Visited: SMPTE 2017 Exhibition Sydney (18 – 21 July)

After returning from my first long-solo-trip, I decided to spend two months “decompressing” and getting ready for my next trip. Part of the reason was so I could attend CeBIT, Vivid Sydney and SMPTE Exhibition. The last time I went was in 2015, and it was very much an event I enjoyed even though I’m not really in the production industry as such. As a technology enthusiast with a lot of interest in computing, radio, broadcast and satellites, it’s nice to keep abreast of new technology and developments that go into making the shows you watch and help deliver it from the studio right through to the end consumer.

On The Floor

This year, it was held in the ICC at Darling Harbour, much like CeBIT but it seemed the show-floor was more densely packed. Since the show is all about motion pictures/television engineers, they really know how to present their goods in a visually appealing way. It was mesmerizing in many ways – from walking past jimmy jibs swinging up and down running their demo, to rows of expensive Canon lenses, past racks of high-end digital microphone equipment, while looking at various analysis tools and bright LED panels. There was a lot happening, but I didn’t really have the time to “soak it in” as much as I would have liked, so I’ll probably recap on some of the highlights. I’d like to share some photos, but the terms of the SMPTE exhibition prohibit photography! Seems a little strange, but I might as well comply …

The first highlight was visiting Silicon Memory Technologies stand, representatives for a large range of brands related to computer storage including LaCie, Seagate, Akitio, Areca, Qsan, Stardom, Synology and Tiger Technology. At their stand, I was introduced to the Synology range of NAS products, as well as the Areca multi-bay DAS solutions. It was impressive to see an eight-bay Areca unit pushing about 1500MB/s read and 1000MB/s write over Thunderbolt (over USB-C connector). Even more interesting? They had a display case which had a Seagate Enterprise Storage 12Tb 3.5″ helium hard drive, as well as a Seagate Nytro XF1230 SATA SSD. Both products are pretty rare to see – I’d love to see even larger hard drives become more mainstream, so the existence of the 12Tb unit even if in limited quantities is encouraging to say the least. However, with the advent of the 50Tb 3.5″ SSD, it seems density is something hard drives might be losing out on, even though they are more financially economical in terms of purchase price.

The next biggest highlight was visiting the Blackmagic Design corner. One of the classic Aussie success stories, they have been featured even in documentaries such as State of Electronics and have been involved in bringing good value products to disrupt the market. It was interesting to see their real-time film scanner in action with 4k/30fps capability, as well as their newer (compact) scaler/format converters. Their product range is also diversifying into audio, so soon it seems they will have their feet in every part of the chain.

I took some time to drop into the Jands stand with the Shure Axient Digital system being on display. What caught my eye was actually the circular polarized antenna, as most in use are “paddle” shaped log-periodic dipoles. After the recent digital restack, the frequency bands available for wireless microphones had changed, so it’s probably something a lot of people might be interested in. It was interesting to hear their new digital system offers uncompressed audio, more channels, encryption and better range on an equal-power basis due to digital gain. It maintains interference mitigation capabilities, while also providing AES-3 and Dante digital connectivity. They also showed me a very tiny IP-rated manpack transmitter with integrated antenna and rechargeable battery – most impressive, as it’s even smaller than my wallet.

On that note, I stopped into the Sennheiser stand as well, just to see their offerings, and it seems they also have a digital offering of comparable feature-set, at least, on paper. But they didn’t take the time to explain it to me in detail.

Another highlight was visiting the Quantum stand – as it turns out, it’s the same brand as the formerly highly-regarded Quantum hard drives, just except they are providing storage solutions instead of drives now. Apparently they’re still heavily invested in tape storage, so that’s a good alternative for some niche applications.

I also stopped by G.Technology’s stand, represented by AVNET, since I spotted quite a few HGST products on show. Interestingly, I didn’t know HGST were into the SSD market as well, but they also have 4k-native hard drives on offer too. The Ultrastar He platform had offered 12Tb drives already, and I believe they had an SMR 14Tb drive as well, but again, are rarely seen.

As with the previous show, there were some drones on show – this year they focused on small compact drones, but CASA were also there raising awareness of safe operation and no-fly zones. They promoted an app at casa.gov.au/droneapp which details no-fly zones.

Rohde and Schwarz were also a nice stand to visit, with their analyzer and modulator being run in the front showing a nice and tight 256QAM constellation diagram. In the back, they were running their PRISMON system which was doing live PSNR and SSIM measurements with an HD-SDI input and a post-decoder output, allowing an operator to see the trend in picture quality over time as well as highlighting which parts of the image are most suffering from compression effects. I liked seeing that, since one of my bugbears is low-quality over-compressed video on the standard Freeview broadcasts – it’s part of the reason I like to keep an eye on their bitrates.

It was already a pretty good show as far as I was concerned. There were quite a few demonstrations from Sony, Panasonic and Canon as well, and various other equipment suppliers showing off several-hundred watt-hour battery packs. Of course, that was not all.

Getting Into Radio and Satellite

To my surprise, at the Sonifex stand, there was some Nautel transmitters on show. I had come across their products at one of the HFCC presentations in prior years at the Gold Coast. While I didn’t visit HFCC, because I was involved as a monitor of Radio Vaticana’s DRM broadcasts, I was aware of their program, so it was an honour to meet their representative and have a chat about where radio is headed. It was also exciting to see their “modern” transmitters in person – unlike older units where external test equipment and only basic displays are provided in the form of needles on gauges, these had touch-screen LCDs showing everything – spectrum, SWR, power, temperature, voltages, etc. It was also surprisingly compact and flexible too, but I suppose that’s what happens thanks to digital technology.

