Link to my review and measurement index thread where one can also find a full review overview, more information about myself as well as my general-ish audio and review manifesto: https://www.head-fi.org/threads/956208/
I only give full stars. My ranking/scoring system does not necessarily follow the norm and is about as follows:
5 stars: The product is very good and received the "highly recommended" award from me.
4 stars: The product is very good and received the "recommended" award from me.
3 stars: The product is good/very good, but not outstanding/special enough to get any of my two awards. ["Thumbs Up"]
2 stars: The product is only about average or even somewhat below that and somewhat flawed/flawed in some areas. [neither "Thumbs Up" nor "Thumbs Down"]
1 star: The product is bad/severely flawed to outright bad. ["Thumbs Down"]
Shure SE425
Source:
Personal unit.
Miscellaneous:
Decent unboxing experience and accessories.
I like the shiny silver mirror-like design.
Build quality is good.
Excellent fit, ergonomics and noise isolation.
Removable cable with MMCX connectors.
Long, good strain relief integration, does not lack a chin-slider. Feels sturdy and one can feel that below the outer shielding, the inner conductors are twisted. Supple.
Two BA drivers per side. Two ways.

Sound:
Largest included single-flange silicone ear tips.
Tonality:
Fairly neutral leaning towards rolled-off/dark-ish in the upper treble. Largely flat and uncoloured.
The lows show a gentle boost of warmth in the fundamental range/lower midrange, comparable to my Ultimate Ears Reference Monitors, with a boost of around 3 dB compared to my Etymotic ER-4S.
While the sub-bass is reproduced with sufficient level, it is generally a bit behind the upper bass in quantity as the lows level starts to gradually decline a little from the lower fundamental range towards the sub-bass.
Except for the gentle lift in the fundamental range that adds just a touch of lower midrange body, the midrange is tuned neutral towards ever so slightly dark, but quite prominent/intimate in the mix. Due to the mild roll-off towards the sub-bass as well as the relatively early treble roll-off, the Shure could also be categorised into the mid-centered side of neutral in-ears.
The treble remains unobtrusive in a positive way in the lower and middle highs, with a moderate dip in the middle treble, just to be around neutral quantity above again.
Above that, however, is the SE425s’ biggest pity, their treble extension, that is simply lacking, with a roll-off that starts already before the upper treble that is relevant for cymbal reproduction, with a muted super treble above that, wherefore the Shure clearly lack the reproduction of many instruments’ overtones and thus perceived “air”, with cymbals for example just sounding as if they were cut off. This also leads to a sound that appears somewhat “veiled”.
Frequency Response:

ER-4S-Compensation
Except for the 7 kHz peak that I do not hear when performing sine sweeps or listening to music, this is also how I perceive my SE425.

ProPhile 8-Compensation
Resolution:
Solid for multi-BA in-ears in this price range. Surpasses many similarly priced dynamic driver in-ears. Nevertheless definitely not class-leading for multi-BA IEMs in this price range, and surpassed by in-ears such as the Rose Technology Mini2, Brainwavz B200 (the good first generation, not the inferior v2), Etymotic’s in-ears, the Pai Audio MR3 and the Eternal Melody EM2.
The bass is very tight, fast and clean, while details in the lows could be ultimately a bit higher, but are still decently reproduced. Due to their bass speed, the SE425 remain clean and well-separated in the lows even in fast music passages. As for this, the Shure even outperform some other multi-BA in-ears with rear-vented BA woofers when it comes to tightness.
Midrange details and speech intelligibility are convincing as well.
While treble details are per se not really lacking, the early and steep roll-off in the treble that just cuts off the upper highs altogether makes the SE425 lack some upper end information.
Soundstage:
Very small and especially narrow soundstage, even to the point that I would say that there is more depth than width. Still more pronounced three-dimensionality than my Sennheiser Amperior, but that’s not a difficult thing to achieve.
Instrument separation is executed well with clean borders, but due to the stage’s small size, it seems a bit cramped.
- - - - - - - - - - - -
Comparisons:
Noble Audio SAVANNA:
The Shure have got the very slightly lighter bass (by ca. 0.5 dB) that also start to lose quantity slightly earlier.
In the mids, the SE425 are somewhat more forward and mid-centric sounding.
The SE425 have got the more forward presence range. In the treble, the Shure start to roll off noticeably earlier, wherefore cymbals sound quite muffled on them.
The Shure have got the slightly quicker upper bass punch, however their lows don’t appear as layered or detailed as the Savannas’. Likewise, in the mids and highs, the Savanna are ahead whereas the SE425 sound more veiled in comparisons, with fine details not being reproduced as effortlessly.
Regarding soundstage, the Nobles’ isn’t only larger in all dimensions but also considerably more realistic, in addition to being more precise as well.
Jays q-JAYS (2nd generation):
The SE425 win in terms of absolute neutrality, though they is more mid-centric and have got the obviously inferior treble extension; the q-JAYS' upper treble is noticeably brighter due to their peak whereas the Shures’ is a little on the darker side.
The q-JAYS outperform the SE425 in terms of resolution. In the mids, treble as well as bass, the Swedish in-ears outputs more details while the Shure sound “restricted”/a bit cloudy in comparison.
The Shure have got a closed BA woofer and as a result of this the quicker and tighter bass in comparison, but the Jays in return have got the more detailed lows and are still far away from being slow or soft sounding.
The Shure have got a very small soundstage whereas the Jays’ is more open, with the more precise instrument separation and, as a consequence of the larger size, better instrument placement.

