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Speaker size: 50mm open back design Frequency range: 20-22kHz flat response design SPL: 112dB hearing threshold Impedance: 32ohm Ear cups outer diameter: 86mm Ear cups inner diameter: 70mm Ear cups material: Walnut Headband material: Stainless steel

Ollo Audio s4


Recent Reviews

  1. Roderick
    Ollo Audio S4: neutral to the extreme.
    Written by Roderick
    Published Sep 11, 2018
    Pros - - revealing, neutral sound that emhasizes nothing.
    -sound quality on general
    - exceptional build quality
    -handmade luxury item
    Cons - -dark(ish) sound is not for everyone
    -small earpads
    -occasional bass honk
    1. Edit: Since the price of S4 is currently only 289€ I've updated the rating from 4.5 to 5. I also added proper fr measurement I did and added some comments about the perceived neutrality as measurements don't look neutral.

    2. Olloaudio is a new headphone manufacturer from Slovenia. Product that sets them apart from others is their BSE(body sound experience) system that is a tactile subwoofer pillow which helps the user to feel the bass instead of just hearing it. However now I'll be focusing only on their hps s4 headphones. These headphones were received from ollo via their endorsement program. I got a 50% discount for publishing my honest opinion on the headphones and I will receive no further compensation.

    3. Introduction

      Ollo Audio HPS S4 headphones

      Price: 349e
      Speaker size: 50mm open back design
      Frequency range: 20-22kHz flat response design
      SPL: 112dB hearing threshold
      Impedance: 32ohm
      Ear cups outer diameter: 86mm
      Ear cups inner diameter: 70mm
      Ear cups material: Walnut
      Headband material: Stainless steel and Italian leather
      Ear pads size: 90mm
      Ear pads material: Acoustic foam, extra elasticity artificial leather
      Cable termination: detachable 2m long Y 2.5mm mini jack
      Connector: 3.5mm jack with adapter to 6.3mm jack
      Servicable: Every part of HPS S4 is replacable with home tools

      Gear used in this review:

      Hegel hd10
      SPL phonitor
      Topping NX1
      Audioquest dragonfly black v 1.5
      My diy PC
      OnePlus 6

      Music of various genres with Spotify premium or flac from pc. Pretty much everything from dimmu borgir to paw patrol theme song.

      After receiving the headphones allmost two months ago I've been using them as my main headphones. It took me a long long time to get a proper impression because before ollo's I had been using mostly sennheiser hd800, Grado sr325i and akg k701. All known to be bright headphones. Ollos have more of a darker tone so it was quite a change.

      Before talking more about ollo's tonality, lets take a look at the headphones.

      Build quality:

      There is no way around it. These are exceptionally well built headphones. Everything except the pads is made of wood, metal or genuine leather. Housings are handcrafted walnut. They're not polished or treated to shine. Headband arch is stainless steel, back of the housing is made of aluminium and so is the baffle/driver cover. Headband is italian leather and earpads are some sorth of fake leather with microsuede like texture. I like the the looks. It is fancy enough but also looks like a robust studio equipment. Something that is ment to be worn and used instead of just being gazed upon.


      What I particularly like is the cup design. Instead of rings made of wood Ollo's uses a solid piece of wood in which the driver is installed. There is no seperate mounting baffle for the driver and wood part is not just a ring. I think this design will add to durability a lot. Wooden rings are known to break when the wood dries too much. I think that will never be an issue with this design. In the picture below you can see how the headphones are built and how the driver is inserted. The black ”baffle” on top of the driver is aluminium.


      The headband is quite normal self adjusting headband. Similar to the likes of used in many AKG headphones for example. The shape looks weird in pictures but it is soft and adjusts to my head perfectly. Only thing I can fault the headband is that they have a small area underneath the band that is sown together.


      I thought the stitch was there because the headband leather had a hole in it but according to Ollo that is how they fix the elastic inside. It does not look good but of course nobody can see it underneath there. It is a small thing but I hope they come up with a better design in the future.

      Headband arch is made of steel. It has a durable feeling to it and I don't think I could break it even if I tried. Bad thing is that the arch is highly microphonic. Microphonic is kind of an understatement...if you plug the arch while it is on your head you get ringing that lasts for 15 seconds! Not that it would affect anything on a normal listening but on principle alone one would like the housing and the headband to be silent and free of possible side noises. I asked Ollo about the headband and according to them the headband does not affect the sound quality. They had actually done measurements about it so propably I'm worried over nothing.

      Cool thing about the headband arch is you can hang them everywhere. Smallest headphone holder ever:


      Pads look a bit cheap in contrast to other parts. They're made of artificial leather but the material is nothing like traditional pleather you get on most headphones. To me the pads feel more like microsuede than leather. I'll talk more about the pads later.

      One thing worth nothing is that as stock S4's come with red fabric cover that is there to tame the highs. Nice and easy way to tune the headphones.


