Sennheiser M4 vs Technics Reference Class Hi-Fi at a Glance
• Sennheiser M4’s biggest strength: up to 60 hours of playback, adaptive noise cancellation, and cushioned over-ear comfort. Trade-off: it is an over-ear headphone, not a compact earbud.
• Technics Reference Class Hi-Fi’s biggest strength: true wireless in-ear listening with adaptive noise cancellation, head-tracked Dolby Atmos, and up to 10 hours of playback per charge. Trade-off: its stated battery life is shorter, and its specifications do not identify it as suitable for swimming.
• Choose Sennheiser M4 for long listening stretches, travel, and listeners who prefer padded earcups and a headband.
• Choose Technics Reference Class Hi-Fi for a pocketable earbud format, multipoint connections, and spatial listening features.
• For actual swimming, neither is a supported pick based on the available product details.
The Sennheiser M4 is an over-ear wireless headphone built around long listening sessions. Its stated playback time is up to 60 hours, and fast charging can add a further six hours of listening after a 10-minute charge. That combination makes it a practical fit for a traveler, a commuter, or someone who would rather charge headphones occasionally than think about battery every day. The fold-flat design also helps when packing, while the cushioned headband and ear pads are intended to support extended wear.
Its sound options are another reason to consider it. The M4 uses 42 mm transducers and aptX Adaptive, and the Smart Control Plus app offers an equalizer, presets, sound modes, and sound personalization. In everyday terms, that gives listeners a way to adjust the presentation for different preferences or types of content rather than relying on one fixed sound profile. Adaptive noise cancellation is designed to respond to ambient noise, and transparency mode lets outside sounds through when awareness matters. Touch controls can also be switched off, which may suit someone who prefers not to use the touchpad.
How We Research
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-10-18 · 8 min read · Independent comparison
Technics Reference Class Hi-Fi is a true wireless earbud set for buyers who want a compact in-ear format and feature-rich listening. Its adaptive noise cancelling is designed to respond to the surroundings, while Voice Focus AI is intended to support clear calls. A three-device multipoint connection can be useful if you switch between, for example, a laptop, phone, and another compatible device. That is a practical distinction for people who do not want to treat their earbuds as belonging to just one device.
The feature that most clearly sets the Technics apart is Dolby Atmos with head tracking. The sound is designed to respond to head movement, creating a spatial effect for supported listening. That may appeal to someone watching movies or listening to music who wants a more immersive presentation than conventional stereo. Technics also specifies magnetic fluid drivers, with a design aimed at low distortion, accurate bass, and smooth mid-to-high frequencies. These are useful details for a listener who cares about sound character, though they do not by themselves guarantee a personal preference.
The stated playback time is up to 10 hours with noise cancellation, with up to 28 hours when the charging case is included. The case supports wireless charging. That setup favors people who want earbuds they can stow between uses and recharge in the case, rather than a headset worn over the head. Technics describes the shape as lower-profile and shaped around the ear contours, and says it is smaller and lighter than its earlier EAH-AZ80 earbuds. Who should skip it: skip these if your priority is the longer single-charge playback stated for the Sennheiser, or if your main goal is swimming. The available details do not say these earbuds are waterproof or intended for immersion.
• Best for long playback between charges → Sennheiser M4. Its stated playback reaches up to 60 hours, compared with up to 10 hours for Technics with noise cancellation.
• Best for a true wireless earbud format → Technics Reference Class Hi-Fi. It is an in-ear set with a wireless charging case; the M4 is an over-ear headphone.
• Best for cushioned over-ear wear → Sennheiser M4. Its padded headband and cushioned ear pads are designed for comfort over longer listening sessions.
• Best for head-tracked spatial audio → Technics Reference Class Hi-Fi. Dolby Atmos with head tracking is its standout feature for compatible movies and music.
• Best for carrying between uses → Technics Reference Class Hi-Fi. The earbuds and charging case are more compact in concept than an over-ear headset, and the case supports wireless charging.
• Best for adjusting your sound profile → Sennheiser M4. Its app includes an equalizer, presets, sound modes, and personalization.
• Best for managing several connected devices → Technics Reference Class Hi-Fi. Its three-device multipoint feature is aimed at switching among multiple devices.
• Best for swimming → neither, based on the listed details. Neither product’s information establishes water protection or suitability for swimming, so I would look for a model explicitly designed for water use.
My Verdict
I would choose the Sennheiser M4 for everyday listening if long battery life, over-ear comfort, and sound customization matter most to me.
For swimming, my recommendation is neither: the listed features do not establish either product as suitable for use in water.
I would not call either the best Bluetooth earbuds for swimming or the best headset for swimming without explicit water-use specifications.
Start with the physical format, because this is not a close contest on that point. The M4 covers the ears with a headband and cushioned ear pads. Technics sits in the ears as a true wireless set. If you already know you dislike ear tips or an in-ear fit, the Technics’ feature list may not change that preference. If you do not want a headband or earcups, the M4 is unlikely to be the right match.
Next, think about how you charge and use headphones throughout the day. The M4’s up-to-60-hour playback figure favors long stretches between charges. Technics divides its listening time between the earbuds and the case: up to 10 hours with noise cancellation, and up to 28 hours when the case is included. The case-based arrangement can fit frequent short listening sessions, while the M4’s longer stated single-charge duration is appealing for extended use.
Noise control is available on both, but the supporting details differ. Sennheiser pairs adaptive noise cancellation with transparency mode, making it possible to switch between blocking distractions and hearing outside sounds. Technics specifies adaptive noise cancelling and emphasizes a voice-focused AI feature for calls. Consider which situation matters more: toggling between isolation and awareness, or managing calls and multiple connected devices.
Finally, keep the swimming question separate from the general comparison. “Over ear headphones for swimming” is a format search, but an over-ear design alone does not establish water suitability. The same caution applies to earbuds: a small in-ear shape does not mean a product is safe for pool use. Since neither product’s listed details establish swimming protection, I would choose a product specifically described for that activity rather than infer suitability from its shape or wireless features.
Neither product’s listed details establish that it is intended for swimming or water immersion. I would not use either for swimming on the basis of these specifications alone.
The M4 is specified for up to 60 hours of playback. Technics lists up to 10 hours with noise cancellation and up to 28 hours including its charging case, so the M4 has the longer stated playback duration.
Yes. Both list adaptive noise cancellation. The M4 also includes transparency mode, while Technics specifies head-tracked Dolby Atmos, Voice Focus AI for calls, and three-device multipoint.
Choose based on the listening experience you want. The M4 offers app-based EQ, presets, sound modes, and personalization; Technics adds Dolby Atmos with head tracking for spatial listening. Those features describe different approaches, so the better fit depends on whether sound adjustment or head-tracked immersion matters more to you.
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