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Philips Fidelio S1

Philips Fidelio S1 In-Ear Earphone Review

Brief: One of the two in-ears Philips deems worthy of the flagship “Fidelio” badge

MSRP: $99.95 (manufacturer’s page)
Current Price: $90 from;  $110 from
Specs: Driver: Dynamic | Imp: 32Ω | Sens: 107 dB | Freq: 5-25k Hz | Cable: 3.9′ L-plug w/mic & 1-button remote
Nozzle Size: 5mm | Preferred tips: Comply T/Ts200, Stock single-flanges
Wear Style: Straight down

Accessories (3.5/5) – Single-flange silicone tips (3 sizes), Comply S200 memory foam tips, and zippered clamshell carrying case
Build Quality (3/5) – The build quality of the Fidelio S1 and S2 earphones is extremely similar but the S1 features a cheap-looking plastic baffle at the front, in contrast to the all-metal S2. Issues have been reported with the seal around the front baffle on the S1. While this has not been the case with either of the two units I have, a nozzle filter detached on one of my units and had to be glued back in place. The S1 utilizes good-quality flat cables with an in-line microphone and single-button remote
Isolation (3/5) – Average, not as bad as could be expected from a shallow-fit design
Microphonics (4.5/5) – Good
Comfort (3.5/5) – The Fidelio S1 and S2 are built around 13.5mm dynamic drivers – large for IEMs, but definitely not unheard of. Philips chose a half in-ear form factor for the earphones, placing the driver enclosure in the outer ear with an angled nozzle fitting into the ear canal. This sacrifices some noise isolation for the comfort of a shallow seal, but the wide housings fitting 13.5mm drivers put a lower limit on the size of ears that will tolerate these earphones – smaller ears just won’t fit the housings comfortably

Sound (8.9/10) – Philips did a spectacularly good job with the tuning of their new high-end Fidelio line, both the two Fidelio in-ears and the on/over-ear models I tried at CES 2015. The Philips Fidelio in-ears sound clear and accurate with just the right amount of bass kick. The low end extends nicely, with very mild overall boost and medium impact reminiscent of the popular VSonic GR07.

The mids are crystal clear, with resolution to rival accuracy-oriented IEMs from VSonic and HiFiMan. The lack of bloat helps, allowing the bass of the Fidelio earphones to shine and keeping the midrange completely clear of bleed. Treble presence is good too – the earphones aren’t lacking at the top end for my tastes, and I’ve been known to enjoy a more energetic sound. At the same time, the treble is free of grain and harshness, though there is some upper midrange lift affecting the tone of guitars and vocals. In comparison, the VSonic GR07 sounds a little peaky and sibilant at the top end while the HiFiMan RE-400 is smoother and more laid-back.

The presentation boasts good width with average depth, reminding me of a slightly more mid-focused and less broad-sounding VSonic GR07. Curiously, the Fidelio earphones are not super efficient for a portable audio product and take more power to reach listening volume than much of the competition. This isn’t a problem except for those who gauge sound quality by maximum attainable volume – there’s still plenty of headroom with portable players. The earphones aren’t picky with sources, either, and sound decent enough from a sub-par Android phone.

There is one small caveat with the both the S1 and S2: they require a very good acoustic seal to perform their best. This is true for almost all IEMs but because of the shallow fit and near-neutral tuning of the Fidelios, there’s not much room for error. The large size of the housings and limited insertion depth play a factor as well. Without a good seal the bass quantity drops, the treble sounds a touch hot and spitty, and the presentation loses its depth.

Select Comparisons

Philips Fidelio S2 ($100)

The Philips Fidelio S1 and S2 really don’t differ much, especially when it comes to sound. In addition to its better build quality and fit kit, the pricier S2 model has a slightly more full-bodied sound with a touch more bass. Both can sound a little hot in the treble, especially without an optimal seal, but the S2 is a touch smoother with stock tips. At the same time, it maintains a marginally more airy sound than the lower-end model.