      Headphones have a dual entry Y-split 2.5mm connections with 3.5mm connector at the end.
      Dual 2.5mm is a smart move. Getting replacement cables is easy since sennheiser hd700, oppo, velodyne, denon, audioquest etc use the same connectors. It seems to me it has become a industry standard over 3.5mm dual connectors. Cable itself is very basic. Nothing fancy. Metal plugs with vowen plastic cover on cable and rubber after the split. You can get one for 20 bucks on ebay. But it works and I'm glad cost of headphones comes from other things than from a fancy cable.

      All in all these are exceptionally well crafted headphones. Pads are not fancy and headband arch resonates sound but besides that these are one of the best built headphones I've seen regardless of price range. It's a nice mixture of luxury materials with a design suited for professional use. Rugged but beautifull.


      The self adjusting headband is propably the most comfortable I've ever encountered. Not that there is anything particularly wrong with the designs used by hifiman, akg or audio-technica but in my opinion Ollo is a step above. The headband looks weird when not worn but because it is so soft and bendy it perfectly adjusts to ones head shape. There is zero pressure on the top of the head.

      Clamping force is mediocre or slightly loose. I have a medium small- medium sized male head. That is no measurement, but you get what I mean. I would personally prefer a tighter fit. These don't fall off when doing some basic home choirs but If I tilt my head fast these might fall off. Luckily steel design allows users to bend the headband to their preferred grip.

      The earpads are where the problems begin. Like I mentioned before I don't really feel that earpads are on par with other design look wise. Unfortunately they're not that comfortable either. For my somewhat pointy average sized ears these are quite good but after 30 minutes or so I have to adjust them. People with larger ears will have bigger problems with these. These are no way on-ears but one might have to tuck the ears in a bit which is not ideal for comfor nor for the sound quality.

      I contacted OLLO and asked why they went with seemingly subparr earpads. They said they tested 20-30 earpads and these were the only ones that sound good enough. I believe that. I tried bunch of other pads. All velour pads are a no go definately. HM5 pleather pads sounded decent, other pleather pads collapsed soundstage or otherwise affect sound in negative way.

      The pads are not absolutely horrid but at $400 standards are quite high. However some of the competition does even worse. Onkyo a800b is less comfortable and one rarely mentions comfort and grado foam pads in a same sentence. In a way I even find Sennheiser hd800 to be less comfortable than Ollo's. Hd800 is just so huge that it feels like I have dinner plates on the side of my head.

      I hope that in the future ollo figures out how to maintain the soundquality and introduce headphones with more comfortable pads.

    4. Update: Here is a fr measurement with ollo and audioquest nighthawk carbon in same picture. I chose nighthawks because remarkable tonal resemblance.
    ollo_vs_nh.jpg It is obvious that S4 has elevated bass and as such not that neutral. However it is so well done that it does sound neutral to my ears. Nighthawks have this overly thick sound and lower midrange gets affected by bass. This is not the case with S4's. Ollo's have more upper midrange presence which adds to clarity alot. Say what you will, but for me S4's sound neutral with a healthy dose of bass.

    According to ollo these were designed to be ”neutral and brutally honest”. I think they have achieved that goal. When I got the headphones I thought these reminded me alot of sennheiser hd600. I do not have the hd600 anymore so I asked OLLO what they think of that comparison. They said I'm not far off. According to them hd650 is closest tonally to shp s4 than any other headphone but sennheisers have slightly brighter treble. I think people who like audioquest headphones might also appreciate the ollo sound.

    That pretty much describes the soundsignature. To my ears OLLO's are very neutral and natural sounding headphones with somewhat dark tone. There is never any sibilance. That is very good thing because the dynamics these pack it could get ear piercing at times. These have a ability to sound somewhat distant on peacefull passages and when the dynamics change these attack right at you. It is really kind of spooky. It is allmost as the signature and soundstage presentation goes from laid back to in your face grado in a millisecond. However on some recordings subdued highs can be bit off a lackluster.

    These are very flat across the board which is good for someone like me who likes to listen loud. However I can't help to feel I could use a bit more energy at top. It is all there but I'd just like more sparkle and air up top. On occasion these feel kind of closed in. On the other hand I never feel that way when listening very good quality recordings. Usually unforgiving headphones are the brighter ones. Ollo's have a fresh perspective on that. For example meat loaf: bat out of hell, is far from being an audiophile approved masterpiece. I'ts a muddy album with boosted highs. Bright headphones make it sound lively but ollos just reveal the bad quality underneath. With S4's highs are more in line with the rest of the sound spectrum revealing how bad it is all done. Meat Loaf is just one example. These completely ruin a lot off my favorite music... Old Iron Maiden etc. And that is a good thing for a headphones designed for studio use. Not so good thing for using these headphones for sheer music enjoyment.

    Soundstage is mediocre in size but it is very proportionate. Everything is imaged very well in space. Many headphones have excess width with lacking debth making them sound unnatural. OLLO's have very well defines soundstage allbeit a bit small. Since these were designed for studio use I think this kind of presentation comes in handy when switching from monitors to headphones. The superstereo effect is one of the major downfalls on headphones and it makes sense to have it minimized on a headphone like this even if it has it's drawbacks. Unfortunately these are not resolving enough for good vertical positioning. I must say though that in my experience no headphones are in this price range.