Conclusion:
Neutral tuning with decent technical performance, especially in terms of bass speed and tightness, but unfortunately clearly too early and steep roll-off in the treble that just cuts off instruments’ overtones and leads to a severe lack of perceived “air” and extension. Narrow soundstage.
A price closer to 200$ is more realistic than the ~ 300$ price tag.
Photos:

I only give full stars. My ranking/scoring system does not necessarily follow the norm and is about as follows:
5 stars: The product is very good and received the "highly recommended" award from me.
4 stars: The product is very good and received the "recommended" award from me.
3 stars: The product is good/very good, but not outstanding/special enough to get any of my two awards. ["Thumbs Up"]
2 stars: The product is only about average or even somewhat below that and somewhat flawed/flawed in some areas. [neither "Thumbs Up" nor "Thumbs Down"]
1 star: The product is bad/severely flawed to outright bad. ["Thumbs Down"]
Shure SE425
Source:
Personal unit.
Miscellaneous:
Decent unboxing experience and accessories.
I like the shiny silver mirror-like design.
Build quality is good.
Excellent fit, ergonomics and noise isolation.
Removable cable with MMCX connectors.
Long, good strain relief integration, does not lack a chin-slider. Feels sturdy and one can feel that below the outer shielding, the inner conductors are twisted. Supple.
Two BA drivers per side. Two ways.
Sound:
Largest included single-flange silicone ear tips.
Tonality:
Fairly neutral leaning towards rolled-off/dark-ish in the upper treble. Largely flat and uncoloured.
The lows show a gentle boost of warmth in the fundamental range/lower midrange, comparable to my Ultimate Ears Reference Monitors, with a boost of around 3 dB compared to my Etymotic ER-4S.
While the sub-bass is reproduced with sufficient level, it is generally a bit behind the upper bass in quantity as the lows level starts to gradually decline a little from the lower fundamental range towards the sub-bass.
Except for the gentle lift in the fundamental range that adds just a touch of lower midrange body, the midrange is tuned neutral towards ever so slightly dark, but quite prominent/intimate in the mix. Due to the mild roll-off towards the sub-bass as well as the relatively early treble roll-off, the Shure could also be categorised into the mid-centered side of neutral in-ears.
The treble remains unobtrusive in a positive way in the lower and middle highs, with a moderate dip in the middle treble, just to be around neutral quantity above again.
Above that, however, is the SE425s’ biggest pity, their treble extension, that is simply lacking, with a roll-off that starts already before the upper treble that is relevant for cymbal reproduction, with a muted super treble above that, wherefore the Shure clearly lack the reproduction of many instruments’ overtones and thus perceived “air”, with cymbals for example just sounding as if they were cut off. This also leads to a sound that appears somewhat “veiled”.
Frequency Response:
ER-4S-Compensation
Except for the 7 kHz peak that I do not hear when performing sine sweeps or listening to music, this is also how I perceive my SE425.
ProPhile 8-Compensation
Resolution:
Solid for multi-BA in-ears in this price range. Surpasses many similarly priced dynamic driver in-ears. Nevertheless definitely not class-leading for multi-BA IEMs in this price range, and surpassed by in-ears such as the Rose Technology Mini2, Brainwavz B200 (the good first generation, not the inferior v2), Etymotic’s in-ears, the Pai Audio MR3 and the Eternal Melody EM2.
The bass is very tight, fast and clean, while details in the lows could be ultimately a bit higher, but are still decently reproduced. Due to their bass speed, the SE425 remain clean and well-separated in the lows even in fast music passages. As for this, the Shure even outperform some other multi-BA in-ears with rear-vented BA woofers when it comes to tightness.
Midrange details and speech intelligibility are convincing as well.
While treble details are per se not really lacking, the early and steep roll-off in the treble that just cuts off the upper highs altogether makes the SE425 lack some upper end information.
Soundstage:
Very small and especially narrow soundstage, even to the point that I would say that there is more depth than width. Still more pronounced three-dimensionality than my Sennheiser Amperior, but that’s not a difficult thing to achieve.
Instrument separation is executed well with clean borders, but due to the stage’s small size, it seems a bit cramped.
- - - - - - - - - - - -
Comparisons:
Noble Audio SAVANNA:
The Shure have got the very slightly lighter bass (by ca. 0.5 dB) that also start to lose quantity slightly earlier.
In the mids, the SE425 are somewhat more forward and mid-centric sounding.
The SE425 have got the more forward presence range. In the treble, the Shure start to roll off noticeably earlier, wherefore cymbals sound quite muffled on them.
The Shure have got the slightly quicker upper bass punch, however their lows don’t appear as layered or detailed as the Savannas’. Likewise, in the mids and highs, the Savanna are ahead whereas the SE425 sound more veiled in comparisons, with fine details not being reproduced as effortlessly.
Regarding soundstage, the Nobles’ isn’t only larger in all dimensions but also considerably more realistic, in addition to being more precise as well.
Jays q-JAYS (2nd generation):
The SE425 win in terms of absolute neutrality, though they is more mid-centric and have got the obviously inferior treble extension; the q-JAYS' upper treble is noticeably brighter due to their peak whereas the Shures’ is a little on the darker side.
The q-JAYS outperform the SE425 in terms of resolution. In the mids, treble as well as bass, the Swedish in-ears outputs more details while the Shure sound “restricted”/a bit cloudy in comparison.
The Shure have got a closed BA woofer and as a result of this the quicker and tighter bass in comparison, but the Jays in return have got the more detailed lows and are still far away from being slow or soft sounding.
The Shure have got a very small soundstage whereas the Jays’ is more open, with the more precise instrument separation and, as a consequence of the larger size, better instrument placement.
Conclusion:
Neutral tuning with decent technical performance, especially in terms of bass speed and tightness, but unfortunately clearly too early and steep roll-off in the treble that just cuts off instruments’ overtones and leads to a severe lack of perceived “air” and extension. Narrow soundstage.
A price closer to 200$ is more realistic than the ~ 300$ price tag.
Photos: