Review - Tangzu x HBB Xuan NV

RY4S - Review (sub 50€)

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Also available on YouTube in Spanish: Acho Reviews YouTube 

More than a review, this is a bit of a discovery and my impressions on what I have discovered, as I really don’t have anything to compare these to… yet.

As a bit of a background, I was discussing earbuds a while back with someone I know and I mentioned how much I hate them, being uncomfortable and sounding thin and… well… crappy.

As someone who likes earbuds, his answer was obviously “That is because you haven’t tried the modern offerings”. Which is a very true, I haven’t tried the modern versions, in fact, in the past 20 years or so, the only earbuds I have owned have been those given to me free, either on a flight or a train, and they certainly haven’t made it to my ears.

So, giving him the benefit of the doubt, I started reading a thread on Head-Fi regarding earbuds. The thread is over 3000 pages long and I admit to skipping a few pages and skimming over a lot of posts but I was intrigued by some of the highly recommended options at very low prices, like, under 10€?!?! For a cheap skate like me, that kind of price is something that interests me, especially when people were praising them.

As I made it towards the end of the thread, the sale on AE started and I thought I would order a couple of these cheaper pairs, giving me an idea of what people are talking about. I must admit that my hope was that I would hate them like I used to and would avoid falling into another rabbit hole.

One of the models I ordered was the RS4Y with MMCX connectors and in the 300 Ohm version. I have no idea who makes them, it says Shenzen Rongyuan Technology on the plastic bag they came in but I don’t know if that is the brand or not, so I’ll just refer to them as the RS4Y.

After a couple of weeks with them, and with the other sets not arriving yet (so I have absolutely no comparison point) these are my impressions and discoveries of a sub-10€ earbud.

Build and Comfort…

Let’s get the comfort part out of the way first, they are not comfortable. At least, I don’t find them comfortable. Before the more knowledgeable earbud owners say anything, no I haven’t tried different covers, only the foam covers they came with, I am a complete noob in this field so I will do some comfort experimenting in the future. Which, as I am willing to keep trying, probably means that they are not that terrible, at least my ears aren’t blistering and I have worn them for many hours over the past few weeks.

As far as build, well, they are a cheap, lightweight, plastic enclosure with MMCX connectors that are not screwed in all the way. As you can see in the photo, the connectors protrude from the bottom and the shape of the earbud housing stops the thread from entering the whole way.

I have had some bad experiences with MMCX connectors lately but these don’t seem to be bad. They are not overly tight but hold the cable well.

On the subject of cable, the cable I am using I purchased from the same store on AE and is an 8 core cable with a 2.5mm TRRS termination. The cable is actually nicely made and I really like the feeling of it, however, it wasn’t included in the price of the earbuds (which is not surprising at 7€!).

There really isn’t much else to say about construction. The packaging was a simple plastic bag and included 3 sets of sponge covers.


When discussing earbuds with the person I referred to above, he was saying that they are like having miniature set of open back headphones. In the case of the RY4S, I have even seen mentioned that it is like a miniature HD600.

Being honest, I am very surprised at the overall sound of these, I expected something much worse. I can actually see the reference to open back headphones as, in comparison to IEMs, they offer much more of an open feeling.

In the bass region is where these seem to suffer the most, although they are not actually that bass light, they have much more bass than I expected. The bass is very dependent upon placement and fit of the earbuds and it did take me awhile to be able to find the sweet spot but now that I have spent more time with them and I am used to putting them in, I can find the correct spot pretty quickly.

That sweet spot does actually present a fair bit of bass, which is well defined and clear throughout the whole of the bass region. I was listening to the album “Until The End Of Time” by Tupac and halfway through decided to swap over to the Moondrop Starfield (after only listening to the RY4S for various days) and I was surprised to find that the increase in bass was not very apparent.

Listening to some of the tracks from my usual test list, “Smooth Operator” is well balanced as far as bass goes, without me feeling it is lacking too much. “Way Down Deep” by Jennifer Warnes has a good bass presence, sounding better to my ears than on other IEMs that have too much bass (this song is very easy to make overpowering with too much bass).

