This has been the subject of much debate and I thought I would weigh in with a little this versus that to help offer a little guidance. I think Minelab was caught off guard by all this because the whole conversation from their perspective was supposed to be about AT Max versus Deus versus Equinox. Yet the majority of the debate is about this Minelab versus that Minelab. I guess that is a credit to Minelab but at the end of the day I am not sure they are too worried about what Minelab you buy as long as it's a Minelab
The Minelab Sovereign and the Excalibur introduced the world to Broad Band Spectrum (BBS) which was Minelabs term for their first generation multifrequency detectors. The Sovereign and the Excalibur are tone based detectors with no screen and so are for people who hunt by ear. They act like very low frequency detectors and because of this are very strong on silver coins. They also do relatively well on gold targets though they are weak on the smallest gold targets. They are very well behaved detectors that handle harsh saltwater environments well, making the Excalibur perhaps the most successful underwater detector made. The BBS detectors are strongly biased against ferrous targets and better ignore ferrous than any detector I have ever used. Ferrous is almost invisible to a BBS detector. This comes at a cost however. The processing speed is very slow and combined with the strong bias against ferrous target masking is a problem with these machines. That is not to say you cannot find targets in ferrous trash. You can. It is simply an area where BBS is very weak.
The next generation introduced Full Band Spectrum (FBS). The Explorer, Safari, and E-Trac further refined BBS and without getting into details the big addition was a two dimensional target id display that locates items on screen with a combination of a ferrous number and a conductive number. This dual target id combined with a screen added more refined discrimination capability to a detector already very well suited to people that hunt by ear. Anyone talking about the Explorer and silver will usually mention the great tones it makes on silver. The frequency weighting is very much in favor of low conductors and the Explorer series became famous for the ability to extract silver coins from park type scenarios i.e. turf hunting. A faster processor speed improved the situation with masking in dense targets to a degree, but the FBS machines still lag single frequency detectors a lot in this regard. The FBS detectors again are excellent at identifying and rejecting ferrous targets.
The Minelab CTX 3030 introduced FBS2 which further refined things. I am being purposefully over simplistic by saying the CTX mainly added an even faster processor, color screen, and the ability to be submerged to 10 feet. FBS2 appears to be a little hotter on small gold items but the main strengths are still in silver and in ferrous rejection. The color screen added new features like target trace that allow more than one target to be displayed at once for world class discrimination capability.
The BBS/FBS series have been extremely popular around the world and are to this day. However, the detectors faced competition in three main areas. They are relatively expensive detectors and they are relatively heavy detectors. And even though they can find good targets in dense trash they also leave a lot behind due to the slow recovery speeds.
The Garrett AT series was revolutionary in creating detectors waterproof to ten feet that only weigh about three pounds and at a price so low it really turned the market on its ear. These detectors have been immensely successful in creating a high value combination of features at a very low price and with decent performance. This combined with top notch marketing makes the Garrett AT series very popular especially in the United States.
The XP DEUS came out of left field and in Europe took the market by storm. These detectors are both extremely light in weight and extremely fast in target response and recovery speed. These two factors alone mean that a detector rally in the U.K. will be almost nothing but Deus detectors with a smattering of other machines. Deus does also focus on low conductor performance, as the recent addition of high frequency coils reveals. Remember that small thin silver items like hammered silver and cut silver coins actually respond as low conductors.
Minelab saw this happening but the truth is coin and relic machines are a far distant second when it comes to profits compared to the gold machines. Any company only has so many resources and the GPZ 7000 development in particular was a major lift even for Minelab. Still, the company knew it would have to address the situation with detectors that did exactly what the Garrett AT and XP Deus did, which was target BBS and FBS where they are weakest. Price, weight, recovery speed, and low conductor sensitivty.
Equinox does all this while also adding the latest twist on their multifrequency technology; Multi-IQ.
The intent here as Minelab has made clear was not to replace the BBS/FBS machines but to augment them with another line that is specifically better in areas where BBS/FBS fall short. Again, weight, price, recovery speed, and I am going to add sensitivity to small low conductors to that list.
I had a CTX 3030 and loved it. Yet I rarely used it. Why? My type of detecting. BBS and FBS favor people who hunt high conductors and typically favor people who hunt in mild to moderate ground. I do just the opposite. I hunt low conductors, gold specifically, and in highly mineralized ground. It is hard for people who do not hunt highly mineralized ground to understand how much it impacts detector performance, but seeing overall VLF depths cut by 50% or more is not unusual. Target id also suffers a lot in bad ground as does target masking from hot rocks and the ground itself. I know a lot of BBS/FBS users have a hard time grasping this, but in my ground there is no major benefit to BBS/FBS except for the fantastic target id capability, especially as regards ferrous rejection. Depth is easily matched or exceeded by the best single frequency detectors, which however suffer in their own way with unreliable target id. And the fact is multifrequency has always been weak on gold - not even Minelab suggests that BBS/FBS machines should be used for gold prospecting, although people can and do find gold nuggets with them. Still, you can't beat BBS and FBS for being well behaved, easy to operate, and in having top notch target id combined with best of class ferrous rejection. Arguably the worlds best machines for hunting silver in turf.
