Onanoff BuddyPhones Cosmos+

Kids' headphones with Bluetooth, noise-cancelling and volume limiting

The Onanoff BuddyPhones Cosmos+ are kids’ headphones that offer adjustable volume limiting via Bluetooth. They scored plus points for their long-lasting battery and stable Bluetooth range. They also earned a good score for their support of a high-quality audio codec and their impressive sound quality with good speech intelligibility. So are these robust, foldable over-ears the best wireless headphones for children, as the manufacturer claims?


With the BuddyPhones Cosmos+, Onanoff have added a pair of wireless over-ears to their range of children’s headphones. Thanks to their six different designs, they will appeal to both girls and boys. They have active noise cancellation (ANC) and, in addition to the Bluetooth 5.0 standard, they support the AAC format, a high-quality audio codec. Three volume-limiting listening modes are available via wireless, enabling hearing protection to be adapted to the listening environment and the child’s age. However, these headphones do not have a slot for SD cards or an integrated MP3 player.


The BuddyPhones Cosmos+ feature an expandable headband that is suitable for children and does not break during the tough and tumble of play or when pulled around. It is robust and designed to bend. The more fragile parts, such as the folding mechanism and the headband size adjustment, are reinforced with metal components. Their foldable design makes them compact to transport.

Other than that, these headphones are primarily made of plastic, which looks hard-wearing, while their soft padding is covered in imitation leather. According to the manufacturer, these are hypoallergenic. However, the Cosmos+ do not have a water-resistant finish according to IPX certification, which would certainly have been a practical feature for a pair of children’s headphones. During the test, we were able to disinfect the Cosmos+ with an eighty per cent ethanol solution without leaving any residue. In addition, the manufacturer states that the headphones have been certified by independent testing laboratories including TÜV and UL. Thus, they meet all important safety, pollutant and environmental standards like RoHS, REACH and PROP65.

Wearer comfort


The fit is loose rather than tight and means that contact pressure is moderate and the headphones are comfortable to wear. However, there is sufficient support to keep them on the head during jerky movements. Since the Onanoff BuddyPhones Cosmos+ are a closed, circumaural model, there is a high degree of shielding due to the design. As a result, external noise is significantly muffled, and very little sound was emitted into the environment during playback. These isolation properties offer advantages in learning scenarios, such as home-schooling. However, this enclosed listening experience can also pose a danger outdoors because things like approaching cars are not heard in the usual way. This should definitely be taken into account!

A snug fit is a prerequisite for passive shielding. This is facilitated by the rotatable and tiltable ear cups, with the oval-shaped ear cups being angled rather than straight. This helps to ensure that the ears are completely enclosed by the padding. The size of the earpieces might be problematic, as the head of the wearer must be a certain circumference for the Cosmos+ to fit correctly.

So for what ages are these children’s headphones suitable? The manufacturer states a minimum age of three years, which didn’t make sense to me. The smallest setting fits an adult with a small head so to me this model does not seem suitable for small children and pre-schoolers. In my estimation, the fit would be more suitable for children from about 7 or 8 years old.

Battery life

Our battery endurance test provided a surprise, as the advertised runtime of 24 hours was virtually doubled. The Onanoff BuddyPhones Cosmos+, with 85dB limiting using an iPad with a volume setting of 75 per cent, only needed external power after a good 47 hours. Even with active noise cancellation, a long listening time of more than 30 hours was achieved. So the Cosmos+ are not only powerful headphones for everyday use but are also suitable for holiday trips. When the battery is empty, charging is done via the USB-C port, which takes just under two hours.

Connection options

The 100 centimetre USB-C to USB-A charging cable supplied is about the right length. The package also includes a high-quality hardshell case that offers space for all accessories in addition to the headphones and enables protected transport. The manufacturer has also thought about wired use. A corresponding cable, which is 120 centimetres long and has a 3.5 mm plug, is included. This means that the Onanoff BuddyPhones Cosmos+ can be connected to the popular Toniebox or a tiptoi pen, which currently do not yet offer the option of connecting children’s headphones wirelessly via Bluetooth.

The BuddyLink function offers an additional option; a younger sibling, for example, can listen in during Bluetooth operation via the audio jack by connecting a second pair of headphones via cable. However, the volume is noticeably lower when listening in via a second pair of headphones, meaning this function is only suitable to a limited extent.


A quick press and hold of the centre remote button on the right side of the ear cup turns the headphones on and automatically puts them into pairing mode. Pairing with a smartphone, tablet, or computer can now take place. With a pre-established wireless connection, the button is used to start and pause playback and to answer and end phone calls. Separate plus and minus buttons are provided for volume adjustment. By holding the buttons down, you can also select a track by pressing the plus button to skip forward and the minus button to skip back. The unit controls were reliable and worked without any delays.