    Sonically S4's biggest downfall is the bass. On one hand it is linear and well extended. Very well extended for an open back dynamic headphone. It does not have the "grip" planar's have but for a mid priced dynamic headphone it is very impressive. Unfortunately there are time I feel bass becomes a bit blurry and honky. I think it is just some particular frequency that triggers the effect because it does not seem to happen with any particular genre of music nor is it dependent on how bassy or fast the music is. It is by no means an persistent issue, just something that happens every once in a while and I found it bothering.

    Without something to compare headphones with, it is just all words without substance. So I compared Ollo's to some of the open headphones I have at the moment.[​IMG]Ollo S4 vs Onkyo a800

    Well regarded and similarly priced onkyo's are a good headphones to compare. Both are open back and easy to drive 32ohm dynamic headphones. Onkyo's are considered by many to be an upgraded version of well known Philips Fidelio X2. Both headphones are made by Gibson so it does make sense. Onkyos are a very nice headphones indeed. However I can't help to feel that compared to Ollo's Onkyo's have somewhat distant sound. I don't mean a large soundstage with back row presentation but something that is just a bit unnatural with a800. It is kind of like sound is coming from a tunnel.

    Bass performance on both headphones is very good for open headphones but I think Ollo's are still step ahead here. On the subbass region Onkyo's start dropping quite drastically as Ollo's just keep on going.
    Onkyo's are not bright headphones but they definately have more treble presence than ollo's. I find onkyo's sound a bit unrefined up top compared to ollo's.

    For someone looking for neutral but with fun treble tilt Onkyo is a better choice but if one prefers more natural midrange and linear bass Ollo's are obviously better headphones.

    Ollo S4's vs AKG K701

    K701 can be had for 150€ these days and along with hifiman he400i I think it is propably the best bargain one can get these days. AKG's sound cleaner on midrange compared to Ollo's but they lack the natural heft Ollo's have. Particularly piano music is a lot more impressive on Ollo's. Ollo's can't match the huge soundstage of AKG's nor the detail retrival qualities. K701 is known for lacking bass and it is obvious that Ollo's have hands down better bass performance. Ollo's also sound more natural on highs, K701 tends to be bit grainy at times. I think Ollo's are step above K701 but considering the low price of K701 it depends on ones preferences if Ollo's are worth the extra money.

    Ollo s4's vs Beyerdynamic DT880 (2003)

    Considered by some to be one of the finest headphones beyerdynamic has ever produced, old 2003 version of classic dt880 is not a headphone to be neglected. It is indeed a fine headphone offering a larger soundstage than Ollo's. Beyerdynamic has a clean, clear sound and Ollo's do sound quite murky in comparison. It is quite the same as with akg 701. It is also same in a way how Ollo easily outperforms beyerdynamic in the bass department like it did with AKG's. Same goes for the midrange. Ollo's have mids that integrate to highs so well that headphones like k701 and dt880 sound kind of like two way hybrids with bad crossover implementation. Then again we have the price issue and I must say these old dt880's are no slouch when that is taken in consideration. However it is clear that Ollo s4's is the better of the two.

    Ollo S4 vs Grado sr325i (gold 50th anniversary edition)

    I'm quite of a fan of these Grado's. I've had some experience with their headphones and I don't think this old sr325i is much worse than RS2e I had couple of years ago. I never had the change to compare the two side by side but that is just the feeling I have, so take it with a grain of salt.

    Anyway... Grados are a formidable opponent to Ollo. Grados have very fun punchy bass, it is not as well extended as Ollo's but it is more fun. Also the bass on grados never gets honky like I've mentioned is the case with Ollo. 10 point's for grado!

    Both have exceptionally beautifull midrange. Presentation is different but both sound just great. Compared to akg and beyerdynamic, Grados sound more beefy, robust. Very similar to Ollo's in that regard.

    Sr325i's are often regarded as brightest off all grados. It makes them fun, in a way. However if one tries to be objective it must be said that highs on sr325i's are way over the top, ridiculous even. It is all fun, cool and exciting until you listen to Metallica: carage inc or something similar.

    Because of the excessive highs Grado's sound airy but they can't really match the soundstage of Ollo's. Width is about the same but grados have little to none soundstage debth.
    So yeah... Obviously Ollo's are the better of the two.

    Ollo S4's vs Sennheiser HD800

    This comparison does not make much sense because of the price difference but since all the headphones above were cheaper why not compare Ollo's to a more expensive one.

    It is obvious that hd800 is a step or two above ollos. HD800 sounds so clear, effortless and fast that Ollo's can't match that. Ollo's have an edge in overall tonality. HD800 is in a sense faulty headphone with it's treble peaks etc. Ollo's are more consistent and...well, neutral. Ollo's also have better bass extension. Comparing these two would be like comparing hd650 and hd800 so I won't go any further.


    Ollo S4's are headphones with exceptional build quality with some comfort issues. Neutral to the extreme soundsignature is not for a music lover looking for a fun sound presentation. Similar sound quality might be available for less $ but without the materials and craftmanship that is invested in these headphones. Ollo's have become a valuable reference headphones for me and I understand why many professionals love them.


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