I stopped by Optus’ stand as well, where they were showing a 4k satellite demonstration program of soccer. It was quite nice and sharp, so I struck up a conversation about the service and whether it was “on the air”. He claimed it was on Optus C1, and running “about 20Mbit/s” with three trial services on a 36Mhz wide transponder. I said that was impressive, but pretty hard to fit that bit-rate in, to which he admitted that they were running a very low amount of FEC to make it happen. I also asked about Optus 10 and what it was “doing” – it is still at the old Optus B3 location but running commercial IP traffic. This corroborates what I had determined on my “hunt” for Optus 10 in 2015.

Lets just say, I couldn’t help myself but to go looking. The first step was to use my “existing” set-up that uses a TBS6925 Professional Satellite Tuner Card with my DiSEqC switch network, window cable (lossy!) and collection of Ku dishes. Unfortunately, as C1 is co-located with D3 and both are primarily used to push VAST and Foxtel paid-services, I only had a 76cm dish “shared” with another LNB to receive D1. As a result, this limited my SNR, resulting in this disappointing result.

They weren’t lying. It’s about 12607Mhz Vertical on C1, running DVB-S2/8PSK at 30MSPS with 9/10 FEC (!!). Very rarely will you see any commercial service use such little FEC, since it requires a very good signal to ensure continuous reception. It’s more common to see lower rates like 3/4 or 3/5, even down to 1/2 in rare cases being used. The final trick they used was to turn off QPSK pilots, which gives a tiny bit extra bit-rate, but also means that consumer gear with low-phase stability might have difficulty maintaining the lock.

Unfortunately, even though I had roughly 13dB SNR (after best alignment of the shared dish), I had a non-zero BER, so data errors were to be expected.

In spite of this, I managed to see that this carried the three test services as expected, with the first having about 27Mbit/s bitrate. Unfortunately, everything is encrypted with Irdeto, so nothing to watch for me.

Unsatisfied with this, I decided to use my other computer that has a Prof Revolution 8000 tuner – this is a cheaper tuner without ACM/VCM or APSK abilities, but is enough for this particular signal. Since it was nearer to my dishes, and I had a “spare” 75cm Ku band dish on a caravan stand, I crimped a fresh RG6 Quad-Shield lead for the Sharp Dual 10700Mhz wide-band LNB to maximise my chances. After all, the above result was from a Sharp Quad LNB, and those normally have a higher noise-figure. With the dedicated dish and a short cable run resulting in a “high” signal, the SNR appeared to be the same (since this other card under-reports) but the signal was error-free.

In my experience, cheap Chinese made 75cm dishes rarely get more than 15.2dB on “on-air” signals, and the best I’ve seen from my 85cm dish was about 17.2dB, so this was about what I would expect.

At that point, the bitrate was more about 28.6Mbit/s on the first Test Service. The NIT clearly identifies the service as belonging to Optus.

Interestingly, the provider name for the first service is set as Harmonic – a provider of encoders and one they had used in the past as well.

Based on the mux area usage, Service A is mostly constant, with B varying slightly over time. There’s still about 11% of the multiplex left in null packets, so it’s not the tightest fit. Still quite admirable, but what a shame I didn’t get any footage from it.

Before leaving, I decided to stop by Telstra Broadcast Services’ stand as well, just to have a chat. It was there that I realized that some of that I was seeing on the air (namely on D2 and Intelsat 19 having some carriers change names to Telstra Broadcast Service) was a result of their acquisition of Globecast Australia. That explains a lot, but I’ve always had good experiences tuning in to Globecast Australia feeds, and we still see some encoders set-up with the old names even today. Even in the new year, I can thank Telstra for bringing us the Sydney Fireworks. It was good to hear from them that the Satellite market is still in high demand – unlike the domestic DTH market where we’ve seen a few providers sink under the water in a few years (e.g. UBI World, SelecTV) and FTA is starting to become rare.

Conclusion

I’m glad I had the opportunity to visit SMPTE Exhibition this year, given that I’m flying out of the country next week. It’s always good to get a refresher on what is “leading edge” technology, even if it is in an area I’m not professionally involved in at this moment. I’ve always had an interest in the technology, and I’ve always been involved “at the fringes” as a technically minded consumer, so seeing it up-close and having the opportunity to discuss it with people who are in the area on a daily basis is both insightful and valuable to me.

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Review: Sandisk Ultra UHS-I 128Gb microSDXC Card (Up to 80MB/s)

At the beginning of this year, I posted about a relatively new (less than a year old) Sandisk Ultra UHS-I/Class 10 microSDXC card of the 80MB/s variety which had a data loss issue. Rather unfortunately for me, I had some personal data at the time, and my doubts got the better of me so I gave it a “second chance” since a full format and immediate integrity test passed.

Half a year later, the same demons returned. The phone it was used with started to freeze in strange ways. It was spending forever just to load up the lock screen. Eventually, I could have no more, so I removed the card and the phone went back to normal. Plugging it into the PC revealed exactly what I had come to expect of the card – data loss.

