User Experience

The Monoprice Monolith M-TWE earphones are larger than average to begin with, mostly to accommodate the extra microphones for the hybrid noise canceling and hear-through modes. This and its rounded shape tapering down at the bottom to accommodate the LED mean that it juts out a lot more, too. It's a good thing then that its overall shape is still somewhat ergonomic, as seen in the photo of the right ear bud placed inside an artificial ear mold that is quite similar to my own set of averagely sized ears. The stock ear tips contribute tremendously since they are longer than usual to where the actual shell is mostly out of the concha for comfort, the LED housing has support from the ear, and the ear tips themselves hold everything in place. The lower weight of the ear buds also helps, but you will absolutely have to hold on to the back to use the capacitive touch pad for the various controls. Good luck with that by the way. The earphones often turned a slide for volume up/down into a tap to switch between ANC/ambient mode/off in order. The earbuds do not get hot—there is plenty of ventilation at least. There is decent isolation, but I was left wanting for more from an ANC TWS set.

Battery life is a key metric for TWS earbuds, and these promise "up to 10 hours" of use when fully charged. Initially, I was not sure if this was with or without ANC on, but it unfortunately was the latter and even then never actually came anywhere close to 10 hours. I got closer to 6.5 hours with the volume at 90% or higher since it's a low-volume set as well, and with ANC + SoundID on, it dropped to nearly half that value. The battery capacity is pathetic to begin with on these larger ear buds, and the case makes it worse with only two extra charge cycles since it too is low on capacity. You will find yourself charging these often if used with ANC; there is no way you are using these on an airplane ride unless it is quite short. Charging time is not quick either given the 500 mA limit, but the lower capacity and a basic form of quick charge means that 5 minutes can give you up to an hour (realistically closer to 40 minutes without ANC and SoundID if you want to listen to something properly), and we saw before how the case can be fully charged under two hours. There is also IPx4 rating here, so these should hold up alright with your exercise routine.

Audio Performance

Hardware and Microphones

Monoprice uses an unmentioned 10 mm dynamic driver driven with neodymium magnets in each bud, and an unspecified number of microphones are included for communication as well as the noise-cancellation and hear-through modes. In addition to the standard SBC codec, these support aptX and AAC. Nothing more, which is a shame as I would have liked to see newer, improved codecs adopted since these are meant to be a high-end audio solutions from the brand. Bluetooth 5.0 support comes in the form of a Qualcomm QCC5124 SOC, which explains a lot. This is a low-power 192 kHz, 24-bit system on an SPDIF interface leading to a dual-channel 99 db class D amplifier. What all that means is that there is just not enough power to drive an average 10 mm dynamic driver, which is why actual volume output is on the lower side. Monoprice also got away with cramming in as small a battery as they could to still claim reasonable battery specifications for highly unreasonable conditions. We will get to the listening experience below, but I have to say I was fairly impressed with the microphones. Voice clarity in calls, both over the network and internet, was good but not as good as what we saw with the Audio-Technica ATH-ANC300TW. I also used these as a Bluetooth headset to connect to a laptop for work, which did the job better than your average TWS earbuds, that's for sure. Timely audio prompts also come up with each status change, which tell you whether your tap on the touch pad has worked as expected or not.

Frequency Measurement and Listening

I will mention that I have a general preference for a warm neutral signature, emphasizing a slightly elevated bass and smooth trebles with detailed mids and good tonal separation. I also generally prefer instrumental music over vocals, with favored genres include jazz and classical music.


Our reproducible testing methodology begins with an IEC711 audio coupler the ear buds can feed into enough for decent isolation similar to real ears. The audio coupler feeds into a USB sound card, which in turn goes to a laptop that has ARTA and REW running and the TWS earphones paired to it. The size M stock silicone ear tips are used unless specifically mentioned otherwise, and I keep the volume/gain fixed to a known value for TWS ear buds unless specifically mentioned otherwise. Testing commences with an impulse measurement to test for signal fidelity, calibrate the sound card and channel output, and test the frequency response of each earbud separately by also keeping the distance from the source to the earbud as consistent as possible. Octave smoothing is at the 1/6th setting, which nets a good balance of detail and noise not being identified as useful data. Also, the default tuning was used for testing, and no app-based settings were chosen unless specifically mentioned. Each sample of interest is tested thrice with separate mounts to account for any fit issues, and an average is taken of the three individual measurements for statistical accuracy. The raw data was exported from REW and plotted in OriginPro for an easier comparison here. I am avoiding the use of the ear mold for wireless solutions because the base of the mold disrupts the connection somewhat.