Moe Audio MOE-SS01 ($65)

Like the dual-driver MOE-SS01, the Fidelio S1 boasts mildly enhanced bass and prominent, crisp upper mids and treble. The Philips earphones boast a touch more sub-bass weight compared to the MOE, sounding more solid when it comes to bass punch. Tonally, the Philips earphones are warmer, with mids that appear a bit fuller and smoother. The MOE-SS01 is brighter and harsher. It sounds a little less natural in terms of tone and timbre but easily keeps up in clarity and detail, which is impressive. The presentations tend to be similar, with pretty good width and average depth.

Astrotec AX-35 ($70)

The Fidelio S1 offers up a more balanced sound while the hybrid BA + dynamic-driver AX-35 tends to be more v-shaped in response. The Astrotec unit has more bass but the extra enhancement comes in the mid-bass region, so it doesn’t have an advantage in bass depth. The Fidelio S1 is more mid-centric in comparison and has fuller, more fleshed-out mids, while the AX-35 is a little thinner-sounding. Neither unit is especially smooth – the S1 has some emphasis in the upper mid/lower treble region, which gives guitars a characteristic crunch, while the treble emphasis of the AX-35 comes in higher up, resulting in a slightly more sibilant sound. The AX-35 has a slightly more 3-dimensional presentation with better layering compared to the Philips, and is also noticeably more efficient.

HiFiMan RE-400 ($79)

Compared to HiFiMan’s similarly-priced RE-400 model, the S1 has better bass depth and more bass overall. However, it still sounds a little less full-bodied and not as warm. Its upper midrange and treble are more energetic whereas the RE-400 is smoother and more laid-back up top with a more forgiving treble character. The S1 also has a wider soundstage while the RE-400 is more intimate, but also more even in terms of depth and width.

VSonic VC1000 ($125)

The S1 is a balanced-sounding dynamic-driver earphone that reminds me in many ways of VSonic’s pricier dynamic-driver sets. Compared to the balanced armature-driven VC1000, it boasts more bass, especially deep bass, and has a warmer overall tone. While less powerful, the low end of the VC1000 is tighter and a bit clearer. Its midrange is more prominent in comparison, and on the whole the VC1000 sounds more mid-centric next to the Fidelio S1. Interestingly, while the VC1000 boasts similar, or even slightly greater, treble energy, it actually does a better job of keeping its treble smooth. The Fidelio S1 appears a little harsher and peakier, and tends to be even less forgiving than the VC1000, which itself is not exactly smoothed-over.

Value (8.5/10) – The Philips Fidelio S1 earphones are well-designed, user-friendly, and have good fit and finish. Offering a flat and level signature with a bump across the bass range, the Fidelio models also feature tangle-resistant cabling and a built-in microphone and remote. The semi-open design makes them great in situations where the higher noise isolation of most other high-end earphones is undesirable—and a great choice for those who don’t like the more intrusive fit of most other IEMs. The only thing that would steer me away from recommending them is the price of the higher-end Fidelio S2 dropping ever close in today’s market.

Pros: Shallow-fit design; balanced and capable sound
Cons: Mediocre isolation; housings on the large side



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Living in the fast-paced city of Los Angeles, ljokerl has been using portable audio gear to deal with lengthy commutes for the better part of a decade. He spends much of his time listening to music and occasionally writes portable audio reviews across several enthusiast sites, focusing mostly on in-ear earphones.


13 Responses

  1. These are $75 on Amazon right now, Is it better to pay extra and go with the s2?

    Do these sound similar to the re400?

  2. Offering a headset version is usually one of my first suggestions to IEM manufacturers when asked for product feedback. Unfortunately the trend of few IEMs having a mic/remote option continues with my yet-to-review list. Only a couple have headset functionality, and almost all are lower-end models.

    If you relax the isolation requirement instead you have the Sennheiser IE80i, which has deep bass and smooth overall sound on-par with the EPH-100. There’s also the Sennheiser Momentum In-Ear, which has deep bass but with a more v-shaped (i.e. treble-heavy) sound signature overall.

    RHA’s higher-end T10i has deep bass as well but I honestly prefer (and recommend) the MA750i over it.

  3. Oh! That surprises me! I think I was expecting the Fidelio’s sound sig to more be a bit more v-shaped than the Trumpets. Good to know!

