Review - Fosi Audio SK02

Review - Plussound Allegro

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TLDR version on YouTube: TDLR - Plussound Allegro

The Plussound Allegro have been sent to me as part of a tour for me to try them out and share my opinions in this review. Plussound have not made any requests other than fixing a limit of one week to spend with them.

I will do my best to be as sincere and unbiased as humanly possible but it is always good to consider the fact that it hasn’t cost me anything to try out these IEMs.

The official page for the Plussound Allegro is here: https://www.plussoundaudio.com/earphones/allegro.html

As always, this is a non-affiliate link.

To avoid being repetetive in my reviews, you can find all the info about how I create the reviews, equipment used, how I receive the products and how to interpret my reviews by visiting: About my reviews


Intro…

I have to be honest and say that I know very little about Plussound other than they are known for their cables. I am not certain if the Allegro are their first set of IEMs or not but on their website they are the only model listed. Specified as the “Launch Edition”, the Allegro cost just over 3200€, a price which I believe makes them the most expensive IEMs to be reviewed on Acho Reviews to date.

Now, before the questions of is it better than X that costs X amount less, it is worth pointing out that after a certain level, it is more about adapting to individual tastes rather than becoming “better” per se. However, it does mean that things that would be considered “inconveniences” at other prices, can quickly become deal breakers at this level.

Anyhow, here are my personal findings and opinions of the Allegro after spending a week with them.


Presentation…

I can’t comment on presentation as the tour unit does not include any packaging, it is just the IEMs inside a (very nice) storage case.

They did, however, include 4 different cable cables and a lot of tips of three different types: silicone, Symbio and Comply.

Also in the case, under the IEMs, there is a cleaning brush, a microfiber cloth, a leather strap (for the cable) and a couple of lengths of edging strip (which I honestly have no idea what it is for).


Build and aesthetics…

The IEMs are certainly on the large side, sporting a copper faceplate that uses square edges and geometrical shapes to give it quite a modern look. While I like the look of the IEMs, I am sorry to say that the shape is something that I find extremely uncomfortable. I was actually joking about the fact that the Allegro could become the first IEMs to bring tears to my eyes. This is due to the fact that they really dig in to the top part of my ear, becoming very painful even after a few minutes, yet I was enjoying the music so I kept on listening 🙂

To try and combat the issue with comfort, I tried the three types of tips included, along with a large selection of tips that I had on hand. As far as sound, I preferred the included Symbio tips (more on that in a moment) but they actually added to the discomfort. In the end, in order to use them for any extended period, I either had to opt for Crystal’s or Xelastec’s (both in a large size). This allowed me to get a seal slightly further out and was a little more comfortable (although still painful after a while). Out of these two, I preferred the sound of the Crystals but as they sit so far outside the ear, and are heavy IEMs, any slight movements caused the seal to break.

Anyway, fit and comfort is a very personal thing and I have said my piece, so let's move on and talk about the included cables.

I have no idea what each model of cable is called (I could have probably researched but you know how I usually avoid that sort of thing 😉 ) but there is a black & white one, a grey one and a black one. I measured with each of these cables and there was no difference, so I just stuck with the black and white one that came preinstalled. The cables certainly seem to be well built and high end but are a little stiff for my personal tastes. They are not overly thick but aren’t something that is easily draped over the ears, as I said, they are just a little stiff.

There have also included a USB cable with inline controls (and DAC/Amp obviously), which is an option when purchasing the Allegro. I am sorry to say that I ran out of time and din’t have chance to test this cable/DAC/Amp.


Sound…

All tracks mentioned are clickable links that allow you to open the reference track in the streaming service of your choice (YouTube, Tidal, Qobuz, Spotify, etc.)

I started off by listening mostly to acoustic/vocal music while I was working and I have to say that I really enjoyed the Allegro (apart from the blades digging into my ears) for a very long session of my favourite genre. I did find that some vocals, especially female, could come across peaky and harsh in the upper ranges but in general, I found them to have a very enjoyable signature.

When moving on to other music, specifically things that included more drums than my usual acoustic guitar and singer arrangements, I found that the upper ranges were more on the harsh side than I had first realized. 

But let’s take my usual test list and put things into perspective with the tracks that I always use for my detailed listening. In this case, as I wanted to spend a long session to come up with in depth opinions, I used the Azla Crystal tips and made sure to not head bang too much 🙂

First, as always, here is the graph comparing them to my usual reference target:

Starting off with “Chameleon” (don’t I always?), the subbass rumbles nicely and keeps it’s posture even when things are getting “heavy” down there. They didn’t actually give me the impression of having as much subbass as they show on the graph but I think that is due to the cleanliness of these low notes, keeping the rumble from taking over the low end.

