6974434225138 · Orange · UK
CMF Buds 2a (store SKU 6974434225138 in Orange on the UK and US Nothing stores) are true wireless earbuds with ANC up to 42 dB, a 12.4 mm bio-fibre driver, four microphones and Bluetooth 5.4 with dual connection.
Specifications checked 26 Sept 2026.
Amazon links open search results. Check the exact variant, current price and availability with the retailer.
Manufacturer specificationsChoose the Nothing CMF Buds 2a for
Choose the Sennheiser HD 660S2 for
700240 · black with bronze accents · 300 ohm · 1.8 m balanced and unbalanced cables
The HD 660S2 is an open-back, over-ear headphone with a 38 mm dynamic driver rated 8–41,500 Hz (−10 dB) at 300 ohms. Sennheiser revised its acoustics for stronger sub-bass, and it ships with 1.8 m 6.35 mm unbalanced and 4.4 mm balanced cables plus a 3.5 mm adapter.
Specifications checked 11 Sept 2026.
Amazon links open search results. Check the exact variant, current price and availability with the retailer.
Manufacturer specificationsSearch links open retailer results, not a matched listing; eBay listings are checked daily. As an Amazon Associate I earn from qualifying purchases. As an eBay Partner, we may be compensated if you make a purchase.
Differences first. Select a topic for its graphic, sources and conditions.
Yes and No describe the listed feature. Missing evidence stays unverified.
Open-back earcups are not sealed. Start here if your listening space is quiet; this construction is not a sound-quality rating.
Open-back. Manufacturer specification
Start with your listening environment. Open and closed earcups suit different surroundings. A closed back is not the same as active noise cancellation. Check the exact cable and headphone output. We do not turn impedance, driver size or unpaired lab results into a sound-quality score.
3 verified differences, most decision-relevant first. Missing information stays separate.
Manufacturer specification · The manufacturer lists AAC and SBC codec support; support for other codecs remains unverified. Charging is quoted with a Type-C cable.
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsManufacturer specification
Sennheiser HD 660S2 — exact model specificationsSennheiser HD 660S2 — operating guide and specificationsCheck the exact configuration and source conditions for your use.
Manufacturer specification
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsManufacturer specification · Sennheiser lists 38 mm as the transducer size.
Sennheiser HD 660S2 — exact model specificationsCheck whether the diameter describes the complete transducer or only its diaphragm. Different labels and driver sizes do not establish better sound.
Manufacturer specification · A pair of earbuds and a charging case (with a lanyard hole); ear tips in sizes S, M and L are in the box. Nothing does not state the ear tip material.
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsManufacturer specification
Sennheiser HD 660S2 — operating guide and specificationsCheck the exact configuration and source conditions for your use.
No source recorded for this side.
Manufacturer specification
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification · ANC up to 42 dB (Nothing's laboratory theoretical maximum) over up to 2900 Hz, with Adaptive ANC and Transparency mode.
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsThe reviewed exact sources do not explicitly establish active noise cancellation absence. Preserve separately sourced acoustic design and passive attenuation; they cannot turn omitted ANC into a false capability. · Manufacturer specification
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification · Four HD microphones in total (two per bud) with Clear Voice Technology and Wind Noise Reduction 2.0.
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsThe reviewed exact sources do not explicitly establish microphone absence. Omission from a package or technical inventory, a stereo audio connector, and a without-remote statement do not establish microphone=false. · Manufacturer specification
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification · Nothing laboratory results at 25 °C, 50% volume, AAC, other features at default settings; actual life varies with use. Talk time is listed separately (earbuds 3.5 h ANC on / 4 h ANC off; with case 15.6 h / 18.4 h).
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsThe reviewed exact sources do not explicitly establish battery life or that no battery is required for operation. A wired/dynamic audio path, omitted charger or Battery included N is not an explicit operating-power requirement. · Manufacturer specification
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · Nominal impedance; check that your amplifier or audio source can drive this load.
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · Sennheiser describes these changes as the S2 revision of the HD 660S.
Sennheiser HD 660S2 — exact model specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification · Nothing says all these features are available on Nothing OS and in the Nothing X app for iOS and other Android devices (Android 6.0 and above, iOS 13 and above); on Nothing OS 1.5.6 and higher the settings are built into the phone.
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsNo source recorded for this side.
Evidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNo source recorded for this side.
Evidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · Optional cables are sold separately; balanced cables need a balanced headphone output.
Sennheiser HD 660S2 — exact model specificationsSennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · Length of the supplied cable.
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification · Fast charge: after a 10-minute charge, up to 5.5 hours of playback with the case or 2 hours without it (ANC off, 50% volume, AAC, Nothing laboratory, 25 °C).
