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Syllable D900 Mini Review – Top Notch Fully Wireless Earphones on a Budget

Introduction –

$100 may not be a large sum of money to an audiophile willing to drop $1000 on a pair of headphones, but for the average buyer, for which these fully wireless earphones are intended, this is likely the most they will ever spend on a set of earphones. So the $100 D900s (that I previously reviewed) could not escape with an excuse like: “it’s a proof of concept”; At this price, they are not just a foray into wireless technology, but will likely be the average buyer’s only earphone and thus, in addition to sound quality, reliability and ergonomics are key.

D900s pictured above

This is where the D900s faltered, their housings were simply too large to produce a comfortable and stable fit, negatively affecting seal and audio performance. The D900 Mini, as the name would suggest, are a lot more compact which, in turn, markedly improves all of these aspects. I can easily say that Syllables third generation fully wireless earphone, is a large upgrade over its predecessor in every way, and the largest upgrade in the D900 series. But that presents several key questions: are these improvements large enough to make them worthwhile? And are the wireless features refined enough to justify the sonic deficiencies when compared to a wired equivalent? Let’s find out.


Disclaimer – 

I would like to thank Johnson from Syllable very much for sending me the D900 Mini. There is no monetary incentive for a positive review, despite receiving the earphone free of cost, I will attempt to be as objective as possible in my evaluation.


About Me – Some background, Gear of choice, Preferences and Biases

I generally prefer a slight v-shape to my sound, but still closer to neutral. I like a lot of detail and clarity, but can appreciate a smooth, laid back sound such as that on the X10`s. I prefer a more neutral midrange within a relatively tight tolerance, but I`m probably more forgiving of brightness over darkness. I`m not particularly treble sensitive and can tolerate large amounts without fatigue, though too much ruins the enjoyment. If I use a different eartip/pad/cover during the review I will note that and describe the sound changes.

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Accessories –

The D900 Mini comes packaged within a much more compact box than the D900s, similar to what you would find on something like the Xiaomi Pistons range. The box has a simple design, it doesn’t even list the model number or specifications, simply the Syllable logo on the front.


Opening up the top reveals the accessories and D900 Mini within the new and improved charging dock. Within two anti-static bags, Syllable also provide a micro-b charging cable and 2 pairs of silicone ear tips in addition to those already installed on the earphones; a pair of medium and large winged flange tips in addition to a new ear tip which has a more elongated nozzle and a large wing, presumably for activity.


New tips in the centre (two right tips?)

Whilst the regular flange tips are generally quite underwhelming, they’re still too thin and flimsy, the new design tips are much improved, with thicker silicone and a very solid, stable fit in the ear. Unfortunately, I was unable to use them on my set since it shipped with two right ear tips, I hope buyers have better luck with retail models. Regardless, I swapped out the stock tips for a set of foam stuff Sony Hybrid isolation tips which fit snugly on the nozzles and provided an even more solid seal despite the absence of a stabilising wing; they also isolate a fair amount more.


These tips are a bit pricey, ~$15 for two pairs shipped from Japan, but they work with a wide range of earphones, isolate almost as much as a foam tip and are one of the most comfortable silicone tips out there, I think they’re worth the purchase.

Onto the new charging cradle, the same design language applies to the one included with the D900s, with a semi-transparent top lid mated to a matte black base but it’s now a lot sharper looking and much more compact than before with a darker top cover that looks much more premium than the lighter dock that came with the D900s. Instead of the stiff clip mechanism that held the cover closed on the D900s, the D900 mini has a much more convenient magnetic cover. The dock also automatically charges the earphones, again, much improved over the D900s which had a power button on the front that I could never quite figure out how to operate despite my best attempts at deciphering the manual. Although the spec sheet doesn’t state the actual capacity of the new dock, I’m guessing it’s around 500mah, providing the D900 mini with 4-6 charges; around the same as the D900s, only the D900s offered twice the battery life of the D900 mini. I would also like to see some rubber feet for the bottom of the cradle since my D900s has become a little scuffed up, but at least it does a good job at protecting the earpieces themselves.


Overall, a nice accessory suite, the new ear tips are much improved as is the charging cradle. Syllable have made small but meaningful advances that largely affect the user experience and the D900 mini is vastly more livable as a result. No issues here.


Design –


As the name would suggest, the D900 mini looks very similar to the D900s and D900 that came before it, just much smaller.