The Bad Egg

Unfortunately, the bad card was not actually reviewed on the site. When I purchased it, I was in such a hurry to commission it for use that I did the testing, neglected to save the results and never said anything about it. The bad card looked exactly like the old (pre-80MB/s edition) 128Gb cards from the front and back, with a green rear substrate with a black “painted” portion with codes. The difference was that it was a superior card when it came to read speeds as compared with the older one.

Unfortunately, it was also superior in losing data. While its older sibling still recalls data flawlessly, this one has failed twice in succession.

Its behaviour in my two preferred card readers proved to be interesting – the RDF8 seems to “time out” waiting for the card, drops the bus and says goodbye. The more patient RDF9 seems to accurately delineate which sectors could not be read and is a better candidate for doing data recovery on “slow” cards. Good to know in case there are other cards that might need recovery.

Regardless, there shouldn’t be any read errors especially for a card which hasn’t been mistreated (e.g. removed during writes), especially when the errors seem to coincide with files that had formerly been readable. I decided that it was time to return it.

The Replacement Egg microSDXC Card

Armed with all the necessary documentary evidence, I set out to return the card. I tried to call Sandisk and obtain an RMA number over the phone as the receipt had encouraged me to do so, but instead, I got a “You are not allowed to call this number,” message and then it hung up on me. As a result, I had no option but to return to the shop without an RMA number, faded receipt in hand.

Contrary to my expectations, the RMA process with Wireless1 was very easy and painless. Once they had identified the receipt number from the faded receipt, I provided the documentary evidence and they were able to issue me a new card on the spot, along with a replacement receipt on regular paper which shouldn’t fade. Much more painless than I had expected.

The package looks just like the original problematic card, and differs from the original version with the increased “Up to 80MB/s” claim.

The internal package, however, is somewhat different. The troublesome card came in a plastic pack but with a paper backing that had been adhered to the plastic. This one uses a cellophane cover over the back instead.

When it comes to “ease of use”, this new packaging was not particularly user-friendly. Despite following their open instruction, the cellophane shredded mid-tear, so I had to use some extra force to break it free.

The card itself looks different. The green substrate is gone, instead replaced by a uniform black at the back. I have good hopes this card may be different – maybe it will perform better and not lose my data?

Card-specific information is as follows:

Capacity 127,865,454,592 bytes
CID: 03534441434c434680e3572a1d0112df
CSD: 400e00325b590003b8ab7f800a404079

Of note is that the card capacity is different to the original cards – another hint as to a different implementation.

Performance Testing

Before using any card, it has to pass a commissioning test to ensure its correct operation. It makes an ideal chance to characterize its performance as well. In this review, the card will be tested with both Transcend RDF8 and RDF9 readers.

HDTune Pro Sequential Read

The card achieved an average of 79.7MB/s with the Transcend RDF8, just shy of the claimed 80MB/s. However, it did achieve an average of 89.7MB/s with the Transcend RDF9, exceeding the claims.

HDTune Pro Sequential Write

When it comes to writes, the card seems to have some bumps in the speed, but averaged 26MB/s on the RDF8 and 26.2MB/s with the RDF9. This exceeds the Class 10 minimum requirement of 10MB/s, and compares quite favourably with the Samsung Evo+ which achieved around 20-22MB/s. Based on sequential performance alone, this card is more than a match for Samsung’s Evo+.

CrystalDiskMark

Testing with CrystalDiskMark has been something I have been doing for a long time, but this card seemed to present some interesting challenges.

Transcend RDF8

When running the tests multiple times, some rather interesting deviations in the 4k performance seemed to present itself. While very slow rates are not unexpected, only on one test was 2MB/s achieved. In the last run, it hung for hours preparing the QD32 tests, and never finished.

Transcend RDF9

The test was run once on the RDF9, and the results look quite good, although the 512kB read accesses are slower than that of the RDF8 by almost half.

Because of the inconsistent performance, the results from this benchmark will not be included in the performance test database. It does point to a bigger issue, which will be subsequently discussed.

ATTO

Because CDM often has some strange results when it comes to 4kB accesses, I’ve gone back to using ATTO. However, even it was not fraught with trouble.

Transcend RDF8

When running ATTO initially, the card produced errors. The program claimed to have errors on reading the file, which seemed suspicious. On dismissing the dialog, the card was found to have an unacceptably slow write speed at 1kB accesses.

Thinking that the card may be a bit stressed under threaded-access, I disabled it and managed to obtain a result.

As the result was taken under a different test regime, it’s not possible to compare it with other tests. However, strangely, it seems that the card had very poor write throughput under 64kB, where it magically recovered.

Further testing showed it was possible to do overlapped I/O tests, but only after giving the card some time to rest. This suggests the card’s controller is perhaps acting similarly to some older SSDs which may have lacked processing power to manage the flash mapping table and perform garbage collection in the background when subject to heavy I/O and instead, resulting in “stalls”. If not that, it could be possible that the card has a throttling mechanism to attempt to prolong its life when used in inappropriate situations that involve numerous small-writes. This inconsistent I/O behaviour makes understanding its small block performance difficult.

Transcend RDF9

Repeating the same test with the other card reader still resulted in inconsistent behaviour, and results that seem to defy expectations – notice how some writes reach 50MB/s. This may indicate that the “peak” performance is higher than seen in the sequential test, but this performance cannot be maintained over the long run.

H2testw

Under more normal read/write situations with the RDF8, no data errors occurred and throughput was close to expectations.