In songs that are dependent upon a lot of bass and sub-bass, this is where the RY4S suffers, as the bass rolls off pretty quickly when moving down towards the sub-bass region. “No Mercy” by Gustavo Santaolalla sounds hollow, as though it is being played on a drain pipe, due to the lack of sub-bass. It is the same with “Bury a Friend” by Billie Eilish, although I don’t miss it too much in this case as I again find it too easy for this song to become overpowering.

As we move into the mids, I think that these are the strong part of this headphone. Voices are nicely presented and have a nice rich tone to them, sounding pretty natural. In reference to the comment about these being a mini HD600, I’m afraid that these are a long way from that point, but are still respectable, especially when factoring in the price point.

However, although I find the tonality of the mids to be nice, I am not overly impressed by the speed with which a lot of the instruments that fall into the midrange are resolved. In tracks that have a lot going on with acoustical instruments, it is easy for the earbuds to start falling apart and struggle to keep up with some of the passages. This causes the songs to sound a little congested and removes the nice tonality of the mids that are much more apparent on simpler tracks. I found this on tracks like “Black Muse” by Prince, where the mids seemed muddy and not well defined. Another example is “Hotel California” (Live acoustic version) where the intro sounds great but when all the instruments are playing together in the main part of the track, again the mids feel congested and make it difficult to pinpoint each instrument.

Up in the treble area, I didn’t find these to be sibilant at all, in fact, I would say they are closer to missing treble than having too much. I didn’t feel that they were lacking too much treble but I think that they could present a little more without moving out of the comfort zone, a little more “air” would be appreciated. Some of my usual tracks for testing treble, such as “Only Time” by Enya, “Hope Is A Dangerous Thing” by Lana Del Rey and “Violent Crimes” by Kanye West, were all presented without sibilance.

As far as timbre, they are not bad. Listening to acoustic instruments and vocals, which makes up a lot of my listening time, guitars and basses did not sound strange and had the body and life that I like to hear. I wouldn’t put them on the level of some of my preferred IEMs or headphones for timbre but they don’t do a bad job.

Soundstage and imaging is decent, better than on the majority of IEMs in the lower price brackets, with a nice width and imaging that places things correctly, although, again, it is not a “wow” factor.

As far as speed and resolution, I already mentioned that it is missing in the mids and I would venture to say that it is not great throughout the whole range, although it is not terrible either. I think the frequencies that seem to resolve better and with more speed, without getting congested are the higher bass areas. Listening to some solo bass tracks, with slap and other techniques, they held their own surprisingly well. However, when it is a busy track, I feel that these details are overshadowed by the congested mid range.

One thing worth noting about these earbuds is that they are pretty power hungry. I know that they are 300 Ohm but that doesn’t always translate into being too difficult to drive. In the case of the RY4S, I needed to set the M2X to high gain and set volume to around 55 in order to listen at my usual (quiet) listening levels. Using the Loxjie P20, which actually works surprisingly well with these earbuds, I found myself at around -28 which is actually a few points higher than when I am listening to the HD6XX.


While I wasn’t absolutely amazed by the RY4S, I was pleasantly surprised. It is true that these earbuds offer a good performance for their price, in fact, they offer a good performance for 5 times their price.

I still find them uncomfortable but not too uncomfortable to use. Maybe using other covers will improve comfort but I will find out in the future.

As I said at the beginning, I don’t have anything to compare these too so I cannot say if they are great earbuds or not, but I do not feel that I have wasted my money. I could probably find enough coins in the center console of my car to buy a set of these, plus a cable and some replacement covers, and still have change left over. For the quality of sound that I have received for that investment, they are pretty darn impressive.

I don’t think that I have been sucked into a rabbit hole, as I won’t be rushing out to spend hundreds of euros on other models, but if this is an example of what you get price/performance wise, then I expect that some of the higher end models must sound amazing.

Once I receive the other models I ordered, I will come back with some comparisons but for now, let’s just say that I am happy with my purchase.

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