Everything in designing metal detectors comes in the form of a trade. When you gain one thing you tend to lose something else. In general putting the fine details of Multi-IQ aside I think the Equinox acts more like a single frequency machine in some ways than what people are used to from BBS/FBS detectors. In particular we have the lightning fast recovery speed and extreme sensitivity to low conductors. Multi-IQ put simplistically adds the target id accuracy that single frequency machines lack in bad ground. In my opinion people coming from hot VLF detectors will take to Equinox more easily than people coming from BBS/FBS detectors. I love hot VLF detectors for what I do so Equinox is a natural fit for me. The move from the more stable well behaved BBS/FBS machines is more jarring for people I think because they are stepping into another world - my world - where they are perhaps less comfortable.
People who hunt low conductors, especially in bad ground, and those who hunt non-ferrous in bad ground know that the ferrous/non-ferrous divide is an area fraught with danger. Reject too much ferrous, and you lose the non-ferrous. It appears impossible with current technology to get a clean ferrous/non-ferrous separation. I mean honestly, all I want is a detector that beeps on non-ferrous and shuts up on ferrous and does it with near 100% accuracy. This would seem simple given the difference in magnetic properties between ferrous and non-ferrous targets, but to this day flat steel, washers, hardened steel bolts and screws, bent nails, nails on end, broken square nails, etc all present problems for all metal detectors. It is a huge fuzzy area, and in the end it appears we have to make an unpleasant trade.
Equinox in targeting the BBS/FBS weaknesses regarding target masking and low conductor sensitivity is making this trade. The machine steps back in a way and favors those who hunt by ear. Most of the commentary I see about target id spread and the potential limitations there fly over my head because I prefer to hunt by ear with a wide open screen in 50 tones mode for general park and beach detecting. If you are a BBS/FBS hunter this should be familiar to you and yes, you get something pretty close to familiar Minelab tones with Equinox. For field hunting (relics) or nugget hunting in dense trash I am more likely to go to a two tone type mode just due to the sheer number of targets but two tones does make a person more susceptible to ferrous squeaks tricking you than 50 tones where the nuances are more apparent. There is no right or wrong here because people seriously do tolerate this kind of stuff to a largely varying degree and so to say 50 tones is a magic bullet is just plain wrong. We all have to find the balance that works for us personally. Just remember there is a reason many Deus users tell people to stick the controller in their pocket and forget about it. Deus and Equinox favor people who hunt by ear.
I apologize if this oversimplifies things but that is what many people need right now. I am leaving price and weight off the considerations below and just talking performance.
BBS - only current model the Excalibur. For people who hunt by ear, great in saltwater, great on silver, very good on gold, superb ferrous rejection. Main weakness slow recovery speed, target masking. Moderate depth in highly mineralized ground on low conductors.
FBS - current models Safari and E-TRAC. Basically same as BBS with marginally improved recovery speed, main addition target id screen with dual ferrous/conductive id offering very high resolution discrimination. Great on silver, superb ferrous rejection. Main weakness slow recovery speed, target masking. Moderate depth in highly mineralized ground on low conductors.
FBS2 - CTX 3030. Slightly improved recovery speed, slightly improved sensitivity to small gold, color screen, target trace. World class discrimination. Great on silver, superb ferrous rejection. Main weakness slow recovery speed, target masking. Moderate depth in highly mineralized ground on low conductors.
Multi-IQ - Equinox. World class recovery speed, world class sensitivity to low conductors in mineralized ground. Very good on silver in highly mineralized ground. Weaknesses are less visual target id resolution compared to BBS/FBS, weaker on silver in low to moderate soils, ferrous handling more akin to hot VLF detectors than BBS/FBS detectors. Unknown yet but may exceed or at least match BBS/FBS in saltwater environments.
Again, I am purposefully oversimplifying things here on purpose. People including myself have a tendency to wander into the weeds with this stuff and get lost in the fine details. The bottom line is BBS/FBS and Multi-IQ are complementary technologies, each strongest where the other is weakest. For a certain type of user (me) Multi-IQ does indeed replace BBS/FBS. In my ground and on my targets including silver I see no benefit at all to BBS/FBS except the ferrous handling. Yet I know that is the price I have to pay to get the performance I want. On the other hand, people hunting silver in lower to moderate ground conditions have the edge with BBS/FBS and if you hate digging any ferrous at all these machines are best of class in rejecting ferrous.
I hope that helps. I have to note again in closing this was never really supposed to be about this Minelab versus that Minelab but when it comes down to it Minelab is really happy to have that discussion. Equinox was specifically designed to compete with the competition, not Minelabs own detectors. Maybe a future version of Multi-IQ will give us the best of BBS/FBS and Multi-IQ in one detector but for now both offer their own strengths and weaknesses. And while Multi-IQ as currently available in Equinox is not perfect, it would be crazy to ignore the weight and price issues. They matter - they matter a lot to some people. Equinox in my opinion offers bang for the buck value that cannot be ignored, and for that reason alone it is going to be a sales juggernaut no matter where our little online debates lead us. And for you who love BBS/FBS - nobody is taking them away from you. Go detecting, be happy!
Disclaimer - all the above is just my outlook and personal opinions and do not represent Minelab in any way, shape, form, or fashion. It is based on my own experience plus reports coming in from other people that I trust but should still be considered preliminary information/opinions. Nobody including me is an Equinox expert yet and no doubt its use will be refined as more people share tips and tricks.