The Shure brand has set some high expectations on discerning audio consumers when the AONIC 50 over-ear headphones was released in 2020, and they do not disappoint. I reviewed it and liked the overall quality and features, though the retail packaging is too elaborate and bulky. Enter the AONIC 40, designed to be more portable and compact, stripping off some over-the-top features while improving others to make it more appealing to the mid-tier segments. In this review, I will compare closely to the AONIC 50.
Design and Operations
The rectangular retail packaging is very much appreciated, as is the more compact hard case which fits the folded AONIC 40. We understand the need to sacrifice some things for quality, like how massive the Sennheiser HD 800S headphones are. I’m not sure whether I prefer the headphones folded flat or in its original shape, but whenever I transport the AONIC 50, I always put it in a soft bag in its original shape, partly because the earcups are very stiff in folding.
More side-by-side photos between the AONIC 40 and AONIC 50. Clearly, the AONIC 40 is designed to be more compact and similar to Bose QC35 and Sony WH-1000XM4 at lower retail price. The headband is less luxurious but my head can’t tell a difference. I find that the ear cushion fits less snugly than the AONIC 50, whose padding is also not as thick as the recent Mark Levinson No.5909 I just reviewed (still thinking fondly about that outstanding can). Interesting observation: the ear cups turn inwards with the AONIC 50 while they turn outwards with the AONIC 40.
Here is a summary of differences and improvements of the AONIC 40:
- Three ANC adjustment levels on AONIC 40 instead of two on AONIC 50
- Max ANC level is better at removing upper frequency hiss
- Supports microphone over USB cable (but audio quality is reduced to voice call resolution)
- Earcups folding mechanism is less tight
Things that I prefer on the AONIC 50:
- Environment Mode max level amplifies surrounding sound more
- Supports LDAC codec vs. aptX HD on AONIC 40
- Hardware switch between ANC and Environment Mode for instantaneous effect
- Digital USB Audio supports up to 32-bit 384kHz, vs. 16-bit 48kHz on AONIC 40
- The larger ear cushions fit better
While most of the above features are self-explanatory, I want to elaborate on the feature where AONIC 40 can enable mic over USB audio, which is the first time I have encountered on a headphone. When enabled, I am able to use the AONIC 40 mic as an input for the apps on the computers as well as smartphones. The major drawback is that the output audio that feeds to the headphone speakers is in low-res mono format, similar to a voice call sound quality. This is regardless of whether I am using the mic or not. This low-res audio is what you get for all audio that is played on the device. So, if you want to make use of this rather useful feature, you may have to enable it when you need it and then switch back to “Listening” mode.
ANC and Environmental Mode
Comparatively, the AONIC 40 ANC is slightly improved over the AONIC 50, which is expected since the AONIC 50 was an older model and ANC technology has improved over the months. There are also three ANC settings instead of two on the AONIC 50. On the AONIC 40, I detect less upper frequency exposure. The usual rumbling noises from vehicular engines, vacuum cleaner, are attenuated, though not as aggressive as Sony WH-1000XM4 and Bose 700.
A major issue with the AONIC 40 is the ear cups fit. The small ear cups are not able to provide a seal around my ears, so external noises get leaked in and in the real world, the AONIC 40 could not achieve effective ANC.
The Environmental Mode turns out to be less aggressive and more natural without the background hiss. This calibration seems to be the norm for most of the Ambient modes I have reviewed. Personally I prefer the ability to increase sensitivity beyond the “norm”, and the AONIC 50 got that. For this, I would prefer the AONIC 50’s Environmental Mode. I would wished that the ANC can also be adjusted in step levels instead of three fixed levels.
Perhaps it is a good thing that the AONIC 40 is tuned differently from AONIC 50, so that the differentiation can reach a greater market for Shure as a whole. The AONIC 40 is consumer-friendly with more prominent bass, though not as skewed as big-bass headphones like Sony WH-XB910N. The details occurring in the midrange and treble could be overpowered by the boomy bass if the original mix is bottom-heavy, but otherwise overall it still sounds balanced and sparkling for most modern genres. For tracks without much bass, for instance, the intro of a ballad pop song, the treble details are forthcoming just like AONIC 50. But once the bass starts playing, the vocals will have to fight for attention. The smaller 40mm driver probably contributes to the congestion. The sound stage is presented such that the instruments are performed close with small reverb reflected outwards to give a sense of space beyond the stage. When ANC is turned off, the bass intensity is reduced.
The AONIC 50 remains my listening favourite when it comes to musical fidelity, because the bass is cleaner, the midrange is more approachable, the treble is sizzling, overall instrumentation is clearer and transparent. But I agree it lacks the rumble and wildness which the AONIC 40 can offer. When listening the AONIC 40 on the go, the bass is what keeps me going. I would prefer the AONIC 40 to have a little less bass so that I can enjoy the treble as well. In any case, the EQ can be applied and saved into the headphones from the Shure PLAY app.
- Bass: 8/10. Prominent presence and intensity.
- Midrange: 6.8/10. Warmth and recessed against the bass.
- Treble: 7.2/10. Sufficient clarity and details, competing with bass for attention.
The AONIC 40 call quality in a quiet environment is loud and boomy towards the mid-low frequencies. In a noisy environment, the mic tries to balance the background noise cancelling with the picking up of the voice, so the voice tend to sound a little thinner and brighter. I compared with the AONIC 50 which achieves similar result.
What I really like is that AONIC 40 (and AONIC 50) allows switching of ANC and Environment Mode during calls, which gives me the choice of whether I need absolute silence or whether I need to be aware of my surroundings.
The Shure AONIC 40 takes feedback from the AONIC 50 to create a new headphone which is more compact, better bass response, stripping off some audiophile features (no LDAC, no 32-bit DAC), and tweaking the ANC and Environment Modes, with reduced retail price to S$399. The target customers for AONIC 40 and AONIC 50 are totally different, with the AONIC 40 getting more bass while keeping the treble almost similarly engaging. Though the ANC is not as powerful as the brand leaders, the overall features on AONIC 40 are better. I would recommend the AONIC 40 for its better audio performance but if you need a capable ANC to kill all trace of noise, you should still bank on Bose and Sony.