Introduction

The budget-friendly in-ear monitors market has never been more competitive than it is now. We have some truly excellent sets out at $50 and under, to where it is getting hard for products to even justify a $70-100 price purely out of tuning. Indeed, the last few weeks saw the debut of sets that cost $20 or less which show that you can truly get well-tuned IEMs without needing to compromise much! Truthear with HOLA comes to mind immediately and then FiiO also tried with its JD3 and JD3 Black Edition. These latter two sets happen to be bullet-style IEMs with smaller shells that insert into the ear canal for great isolation while still being comfortable so clearly this is a lucrative, albeit niche, market for others to be involved in.

MOONDROP is an audio brand that has made a mark for itself in the IEM market at various price points. We’ve extensively covered the brand’s offerings, including several high notes and some low ones, and I was even impressed by its debut in the over-ear headphone market too. We are not looking at a $600 product today however, and not even 1/10th the cost at that! The recently released MOONDROP Quarks DSP is an update to the Quarks IEMs that arguably first triggered this whole race to the bottom, and goes with a Type-C connector that easily plugs into your phone or laptop without the need for an external DAC/amp. Indeed, the use of an integrated source means MOONDROP also uses digital signal processing—hence the DSP in the name—to have preset digital filters for a tonality that is much harder to achieve with just audio engineering at this price point. There’s even more here to help sweeten the deal and yet the question remains as to whether the Quarks DSP actually sounds good or not. Thanks to HiFiGo for providing a review sample to TechPowerUp as we aim to answer this today in this article which begins with a look at the product specifications in the table below.

Packaging and Accessories

Packaging is on the simpler side for the MOONDROP Quarks DSP, which isn’t surprising given the more value-oriented offering it aims to be. For once we don’t get female artwork on the product box for a set of MOONDROP IEMs, with the company choosing to go with just a simple render to showcase the elementary particles that the Quarks DSP takes its name from. On the back is a factory frequency response that I continue to urge all manufacturers to follow in addition to product specifications. The box opens up from the side to… well never mind there’s that female artwork after all. At least this is functional in the form of a wearing guide for those new to IEMs, and underneath we find the Quarks DSP shells placed in a layer of cardboard for added protection on their way to you. The rest of the accessories are placed separately in the bottom layer.

MOONDROP adds in more paperwork in the form of some usage and maintenance tips and a warranty/QC card itself. We also get a soft drawstring-style carry pouch to help store and carry the IEMs in. Rounding off the unboxing experience are the provided silicone ear tips in sizes S/M/L. These are generic single-flange tips that are worth trying out certainly, although you may wish to consider aftermarket tips if you do not get a decent fit and/or seal with them.

Closer Look

The MOONDROP Quarks DSP has a permanently attached cable similar to the MOONDROP Chu we saw before, and now I am reminded that it was really the Chu that kickstarted the excellent value-for-money train when it comes to inexpensive IEMs coming out of China. The Quarks DSP differs from the earlier Quarks in using a Type-C digital connector headed to the source and there is a DAC underneath the branded plastic housing to convert the digital audio signal to analog in addition to adding in EQ filters to affect the frequency response of the set. There is very little information otherwise provided about the cable, so I can only speculate that underneath the basic silicone sleeving is pure copper conductor alone. We then see a similar circular splitter without any cable cinch as on a few other inexpensive MOONDROP IEM cables and then comes a bonus feature in the form on an in-line microphone with tactile volume controls on the split wire headed to the right channel itself. Both channels terminate on the underside of the IEM shells where L/R marking comes in the form of the black/red Quarks symbol seen on the back.

To say the Quarks DSP is tiny relative to other IEMs would be an understatement—these are certainly the smallest IEMs I’ve reviewed to date. MOONDROP has gone with polycarbonate housing that has two pieces glued together, with a cutout at the bottom for the cable itself. The shells get a clear finish which provides a closer look at the dynamic driver used inside. These are clearly bullet-style IEMs which fit straight into the ear canal rather than having the cable go over and around the ears and thus the lack of a cable cinch isn’t as big a deal as the lack of a shirt clip to minimize microphonics from the IEM and microphone cable in use. The face plate here is simply the back with the design we saw earlier and the nozzle is a narrower section that measured under 5 mm to not be a dealbreaker for those with smaller ear canals either. There is a metal mesh placed towards the end here so any contaminants are less likely to enter the acoustic chamber. Installing the provided ear tips is simple enough given the hard stop provided where the nozzle meets the wider shells, as seen above, and using the QUARKS DSP is as simple as plugging the Type-C connector into the equivalent port on a compatible phone or computer. Those on iOS will require a USB OTG adapter, at least for now while we still have iPhones and iPads using the Apple Lightning connector. My phone immediately recognized the Quarks DPS as earphones ready to go and here we see also how the cable ends up being the brightest part of this combo.

Fit and Audio Performance

Seen above is the right side of the MOONDROP Quarks DSP installed in an anthropomorphic pinna that does well in showing my own experience with these. I have average-sized ears, and found the provided size M silicone tips to work best. Given the Quarks DSP is a straight-insertion set of in-ear monitors, it would be a fair assumption that it will fit just about anyone. The smaller size and bullet-shaped shells directly enter the ear canal and the cable falls straight down meaning you have more leeway in positioning the IEMs in your ears than with the more common approach of the cable going around the back of the ear and being a support point at the top. The Quarks DSP is held in place just by the fit then, which makes a good seal all the more critical. These weigh ~4 g per side to where to where I had zero physical fatigue even for longer periods of use. I still recommend finding a cable clip to secure the cable to your shirt, if only to help with keeping the in-line microphone fixed in place when you want to use it while also reducing any potential cable microphonics. These are also fully closed so passive isolation is on the higher side of average and you can also angle the nozzle in to better fit deep into your ear canal. It can cause some pressure build-up over time though, so I recommend taking a break every 30 min or so to just relax and take them out, clean out any ear wax if found on the ear tips, and re-insert for more usage.

