Oxygen Successor?

Here's the first in-depth review out of three for my previous Tanchjim brand history post. We'll be going over the Tanchjim 4U with detailed measurements.

Unfortunately I only have one sample. All measurements should be taken with a grain of salt and should not be viewed in absolute terms; any major consideration for each measurement will be commented on.

The 4U retails at an MSRP of $70, but is now always on sale for less (down to $50 at times).

The Tanchjim 4U comes with minimal accessories: two sets of tips (one with narrow bore, one with wide bore and shorter), a metal tool for the tuning switch, a Tanchjim branded pouch, and a thin 2 core cable. The provided tips are nice and since there are two types, it is possible to find the ideal fit and sound using only these. The cable is also on the thin side, but it handles very well and the ear hooks are soft and pliable.

While the accessories aren't the best, they are acceptable for the price and don't have any glaring flaws; for most people, these stock accessories should be enough for a good experience.

Build quality and Comfort

The shell is made entirely of metal and is not too heavy, with a polished mirror faceplate that can pick up a lot of scratches if not handled with a lot of care. This is Tanchjim's first IEM with this shell type, and thankfully it works really well. The shells also have a small profile and should fit in the concha bowl of most people. The nozzle lip is around 6.3mm, 4.8mm at the base, and is extended enough to allow for both shallow and deep fit. The 2 pin socket is what I would call semi-recessed: most 2 pin cables, recessed or flat, will actually fit and look nice.

The comfort of the 4U is excellent. The IEMs practically disappear in the ear, and because the shell has good proportions in terms of nozzle length to angle, the use of different tips for both sound and fit improvement is possible.

Objective sound

The tuning is quite common nowadays and is the usual V-shape sound that the Oxygen had. The ear gain is located at 3 kHz and is fairly elevated. Bass response is also boosted and provides a nice balance to the overall tuning.

The insertion depth variation can be seen, and should be taken with a large grain of salt. On my specific unit, there seems to be something that creates a very large treble peak, with deeper insertion reducing it a lot. The channel matching shown in the graph above is as good as it gets. There is a slight difference for the treble peak but nothing out of the ordinary and inaudible.

Distortion shows no notable problems or concerns.

The tuning switch options all reduce bass in varying amounts. For most people, the default and pop modes will be the only viable options.

Subjective sound quality

The sound of the 4U is excellent and reminds me a lot of the Oxygen and Hana IEMs from Tanchjim. At this point in time, the tuning has spread everywhere but the 4U still has that special V-shape refinement that the Oxygen had.

The bass is present and has quite a bit of rumble and impact. It is not for bassheads, but it is very versatile and can cover any genre with good to excellent quality. It is not the most unique of bass presentations, since this tuning has been done countless times now, but it is quite refined without having any bloat or limpness. With the pop mode, the sub bass rumble quiets down and lets the mid bass punch come through more. It also seems to clear up the rest of the tuning.

The mid range is also classic when looking at the rest of the market. It features a fair bit of energy which gives vocals and instrument a nice bite without veering into bright territory. Details and vocal nuances are also noticeable but not distracting. It might be a bit shouty for some, but in general I found that the forwardness made the overall sound profile energetic and fun, which complimented well the bass and treble.

The treble is, for a lack of better words, average and very similar to other 1DD that we've seen with this type of sound. It is there but might be unrefined depending on the listener. As seen with the insertion depth measurements, the treble response will vary quite a lot and peaks and dips might appear at good or bad locations. I would say that in my case, the treble was good enough and had enough energy. While I did have some weird timbre issue with high frequency instruments, it wasn't a deal breaker, just something different.

Comparisons

Oxygen

I would consider the 4U as a logical successor to the Oxygen, both featuring the same type of sound. Of course, the biggest differences are in the price (Oxygen being around 3 times more expensive at launch) and the shell design. Overall, I prefer the 4U due to its better comfort and slightly better tuning; the Oxygen was, in my case, a tiny bit more V-shape, and that made it less versatile and more fatiguing in the long run. Bass was better on the Oxygen, while the treble and mid range on both is about the same.

Simgot EA500(LM)

The 4U's main competitors in the same price range would be the Simgot EA500 and the LM version. All of them feature bright and V-shape tunings and use the same driver configurations, all in all-metal shells that have similar levels of comfort.

The 4U I found was the tamest of them all. The original EA500 was a bit brighter and was actually close to the pop mode 4U, while the EA500LM sounded like the Oxygen but even more V-shape. The timbre and overall smoothness of the 4U makes it more appealing for me. The EA500 had smoother treble but the bass and brightness made it a bit too fatiguing, and the same for the EA500LM which had better bass but was, just like the Oxygen, too much.

Conclusion

As I said in my long Tanchjim history post, I think that the 4U is logical and ultimate refinement of the Oxygen and Hana line, all in a shell that is ergonomically non-controversial. If you want that classic yet evolved Chi-Fi sound without compromises, this one is it.

The overall fit of the 4U is also good and shouldn't pose any issue, and the product as a whole separates itself from the crowd by being having that old school tuning that doesn't go too far and still remains universal without being too fatiguing.