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Astrotec S70 Review – Confused Identity

Pros –

Perfect comfort, Slim and reliable charging case, Effective ANC and Ambient modes, Responsive touch controls, Improved treble tuning, Great wireless range

Cons –

Highly recessed and veiled midrange, Poor technical performance, Limited codec support and high latency

Verdict –

Astrotec has created a great earphone to live with day to day but also one that is not especially enjoyable to listen to.

Introduction –

Astrotec is an experienced audio manufacturer and one of the original ChiFi hits. They’ve previously focused on premium high-end designs but are now using the techniques and technologies they developed here in their approach to more affordable products. Their TWS line-up exemplifies this best. They did have some growing pains; the initial S80 offered a high-quality sound from its Be-plated driver but an awkward form factor and awkward usability, the S80 Plus was more compact but did so at the sacrifice of sound quality. Still, it’s clear that the company is receptive to user feedback and continuously improve each model. On such an upward trajectory, the S70 is not only their most sophisticated design but also their most affordable. It uses a Japanese imported LCP diaphragm driver and introduces ANC/Ambient modes and a stemmed design promising improved call quality. It offers all of this for just $49 USD.

You can read all about the S70 and treat yourself to a set on their website here.

Disclaimer –

I would like to thank Ryan at Astrotec very much for his quick communication and for providing me with the S70 for the purpose of review. All words are my own and there is no monetary incentive for a positive review. Despite receiving the earphones free of cost, I will attempt to be as objective as possible in my evaluation.

Contents –

Specifications –

  • Drivers: 6mm Japanese-imported LCP Diaphragm DD
  • Frequency Response: 10 Hz – 20 kHz
  • Impedance: 32 Ohms
  • Sensitivity: 110 dB
  • BT: 5.0 w/AAC, SBC
  • Playback: 4.5hrs, 4.5hrs (ANC on), 3.5hrs (Call)
  • Charge time: 1hrs (earphones), 1.5hrs (case)

Behind the Design –

LCP Diaphragm

Liquid crystal polymer dynamic drivers have become very popular recently for their desirable acoustic properties. It is a very hard material which permits a thinner, lighter weight diaphragm for a more agile transient response and a more detailed sound. Compared to metal-plated or metal drivers, they are cheap to produce which brings down the cost of the overall earphone. The same driver tech can be seen in the CFA Honeydew and Moondrop Aria.

Unboxing –

At such a price point, I wouldn’t expect much glamour, but Astrotec stick to a respectable experience as they’ve become known for. The box is small but well-presenting, with a screened outer sleeve and hard box inside. Lifting off a paper cover reveals the earphones and below, the charging case. A short type-C cable is included in addition to 3 pairs of silicone ear tips with the medium pair being pre-installed on the earphones. I had a great fit experience with this earphone and didn’t feel memory foam tips were required, but this may have been a nice addition. Altogether, a perfectly fine experience for an affordable noise-cancelling IEM.

Design –

The S70 takes clear inspiration from the chic styling of the Moondrop Sparks but assumes a more uniform transparent approach to design. I find it charming and high-tech with the purple and black colour options offering a louder or cleaner approach for different users. The silhouette is reminiscent of a traditional cable-down earphone which should make the fit familiar to audio enthusiasts. The plastic construction is exceptionally lightweight but still feel well put together with well-matched seams and no sharp edges. They have a satin finish that improves the in-hand feel.

That said, visible internal glue marks on the joins and haphazard internal wiring mean these earphones don’t look especially premium. Do note that these are both issues non-transparent earphones sidestep, so take this as an observation rather than a knock on Astrotec’s craftsmanship. These earphones do lack an IP rating meaning they should not be used for exercise nor in moist environments. Otherwise, this represent a functional, non-frills TWS design with a little extra flare in the form of their transparency.

Fit & Comfort –

Astrotec mention on their website that they targeted a shallower fit to optimise comfort, and this was indeed my impression of the S70. Moving some electronics to the stems has permit a more streamlined upper housing with a rounded profile that avoids hotspot formation with the stems resting gently by the outer ear. The oval nozzles are well-angled and position the housings neutrally, further enhancing comfort. As aforementioned, the fit is shallow with very low wearing pressure which should make them accessible for those not accustomed to IEMs.

The oval tips help too, as they conform better to the shape of the ear canal. In turn, I often forgot I was wearing them and had no issues with comfort even after hours of listening; I would easily consider the S70 to be one of the most comfortable TWS designs on the market. As they are so light, fit stability also wasn’t an issue and I was able to run in them with no issues – though do note the lack of water resistance here. Despite the oval nozzles, you are able to swap in regular ear third party tips if you don’t get a sound seal on the stock tips.

ANC Performance –

I have been very disappointed with the ANC performance of many TWS earphones, but implementations are rapidly improving. At $49 USD, I didn’t have much hope for the S70, but found it to be surprisingly effective during testing; this is a sound and functional ANC implementation that is clearly not just a marketing gimmick. Of course, they don’t cancel as wide a frequency range as my Sony WF-1000XM4’s, but those cost almost 6x as much. The S70 provides strong cancellation of constant, low frequencies such as the rumble on a train, car or airplane. These noises are cancelled almost entirely and produce a slight pressure on the ear but nothing that caused discomfort for me.

That said, compared to a pricier ANC earphone, they cancel quite a narrow band of frequencies so voices and higher-pitched noises such as the whoosh of air conditioners is only dampened by the passive noise isolation. They isolate decently but nothing exceptional. I found the overall package was able to attenuate external noise better than a sealed earphone like the Lypertek TEVI/Z7 and they were great for general day to day commute. The S70 performs better than milder implementations like the Momentum TW2, cancels low-freqs similarly to models like the 1More ANC TWS and M&D MW08 but offers less attenuation of higher-frequencies. And it is clearly inferior to market leaders such as the WF1000XM3/4 and Bose TWS earphones.

Ambient Mode

This is surely a feature that I feel most earphones should include given that most chipsets support this and essentially all TWS earphones will have a mic. That said, the implementation is not always ideal. For instance, both Master & Dynamic’s and Lypertek’s are quite quiet, the Soundfree S20 was especially tinny and made voices difficult to discern. The S70 has a very solid implementation. Though accompanied by a prominent hiss, it has good volume and immediacy with high vocal intelligibility.

Charging Case –

It’s great to see Astrotec has been so responsive to feedback and consider features and qualities important to daily usability. The charging case is part of the equation, the case is medium sized but especially slender due to the upright form factor and slim, stemmed earphones, meaning it is highly pocketable. It sports a matching transparent aesthetic and feels dense and well-constructed with no squeaks and great tolerances. It charges via a bottom-mounted Type-C port but does not support Qi wireless charging. The hinge action is smooth and free of wobble but has no reverse magnet.

A diffused RGB status LED is inside between the two earbuds, it looks high quality similar to an Airpods case. I have no complaints about the case other than the fact that the earphones can be somewhat difficult to remove due to their rounded design. I had best luck pinching the silicone tip and lifting, conversely, I found the earphones would dock/power off reliably in the case, which is a huge annoyance on many competitors.

Usability –

Astrotec has also tackled usability well and, as aforementioned, this is a highly impressive and surprisingly well-executed feature set for such an affordable earphone.


The S70 enters pairing mode automatically once removed from the case for the first time and quickly auto-reconnect to the previously paired device. If the device is not available, they will once again enter pairing mode and more can be added. While I can’t confirm the exact chipset, it’s likely Astrotec isn’t using a Qualcomm chip here and codec support is limited in turn. The S70 support only AAC and SBC which have a lower quality ceiling than aptX and LDAC and higher latency. With BT5.0 support, the earphones support mono connection which is useful for extending runtimes.

The other side quickly connects in stereo once removed and playback isn’t interrupted when one earbud is placed in the case either. Latency is indeed higher than preferred with overt lip sync when watching videos. In turn, they won’t be the best choice for multimedia consumption. Conversely, range is very good, I was able to traverse through two rooms with double brick walls without any audio breakup or artefacts, a distance where most start to break up. Of course, this will be further improved with a line-of-sight connection. Besides latency, I have few complaints here as the S70 connected quickly and reliably for me during daily use.

Battery Life

The S70 isn’t a large earphone nor is the case and battery life falls in line. I find this a fair compromise and personally don’t mind topping up the case more often in favour of a more pocketable form factor. The earphones are rated at 4.5hrs both with ANC on and off at 60% volume. I found they had a medium volume output and found myself listening at around 30% with ANC on, where I was able to meet that figure dead on. This isn’t hugely impressive but isn’t a bad result for an ANC earphone of this size and sufficient for daily use. There’s a small buffer here for higher volume listeners and battery degradation over time. The case offers about 4 additional charge cycles from empty to full. A full charge is quoted to take around 1hr, but the case can quick charge the earbuds initially, offering 90mins of playback time in 10 minutes.

Call Quality  

The benefit to a stemmed design is that the mic can be placed closer to the mouth, permitting much improved call quality. Indeed, this was the case here, representing a huge leap over the S80 and S80 Plus before it. No longer is it a clear weakness of this earphone. While still not the best in terms of clarity or background noise attenuation, recipients noted that I sounded immediate and intelligible. Background noise cancellation wasn’t the best, but call quality remains acceptable due to the position of the microphone which naturally amplifies the voice.


I hate most touch controls with a passion and this was my impression on both of Astrotec’s TWS earphones. The S70 is a huge improvement once again, the touch panels are easier to locate as the faceplates have a perimeter ridge and convex surface that naturally guides the finger in place. In addition, the touch surface is bigger so I experienced fewer missed commands. I found the touch controls to be fairly responsible and accurate during daily use. Voice cues indicate whether ANC is on or off and aware mode is signified by a chime to aid feedback. I found the 1.5s hold was suitable for day to day use.

Next Page: Sound, Comparisons & Verdict

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