QX-Over Closer Examination

At this point, I would have been collecting my thoughts and concluding the review, but then Qudelix came out with a very interesting accessory for the Qudelix-5K just a few weeks ago. Termed the QX-Over, these earphones are an active digital crossover with the 5K itself! We have seen plenty of hybrid and even tribrid IEMs with active crossovers between different drivers, but this is the first time I have experienced one with a portable DAC/amp. It takes advantage of the 5K's proprietary DSP such that the DACs take in stereo input from the source and then split it into two independent stereo low and high frequency bands for output to the QX-Over, which is recognized automatically. We saw specific sections of the app refer to the QX-Over too, and the latest update adds a brand-new EQ preset for the same.


The QX-Over arrived with the Qudelix-5K itself, and its packaging is also a bare cardboard box with printed-on information. This is a slightly smaller box, but again with a seal on top, and opening the box, we see the contents right away as before. There are once again no included user guides, but it's fairly straightforward with the app being the more involved, already covered facet. Inside the box, a wax paper wrap has been put over the earphones, and a plastic bag holds the only accessories.


These accessories are replacement ear tips, and Qudelix throws in two sets of sizes S and M silicone ear tips, both with the common bore size of 5.4 mm. These are slightly stiffer than most IEM silicone tips, and the earphones come coiled—these are neither wireless nor with a detachable cable.


Qudelix already does a good job of explaining why active digital crossovers work better than passive ones, so I will only mention that the seemingly weird dual connectors on the cable are a result of this, with the longer plug acting as a common ground and the shorter one catering to the four-channel DAC/amp with the Qudelix-5K as it pertains to low and high signals on the left and right channels separately. This is why you can only use the QX-Over with the Qudelix-5K. The cable is quite thin to help maneuver it as needed to reduce microphonics and has three individual wires each catering to the ground, low, and high band signals as needed before terminating in the ear buds themselves.


The ear buds have the large-sized silicone ear tips pre-installed, and Qudelix warns against using aftermarket ones unless the tip bore is larger than the nozzle itself. There are no L/R markings, but the notch on the side helps identify the left and right channels such that the notch facing you when you hold the ear bud that has the ear tip facing in will be the left one. The weird geometry for the shells is deliberate in order to fit the two separate 8 mm dynamic drivers per channel. This almost results in a figure of eight design with a handy spot for grip in the middle. These are not the most premium-looking or feeling ear buds, or the most comfortable, but once you see the price point, you will be far more forgiving. Let's hold off on that until after we test it fully, though. The nozzle is 4.8 mm wide and has a fine metal mesh to prevent contaminants from entering the acoustic chamber.


The 5.4 mm bore of the ear tips is thus indeed more than the 4.8 mm wide nozzle, making any of the provided ear tips fairly easy to fit as well. At this point, you will see that there is only one way to connect the QX-Over with the Qudelix-5K, making use of both the 3.5 mm and 2.5 mm ports accordingly. You are now able to use the QX-Over/Qudelix-5K combo in Bluetooth or wired over USB Type-C, and the mobile app detects the earphones instantly, too.