or Manticore increasingly gives you both approaches.
Seen that way, the progression is about flexibility rather than making older technology suddenly ineffective.
Simultaneous Multi-Frequency vs Single Frequency for UK Detecting
For typical UK detecting, there isn't one frequency system that answers every question.
If most of your detecting is ordinary inland pasture or cultivated ground, a good single-frequency detector remains perfectly capable of finding coins, artefacts and other non-ferrous targets. The Simplex Ultra and Deus 1 evidence gives us no reason to pretend otherwise.
Selectable frequency adds flexibility. Machines such as the X-Terra Pro let you change the operating frequency instead of accepting one fixed choice, while coil-dependent systems such as Deus 1 can provide a particularly broad range of options.
Simultaneous multi-frequency takes another step by allowing the detector to work with several frequencies together. That becomes particularly attractive when you want one detector to move between different target types and conditions without repeatedly deciding which single frequency to use. Wet salt beaches are an especially relevant example because several manufacturers specifically use their SMF systems to deal with those conductive conditions.
The most advanced machines increasingly combine both ideas. Legend, Equinox 900, Deus II and Manticore provide SMF for broad general-purpose detecting but retain selectable frequencies when the operator wants to take control.
That is probably the most useful way to understand the technology.
Fixed single frequency gives you one frequency.
Selectable single frequency lets you choose one.
Simultaneous multi-frequency lets the detector use several together.
The more advanced machines let you decide which of those approaches you want to use.
None of that guarantees that one detector will find a particular object deeper than another. Frequency is only one part of a much larger system, and our field evidence repeatedly shows the importance of recovery behaviour, coils, ground conditions, settings and operator experience.
SMF is a genuine technological development, not just a marketing phrase. But it makes most sense when treated as another useful tool rather than a magic replacement for everything that came before it.
Comparison Articles 1–12
The 12 Detectors - Reviewed