Bluetooth connection reached a high range of up to 14 metres within an urban environment, which offers children a lot of freedom of movement. The speech intelligibility of the microphone, which can be connected to the USB-C port if required and attenuates background noise, was also impressive. However, it should be noted that the voice is amplified very loudly, so we recommend not placing the microphone too close to the mouth. The flexible headset construction makes this possible without any problems.

Loudness limitation

The Onanoff BuddyPhones Cosmos+ provide a total of three listening modes to choose from. By holding down the plus and minus buttons at the same time, you can switch between them. The Toddler mode with a limit of 75 decibels is intended by the manufacturer for small children. For children and adolescents up to 14 years of age, the 85 dB limit of Kids mode is recommended. Maximum levels of 94 decibels are possible in Travel mode, which is provided as an option for noisy environments. However, you cannot see from the outside which listening mode is being used, it would have been good if this could be indicated by an LED. Since the travel mode is not suitable for ordinary listening situations and does not provide sufficient hearing protection in everyday life, the volume limit should be checked regularly. Excessive volume levels can also be reached in wired use because the different listening modes are only available in wireless mode. With a mini-jack connection, the limit is fixed at 94 decibels.

Noise cancellation with the BuddyPhones Cosmos+

On the right side of the ear cup, there is an ANC button for switching the active noise cancellation on and off. An LED that glows green signals when noise cancelling is active. Low, static external noises are attenuated quite effectively, which is particularly helpful when travelling on a train or plane. Voices or high-frequency sirens and ringing tones remain audible as there is only a slight reduction in the mid and upper frequency range. The performance of the noise suppression is not high, but it is solid considering the price range.

ANC mode can also be used wired, which is a plus. Via cable, the BuddyPhones Cosmos+ achieve a better playback quality, as noise cancelling in Bluetooth mode has a negative effect on the sound. When used wireless, the reproduction loses clarity and accuracy, which is not the case when wired. However, in both modes, background noise is perceptible when playback is paused.

Basic sound and study mode

When I tested the two Bluetooth BuddyPhones Play and Wave in 2018, I characterised both pairs of headphones as muffled. The water- and dust-resistant Wave model, in particular, didn’t convince me from a sound perspective. Now with the Cosmos+, quality of reproduction has improved considerably; they have an appealingly clear and uncluttered sound image both via cable and wireless:

The presentation seems neither dull nor muddy. Indeed, the basic warmth was pleasing and conveyed a harmonious listening experience. The basic sound has a decent voice reproduction with good intelligibility. This can be further increased for listening to educational content in study mode by noticeably lowering the bass range. However, there is no boost in the upper frequency range, which used to lead to overdriving in the 2018 models. Regrettably, the learning mode can only be used in Bluetooth mode and not in wired, as was the case with active noise cancellation. Wirelessly, however, speech intelligibility can be increased in all three listening modes using a slider below the ANC button. In the case of atmospheric audiobooks with several voices and an acoustic background as well as music and singing, the basic sound again shows off its advantages with a detailed, lively and coherent reproduction. The Onanoff BuddyPhones Cosmos+ thus cover a wide range of applications.

Maike Paeßens
4 months ago by Maike Paeßens
  • Rating: 4
  • Sound
  • Handling
  • Price/Quality
  • Function

The Onanoff BuddyPhones Cosmos+ do not offer adequate hearing protection in wired mode, while the children’s headphones via Bluetooth have adjustable loudness limitation. On the plus side, the long-lasting battery and the high, stable Bluetooth range are good points. The support of a high-quality audio codec and convincing sound quality with good speech intelligibility are also positives. These robust, foldable over-ears are delivered with a high-quality accessory package that includes a hardshell case for transport.

  • Comfortable fit
  • Robust, foldable design
  • Long battery life
  • High, stable Bluetooth range
  • Adjustable volume control via Bluetooth
  • 3.5 mm audio input
  • BuddyLink function for listening with others
  • Pluggable microphone with good intelligibility
  • Supports AAC codec
  • Hard case
  • No IPX certification
  • Earpieces appear too large for small and preschool children
  • Wired listening only possible with 94dB limit
  • ANC mode with perceptible background noise

Technical specifications

  • Ear couplingOver-ear
  • Typeclosed
  • Transducer principledynamic
  • Frequency response (headphones)20 - 20.000 Hz
  • Impedance± 15% 32 ohms
  • Sound pressure level (SPL)up to 94dB at +/-3 dB
  • Weight with cable245 g
  • Weight without cable224 g
  • Cable length120 cm

What's in the box

  • Detachable microphone
  • Mini jack cable
  • USB-C to A charging cable
  • Hard case

Special features

  • available in various designs and colours
  • BT codecs: SBC, AAC
  • BT version: 5.0

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