Discussion – microSD Endurance, IOPS, TLC and Beyond

This card is the first card to really frustrate my attempts at benchmarking it. The I/O behaviour of the card seems to vary as a result of the previous access patterns and amount of “dwell time” between tests. The speed does also vary from reader to reader subtly. The reason for this isn’t entirely clear, but as I had earlier stated, my hypothesis is that the card’s internal flash mapping table management and CPU may be responsible for a bottleneck when many small accesses occur in quick succession. This maybe because the card is attempting to consolidate writes (maybe it has some pSLC cache?) or do some garbage collection/wear levelling. An alternative hypothesis is that this is an attempt at write-throttling to attempt to prolong the card’s lifetime in some “abusive” applications which result in constant writes.

For normal uses which involve bulk data transfers in large blocks, the card seems to perform just fine – in fact, for a “value segment” card, its performance is notably good. However, if small accesses are necessary, this card’s inconsistency does make it a little hard to recommend. Use in single-board computers to run operating systems is one place I can envisage such I/O limitations to cause problems.

Unfortunately, where high density consumer flash storage is involved, it is very likely all products are now triple-level cell (TLC) flash with a more limited endurance of somewhere between 300-500 cycles (realistically speaking). As a result, if you carefully read the warranty guidelines, Sandisk excludes warranty for:

(i) normal wear and tear, (ii) video monitoring, security, and surveillance devices, (iii) internet protocol/network cameras, (iv) in-car recording devices/dashboard cameras/black box cameras, (v) display devices that loop video, (vi) continuous recording set top box devices, (vii) continuous data logging devices like servers, or (viii) other excessive uses that exceed normal use in accordance with published instructions.

Other manufacturers are following suit as well. As a result, if you do operate such equipment, using “regular” microSD cards may result in rapid failures which can be disastrous – imagine a security camera or a dashcam that had destroyed the card, but the owner is not aware until they try to recover the footage post-accident. The card that failed before was not subject to any abusive use, but still began to lose data.

As a result, Sandisk has introduced a high endurance product category as an answer to their needs, however, they’re not so clear as to how much endurance they have, merely to claim up to 10,000 hours of Full HD recording for the 64Gb card, and 5,000 hours for the 32Gb card. Of course, the amount of writes depends on the bitrate – their specification is based on 26Mbit/s, so from my math that’s:

5000h * 3600s * 26Mbit/s / 8 = 58,500,000MB written
32Gb card = 32,000,000,000 bytes
          = 32,000MB
Cycles = 58,500,000/32,000
       = 1828.125

The endurance is a lot higher than your “average” TLC 300-500 cycles, but still falls short of MLC’s (approximately) 3000-5000 cycles. Maybe it’s MLC and they’re being a bit conservative, but it’s still interesting to know. Unfortunately, the price you pay is the cards only claim up to 20MB/s read and write speeds.

The issue of uneven I/O performance also seems to be something the industry is trying to work around, with the introduction of “A-class” figures (Application Performance Class) which is supposed to denote the IOPS performance capabilities of cards. However, this hasn’t really been seen on consumer level products at this stage.

But before things get better, it seems we might be on track to make things worse. Increasing demand for flash, a supply shortage and the constant demand for lower price has moved the market to contemplate and manufacture quadruple-level cell (QLC) flash which pushes the boundaries even more, with potentially worse effects on write speeds, data retention and cycle endurance. At this stage, it’s pretty hard to be enthusiastic when the shortcomings of some TLC products are already rearing their head.

Conclusion

I managed to get my card replaced painlessly on the spot at Wireless1, which was great, and the replacement card is of a different design to the original. Sequential speeds were quite good, achieving about 80MB/s-90MB/s on read and about 26MB/s on write which makes it the best 128Gb microSDXC card I’ve tested so far.

However, the random small block performance proved to be problematic to determine as the card appears to stall when subject to large numbers of small accesses, requiring time to recover. As a result, this card is not recommended for applications where small accesses may be necessary – e.g. use in single-board computers as primary storage. Why this card stalls is not known for sure, but could be related to its internal organization or a deliberate attempt to preserve its life through write-throttling. It is the first card to frustrate my benchmarking attempts, and for that reason alone, deserved its own blog post.

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Review: Mixcder MS301 Bluetooth V4.2 Wireless Headset with aptX

Whenever I’m out and about, especially when commuting on public transport, I’m often listening to music or watching a video on my phone. Having a set of headphones over my head is my way of making the commute more bearable by “tuning out” the outside world. When I look around, it’s something a lot of people do. It’s rare to see people not fully absorbed into their smartphones with a set of headphones or earphones on.

But as technology advances, the frustrations of tangled, snagged or broken cables are something users often wish they didn’t have to contend with. Likewise, manufacturers are slowly following Apple’s lead in removing the “legacy” 3.5mm headphone socket. The result is clear – a preference for Bluetooth wireless audio devices.

While there is a big market for Bluetooth stereo headsets, they have never quite met everyone’s expectations. For one, the Bluetooth connection is limited in bitrate and thus audio quality is compromised due to the use of compression. Most headsets on the market use the “standard” SBC (sub-band coding) codec, which is adequate but not “hi-fi”. It’s often likened to 128kbit/s MP3 encoding with some audible artifacts especially in treble and stereo imaging. There is also a 200-250ms delay due to encoding/buffering which can result in synchronization issues. It is one reason why I still very much prefer a cabled solution.