D900 Mini – D900s

If you haven’t read up about the D900s, I actually reviewed them a few months ago, and whilst the technology was all there, the way it was implemented created an almost unusable product; mainly the ridiculously large housings prevented any kind of seal, isolation or fit stability. With the D900 mini, Syllable have gone back to the drawing board, streamlined the housings, tightened up the tolerances and alleviated the fit issues I had with the D900s almost completely.


Running over the physical features, the earphones have the same basic profile and controls as Syllable’s other earphones, the power/multi-function button lies on the outer faces of each earpiece, however this time the button does not light up to display status, instead there is a small LED on the tops of the earphones that illuminates various colours.


It can be harder to see, especially in bright light, but looks cleaner and more refined in general. Once again, the left earpiece is the “master” earpiece, which connects to the source then relays that audio to the right driver. For single ear use, you can actually just invert the left earpiece and wear it in your right ear without hassled, the earpieces are both identical in shape. This does present some concerns with orientation. Whilst using the winged tips does make it easy differentiate between the two, using the hybrids, I had to resort to the tiny print on the inner faces of both, not ideal but manageable. Two gold plated inlets lie at the bottom to allow for charging via the included 2-pin cradle, they worked reliably in my testing.


The nozzle is the same oval shape as the D900s, despite being unconventional, all 200 size ear tips I tried (Spinfit CP100, Sony Hybrid, Comply TS200) had no issue sealing onto the sound tube. The stock tips are similarly keyed to keep them in the right orientation since the earphones themselves are so rounded.


Build quality is decently improved over the D900s too, they still have that cheap gloss plastic finish, but the D900 mini feels less hollow and just better put together in general. The seams between the outer and inner faces are smoother and, perhaps most importantly, the buttons no longer rattle (as you can imagine, a big problem when running). It seems the tolerances have been improved overall and whilst the D900 mini does not feel like a premium earphone, any shortcomings such as the glossy black finish don’t affect usage. They also retain the IPX4 water/sweat resistance of the D900s, so they should make for a fine sports earphone, just don’t full submerge them in water.


D900 Mini and Westone Adventure Alpha

The D900 mini is still quite large for earphone standards, but the way they are shaped actually makes them quite ergonomic. Although the large housings contact a lot of the ear, once inserted, the earphones are quite comfortable due to their very rounded design. They have a similar fitment to a larger monitor style earphone, sitting predominately in the outer ear and sort of locking into the back of the ear. Being fully sealed, they also isolate very well, not quite as well as the Westone’s and Shure’s of the world, but pretty close since they fill so much of the ear, which is great for exercise and activity in noisy areas. That being said, they do have considerable driver flex which is worrying as always but did affect performance during my 2 weeks of testing. Fit stability is also pretty good due to the aforementioned reasons, they stayed in place during my usual 6Km run and also various gym workouts, requiring only a few adjustments here and there. With the new winged tips, I’m guessing they would be even better but I can’t affirm this.


Using a fully wireless earphone is a truly liberating experience; it’s something that’s easy to discount until you try it yourself. The obvious benefits include no cable noise, no snagging, tangles or knots and you don’t have to wind the cable back up for storage after you’ve finished listening. All in all, the earphones don’t get in the way in daily use nearly as much as a wired earphone, there’s no routing the cable through your jumper or untangling them from your pocket, they simply work. Removing them and placing them in the dock is similarly convenient, especially on public transport; I’ve almost missed my stop a few times when fumbling to wrap my earphones back into their case. With the new magnetic lid, it’s just snap and go, you also don’t have to worry about cables and charging like a semi-wireless earphone. So overall, they are a world apart from the D900s, the Bluetooth connection is solid and I couldn’t be much happier with the fitment either. As I will soon divulge, simply achieving a decent seal also works wonder for sound quality too.


Usage –

The D900 mini are one of the easier Bluetooth earphones I’ve used, controls are simply activated through the single buttons on the outer faces and are commands denoted via basic audio cues.


You have to power on both separately, after which, they will pair to each other however powering off a single earpiece will also power off the other earpiece too, just to make things a little easier. It can be a bit fiddly to get the D900 mini into pairing mode at first, you have to power off the left earpiece then wait a few seconds for them to fully power down. After that you hold the power button for 5s, wait for the earphones power-on and, after a few more seconds, enter pairing mode (higher pitched beep). The LED flashes blue and red and the earphones becomes available to devices as Syllable Mini. Once paired, most of the pairing process becomes automatic, for instance, my usage goes as follows:

  1. Hold the power button 2s to power on (single beep)
  2. Repeat for the second earpiece
  3. Both earpieces automatically connect to each other (3 note chime)
  4. Earphones automatically pair with last connected device (single beep)

Whilst pairing is quick, unfortunately the D900 mini can only be connected to one device at a time; you’ll have to hold the button for 5s to reset the earphones if you want to connect with another device. It’s a small inconvenience, mostly excusable for the price but still noteworthy if you have many devices. Since I use my wired earphones around home, I usually just keep it paired to my Sony NW-A25 since that’s the player I use when out and about.