The MOONDROP Quarks DSP uses a single dynamic driver per side, which is effectively the norm for the market being targeted. The compact shells mean a micro driver is used with a 6 mm polymer diaphragm and external neodymium N52 magnets driving it back and forth. The diaphragm is associated with a copper-clad aluminium wire (CCAW) voice coil. The acoustic chamber has a special cavity design meant to make the most of the driver assembly that feeds straight into the ear canals. All this comes together to make for a set of IEMs with an average rated impedance (16 Ω) and below average sensitivity (113 dB/Vrms = 95 dB/mW), which would have made for a weird need of a source that would have been undoubtedly more expensive than these IEMs. Thankfully we do not need to worry about it given the Quarks DSP already has a DAC with it’s own tiny amplification stage built in the cable and all you need to do is plug it into a compatible device. The in-line microphone is also automatically recognized so you end up with a headset and not just headphones with the Quarks DSP!

Testing was done similar to all other IEMs including the MOONDROP Chu. Seen above is the measured frequency response for both channels of the Quarks DSP plotted against my personal IEM target, which can be inspected further here if interested. I have also added in the average response against the Harman 2019v2 in-ear target given it was clearly what MOONDROP was going for with the Quarks DSP. First up, we see the channel balance on my sample is more than satisfactory given the budget nature of these IEMs. There’s no difference between them until ~2.5 kHz although the only region where I perceived some imbalance—after actively looking for it—was from 5-6 kHz.

I am not the biggest fan of the Harman target as mentioned separately before but it is one of the most science-backed earphone targets based on research involving user preferences across different backgrounds. It ultimately recognizes that the average consumer likes a fairly substantial bass and treble presence—this is why the V-shaped tuning is so popular with mainstream IEMs and headphones—but also keeps it such that the mids remain clean. On my end I’d rather see a lower bass shelf and ear gain, and occasionally the rise in the mids from 200 Hz onward leading to the ear gain makes for a subtle bass tuck which loses impact for bass guitars and drum strikes. What MOONDROP does with the Quarks DSP is follow the target quite well and arguably improves upon it in some places too. The ear gain, for example, is clearly less pronounced and far closer to my own preferences to where I did not notice female vocals and some string instruments sounding too forward or shrill. The bass shelf also has a bit more emphasis in the mid-bass without coming off overly boomy or even affecting the mids which is otherwise pristine and clean. Indeed, tonally I could only ask for some more treble extension but, in terms of using both acoustic engineering and DSP, the Quarts DSP gets the job done.

The issue is tonality isn’t everything, although it’s certainly the biggest factor in this price range. The driver used in the Quarks DSP is unimpressive for technical performance and ends up being over-stretched to a degree via DSP too. I didn’t feel the bass was as much as the graph suggests but mostly because there’s not much impact or weight behind the notes. The driver is less dynamic in use thus and don’t go expecting it to be an EDM monster either. Vocals are mostly forward-facing and help with instrument separation even if imaging is slightly hazy and the soundstage is pretty much isolated inside the head. It’s decent on detail retrieval though but then comes the biggest issue wherein sometimes I noticed a slight background hiss. This was isolated to the DAC used in the USB Type-C input to where the convenience of the digital plug now also means you can’t use your own source either. Others reported it being more annoying and even present during actual playback, which I did not experience, so your mileage may vary. The in-line mic is also more a feature to be ticked off on rather than something which can replace an inexpensive lapel mic, but once again we are talking about the convenience compromise here.

For context, I have the MOONDROP Quarks DSP compared against some of the better budget IEMs released recently, including the Truthear HOLA, the TangZu Audio Wan’Er S.G which will get its own quick look article in due course of time, and the FiiO JD3 Black Edition. The FiiO JD3 is also a bullet-style set of IEMs with an in-line microphone, and the newer black edition also tries to go for a Harman-style tuning. The Quarks DSP is better tuned in my opinion though, and is even smaller to add to the comfort factor. Both have in-line microphones and the JD3 goes with an adapter for Type-C connectivity without any DSP so that might explain the Quarks being tuned better than far more expensive sets. That said, the JD3 does not have any background hiss/static noises and has metal shells so I can see it being a better set for some. The real competition comes from the more traditionally-designed HOLA and Wan’Er S.G. with both tuned very well and sounding even better than the Quarks DSP for $4-5 more—which is as much as 25% more, to be fair. I’d personally go with either of these if, and this is a big if, you already have a source with a 3.5 mm output and don’t miss out on the in-lin microphone. You can get most budget IEMs with optional mic cables for $1-3 more though! In this sense I see the Quarks DSP more as a proof of concept of what DSP can do, and indeed this has been followed up by other IEMs from MOONDROP and a few other brands to where I am excited to see this used with better drivers in the $100 price range too one day. As it stands, the MOONDROP Quarks DSP costs $14.99 from authorized retailers including HiFiGo, as of the time of this article. It’s not going to hurt most wallets and even a basic phone dongle sometimes costs more than that to where you do get a lot more bang for your buck here.