However, when I was approached by Mixcder about reviewing their MS301 which features aptX low-latency support, I decided it was worth giving it a go – after all, I did have an aptX capable Bluetooth dongle. This review of the MS301 was made possible thanks to their generosity, and is performed with their agreement to the review challenge terms.

What is aptX? Why does it matter?

As mentioned in the introduction, traditional Bluetooth A2DP (stereo audio) devices typically use the Bluetooth SIG’s standard sub-band coding (SBC) codec. This is a computationally inexpensive codec with no additional licensing requirements, and is thus the most popular amongst devices. Unfortunately, it has limitations when it comes to quality which can result in audible artifacts. Thankfully, the Bluetooth SIG also allows for third-party codecs which can provide better quality, of which MP3, AAC and aptX are options. In the market, very few to no devices are known to use MP3 due to licensing issues, and AAC appears to be used by Apple products primarily.

aptX was introduced to Bluetooth headsets by Cambridge Silicon Radio (CSR for short, now part of Qualcomm). This codec operates at a higher bit-rate of 352kbit/s and offers higher quality than SBC (which runs up to 328kbit/s at best quality, often less and with a less efficient algorithm). There are several variations of aptX, including low-latency which runs at just 40ms latency making delay imperceptible, and high definition/lossless which offers a “near lossless” experience with higher sample rates and bit-depths. For these functions to operate, you must have both sender and receiver aptX-compatible, which normally means of a “compatible” chipset and with licensing fees paid. Otherwise, devices will revert to a “basic” SBC mode.

The Mixcder MS301 supports the “regular” flavour of aptX as well as aptX low-latency mode. Failing this, it should fall-back to regular SBC mode for other devices. Note that some others have confused aptX-LL as meaning lossless – it does not mean lossless, but merely low-latency.

Support for aptX is listed on Qualcomm’s site, of which there are a fair number of devices supporting aptX, but much fewer supporting aptX-LL or aptX-HD. However, some Android devices can be hacked to enable aptX even if not officially supported (at your own risk). When it comes to PCs, only those using CSR Bluetooth chipsets with the Harmony stack support aptX. Of note is that no Apple devices support aptX, thus using an aptX device with an Apple device will result in an regular SBC connection.

As a result, it might pay to do some research beforehand to see if your devices support aptX before buying a headset. However, even if your device does not support aptX, it should still work with your device albeit without the benefits that aptX brings.

The Package

The unit comes packaged in a black coloured cardboard box. The front side has a iridescent gold-coloured print sporting a line-art drawing of the headphones themselves, along with the aptX logo. It lists some features including 10m transmission distance, 20 hour talk/play time, last-call redialling and 2200 hours standby.

The rear of the box provides the specifications – the key specifications are a 40mm driver, 32 ohm impedance, 20Hz – 20kHz frequency response, 90+/-3dB sensitivity, 500mAh rechargeable lithium battery.

The headphone is supported on a black plastic tray with a box including some accessories.

The included accessories include a thin microUSB charging lead, a 3.5mm to 3.5mm stereo lead for wired usage, and a multi-lingual instruction manual booklet.

The headphones themselves feel moderately weighty due to the use of metal parts and construction, with padded surfaces covered in a soft pleather material. The headband has the brand embossed into it.

A closer look at the stitching of the material on the headband seems to show some waviness.

The branding is also on each of the metal earcups, which is not as discreet as it could be, but isn’t too conspicuous. The headband is internally a stainless steel band, which connects to a metal hinge section.

The hinge itself feels fairly durable as a result. The metal hinge is connected to the metal earcup through a plastic grommet to allow the earcups to swivel in one dimension. This arrangement was smooth on one side, but slightly tight on the left which resulted in some creaking noises when adjusted.

The internal plastic backing of the headband has a number of click detents allowing for the headband to adjust in length to suit various sizes and shapes of head.

On one side of the interior face of the headband, the model number is printed. The other side has a label with regulatory approval numbers on it.

Removing it reveals the aptX logo.

A closer look at the rear of the earcup shows that only the rear portion is metal, with a small vented “gap” between the rear and front plastic portion. This gap is intentional, and provides the ability for the earcup to pivot up and down to ensure a comfortable fit. The front plastic portion does have a slight amount of “creak” to it on one side.

Each earcup is externally covered with a generous amount of pleather. The foam inside is not quite filling, resulting in a bit of a “baggy” look. The inner surface of the ear cushions is covered with a plastic-like material of a different texture and some fabric. The left and right orientations are printed on the fabric inside the cups for easy reference.

The right side earcup houses the main controls which include a power button, power LED (which shines through a hole in the casing), volume up and down buttons, a 3.5mm jack for “emergency” wired operation and a microphone. There is an extra hole at the top which does not seem to have a specific function.

The left-side earcup provides access to the microUSB charging port and a hole is provided to show the charging status.

The hinges allow the unit to swivel with the cups laying flat for transport.

It is also possible to contort it into a more compact shape, although as pressure seems to be applied onto the earpads, this is not recommended.

Teardown

Disassembly starts by removing the ear cushions, which are fitted with a bayonet mechanism. This is done by rotating and then unclipping the whole assembly – if you attempt to peel the cushions off, you are likely to damage the cushion. Undoing four screws lets us gain access to the driver.

The driver is unmarked, and its make is unknown. There is a piece of felt wadding inside the chamber to provide damping. This being the right earcup, there is a piece of self-adhesive tape which is metallized and acts as the antenna for the unit. Notice how it is torn – this was how it was received.

After carefully peeling it away to try and prevent any further damage, we can see the metallized pattern on the rear. I don’t believe the design intended for the antenna to be torn, as it seems this basically breaks one of the elements of the antenna and disconnects it. This may adversely affect the performance of the unit, and demonstrates poor manufacturing QC or a design problem, especially when the stiffness of the soldered coaxial lead is taken into consideration.

The active side shows the use of a module featuring a CSR A64215 chipset. A look at the datasheet shows this particular chipset as being capable of Bluetooth v4.2, 9dBm transmit power and -90.5dBm receiver sensitivity, AVRCP v1.6, wideband speech support with HSF v.1.6 with mSBC, cVc technology with wind noise reduction, multi-point A2DP support, aptX/aptX low latency/SBC and AAC support and wired audio support. While the chip itself is capable of these features, not all of them will be available in end products.

The module’s antenna output is connected to a socket where a coax lead brings the signal to the torn printed flexible antenna. Aside from that, there are a few wires which come from the other ear-cup that bring power and driver connections from that side. A single microphone capsule is seen as well as a few switches, a 3.5mm socket and indicator LEDs.

Removing the screws allows for the underside of the PCB to be examined. There are no components mounted on the underside, but there appears to be many provisions for ESD protection diodes which have not been fitted. These may not be entirely necessary, but their absence implies a cost-reduction measure. The PCB manufacture date is 3rd week of 2017, and the project itself is dated 23rd November 2016, making this a pretty fresh product. Its project name appears to be B032P or BT15215.

Opening the other earcup, I realize I’ve forgotten to show the intermediate disassembly step where the plastic pivot hinges are removed. These are screwed in, however, are plastic so it would not be advisable to place too much stress on the front portion of the earcups themselves.

As promised, there is a BYT Li-Polymer 3.7v 500mAh cell. This one was manufactured 7th February 2017, making it very fresh as well. The board features charge regulation for the battery, which is itself protected with its own protection PCB.

The underside of this PCB does not have any components either. So that’s all the internals covered – it’s definitely using the “right stuff” to have aptX capabilities, and it seems to have proved itself to be honest in regards to the battery capacity. However, the lack of ESD protective components on the PCB, the torn flexible antenna and the plastic pivot hinges seem to be some negative points on the construction.

Set-Up

Regular users of Bluetooth devices will find set-up simple and familiar. Pressing and holding the power button puts the unit into pairing mode, and Bluetooth Secure Simple Pairing means that in most cases, entering a PIN code is unnecessary. The unit makes things somewhat easier by featuring voice feedback in the form of voice prompts so looking at the LEDs is not necessary.

Android with aptX-compatible Qualcomm Bluetooth Stack

Pairing with my Mi Max was easily achieved by scanning for the device while in pairing mode, and clicking on the device name.

Once connected, the device also shows its battery status in the status bar of the phone. This is a feature of some, but not all, Bluetooth headsets.

To verify the ability of the unit to connect in aptX mode requires CatLog and root access. Once some music is played, the log should display the codec selected as aptX. A quick check of the OUI shows that the internal module is a Shenzhen Boomtech Industry Co. Ltd module.

In the case your device does not support aptX, or you are using a headset without aptX support, you will see SBC instead (like the screenshot below).

Windows 7 with CSR Bluecore-based USB Bluetooth & aptX-compatible Harmony Stack

Adding the device follows the same basic routine of placing the device into pairing mode and adding a new device.

Pairing is established quickly with no PIN code required.

When properly completed, the unit should connect automatically and the aptX banner should display to confirm the presence of aptX connection.

The device will also come up in the sound devices, and can be set to default to route audio through it.

While it was possible to get it to work, it wasn’t always quite this easy. In fact, initially, I ran along a few issues which are due to the no-longer-maintained CSR Harmony Bluetooth Stack being just plain buggy.

The first time I tried, I could pair the device, but the Bluetooth Audio Renderer for Bluetooth Stereo Audio came up as “Not plugged in”. The aptX banner also did not appear.

Manually attempting to connect to A2DP (Sink) resulted in a time-out after a minute of waiting. No audio aside from the “telephone quality” handsfree was achieved under this situation. Rather interestingly, this unit also claims to do A2DP (Source) and Serial Port connectivity too.

In order to resolve this issue, I had to go to device manager and remove the two Bluetooth Audio devices.

Then I had to unpair the device by removing it within CSR Harmony.

Then, I set the headset to pairing mode, and paired the device. At this time, the drivers should re-install. Then, turn the headset off, and then back on so it auto reconnects. At this time, you should see the banner indicating success.

Unfortunately, this seems to be a temporary fix. Once the device is unpaired or the computer is restarted, the same symptoms will re-occur and following this procedure is required to restore connectivity. This seems to be the fault of the Harmony stack software which was last updated about five years ago, but sadly, is the only Bluetooth stack that allows aptX connection on a PC at this time to my knowledge.

Note that this is not a problem with the Mixcder MS301, but more a problem with the CSR Harmony software. However, if you do use the CSR Harmony stack, you may have problems connecting even in SBC mode.

Windows 10 with Broadcom-based Bluetooth Solution

Unfortunately, when using non-Qualcomm/CSR Bluetooth solutions, it is not possible to achieve aptX compatibility. However, pairing and using the headset is still just as simple and completed with no issues.

