Sound Analysis.

After 100hrs of burn in, I hear Sirius as having a nicely balanced full body sound signature with a neutral smooth tonality. The sound is detailed, resolving, non-fatigue, and with a very natural smooth timbre characteristics. What I was really impressed with, unlike some other hybrid IEM/CIEM models where low end seems to be a bit disconnected from mids/treble, here you have a unison coherency with a smooth detailed sound across entire frequency range.

Low end has a deep sub-bass rumble with a smooth analog texture that adds a nice weight under the mid-bass snappy punch which has a decent speed for a dynamic driver. Not quite as fast as BA driver performance, but still with a decent attack and average decay speed making bass sound natural and realistic. The bass is not super tight or very articulate, but it has an excellent control for a dynamic driver without spilling into lower mids.

Lower mids have a good amount of body which adds to an overall sound characteristics, but at the same time it doesn’t add too much to the thickness of the sound, still keeping it well balanced and neutral, though far from lean. Upper mids are very detailed and resolving, never too bright or harsh. They especially shine when it comes to vocals, both male and female, delivering a very natural, organic, clear tonality.

Treble has a nice extension, good definition, modest amount of airiness and sparkle – it’s there but in a moderate amount and not over the top. You definitely not going to miss the details of your crash cymbals, but the sparkle of the extension tail will be on a shorter leash. The sound is absolutely non-fatigue, without a single hint of sibilance – intended for an extended enjoyable listening.

Soundstage is close to a holographic 3D level, expanding in all 3 dimensions. With that, you can also expect a great imaging with a very convincing placement and positioning of instruments and vocals. At the same time, layering and separation of instruments is good, but not outstanding which in my opinion is a result of moderate amount of airiness and the smooth neutral tonality.

Comparison.

Sirius vs Andromeda – soundstage expansion nearly the same in all directions, though I feel Sirius is a touch wider, while Andromeda is a touch deeper. Andromeda has a little more transparency and slightly better layering and separation. The quantity and quality of sub-bass and mid-bass are nearly the same. Sirius has a little more body in lower mids, making sound more balanced, while upper mids are nearly the same, very detailed, resolving, non-fatigue, though Sirius is just a little smoother in upper mids. Both have an excellent treble extension, crisp, well defined, detailed, but Andromeda has a little more sparkle and airiness while Sirius is a little smoother at the top. Also, Sirius has zero hissing, while Andromeda has some.

Sirius vs Pristine-R – Pristine has a bit of hissing; soundstage depth/height/width are similar. Sirius has deeper, meatier sub-bass, while Pristine has faster mid-bass. Pristine lower mids are leaner and little thinner in comparison, while Sirius has more body, and upper mids in Pristine are brighter and a little more revealing; Sirius upper mids sound smoother and warmer in comparison. Pristine treble is crispier and brighter, but otherwise have a similar extension and level of airiness. While Sirius is more balanced with a more natural tonality, Pristine is more reference quality with a flatter sound and more revealing tonality.

Sirius vs ES60 – ES has a little bit of hissing; soundstage is nearly the same, maybe with Sirius being a touch wider, but it’s very close. Both have a similar sub-bass expansion in terms of quality, but Sirius definitely has more sub-bass weight, while ES has a little faster mid-bass punch with overall bass being tighter. Sirius lower mids have a little more body, but not by a lot; upper mids in ES are a little brighter and more revealing but still equally natural, detailed, and smooth. Both have a clear and detailed treble with a great definition, but ES extends further and has more airiness. While Sirius is balanced neutral, ES is more reference neutral when compared.

Sirius vs K10UA – very similar soundstage expansions, with Sirius being a touch wider. Similar sub-bass extension in terms of quality, but Sirius has a more textured sub-bass rumble, a little higher in quantity; mid-bass punch is the same. Lower mids in Sirius have more body and warmer, while upper mids in K10UA are more revealing and brighter, and a little bit grainier in comparison. K10UA treble is brighter, crispier, more extended, and with more airiness.

Sirius vs A83 – both have a similar height/depth while Sirius is more expanded in width. A83 low end is more lifted, both sub-bass and mid-bass are higher in quantity, but not by a lot. Lower mids in A83 are thinner, definitely not as much body as in Sirius, and upper mids are brighter, more revealing, and at the same time noticeably harsher in comparison (just in relative comparison considering Sirius upper mids are smooth and detailed). A83 treble is brighter and crispier, with more airiness, but it also sounds a little harsher in comparison to Sirius. There is definitely more coherency in Sirius driver tuning while A83 follows a more common 3-way hybrid tuning where you can distinguish low end performance of dynamic driver and upper mids/treble brighter tuning courtesy of BA drivers.