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsNo source recorded for this side.
Evidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNo source recorded for this side.
Evidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · The 4.4 mm balanced cable needs a balanced headphone output; an XLR-4 cable is optional.
Sennheiser HD 660S2 — exact model specificationsSennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · Nominal clamping force; individual fit and comfort can differ.
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification · Customisable (footnote 7): double tap, triple tap, tap & hold and double tap & hold can be set to next song, previous song, volume up, volume down, voice assistant or switching noise cancellation modes, via phone settings on Nothing OS 1.5.6+ or the Nothing X app on Android 6.0+/iOS 13+.
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsNo source recorded for this side.
Evidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · Rated at 1 kHz and 100 dB SPL; other models use different test levels, so compare with care.
Sennheiser HD 660S2 — exact model specificationsSennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · Replacement procedure shown in the manual.
Sennheiser HD 660S2 — exact model specificationsSennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification · Fast Pair works on supported Android devices running Google Play services 11.7+ (back to Android 6.0); Find My and device renaming support need Android 10 or later.
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsNo source recorded for this side.
Evidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · Rated to EN 60-268-7; the maximum input the headphones can handle, not the amplifier power they need.
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification · The Other features table says 'less than 110 ms under Game Mode' with a Nothing Phone; footnote 5 says latency can be reduced to as low as 110 ms with Nothing phones and Game Mode on. Source field: Low lag mode.
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsNo source recorded for this side.
Evidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · Static magnetic field at the headphone surface.
Sennheiser HD 660S2 — exact model specificationsSennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsNo source recorded for this side.
Evidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · Rated at 1 kHz with 1 V rms; not directly comparable with dB/mW ratings.
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · Replacement procedures are in the manual; spare-part availability varies.
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification · The Sound features table says 'Ultra Bass Technology'; the product copy calls it 'Ultra Bass Technology 2.0'.
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsNo source recorded for this side.
Evidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · Sennheiser does not give the frequency range or comparison model for this claim.
Sennheiser HD 660S2 — exact model specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
The specification lists 'IPX2 case', but footnote 4 says the IP54 test applies to the earbuds and 'the charging case is not supported'; the case rating is therefore left out. · Manufacturer specification
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNo source recorded for this side.
Evidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification · Each earbud. The charging case weighs 42.75 g.
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNo source recorded for this side.
Evidence is missing or conflicting on at least one side. This is not a verified difference.
Manufacturer specification
Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsNo source recorded for this side.
Evidence is missing or conflicting on at least one side. This is not a verified difference.
No source recorded for this side.
Manufacturer specification · Approximate, without the cable.
Sennheiser HD 660S2 — operating guide and specificationsEvidence is missing or conflicting on at least one side. This is not a verified difference.
0 shared fields have the same recorded value.
Choose a starting point, then fine-tune your must-haves.
These shortcuts select the features shown above. Check the fit against your own equipment and listening space.
A feature match describes the selected requirements. It doesn’t rate sound or comfort.
Select a feature to check your fit.
Select a feature to check your fit.
| Specification | Nothing CMF Buds 2a | Sennheiser HD 660S2 |
|---|---|---|
Wearing styleDifferent SourcesNothing CMF Buds 2a Manufacturer specification · A pair of earbuds and a charging case (with a lanyard hole); ear tips in sizes S, M and L are in the box. Nothing does not state the ear tip material. Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 Manufacturer specification Sennheiser HD 660S2 — operating guide and specifications | In-ear, true wireless (ear tips in sizes S, M and L) | Over-ear (circumaural), open-back dynamic headphones |
Weight per earbud SourcesNothing CMF Buds 2a Manufacturer specification · Each earbud. The charging case weighs 42.75 g. Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 No source recorded. | 4.28 g | Not provided |
Dimensions SourcesNothing CMF Buds 2a Manufacturer specification Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 No source recorded. | Each earbud 32.5 x 20.3 x 24.3 mm; charging case 54.7 x 54.7 x 23 mm (height x width x depth) | Not provided |
Dust, sweat and water resistance SourcesNothing CMF Buds 2a The specification lists 'IPX2 case', but footnote 4 says the IP54 test applies to the earbuds and 'the charging case is not supported'; the case rating is therefore left out. · Manufacturer specification Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 No source recorded. | IP54 (earbuds) | Not provided |
Weight SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · Approximate, without the cable. Sennheiser HD 660S2 — operating guide and specifications | Not provided | 260 g |
Acoustic design SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification Sennheiser HD 660S2 — operating guide and specifications | Not provided | Open-back |
Replaceable parts SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · Replacement procedures are in the manual; spare-part availability varies. Sennheiser HD 660S2 — operating guide and specifications | Not provided | Detachable cable and replaceable ear pads |
Ear pads SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · Replacement procedure shown in the manual. Sennheiser HD 660S2 — exact model specificationsSennheiser HD 660S2 — operating guide and specifications | Not provided | Velour ear pads; replaceable |
Rated contact pressure SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · Nominal clamping force; individual fit and comfort can differ. Sennheiser HD 660S2 — operating guide and specifications | Not provided | Approximately 6.0 N ±1.0 N |
Wired / wireless connectionsDifferent SourcesNothing CMF Buds 2a Manufacturer specification · The manufacturer lists AAC and SBC codec support; support for other codecs remains unverified. Charging is quoted with a Type-C cable. Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 Manufacturer specification Sennheiser HD 660S2 — exact model specificationsSennheiser HD 660S2 — operating guide and specifications | Bluetooth 5.4 (AAC, SBC) with dual connection; USB-C charging on the case | Wired analogue stereo; 1.8 m cables with 6.35 mm unbalanced and 4.4 mm balanced plugs; included 3.5 mm adapter |
Battery life SourcesNothing CMF Buds 2a Manufacturer specification · Nothing laboratory results at 25 °C, 50% volume, AAC, other features at default settings; actual life varies with use. Talk time is listed separately (earbuds 3.5 h ANC on / 4 h ANC off; with case 15.6 h / 18.4 h). Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 The reviewed exact sources do not explicitly establish battery life or that no battery is required for operation. A wired/dynamic audio path, omitted charger or Battery included N is not an explicit operating-power requirement. · Manufacturer specification Sennheiser HD 660S2 — operating guide and specifications | Earbuds up to 5 hours with ANC on and 8 hours with ANC off; with the charging case 23 hours with ANC on and 35.5 hours with ANC off. | Not listed by the manufacturer |
Charge time SourcesNothing CMF Buds 2a Manufacturer specification · Fast charge: after a 10-minute charge, up to 5.5 hours of playback with the case or 2 hours without it (ANC off, 50% volume, AAC, Nothing laboratory, 25 °C). Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 No source recorded. | Full charge (0-100%) in 89 minutes with the case connected to a USB-C cable; with the case unplugged, the earbuds charge inside it in 57 minutes | Not provided |
Bluetooth codecs SourcesNothing CMF Buds 2a Manufacturer specification Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 No source recorded. | AAC, SBC | Not provided |
Multipoint (dual connection) SourcesNothing CMF Buds 2a Manufacturer specification Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 No source recorded. | Yes | Not provided |
Low lag mode SourcesNothing CMF Buds 2a Manufacturer specification · The Other features table says 'less than 110 ms under Game Mode' with a Nothing Phone; footnote 5 says latency can be reduced to as low as 110 ms with Nothing phones and Game Mode on. Source field: Low lag mode. Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 No source recorded. | 110 ms with a Nothing phone in Game Mode | Not provided |
Quick pairing SourcesNothing CMF Buds 2a Manufacturer specification · Fast Pair works on supported Android devices running Google Play services 11.7+ (back to Android 6.0); Find My and device renaming support need Android 10 or later. Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 No source recorded. | Google Fast Pair and Microsoft Swift Pair | Not provided |
Battery capacity SourcesNothing CMF Buds 2a Manufacturer specification Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 No source recorded. | Earbuds 43 mAh each; case 460 mAh | Not provided |
Included cable length SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · Length of the supplied cable. Sennheiser HD 660S2 — operating guide and specifications | Not provided | 1.8 m |
Supplied plug configuration SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · The 4.4 mm balanced cable needs a balanced headphone output; an XLR-4 cable is optional. Sennheiser HD 660S2 — exact model specificationsSennheiser HD 660S2 — operating guide and specifications | Not provided | 6.35 mm unbalanced cable; 4.4 mm balanced cable; 6.35 mm-to-3.5 mm adapter |
Included and optional cables SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · Optional cables are sold separately; balanced cables need a balanced headphone output. Sennheiser HD 660S2 — exact model specificationsSennheiser HD 660S2 — operating guide and specifications | Not provided | Detachable 1.8 m unbalanced and 4.4 mm balanced cables included; XLR-4 cable optional |
DriversDifferent SourcesNothing CMF Buds 2a Manufacturer specification Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 Manufacturer specification · Sennheiser lists 38 mm as the transducer size. Sennheiser HD 660S2 — exact model specifications | Custom 12.4 mm dynamic driver, bio-fibre + custom TPU diaphragm, Dirac tuning | 38 mm open dynamic transducer; aluminium voice coil and vented magnet system |
Sound features SourcesNothing CMF Buds 2a Manufacturer specification · The Sound features table says 'Ultra Bass Technology'; the product copy calls it 'Ultra Bass Technology 2.0'. Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 No source recorded. | Dirac, Ultra Bass Technology, Custom EQ; tuning by Nothing and Dirac | Not provided |
Nominal impedance SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · Nominal impedance; check that your amplifier or audio source can drive this load. Sennheiser HD 660S2 — operating guide and specifications | Not provided | 300 ohm |
Rated frequency range SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification Sennheiser HD 660S2 — operating guide and specifications | Not provided | 8–41,500 Hz (−10 dB) |
Rated sensitivity SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · Rated at 1 kHz with 1 V rms; not directly comparable with dB/mW ratings. Sennheiser HD 660S2 — operating guide and specifications | Not provided | 104 dB SPL at 1 kHz, 1 V rms |
Frequency equalisation SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification Sennheiser HD 660S2 — operating guide and specifications | Not provided | Diffuse-field equalised |
Rated total harmonic distortion SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · Rated at 1 kHz and 100 dB SPL; other models use different test levels, so compare with care. Sennheiser HD 660S2 — exact model specificationsSennheiser HD 660S2 — operating guide and specifications | Not provided | ≤0.04% at 1 kHz, 100 dB SPL |
Rated long-term input power SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · Rated to EN 60-268-7; the maximum input the headphones can handle, not the amplifier power they need. Sennheiser HD 660S2 — operating guide and specifications | Not provided | Maximum 500 mW under EN 60-268-7 |
Published acoustic changes SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · Sennheiser describes these changes as the S2 revision of the HD 660S. Sennheiser HD 660S2 — exact model specifications | Not provided | Revised 300-ohm coil, more compliant surround, 70 Hz resonance and revised transducer airflow |
Manufacturer sub-bass claim SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · Sennheiser does not give the frequency range or comparison model for this claim. Sennheiser HD 660S2 — exact model specifications | Not provided | Double the sound pressure at the lowest frequencies |
Microphone SourcesNothing CMF Buds 2a Manufacturer specification · Four HD microphones in total (two per bud) with Clear Voice Technology and Wind Noise Reduction 2.0. Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 The reviewed exact sources do not explicitly establish microphone absence. Omission from a package or technical inventory, a stereo audio connector, and a without-remote statement do not establish microphone=false. · Manufacturer specification Sennheiser HD 660S2 — operating guide and specifications | Yes | Not listed by the manufacturer |
Active noise cancellation SourcesNothing CMF Buds 2a Manufacturer specification · ANC up to 42 dB (Nothing's laboratory theoretical maximum) over up to 2900 Hz, with Adaptive ANC and Transparency mode. Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 The reviewed exact sources do not explicitly establish active noise cancellation absence. Preserve separately sourced acoustic design and passive attenuation; they cannot turn omitted ANC into a false capability. · Manufacturer specification Sennheiser HD 660S2 — operating guide and specifications | Yes | Not listed by the manufacturer |
Companion app SourcesNothing CMF Buds 2a Manufacturer specification · Nothing says all these features are available on Nothing OS and in the Nothing X app for iOS and other Android devices (Android 6.0 and above, iOS 13 and above); on Nothing OS 1.5.6 and higher the settings are built into the phone. Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 No source recorded. | Nothing X app (Android and iOS): customise equaliser and controls, find my earbuds, low lag mode, software updates | Not provided |
Controls SourcesNothing CMF Buds 2a Manufacturer specification · Customisable (footnote 7): double tap, triple tap, tap & hold and double tap & hold can be set to next song, previous song, volume up, volume down, voice assistant or switching noise cancellation modes, via phone settings on Nothing OS 1.5.6+ or the Nothing X app on Android 6.0+/iOS 13+. Nothing (UK store, nothing.tech) — CMF Buds 2a product page with technical specificationsNothing (US store, us.nothing.tech) — CMF Buds 2a product page with technical specificationsSennheiser HD 660S2 No source recorded. | Touch controls: double tap to skip forward or answer/hang up calls; triple tap to skip back or reject calls; tap and hold to switch between Active Noise Cancellation and Transparency Mode. | Not provided |
Static magnetic field at the surface SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification · Static magnetic field at the headphone surface. Sennheiser HD 660S2 — exact model specificationsSennheiser HD 660S2 — operating guide and specifications | Not provided | 4.5 mT |
Operating temperature SourcesNothing CMF Buds 2a No source recorded. Sennheiser HD 660S2 Manufacturer specification Sennheiser HD 660S2 — operating guide and specifications | Not provided | −10 °C to +55 °C |
Closest headphones to this pair by shared key specifications. Not a popularity ranking.
Each record represents an explicitly checked model and configuration. Original import: 5 Sept 2026; this is not its verification date. This is not a list of current offers or a popularity ranking.