As for the reliability of the connection once the earphones are paired, the D900 mini, thankfully, proved to be stable and clean with acceptable if not standout range. Once again, this represents a huge upgrade over the D900s and D900, both of which had considerable Bluetooth reliability issues. For instance, with the D900s any distance over 1m from the source would cause complete loss of audio and even in close proximity, the right earpiece would consistently lose connection with the left and audio on a whole was spotty. The D900 mini does still occasionally lose signal, especially on rainy or humid days, but not nearly to the extent that the D900s did. To quantify the difference, if the D900s had about 50-60% reliability, the D900 mini is probably closer to 95% and completely solid on a good day. The range is also much improved, I can walk about 2-3m away from my phone without breakup but any more and audio becomes extremely intermittent. Of course this is line of sight, if there’s any kind of obstruction you won’t have much luck with the D900 mini. Not once did the left earpiece disconnect from my HTC 10, iPod Nano 7g or Sony NW-A25, but the right earpiece did occasionally disconnect from the left one. Again, the vast majority of the time, audio is rock solid, and the earphones do quickly reconnect if they lose signal, gently fading audio back in, there’s no popping or interference.


Syllable quote 2 hours of runtime, identical to the original D900 but half that of the much larger D900s. I do feel that the D900 mini has more of an achievable quote, I couldn’t quite manage to get 4 hours out of the D900s but managed to squeeze 2 hours and 14 minutes from the D900 mini, beating out Syllable’s estimate. It should be noted that I am generally a low volume listener, most of the time, these earphones were around 3-4 volume notches of 15,  on higher volumes you might get closer to 90 minutes. In practice, battery life was sufficient, it lasted the duration of my 6k run and quick weight training session (~90 minutes) at middle volumes. You will have to charge them after every use and you’ll have to make use of that charging cradle should you want to use them all day but charging times are relatively quick and I much prefer the smaller form factor over the added battery life of the monstrous D900s.

From my Sony NW-A25, they did have plenty of volume, more than would be safe, so in combination with the strong noise isolation, the D900 mini should serve even the highest volume listener quite well. The 4 LEDs on the charging cradle that denote the remaining charge are very bright, they’re almost blinding at night. The cradle also makes a high pitched whine when charging so I wouldn’t keep them in my bedroom. During the day, these issues are less pertinent and the charging cradle otherwise worked reliably. I got around 5 charges out of it which is also pretty spot on with Syllable’s estimates, it also charges quite quickly since the earphones have such small batteries.


Sound –

Just to clear the air and kind of set up what you can expect from these earphones I will strongly state that these are not in any way tuned like an audiophile earphone; for example, the $15 Xiaomi Pistons 3’s sound much better, more balanced and more refined. However, the D900 mini is perfectly listenable and much cheaper than the D900s (they go for just ~$36 on Aliexpress shipped to Australia as opposed to $100 for the D900s), they sound much better than the D900s (perhaps due to the seal?) and comparable to any $50 consumer earphone you would find in a retail store with the addition of all that wireless technology.

They do carry that very warm, low end dominated consumer sound that starts off powerful and tapers off as you head up the frequency range. The sound is well suited towards loud environments and activity with a very laid-back tone that avoids high volume, high duration fatigue (even though you are limited to 2 hours of listening anyway), but is too thick for home listening. The dark upper midrange and high end also sap detail and crispness from the sound; female vocals are listenable but not enjoyable on this earphone, whilst bass and lower mids sound quite good if somewhat muddy. Syllable have implemented a DSP that actively adjusts the sound based upon volume, from their website it seems that bass is increased at lower volumes to maintain a rich sound, it would be interesting if they could increase the high end more as well since you’re less susceptible to fatigue at lower volumes.

