Synergy
Efficiency & Sensitivity
The COSMO rated 15Ω in impedance with an SPL of 100dB/Vrms so it doesn’t seem inefficient on paper.
Despite this rating, I found it requires strong amplification power to bring up the dynamics and to sound more open and brighter in the treble.
Where possible opt for a high gain mode for the COSMO to sound properly driven and do not worry about high noise floors as it’s not overly sensitive.
Pairings
MOONDROP states that the COSMO is easy to drive, even though it is rated at just 15Ω it is power demanding. You will need a good desktop amplifier to give it enough current and not sound muffled or too flat.
For example, paired with the 8W-capable FiiO K19, the COSMO treble opens up and the bass sounds a lot tighter and cleaner.
Lighter voices are more smoothly presented compared to the RME ADI 2 Pro which has a stronger focus on separation between the virtuoso and the backing instruments. The presentation is airier and more relaxing, though it feels less textured in the lower mids.
With less powerful gears the bass decay feels more elaborated with a more refined reverb and nasal tone which I enjoy with classic Motown and ’70s music, though one caveat is a slight lack of bass detail.
When sufficiently powered the midrange gets cleaner with a small nudge in the fundamental bass frequencies that strengthen its presence and enhance chest resonance from male vocal performances.
Generally, I prefer a powerful and brighter amplifier that helps open up the treble. Also, you will need a strong decoder, (DAC) in terms of Vrms output and resolution for added texture and dynamics on the low end.
Pairing the COSMO with the RME ADI 2 Pro yields pleasant results. Its sound is nicely defined and rounded in the treble while having elements across the mids more stereophonically presented,
However, it would still be preferable to give it more power for a firmer attack and help boost the clarity in the treble.
Select Comparisons
MOONDROP VENUS
Technical
The VENUS was released in late 2022 and features a CNC-machined framework, with a 100mm driver similar to the COSMO.
The features on the COSMO are improved based on VENUS’s design and it moves on to using the VDSF target curve as a reference. It also now uses a thinner diaphragm at 0.500n called a Nanoscale Ultra-thin Diaphragm.
The Venus is 18Ω in impedance and slightly higher than COSMO’s 15Ω rating. However, the sensitivity for both headphones is the same, measuring at 100dB/Vrms @1kHz. Both headphones can achieve <0.05% nonlinear distortion.
Design
The COSMO has some noticeable improvements over the VENUS design including an adjustable headband, a more mature use of material, and enhanced hinges.
The yoke earcup connections are more secure with a lock on the COSMO when compared to the loose holding clip-on design on the VENUS.
Despite these improvements, the VENUS has a more interesting faceplate design on its housing with cooler radial lines, though the finishing isn’t as smooth as on the COSMO.
Performance
Using the Shanling M5 Ultra to test, the Venus sounds more youthful and vibrant, with a brighter treble that helps with clarity and perceived definition.
Percussion and higher notes on string instruments are more effortlessly presented on the VENUS while on the COSMO it is more rounded in the upper vocal range and beyond, putting the focus on the vocal range.
In contrast, the Venus doesn’t sound as mids intensive and polished as the COSMO, which presents the vocal with more thickness and texture, sweetening it with the sharp roll-off. The current drain with COSMO also seems higher as the M5 Ultra gets hotter much faster.
There is room for both headphones to scale up and sound more defined and dynamic with desktop sources. However, the pairing direction will be quite different as the comparatively more V-shaped tuning on the VENUS is more forgiving with more detail and air from portable sources.
The COSMO starts with denser, more textured mids and elaborative bass which requires a defined and brighter setup to power it, or else it may sound veiled or boxy.
The impression given by the COSMO alongside the VENUS reminds me of switching from the Sennheiser HD 800 to the HD 820, which adds more presence to the harmonics while dimming the air for stronger sibilance control.
This results in narrowing the staging performance but on the other hand, the vocal image feels more intimate and stereophonic. This works well if you are a vocal lover but not so much if you are into Classical music.
HIFIMAN Ananda Nano
Technical
There are some fun similarities between the COSMO and the HIFIMAN Ananda Nano which also features a Nanometer Thickness Diaphragm for faster response.
On paper, the Nano is rated 14Ω in impedance and 94 dB @1kHz in sensitivity. So it would seem less sensitive compared to the COSMO but in practice, the Ananda Nano is more responsive to power.
Design
The Ananda Nano is based on HIFIMAN’s ovoid-shaped cup design and feels as big as the COSMO when worn.
The Ananda Nano weighs just 419.6g and feels quite a bit lighter than the COSMO, probably because of the COSMO’s metallic structure. At the same time, the COSMO has a thicker, braided cable that looks more premium.
Performance
The Ananda Nano is more responsive to power and can be driven more easily on a portable source sounding more textured in the bass and extended in the upper register. It maintains a light and joyful pace with jazz and pop due to its fast response and clean, slightly V-shaped tuning.
The COSMO sounds darker, richer, airier, and more stereophonic in the mids. However, I do not recommend it for portable use due to its greater power requirements.
Using the RME ADI 2 Pro and K19 to compare the two, the HIFIMAN Ananda Nano kicks cleaner in the bass and has better overall balance, though it does not sound as intense, and colored in the mids as the COSMO.
The vocal, or acoustic elements across the mids sounds project with stronger overtone details and body whereas the Ananda Nano defines the backing instruments more clearly, spreading the attention more evenly instead of just the virtuoso.
The tuning style is quite different between the two so as the favored music genres they can cater. I prefer the Ananda Nano for instrumentals, EDM, Jazz, and live instrumental recordings, as it carries more energy in the top end sounding faster and cleaner.
The COSMO, after swapping its pads and to SPC cable, would be the pick for vocal works, acoustic guitars, and strings for its richer and more textured performance.
My Verdict
The MOONDROP COSMO open-back planar headphones are tuned with a stronger focus on the mid-range frequencies, blending in its planar driver technology’s penchant for rich texture and precision imaging.
The overall balance and bass performance could benefit from earpads with more breathable fabric and thicker padding. Something I hope MOONDROP would consider by providing an additional set of ear pads such as the ones from the PARA.
It also requires some studied matching since it can present a greater synergy and power challenge to your DACs and amplifiers than its predecessors.
The COSMO would be a good alternative for those who want a more colored planar headphone tuning, and one that delivers more weight to vocals. With some simple tweaks, it could achieve a better tonal balance and sound that is even more expressive with vocal performances.
MOONDROP COSMO Technical Specifications
- Model: COSMO 100mm Nanoscale Ultra-thin Flagship Planar Headphone
- Sensitivity: 100dB/Vrms (@1kHz)
- Impedance: 150±15% (@1kHz)
- Frequency Range: 13Hz-58kHz (IEC61094, Free Field)
- Effective Frequency Range: 20Hz-20kHz (IEC60318-4, -3dB)
- Headphone Jack: 3.5mm
- Cable Plug: 4.4mm
