Single Dynamic Driver IEM with 3 differently tuned nozzles – £219.99

Simgot – Fermat’s Last Theorem

With gratitude to Simgot for including myself in their reviewer distribution, I hereby contribute my take on Fermat’s Theorem. No money has been exchanged in return for this, or any other review, for that matter. Simgot also provided me with the LC7 cable. I worked out that this constituted a grand total of 9 listening modes. I did them all, just for you. 

First off, you’ll want to know why this IEM is called Fermat’s Theorem. The Fermat is also known as the EA1000. I suspect that no other IEM will be called anything like the Fermat, so, at least for me, I’ll find it easier to remember. Think about it – it’s already making an impression, before it’s had a listen…. Fermat’s Theorem is a  mathematical problem posed by a French gent called Fermat. Arguably one of the greatest challenges ever presented, it was finally answered by Alan Wiles, in 1995, over 350 years later. I no more understand the question than the solution, but more information is contained in the packaging of the product. In particular, you can become a member of the gold card club. The equation that proves the theorem to everyone’s satisfaction is embossed on it, so you can put it in your wallet and proudly display it whenever the conversation turns to either 1637, or integers. The company’s brand is described as a salute to Science and Art, and I believe, in the EA1000, they’ve outscienced all but the most sciency of us. 

I am a member of the Gold Card Club!

About the Simgot EA1000

Does the Fermat justify the lofty aspirations of the Theorem that took three and a half centuries to crack? It does not have the glamour of the multi driver hybrid setup, a useful marketing tool as well as , arguably, a way of overcoming some limitations of the tinyness of the in-ear model. Of course, a single driver design cannot suffer from crossover distortion, a problem which has to be addressed with every other hybrid earphone. 
Worry ye not; Simgot has some tricks up their sleeves! Instead of going with a hybrid setup, the EA1000 has a 3 nozzle system. There’s 3 different sound signatures to go for. Simply unscrew a nozzle from the driver housing, screw a different nozzle in, and you’ll have a sound that corresponds to 1 of 3 different frequency curves.

Harman research is renowned for it’s frequency curve. It took a huge sampling of the sound signatures preferred by the music listening public and took an average of them all. Voilà! This was born the Harman Frequency Response Target. This is a curve that many manufacturers have placed their reputations on, and they tune their products to stick as closely to the curve as their drivers can handle. The Harman response is, by definition, a jack of all trades, and a master of none. Not many people chose that exact bass hump and reduction in treble, but there again, manufacturers are pandering to the masses, and it makes sense to follow the path of least resistance, as the Harman Frequency Response Curve will be ok for the majority of listeners.

It’s often best to play it safe when you’re looking for mass appeal. What Simgot has done is to take 3 tweaks of the Harman Curve, and tune their nozzles accordingly. The tuning is subtle, as I’m sure has been mentioned before. Nevertheless, married to a decent source, the flavours of each become apparent. Yes, I am also willing to include my Samsung A52 smartphone in my list of good matches. I accept, and have no issue, with those of you out there who are minimalists, and use nothing but a phone to listen to your music. That is surely the aspiration of every portable audio enthusiast. It certainly takes a lot less space in one’s apartment/rucksack or trouser pocket. For those of you who have seen the light; forgive me! I shall be basing the majority of my insights on the splendiferous Fiio M11. 

What it is about there always being something unique about each iem I show you? It is a tribute to the imagination of the research teams that they find new ways to fill what is in reality a tiny space of driver and housing. Simgot’s latest iem here has SDPGD and PR logos proudly displayed on its shiny packaging. The first abbreviation stands for ‘sputter deposition purple gold diaphragm’,  the second relates to a new design of a resinating chamber, called ‘passive radiators’. The dynamic drivers have dual magnets, the diaphragm of the drivers have been sparkled up with a few layers of gold, they sit in a new acoustic chamber, and the nozzles can change the signature. All in all, a very good sell. The whole thing is presented in a shiny box, with the signature Simgot case. It’s ready to roll with a silver plated oxygen free copper cable in the Litz, or woven, design. The cable has a velcro tie and a chin strap, and is terminated in a 3.5 jack.

Simgot realise that many of us have balanced connections on some of our more bespoke devices and to that end, have also supplied me with their LC7 cable, available for $69.99, which not only sports the usual 3.5 jack; it can morph into a 4.4 as needed, an unbalanced or balanced cable; not something I normally see.

The LC7 Upgrade cable

The Sound Test

The smartphone test was quickly underway. 3 nozzles, 3 signatures. Will I like the red, blue or black nozzle? For the Samsung phone I went for the red nozzle. The silver steel tube, built around the Harman 2019 curve. This was regardless of which cable I was using. The LC7 cable is much heavier, and would be more problematic for a vigorous workout, but sounded better, needless to say. The Fiio M11, again, no surprises, worked best with the LC7 cable and a 4.4 jack popped onto the end of it. For the M11, my preference was for the copper nozzle. The bass was faster and the mids were slightly more pronounced. The stock cable had a softer sound than the upgrade cable. The termination of the LC7 cable did not initially fit into my A52 jack. With the protective case off, no problems. The Fiio M11 was fine with either cable. My case is a rather bulky affair. It’s a sort of pelican design. Thinner cases should accommodate fine, but worth noting if you are thinking of pushing the EA1000 a bit more. 

I am pleased to say that I was impressed with the Fermat’s. They gave a really good account of an HDCD version of ‘It’s still rock n roll to me’ by Billy Joel from his 1980 album, ‘Glass Houses’. This was an Audio Fidelity release, and was an extremely limited edition. This version has long since been out of print, is not available on any streaming platform, has an incredibly high sound quality, and proves that retro is not only alive and well in the 21st Century, in many cases it is a darn sight better. The song was chosen for its fidelity, driving rock sound and use of brass instruments, always a good test for an earphone. The rich tonal cleanliness of the track shone through on the EA1000, with the smooth, silky delivery on my smartphone, contrasting with the attack of the M11. There will be a lifetime of adventures out there for the swapper; does the copper suit classical music better than the middle of the road red nozzle? Will rock , or pop, or hip hop , benefit from the slight bass light of the blue nozzle? I can state that I believe the effort will be rewarded for those who will become loyal followers of the Simgot Fermat. 


In the right environment, say in front of TV you need to avoid watching, in a bed where your partner is fast asleep and you’re not; this is where the qualities of an IEM like this can flourish, and a full size headphone, such as the similarly priced HiFiMan Sundara, can be beaten. It’s difficult to see where they can improve on the sound of a single dynamic driver at the price level of £219.99. There are hybrids out there that people will prefer, there are planar iems in this price range; but they both offer a different sound. The punchy delivery of a single dynamic driver is a timeless enjoyment that , thankfully, has survived, and even flourished, despite the relentless quest for the answer to Hi-fi’s ultimate question – how can I improve the sound quality? Sometimes, my friends, the answer to the future lies in the achievements of the past.