Next to A83.

Next to Andromeda, ES60, A83, Pristine-R, K10UA.

Source pair up.

In general, I found no hissing with most of the sources and a clear black background. Treble was well defined, crisp, and smooth. Majority of differences were in bass performance and soundstage expansion.

L5Pro – wide staging, rich warm organic tonality, full body sound, great sub-bass rumble and strong mid- bass punch. Clear detailed mids, detail smooth extended treble.

X7 w/AM2 – wide staging, crisp brighter tonality, leaner sub-bass, punchy fast mid-bass a bit north of neutral, overall tight articulate bass, leaner lower mids, very detailed upper mids, crisp well defined treble.

L3 – SE: average staging, great sub-bass rumble, strong mid-bass impact, well balanced lower mids and clear detailed upper mids; snappy crisp treble. BAL: a little wider soundstage, bass a little more balanced and tighter in comparison to SE (a touch less sub-bass, and more articulate mid-bass punch). Similar lower mids and clear detailed upper mids. Treble is a touch crispier, but very subtle change. Overall SE/BAL in here are very similar, but I do hear a slight advantage of BAL where overall sound is a bit tighter and a touch more detailed.

LPG – wide soundstage, tight detailed sound, nice sub-bass rumble and tight punchy mid-bass, very detailed clear mids, upper mids quantity is more balanced in comparison to other daps, crisp bright treble. Very resolving and transparent sound.

Opus#1 – SE: wide soundstage, excellent sub-bass rumble and tight mid-bass punch, overall an articulate bass performance. Mids are clear and detailed, very resolving, well balanced (similar to LPG). Crisp bright treble. BAL: soundstage is a touch wider in comparison with SE, sound is very similar to SE performance but I do hear a little better layering/separation, slightly more airiness too.

DX80 – wide soundstage, very balanced sound, excellent pair up with a great sub-bass rumble, nice mid- bass punch, overall bass is not very aggressive but tight and articulate, clear detailed mids, bright crisp treble.

X5ii – soundstage width just average, very good tight bass with a balanced sub-bass (moderate rumble) and tight punchy mid-bass, clear detailed mids, clear bright crisp treble. Also a great pair up.

N5 – SE: a little hissing, clear detailed sound, nice sub-bass rumble, tight mid-bass punch, articulate bass presentation; clear detailed mids, maybe even slightly mid-forward, bright crisp airy treble. BAL: wider soundstage, sound is more balanced in comparison to SE, otherwise very similar to SE.

Micro iDSD (ECO mode) – wide soundstage, amazing holographic expansion, very balanced transparent layered sound, excellent sub-bass rumble, fast punchy mid-bass, tight articulate bass, very detailed natural mids, bright crisp treble with plenty of airiness. Probably the best pair up.

Opus#1 SE and BAL.

Conclusion.

It’s not an easy task for a company to make a leap from their own established flagship to a new one at 3x the price. In my opinion it was a risky move for Fidue because many people might not be comparing this new IEM to other TOTL brand names/models but rather will try to justify if Sirius is worth 3x the price of A83. If you think about it, Fidue is not just adding 2 additional BA drivers, but rather replacing current config with all new four premium BA drivers and a new exclusive Dynamic driver. With a recent flood of Chinese DIY hybrids featuring 5+ driver designs, many people don’t realize those are using either no-name or cheap entry level Knowles drivers (thus a reason for a budget price) and have a poor QC. Here you have premium drivers, all metal premium high quality shell, new improved mmcx connectors, 8 core SPC premium balanced modular cable with Rhodium plated plugs, nice accessories – all a big leap in the design backed by Fidue reputation and QC.

Furthermore, you are dealing with a more mature sound tuning in comparison to A83, where Sirius has a nicely balanced full body sound signature with a neutral smooth resolving tonality and a very impressive soundstage expansion. If an improvement in overall build and design is not enough to convince you about added value, which also contributes to an additional cost, in my personal opinion the sound tuning of Sirius propelled it to the level where I feel it deserves to be compared to other TOTL IEMs/CIEMs, some at much higher price. I believe Sirius crossed the threshold and reached TOTL level where you’re no longer judging it as “good” or “bad”, “worthy” or “not worthy”, but rather looking at it as another flagship where it comes down to the sound tuning preference. For sure, Fidue raised the bar with Sirius release and now ready to play with big boys!