In the ever-evolving world of True Wireless Stereo (TWS) earbuds, two titans have emerged to capture the attention of audiophiles and casual listeners alike: the newly released Bowers & Wilkins Pi6 and the Sennheiser Momentum 4 TWS. As an avid audio enthusiast, I've had the pleasure of putting both of these premium Bluetooth earbuds through their paces. In this comprehensive comparison, I'll break down how these two heavyweights stack up against each other in terms of design, comfort, sound quality, and overall user experience.

Design and Specifications

When it comes to TWS earbuds, design isn't just about aesthetics—it's about functionality, durability, and comfort. Both the Pi6 and the Momentum 4 TWS bring their A-game in this department, but with some notable differences.

The Bowers & Wilkins Pi6 boasts an impressive 8-hour playtime on a single charge, with an additional 16 hours provided by the charging case. This gives you a total of 24 hours of listening time before you need to plug in. On the other hand, the Sennheiser Momentum 4 TWS offers a slightly shorter 7.5-hour playtime per charge but compensates with a whopping 30 hours from the charging case, totaling 37.5 hours of use.

In terms of codec support, the Momentum 4 TWS takes the lead with an impressive array including SBC, AAC, aptX, LDAC, LC3, and aptX Lossless. The Pi6, while not as extensive, still offers a solid selection with aptX™ Adaptive, aptX™ Classic, AAC, and SBC. Both earbuds support true 24-bit resolution and utilize Bluetooth 5.4, ensuring high-quality wireless audio transmission.

One area where the Pi6 pulls ahead is in its multipoint connectivity and licensed MFi (Made for iPhone) compatibility. While I didn't encounter any issues using Siri with the Momentum 4 TWS, the Pi6's explicit MFi support might provide a more seamless experience for Apple users.

Both earbuds come with a range of ear tip sizes (XS/S/M/L) to ensure a proper fit for various ear shapes. However, I found the Pi6 to have a slight edge in terms of size and weight. Despite housing larger drivers, the Pi6's dimensions are smaller, making them feel lighter in my ears compared to the Momentum 4 TWS.

Comfort and Fit

When it comes to comfort, both the Pi6 and Momentum 4 TWS perform admirably. The design where the earbuds touch your ears is remarkably similar between the two models, which speaks to a shared understanding of ergonomics in the industry.

In my testing, I found both pairs easy to fit, and neither gave me any issues with falling out during use. However, the Pi6's smaller size did give it a slight edge in terms of comfort for my particular ear shape. The lighter feel made them almost unnoticeable during extended listening sessions.

That being said, the difference is minimal, and I can't stress enough how important it is to test earbuds with your own unique ear shape. What works perfectly for me might not be ideal for someone else.

Active Noise Cancellation (ANC)

In the realm of ANC, the Momentum 4 TWS takes the lead with its stronger, adaptive noise-canceling feature. While using these earbuds, I could still hear outside noise via the adaptive microphones, but there was definitely the characteristic "whoosh" noise that indicates effective ANC.

The Pi6, on the other hand, offers a lighter touch with its ANC. While it doesn't do as thorough a job at canceling out external noise, some users might prefer this less aggressive approach, as it can contribute to a more natural listening experience.

Sound Quality

Now, let's dive into the meat of the matter: how these TWS earbuds actually sound. Both the Pi6 and Momentum 4 TWS offer exceptional audio quality, but with distinct characteristics that cater to different listening preferences.

Soundstage

Both earbuds provide an intimate, "in your head" kind of sound that's characteristic of IEMs. However, there are subtle differences in their presentation.

The Pi6 offers a closer stage with a bit more verticality to the sound. This creates a more holographic quality to the audio, which can be particularly engaging for certain types of music. On the other hand, the Momentum 4 TWS presents a wider soundstage with a flatter, more neutral presentation. This allows for slightly more detail retrieval, especially in complex mixes.

To test this, I listened to "Verinnerlichung" by Paysage D'Hiver on both earbuds. The Momentum 4 TWS captured the spatial presentation of the song with impressive width, creating an expansive soundscape. The Pi6, while not as wide, accurately captured the intro's image, creating an immersive feeling of sound coming from behind me.

Honestly, on this track, I found it difficult to choose a clear winner. Both earbuds presented the music in a visceral, engaging way, albeit with different strengths.

Bass Response

When it comes to bass, the Pi6 and Momentum 4 TWS take notably different approaches. The Pi6 offers a strong bass presence but with a relatively flat tuning across the bass frequencies. This results in a warm, full-bodied sound that can be particularly pleasing with certain genres of music.

The Momentum 4 TWS, in contrast, offers a more defined and punchy bass response. While not as warm as the Pi6, it provides better separation and clarity in the low end.