In a little more depth, the D900 mini’s have average sub-bass extension, a large lower and mid-bass emphasis and a decent boost to the upper bass as well. Bass is muddy and bloated, losing a lot of definition and there is considerable spill into the midrange. Male vocals are still perfectly prominent and remain clear enough for videos and movies. Lower mids are thick and warm but remain relatively balanced with the powerful low end. Upper mids on the other hard, are dark and veiled but listenable. As expected, detail retrieval is minimal, the D900 mini doesn’t have a lot of clarity nor crispness; female vocals often sound truncated and somewhat thin, contrasting to the lower midrange. Treble is unremarkable, being quite recessed and rolled-off. Higher cymbals sound very distant whilst high hats were barely discernible at all.

Sound staging is interesting on these earphones, they have a surprising amount of depth to the sound but minimal width. It’s an odd presentation and imaging, as a result, is not ideal. They have average instrument separation and tend to get congested on some tracks, rock, in particular, can overwhelm these earphones. Pop and jazz sound much better simply due to the style of mastering; Syllable do state that these are tuned for pop music so I suppose it isn’t much of a surprise that they pursue such a warm, depth focussed sound, but it does work most of the time.

Drivability comments don’t really apply to these earphones, the supplied sensitivity and impedance ratings don’t really mean anything. Of course, they do vary ever so slightly based upon the audio codecs your phone supports. My Sony Walkman and HTC 10 both support apt-x which produces noticeably less lag and slightly better quality than my iPods and laptop. My HTC 10 in particular cuts out the most, the metal build is probably affecting signal strength, whilst the Sony produces the strongest connection and the most range. On all of these sources, the D900 mini reaches very high volumes but also gets quiet enough for low volume listeners. The amp circuitry in these earphones is not fantastic, there is an ever-present hiss, it’s relatively low frequency but is quite noticeable, even when music is playing. It doesn’t bother me outdoors but does on quieter tracks when at home.


Verdict –


I honestly set out quite sceptical; Syllable didn’t considerably improve the D900s over the D900 and I assumed the D900 mini would once again, be the same product in different wrapping. But Syllable have been hard at work and a lot has changed since the D900s, a LOT. To directly answer the questions I asked at the outset of this review, yes, the D900 mini are a pretty nice purchase for the upcoming holidays and a worthy alternative to the better wired earphones available for $35. Syllable have fixed all of the ergonomic shortcomings of the D900s simply through the smaller housings and have similarly improved the build quality and finish. On the other side, a vastly decreased asking price more or less justifies the average sound quality and modified tuning has taken the edge off the somewhat harsh sounding D900s.

Accessories – 9/10, Much improved charging cradle and new silicone tips are similarly a lot sturdier. The inclusion of a soft pouch aids portability. I would still like for the D900 mini to come with the rubber joining band that was included with the D900s. The stock flange tips are just okay.

Design – 8.5/10, Comfortable even if they are still a little large. Stability is quite good even without winged ear tips. Isolation is great, as good as any other sealed earphone if not better. Finish is improved but the glossy black plastic still feels cheap. Smooth seams and no button rattle. You will still look like an alien wearing these outdoors.

Sound ratings are universal regardless of price where 1 is unlistenable, 5 is average and 10 is close to perfection (since perfection is inherently subjective)

Bass – 4/10, Average sub-bass extension, heaps of slam and impact due to lower/mid-bass boost.  Quite bloated and muddy, missing definition and texture. About average in quality overall.

Mids – 5/10, Lower mids are a little thick but still quite clear and present. Bass spill warms lower mids. Upper mids are smooth and inoffensive but recessed and lacking both detail and clarity. Female vocals sound truncated and somewhat veiled. Midrange is still decently balanced.

High – 3.5/10, Smooth and recessed, lower treble has decent resolution and nice texture but quickly rolls off above that. Upper treble notes are almost completely missing.

Soundstage, Imaging and Instrument Separation – 4/10, Decent soundstage has good depth but lacks width. Imaging is above average but separation is mediocre due to the thick, dark sound.

Overall – 7.5/10,  With reliable fully wireless technology, a stable fitment and very strong ergonomics, the sonic shortcomings of the D900 mini are easier to forgive, especially at $36 AUD. If you’re looking to get into wireless technology, the fully wireless D900 mini epitomizes the benefits of Bluetooth liberation at an economical price, just don’t expect the sound quality to blow you away. Of course, Syllable could improve the sound quality, but they would also have to increase the price. Again, these are a consumer earphone and the current pricing is spot on, they will sound fine to the average listener but are nowhere near a decent budget wired equivalent.

As an extra note, I’ve added the Amazon links to the D900 mini are below. I understand that Syllable’s lineup is getting quite confusing, especially since the D900s has “mini earphone” in the title. For international buyers, they are also available from Aliexpress.

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