Disclaimer

Special thanks to Sennheiser for providing this opportunity to review the new Momentum 4 Wireless (or M4 from here on). I have not received any incentives for writing this review. All the comments are opinions of my own. I am not a professional reviewer, just a headphone enthusiast and music lover.

Build Quality

The M4 is built with mostly plastic materials. Although they do seem to be solid and they feel a little weighty when holding them. There is some padding under the headband so it doesn’t create hotspot on top of the head. The headband gimbals can be adjusted freely, there are no clicks. This allows for fine adjustment and there is enough friction to hold the gimbals in place after the adjustment. I do wish the gimbals could extend just a few millimeters more to have a better fit for my large head.

The other thing that bothers me was the ear pads. The M4 is advertised as over ear, or circumoral headphones. However, the inner diameters of the ear pads are on the smaller side and will not accommodate people with larger ears. The pleather materials of the pads are not breathable and they warm up the ears quickly. Since the ear pads require special mounting rings. This will limit the choices of using aftermarket pads.

The M4 is a set of feature-rich headphones. Although the M4 was not quite comfortable for me, I did not spend time to test all the features. I will keep this review short. I will also compare the M4 with my AirPods Pro (Gen 1) since that’s my only Bluetooth earphones in the similar price range.

Bluetooth Connectivity and Controls

My main reason for getting the Bluetooth headphones is for meetings and phone calls (working from home most of the time) plus the mobility. Therefore, Bluetooth connectivity and sound clarity are more important to me.

I really like the Bluetooth connectivity of M4. The Bluetooth pairing was very easy with my iPhone, LG V30 phone as well as my laptop. The M4 can connect to two Bluetooth devices at the same time. I can play music on iPhone then switch over to the V30 without having to disconnect the iPhone. I do need to pause the music on iPhone before using the V30. The setup of the Sennheiser Smart Control App is very easy and smooth for the Android phone (V30). However, it took me several attempts to connect the Smart Control App to M4 on the iPhone.

The touch controls were easy to operate, and I didn’t experience any misfiring.

Sound

Clarity of the sound during phone calls were excellent. I can hear the conversation clearly and my voices can be heard by the other parties with great clarity as well. The sound quality during phone calls on M4 was superior to the AirPods Pro.

I think the overall sound quality of M4 for music is also very good. The clarity and soundstage are great. The bass is full and impactful, although I feel it could be a little overpowering sometimes. I did listen to the M4 in passive mode using the provided headphone cable. The M4 sounded dull. The wireless mode sounded better and much more alive. I didn’t play with the EQ in the Smart Control App.

The M4 performs very well in terms of noise canceling. It can block out most of the ambient noises when the NC is activated. I didn't test the NC against the Bose (QC25). I didn’t use the M4 outdoors so I can’t test the wind noise reduction feature.

Comparison

Comparing to AirPods Pro, this doesn’t seem to be a fair game. The M4 is $100 more expensive in MSRP and it’s a full-size headphone versus the ear buds AirPods Pro. The M4 has much better battery life, 60 hours for M4 versus 4 hours for AirPods Pro (with one charge). The M4 can connect to two Bluetooth devices while AirPods Pro can only connect to one. In terms of noise canceling, I think M4 and AirPods Pro performed equally well. However, for sound quality on the iOS devices I prefer the AirPods Pro. The AirPods Pro sounded more open, and the bass is more controlled and has better details.

Final Thoughts

I like the new Momentum 4 Wireless. The Bluetooth connectivity, the sound quality, the touch control, and the battery life are the strong selling points. If the headband gimbals and the ear pads could have been improved, then I would definitely give it a 5-Star rating.

Overview

First, I want to thank Audio46 for sponsoring this product tour.

I don't write reviews very often. So I am just going to share my impressions and will keep my review short. Besides, there have been several very thorough and comprehensive reviews already posted on this thread. I will also provide some quick comparisons between the A4000 and some of my single DD IEMs, such as JVC FX750, Monster Turbine Gold, and Sennheiser IE80.

I did most of the listening using the Chord Mojo connected to my laptop. The music sources include Spotify streaming audio and some lossless tracks from my library.

Comfort and Build Quality:

From the product photo it did make me question the fit and comfort of the A4000. I understand there were reasons that the shell was designed this way. However, the A4000 does fit my ears relatively well. I didn’t feel any stress or pressure points after wearing them for extended amount of time.

The packaging is rather simple. The accessories include a full set (5 pairs) of Final’s Type E ear tips with variable sizes and a silicon carry case (not crazy about it). The Type E are my favorite ear tips. I have tried using other tips, such as Azla SednaEarfit Light, Xelastec, and Acoustune AET07. They all killed the treble of the A4000 for whatever reason.

The real complaint I have is the cables. The detachable cables are really soft, although they are not tangle-free. They also feel a little on the thin side. Frequently I was having trouble keeping the cables remain in place behind my ears. I wish the cables could have the built-in ear hooks. The A4000 does come with a pair of clip-on type of ear hooks. Although they look frigid and not that promising so I didn’t even want to try them. The other issue I had with the cables is that the 2-pin connectors are keyed. That means it’s difficult to find a 3rd-party replacement cables that will fit the connectors.

Sound Impression

The sound signature of the A4000 can be summarized as clean, natural, airy, and non-fatiguing. Upon the first listen I was immediately impressed by the clarity and how open the soundstage is. There are good extensions in both bass and treble regions. I can feel the bass rumbles if it was present in the music recording. I remember some frequency response charts showing that there is a small peak in the 2-4 KHz area. That might have something to do with the improved clarity. It also made A4000 sounded like some high quality BA drivers. The mid-range also sounded smooth and balanced, it’s not forward or recessed. Although sometimes the male vocals may sound a little thin. Imaging and separation are both decent and on par with the IE80 and FX750.

Switching to the IE80 and FX750, the first thing I noticed was the warmer tone and the thicker lower end on the IE80 and FX750. People who prefer the warmer sound would most likely prefer the IE80 and FX750 over the A4000. The A4000 does have the upper hands on soundstage and clarity.

Switching to Turbine Gold, I think it sounded closer to A4000 than IE80 and FX750. The Turbine Gold also has a similar soundstage and clarity as the A4000. The Turbine Gold has metal shells so they are heavier and not as comfortable as A4000.

Some More Thoughts

The impedance of A4000 is 18 ohm. Although the sensitivity is only 100 db/mW. Therefore it requires a little bit more power to drive the A4000 compared to the IE80 (16 ohm, 125 db/mW).

I haven’t spent much time with the fast-growing Chi-Fi so I can't make a comparison to some of those IEMs in the similar price range. My daily driver is the qdc Anole V3. The clarity and soundstage of the A4000 is comparable to the Anole V3, maybe slightly better in soundstage for the A4000. The bass is a little punchier on the A4000 as well. The Anole V3 does have better fit and has better built quality. Consider the price differences, the A4000 is an impressive product and punches above its price point. However, the cables are a show stopper for me and this is the reason I am giving it a 4-satr rating.