To explore these differences, I listened to Chopin's "Piano Concerto No. 2" performed by the Slovak Philharmonic Orchestra. The Pi6's warm signature added a lovely richness to the piano's tone. While the separation in the strings wasn't as clear as on the Momentum 4 TWS, the overall tone of the instrument was incredibly pleasant.

The Momentum 4 TWS captured more clarity and definition in the performance, but it couldn't quite match the Pi6's pleasing warmth. I found the Pi6 particularly adept at handling classical music and solo performances, adding body to single instruments in an impressive way.

Switching gears, I also tested both earbuds with "Davidian" by Machine Head. Here, the Momentum's clarity really shone through, adding definition to the high-gain guitar sound. The Pi6, while still enjoyable, felt a bit hazier on this track, especially in the lower frequencies where there was already a lot of bass in the mix.

For bassheads, the Pi6 might be the preferred choice. However, if you prefer a flatter sound signature with a little added bass punch, the Momentum 4 TWS is likely to be more your speed.

Midrange Performance

The midrange is where both of these earbuds really show their pedigree. The Momentum 4 TWS continues Sennheiser's tradition of expertly tuned mids, offering clear and distinct midrange frequencies. While not quite on the level of open-back headphones like the HD800s or HD600, the Momentum 4 TWS delivers impressively detailed mids for a pair of TWS earbuds.

The Pi6 takes a slightly different approach, offering plenty of detail in the mids but with added body and warmth from the low-mids. This tuning is particularly flattering to female vocals, especially in modern mixes where it can help balance out overly bright productions.

Both earbuds handle vocals well, with the Pi6 being slightly more forward in its presentation. If you're a vocal lover, especially of female vocals, you might find the Pi6 more to your liking. However, if you prefer a more balanced presentation across all frequencies, the Momentum 4 TWS might be the better choice.

Personally, I lean towards the Momentum 4 TWS for its more neutral approach, but I can certainly appreciate the appeal of the Pi6's warmer, more intimate midrange presentation.

High-Frequency Response

In the high frequencies, we see another divergence in approach between these two earbuds. The Pi6 features slightly sharper highs, likely to compensate for its more pronounced bass response. While not sibilant, the highs are definitely more pronounced than on the Momentum 4 TWS.

The Momentum 4 TWS sticks closer to the Sennheiser house sound, with flatter highs that don't emphasize any particular part of the high-frequency range. Interestingly, despite being less pronounced, I found the Momentum's highs came through with a bit more clarity. This is likely due to less competition from the bass frequencies, allowing the more subdued highs to shine through.

To test the high-frequency performance, I listened to "Waltz For Debby" performed by Cannonball Adderly, Bill Evans, Percy Heath, and Connie Kay. Both earbuds added some extra bass that made the double bass playing more prominent than I'm used to hearing. The Pi6's more revealing highs brought out more detail in the cymbals and high notes, while the Momentum 4 TWS provided a mellower, more relaxed presentation of the track.

Connectivity and Smart Features

Both the Pi6 and Momentum 4 TWS offer robust connectivity options, but the Pi6 edges ahead with its multipoint connectivity and MFi certification. This allows for seamless switching between multiple devices and ensures optimal compatibility with Apple products.

That said, I didn't encounter any significant issues using the Momentum 4 TWS with my iPhone, including Siri functionality. Both earbuds performed reliably in terms of connection stability and range.

Battery Life and Charging

While both earbuds offer impressive battery life, the Momentum 4 TWS takes the crown here. With up to 37.5 hours of total playtime (including the charging case), it outperforms the Pi6's 24 hours by a significant margin. However, the Pi6 does offer slightly longer playtime on a single charge (8 hours vs 7.5 hours), which might be preferable for those who don't always carry their charging case.

Conclusion

After extensive testing, I can confidently say that both the Bowers & Wilkins Pi6 and the Sennheiser Momentum 4 TWS are exceptional Bluetooth earbuds that deserve their place at the top of the TWS market. Choosing between them ultimately comes down to personal preference and prioritization of features.

If you prioritize a warm, intimate sound signature, slightly better comfort (for my ears, at least), and seamless integration with Apple devices, the Pi6 might be your best bet. Its performance with vocals and classical music is particularly impressive.

On the other hand, if you value a more neutral sound signature, superior ANC, and longer overall battery life, the Momentum 4 TWS could be the better choice. Its wider soundstage and clearer bass definition make it a versatile option for a wide range of musical genres.

Both of these TWS earbuds represent the cutting edge of what's possible in the world of wireless audio. Whether you choose the Pi6 or the Momentum 4 TWS, you're getting a pair of earbuds that deliver exceptional sound quality, comfort, and features. The choice between them comes down to subtle differences in sound signature and feature set, making either a worthy addition to any audio enthusiast's collection.