Why is HP-C28BT better than C40i?
- Earbud weight (each)3 g vs 5.8 g+93%
Why is C40i better than HP-C28BT?
- Battery life3.5 h vs 7 h2×
- Driver size6.1 mm vs 12 mm+97%
- Charging time1.5 h vs 1 h+50%
Specifications
Side by side
| Sound | ||
| Fit | In-ear | In-ear |
| Ear cup design | — | Open-back |
| Driver type | Dynamic | Dynamic |
| Driver size | 6.1 mm | 12 mm |
| Number of drivers | — | 1 |
| Lowest frequency | 20 Hz | 20 Hz |
| Highest frequency | 20,000 Hz | 20,000 Hz |
| Impedance | 16 Ω | 22 Ω |
| Sensitivity | 90 dB | — |
| Hi-Res Audio | — | Yes |
| Adjustable equaliser | — | Yes |
| Noise control | ||
| Active noise cancelling | — | No |
| Battery & charging | ||
| Battery life | 3.5 h | 7 h |
| Total with charging case | — | 21 h |
| Charging time | 1.5 h | 1 h |
| Quick charge (claimed) | — | 10 min → 5 h |
| Fast charging support | — | Yes |
| Connectivity | ||
| Wireless | Yes | Yes |
| Bluetooth version | 5.3 | 5.4 |
| Bluetooth codecs | AAC, SBC | AAC, SBC |
| Hi-res codec (LDAC / aptX HD / LHDC) | No | No |
| aptX | No | No |
| LDAC | No | No |
| Multipoint (two devices) | — | Yes |
| USB-C | Yes | Yes |
| Design & build | ||
| Earbud weight (each) | 3 g | 5.8 g |
| Protection rating | IPX4 | IPX4 |
| Water resistance (IPx) | IPx4 | IPx4 |
| Colours | — | Midnight Black, Desert Bronze |
| Features | ||
| Touch controls | Yes | Yes |
| Hands-free calls | Yes | Yes |