With “Royals”, the subbass hits nicely and portrays that “dirt” that is part of the low end in this track. Again, I didn’t find that the subbass was as present as I would have imagined by looking at the graph, or to put it better, when I measured the Allegro and saw the results, I was surprised to see such an elevated low end.

The midbass is something that would worry me if I looked at the graph before listening, as I have a tendency to get fatigued very quickly with excessive midbass, especially if the midbass is not very clean and controlled. This is a non issue for me with the Allegro as the midbass is very clean and defined. The quickest test for me is “Crazy” by Daniela Andrade, which can make me nauseous very quickly if the midbass is excessive and not controlled enough, in this case, absolutely no issues.

With something a little more electronic such as “No Sanctuary Here”, the midbass gave the same impression that the subbass did with “Chameleon”. The presence is there but the hits are very clean and controlled, making it seem like there is less presence than there actually is. There is certainly no sensation of bloat to my ears and even faster and busier tracks in the low end, such as “The Room”, are well defined and do not make the bass feel like it is merging with the guitar, nor does it overpower the bass drum.

In the midrange I find that the transition from the lower ranges is very clean, with no noticeable issues. I don’t know at what point the crossover happens but I found that the DD and BA drivers work well together to make the mids sound smooth and collected. I liked the timbre of acoustic instruments especially in the lower midrange, with the DD adding that bit of natural taste to the cleanliness of the BA drivers.

As we move up into the higher mids, again looking at the graph, I would have expected vocals to not be as forward as they are in reality. I found that vocals didn’t take a step forwards but they didn’t blend into the background either having just enough light on them to be the focus point. There were a few male vocals that I did find to be a bit further back than usual, such as Prince in “Black Muse” where his voice seems to be slightly further back than the female vocals.

However, as we move past this point, things start to go downhill in the upper ranges. As I said, with acoustic/vocal music, I found a few female vocals to have a few peaks that could be irritating but not terrible. When we start to add more instruments in these upper ranges things do start to become a lot more peaky and very harsh on occasions.

For example, the plucks in “Elephants On Ice Skates” can actually make me wince on occasions, as can the cymbals in “The Room” or even the snare hits in “Jack of Speed”.

I already know that I am sensitive to 5kHz peaks, which isn’t going to help things, but in this case, the dip before this mark with the additional presence moving up from there puts too much focus on this range, making it uncomfortable with certain tracks and genres.

Sibilance is also present, using the usual “Code Cool”, I would place Patricia Barber (on my completely non-scientific -12 to +12 scale) around a +3 or +4. The hi-hats don’t really help in this track either, adding to the harshness when sibilance occurs. Paul Simon in “Diamonds on the Soles of her Shoes” is much the same.

Details are good, with good image placement and a nice open sensation, not huge but still very enjoyable and above what I have come to expect as average from IEMs. “Bubbles” may not have the largest 3D imaging I have ever heard but it is certainly at a level to make the track enjoyable for what it is.


Conclusion…

The Plussound Allegro are a high end set of IEMs that, pardon the pun, come apart in the high end. 

If I ignore the issue I have with the comfort of these IEMs, which is obviously a deal breaker for me personally but may not be an issue at all for others, then I have to say that there are things about the Allegro that I have really enjoyed.

I find that the lows and mids work very well together, giving both good sound and great performance in those areas, with details that are impressive and, in general, a pleasant experience in those ranges.

I find that they work very well for acoustic/vocal centric music, which makes up a large portion of what I actually listen to, only showing a less than “comfortable” treble on certain vocals in this genre, mainly female (although some male vocals also). 

The problem arises when there is more going on in this upper ranges, such as percussion etc., which starts to put more focus and emphasis on the higher end, making the sharpness become much more apparent. In these cases, the upper ranges, at least to my ears, do become very uncomfortable. There are spikes and sibilance that can actually cause me to wince at certain points in time.

It is very possible that with a combination of different tips (the Symbio did seem to tame them slightly, although not enough) and possibly some filters, that this would not be apparent and result in a more balanced signature in these upper ranges. The issue is that, due to the fit and how painful I find it, I am very limited to what tips I can actually use.

If these are actually the first IEMs by Plussound (again, I am not sure on this), then I think they have proven to be very capable and have already created a very good base that just a few tweaks could turn them into something that is excellent.


All FR measurements of IEMs can be viewed and compared on achoreviews.squig.link
 
All isolation measurements of IEMs can be found on achoreviews.squig.link/isolation

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