Bear in mind that these results are best compared with other TPU results because of the variables at play, and I will also say that I had to turn the volume up to 90% on my laptop to get appreciable output from these since the low-power amp of the SOC is likely holding back the dynamic drivers. Regardless, we can now see how the left and right channels work across the rated frequency response in the Monoprice Monolith M-TWE, or at least the useful part of it. The left earbud was separately tested from the right one, and colored differently for contrast. I did my best to ensure an identical fit for both inside the IEC711 orifice, so note how the left channel ends up having a slightly boosted response in the low frequency (bass), a dip in the mids, and a boost again in the highs (treble) compared to the right channel, in addition to a slightly less smooth mid-bass profile. I will also mention that there was no discernible break-in effect.

This is the first frequency response graph for the Monoprice Monolith M-TWE I could find online, so you are welcome, internet! There will always be a small error bar associated with TWS devices since the client and connection is important too, which the multiple mounts that were then averaged out helps address somewhat. It was thus interesting to see the general response across both channels, including the disappointing bass response compared to the marketing talk. Sub-bass is practically non-existent to begin with, and the single dynamic driver is clearly tuned more with a specific boost peaking around 50 Hz, where the transition into the mid-bass usually occurs. This is a relatively significant bump from the baseline, so there is a better bass response than with the ATH-ANC300TW we saw before in terms of amplitude. But the bass boost quickly drops off, back to the baseline just past 100 Hz, followed by a shoulder that then tapers further down into the mids. The overall nature of the curve is close enough to the rated one in the SoundID app, but clearly points out the power limitations to the driver, which is also not tuned very well.

The mids are consistently on a rise, meaning you get more warmth the higher the frequency, rather than getting the warmth naturally from the lows. This results in a somewhat awkward response to vocals in particular, but does lend itself better to instruments. This region is the strongest area of the Monolith M-TWE, with a mediocre bass response before. There is good detail with clear tonal separation here, but imaging takes a hit because of that ever-increasing response to where you may at times struggle to distinguish between instruments of the same class. Soundstage is equally average at best when it comes to being open, which might as well be what I heard in my listening experience. Good is that the soundstage not being very wide has the imaging here fills up a smaller virtual room. This combined with the pretty good tonal separation for vocals and different instrument classes means you can still identify directional aspects of the source for different notes. Expect this to be more like in a smaller, more intimate setting, such as an underground band lounge instead of a concert hall.

As you tread forward, you are greeted to energetic upper mids that then end up with a typical transient response for such TWS earbuds. To its credit, Monoprice managed to get things here more stable without harmonic distortions in the highs, so there is still plenty of detail without any hissing. Once past 10 kHz, things change for the worse, with Bluetooth-associated hissing actually showing up around 13 kHz and onward before the inevitable dip to never-ever land. There really isn't a specific genre I would have as the best for these, but anything that concentrates more on vocals would be better. Country music perhaps, or even pop/Kpop/baby metal. Compared to the ATH-ANC300TW, the Monolith M-TWE is generally better overall, but only just. I had a significantly better time listening to the EVA2020 x final, especially in the mid-bass and upper-mids. When it comes to other TWS earphones around the same price range as these, I would once again say the Audio-Technica ATH-CKS5TW outperforms these easily with far superior tuning and better use of a smaller driver that is not power-restricted. The Lypertek PurePlay Z3 also does much better and costs less while offering Bluetooth 5.1 with aptX TWS+ support.

Noise Cancelling

After having experienced very impressive active noise cancellation with the Audio-Technica ATH-ANC300TW, I was curious what the Monoprice offering would do. Turns out it isn't as good. I had to triple check my results because there was barely a 10 dB drop, and in practice, it felt like next to nothing had actually happened. A low hum is generated, which explains the comparatively boosted bass response, but then it doesn't do much beyond tempering down slight background noise. Noise suppression is more like it, and you get most of that from the seal and form factor itself. Do not buy this for ANC, especially as it causes even further loss of details throughout. Clarity in the lows is most heavily affected, but then there is an ugly peak around 550 Hz that makes vocals and instruments tougher to listen to. I will say that the unimpressive highs from before remain equally unimpressive. It not getting worse is probably the only good thing to mention in this section, at least until you get to ambient mode, which is actually really good. This makes me wonder if there is an issue with the actual programming or firmware for ANC, since the microphones are clearly picking up ambient noise quite well. Is it a bad filter? This should have been figured out earlier, and if I somehow got a lemon, it is poor QC, but at least not as lethal to the sales of the earphones. Knowing that ANC is a battery killer with these, I'd rather not use it anyway and save the juice for SoundID, which adds a lot to the listening experience in my opinion.