    Yes, the mic/controls aspect is certainly a limiting factor but given the sheer number of hours they’d be in my ears all day and with countless phone calls/interruptions, I’d be losing my mind with how frequently I’d have to be pulling my phone out of my pocket and pulling the ‘phones out of my ears. I find it somewhat odd that the number of great IEMs with mic/controls is so few given that everyone and their dog seems to have a smartphone these days. I’d love to try a GR07 BE and those EPH-100 have been top on my list, but alas…

    I will give the MA750i some serious consideration – thanks for the suggestion!

    Opening the constraints up on sound sig, say something still with good bass extension but moving away from neutral, is there anything (still with mic/control) worth looking into (be it on your list or on your ‘yet-to-review’ list)?

  4. Hmm.. probably not a bad way to go but you are moving in a more neutral and “flat” direction from the MD Trumpets. Certainly not more oomph than the Trumpets, and the isolation is not as good either.

    Your mic/controls requirements unfortunately eliminate the IEM I would normally recommend for this, which is the Yamaha EPH-100. The RHA MA750i should be a decent compromise, though. More bass and isolation than the Philips Fidelios, less than the EPH-100. Never found these to be lacking in rumble or slam, but they stop short of “Basshead”.

  5. Yes, I have a B2M and agree that it’s quite good. Not perfect, but as you said nothing is. It will get a review 🙂

  6. Hi Joker,

    How would the Fidelio S2’s stack up as a replacement for Miles Davis Trumpets?

    My Trumpets (which were the perfect on-the-go IEM for me) finally kicked it and I’ve been losing my mind trying to find a substitute. I loved the warm/balanced signature with slight bass boost from the Trumpets, as well as the isolation (I used them to block out noise in the shop at work). I’m not an all-out basshead but I am a bass player and drummer, so I appreciate a punchy bass presence and, more so, extension down into sub-bass. The Trumpets were fantastic but I always wished they had a touch more oomph in the low end.

    These are my go to stress tests for picking out ‘phones: (Sub-bass stress test) (Upright bass should be strong without the trumpets wrecking the ears) (Kick bass should be fat and punchy, not dry and hollow)

    I’ve been having a hell of a time finding a nice sounding replacement because I need need need a mic and controls (iPhone) and would prefer an IEM that isn’t over ear. Seems to be a tall order these days…

    Do you think the Fidelio S2 would fit the bill or do you have something else in mind that would?

  7. Hello Joker, on an unrelated note, the NarMoo B2M has lately come to my attention as a pretty amazing low-priced IEM–worthy of the attention of your public. No IEM at their price will be perfect, but they improve over the S1 in several ways. Bass extension is awesome, yet they remain lean and not bloated in the mid-bass; mids are nice and very present, avoiding a V-shaped signature; treble is very extended and detailed. Lots of detail, texture, and instrumental color, while remaining smooth and avoiding the edginess of the S1 in the upper mids. Possibly only a slight bit of congestion in the midrange (common to dual-driver IEMs?). Maybe you’ll consider gracing these pages with a review.

  8. Was stuck on planes a couple of times with a laptop but no internet access. Those old InnerFidelity drafts gave me something productive to do 🙂

    BA200 is still going to be flatter overall, with leaner and tighter bass, more level mids, and no upper mid boost. S1/S2 are bassier but still tend to sound a little brighter thanks to that ~5kHz presence bump.

  9. ljokerl has had a bit of time?! Clearly, you aren’t swamped enough 😉

    I remember keeping tabs on the Amazon Japan price of the S2. It dropped to as low as 49$, which would have been a pretty sweet deal (forwarding included). Sadly, trigger finger wasn’t itchy enough.

    Very briefly, how does the signature compare to the BA200?

  10. I’ve had a bit of time to re-write the older InnerFidelity reviews for inclusion here. Got the next 3 done as well.

    Interestingly, two years later I am not as sold on the S1 over the S2 as I was originally. The price gap is much smaller now (and in some countries nonexistent as the S2 can be had for ~$100) and the S2 has proven more durable based on user feedback with the couple of extra metal bits it has. I think I’ll end up switching the buyer’s guide over to the S2 after that review goes up 🙂

  11. Thanks, and correct – there’s only one version as far as I know and it’s got the mic and 1-button remote.

  12. Two and a bit years later, it finally made it to THL 😀

    Nice to see it’s still relevant today. If it wasn’t for Phillip’s (extremely) poor worldwide availability these might have been more popular.

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