Once Bluetooth was turned on, the device placed into pairing mode, and a scan initiated, the device could be paired. No PIN code entry was required.

A short wait was necessary as Windows configured the drivers for the device.

Once ready, connection was established and audio routed through the device just fine.

Apple iOS 9.3.5

Unfortunately, I don’t use Apple devices primarily, so the “latest” device I use is an iPad 3rd-generation. Of course, we won’t get aptX capability, but pairing was easily completed and audio worked just fine, although presumably in SBC mode.

The battery indicator is also available under iOS.

Subjective Opinions

When it comes to audio products, opinions often differ widely. In this section, I’ll describe my experiences and feelings about the products, which some people may disagree upon. However, I won’t be drawn into arguments about it. For reference, I currently prefer the Audio-Technica M50x headphones as the “standard day-to-day reference”, and have listened to a good number of other wired headphone products ranging from AU$20 through to AU$350. While it may feel a little unfair to compare the product with a much more expensive product of a different category, this is the only way to adequately understand the strengths and limitations of a product.

That being said, everyone has a different idea of what “sounds” right or what sounds good, so feel free to ignore my opinions and form your own. That being said, I will remind you that I’m reviewing the product independently, with no financial incentive.

Ergonomics and Fit

The unit itself feels fairly good with a heft that implies some level of quality. It has good balance between the earcups, so as not to feel lopsided. The soft pleather also feels plush and sufficiently durable for everyday use. The headband has sufficient adjustment range to cater for larger heads, and the metal accents help improve the appearance and durability of the product.

When wearing the unit for extended listening sessions however, some discomfort can be felt. The clamping pressure feels slightly higher than other products. The wide and “baggy” pleather earcups form a positive seal to help improve isolation, however, the design is a hybrid supra-aural and circum-aural design with the pad both applying pressure to your ears and its surrounds. These two factors combined results in reduced breathability and “warm” stuffy ears. At least it does somewhat mitigate the risk of the unit falling off your head due to the amount of contact.

Isolation is average to fair. While the design of the earpads definitely help isolation, the vented rear plastic earcup defeats this to some extent, allowing some sound leakage in and out of the unit.

The design of the unit appears to deliberately ignore the inbuilt charging capabilities of the CSR chip and opt for a standalone charger IC. This design choice results in the possibility to use the unit to listen to audio while charging, which some people may find handy. The charging LED is easy to interpret and separate from the main Bluetooth LEDs – a red LED lights to indicate charging and turns off when fully charged.

All of the interface buttons are on the right side earcup, which makes it easy for one-handed operation. Like other CSR based devices, just three buttons are provided, which is easy to navigate by feel but results in the need to double-click the power button for redial, or long-click the volume keys for next/previous. To avoid the need to reference the LEDs, voice prompts are provided through the headset, but the voice prompts and tones are fairly loud. This may ensure that all users can clearly hear it, but is also very disconcerting to those with more sensitive ears as the “end of volume range” beep and battery low beep can be loud enough to startle. There doesn’t seem to be any way to change this, unfortunately. The LED on the right side earcup does indicate status, and when connected, shines a solid blue which is less distracting than the flashing blue of many other headsets.

The unit does offer battery status monitoring over Bluetooth so that your phone can display the battery status. However, in testing, this was found to be very approximate. In one case, it showed about half-full and dropped into the red after merely a minute or two of playback. As a result, it cannot be relied upon as an accurate gauge of remaining power.

As the device is wireless, it is expected that users might choose to take the unit around. The hinges do have extra articulation to allow the unit to be contorted into a shape which minimises its space requirements, however, it does not come with any protective bag or casing thus leaving its pleather surfaces at risk of damage.

Bluetooth Sound Quality

I first started by auditioning the unit connected via aptX using FLAC files of music I was familiar with. I spent at least 60 hours throughout two weeks listening to the headphones in aptX mode, and then several hours afterward listening to it in SBC mode paired to devices which did not offer aptX.

The character of the headphones seem to have a slightly veiled and laid back treble, offering a warmer presentation. This is not unexpected, since my reference M50x are sometimes criticized for being a bit too clinical and “sharp”. The upper midrange seemed a bit resonant and boosted, which reduced the clarity of the audio slightly. The unit was not especially bassy, offering a good balanced bass although one which does not extend very deeply, thus some basslines are almost completely lost. If I had to summarize the sound quality in general, it would be more balanced to warm, but very “average” in the clarity department and something like a AU$40 wired set of headphones.

Unfortunately, this does not make them audiophile quality. This is particularly problematic, as people who specifically look for aptX on Bluetooth products tend to be those who look for higher fidelity products, and this one seems to fall a short of my expectations.

My frustrations were amplified somewhat by the fact when switching over to SBC-only devices, it was extremely difficult to distinguish the difference in quality between SBC and aptX mode due to the limitations in the sound quality of the unit. I could not be certain, but it seemed SBC didn’t have as well defined treble, but I could not confirm it definitively. I think this illustrates clearly just how limiting the quality of the drivers and earcup design is.

Unfortunately, there was another drawback which seems common to many Bluetooth products. During idle connected periods prior to being commanded to standby, the unit does have a noticeable amount of background white noise hiss. This is somewhat distracting during quiet portions of music, and persisted regardless of which codec was used. When commanded to standby, the unit drops to dead silence with a quiet “tick”, but this merely makes it more apparent just how noisy the module is when in operation. However, one positive is the maximum volume is more than adequately loud.

Directly-Connected Sound Quality

In a rather surprising twist of fate, when directly connected to my Soundblaster X-Fi Xtrememusic, the headphone has a slightly different quality. The treble was more prominent and stronger, verging on tinny but still lacking in fine detail. The bass was still somewhat limited. The upper midrange seemed more recessed and lacking in comparison. Unfortunately, I’d have to say the directly connected sound quality sounds extremely average, which probably stems from the design of the headphones and the driver units in use. While it certainly is not bad for casual listening, it’s not commendable in any particular way.

As a result of this result, it seems to suggest the CSR-based module while capable of directly driving speakers, may not be optimized to do so. Higher end aptX headsets may use its I2S capability and use that to drive an external DAC or buffer the output with an opamp rather than use direct connection.

Having the option of direct connection is a good thing, especially if users remember to bring their cables, so that they can use it with devices without Bluetooth capabilities or when the battery is depleted.

Testing

Battery Charging

I first depleted the headset by running a run-time test until it shut down on its own. Using my Keysight U1461A as a data-logger and my USB current shunt, it was found that the unit charged in 2 hours and 1 minute – pretty much right on time. The delivered charge was 510mAh from the USB, and due to the linear regulator, all of this would have been delivered to the cell minus a little bit to light up the status LED. As a result, the onboard battery is an honest battery with a capacity of 500mAh. Charge tapered and terminated as expected, and thus indicates it is safe to leave this unit plugged and charging.

Battery Runtime

Battery run-time was assessed by setting the unit to my preferred listening volume in a quiet room and running a song on loop with the audio recorded by a microphone. Total running time was found to be 25 hours and 56 minutes, exceeding the 20 hours claimed. This was with aptX audio, although run-time is likely to vary depending on the loudness, RF signal level, codec and playing material.

The claimed 2200 hours of standby is about three months and is a big claim, but what type of standby was not specified. When connected but idle in standby, the LED indicator shines a continuous blue – with this drain on the battery, I find it unlikely that 2200 hours of standby can be achieved. Instead, I suspect they mean on a soft-off state, or maybe even a disconnected standby state.

Microphone Voice Quality

I checked the quality of the microphone by recording a sample with myself speaking inside my quiet room environment. The resulting audio has a bass-heavy character lacking in treble detail. This was intelligible for the most part, although when tested “on call” with several people, they did note that it was difficult to understand when I was speaking quickly. This is likely due to the fact that there is no microphone boom – the mic merely sits inside the earcup and thus gets less-than-ideal sound.

This is no major issue, as most users will probably be using it to listen to music more than to make calls with, however should still be considered.

Transmission Range

I tested the range of the unit paired with my Class 1 (50m) CSR USB dongle, and my Mi Max mobile phone. With the Mi Max, I could easily reach 10m with clear audio despite the torn antenna, which may have been due to a good antenna design on the Mi Max.

However, with the Class 1 (50m) CSR USB dongle, I did have difficulties at around 4-5m, with occasional audio stuttering. At 10m, the unit was stuck in a continuous connect/disconnect loop. I suspect that if the antenna was not torn, the performance may have been improved.

The use of metal earcups and metal hinges makes adequate RF design difficult due to the potential for shielding or multipath reflections to arise due to the close proximity of the metal.

Conclusion

The Mixcder MS301 is a Bluetooth headset with a bit of an identity crisis. On the one hand, it offers an aesthetically pleasing metal-accented construction with lush black pleather earpads and premium aptX low-latency codec support. On the other, it targets a low price to give value for money. In the end, the result seems somewhat of a compromise.

For those specifically looking for aptX support and high-fidelity audio, they will be somewhat disappointed by the recessed treble, resonant upper-mid range and limited depth of bass. They might also be distracted by the background hiss that pervades every quiet section. If you’re specifically looking for high quality audio, you’re probably looking at much pricier products from major brands anyway.

For those looking for a Bluetooth headset with a decent build quality and better quality than the average “cheapy” plastic unit, then this unit does have merit as a step-up, offering more definition and better build quality. It is suitable for casual listening, and feels sturdy enough for everyday use. In this case, aptX is probably not on your priority list, but it doesn’t do you any harm so you might as well have it. It will connect as regular headsets do, in SBC mode. Given its retail price of about US$90, it does command a premium over a wired headphone of similar characteristics, but isn’t as expensive as (the few) other aptX capable options.

However, there was some observed build quality issues, mainly with the torn flexible antenna which may compromise performance slightly, and slightly creaky hinge and plastic cup on one side. The semi-open design also means that isolation isn’t as good as it could be. The hybrid supra-aural and circum-aural earcups with higher clamping pressure also isn’t as comfortable or breathable as some other products.

At no fault of the product itself, aptX support itself is also patchy due to the issue of licensing. Only a limited number of products support aptX which should bring better audio quality, of which no Apple products support it. Even fewer support low-latency. As a result, most users will never experience any latency advantage. Even if you do have aptX support, it seems doubtful that this particular set of headphones will let you experience it fully. I certainly found it difficult to discern any advantage from aptX over SBC, so I suppose if you’re considering buying this particular unit, it shouldn’t be because of the advertised aptX support.

Thanks to Mixcder for providing this unit for review.

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