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The Ollo S4X: a boutique headphone, at a boutique price

Hi all! We’re taking a look at the Ollo S4X. This is a headphone that has recently been the center of some controversy, as DMS took issue with the tuning of this headphone, and how it was represented on the Ollo website. And these are the very same headphones that DMS had in his review, thanks to Dave, the newly rebranded Honest Audiophile. Dave reviewed them first, sent this set to DMS first, and it looks like I’m next in line. And, I don’t really care about the graphs or the marketing, I just care what they sound like, as some have claimed that these are better than a 600 series Sennheiser… So, the Ollo S4X… Let’s get InToit!

The build of the S4X has its upsides, but it ultimately leaves a lot to be desired. Let’s start with the cups. I like that they are wood, and opened-back. But, I’m unsure why they are so small. These are basically on ears, and because of this they do become uncomfortable after a period of wear, as they press on the upper or low portions of my pinna. The clamp isn’t bad, and it’s better than other headphones, but they still hurt after about half-an-hour. The pads are solid leatherette on the outside and the inside, and have a velour material on the portion touching your face. They’re nice and soft, but again still lead to discomfort after a decent period of listening.

The cups themselves can also swivel fully, and applaud this move by Ollo, as it allows for comfort adjustments, and for one to lay them flatly, in any direction. The headband is comprised of a tension, suspension strap, composed of leather tongues and soft, textured, rubber strap, and an anodized, black steel frame. While the strap is comfortable, the frame is extremely microphonic. I have seen pictures of other headphones by Ollo utilizing a different frame, which seems like it would be less microphonic, but it is my understanding that these are microphonic too. I would have preferred for Ollo to use something like a nitinol fame here to cut down on microphonics, and to enhance the premium feel of this set.

2.5mm TRS connections are utilized at the cable’s initiation points, and the single-ended cable that came in the box terminated in a 3.5mm TRS connection with a quarter-inch adapter, and was similar to New Fantasia cables, which one can buy off Amazon for approximately $17 bucks. Given the price of this set, at 399 Euros, approximately $486 dollars at the time of this review, I would have expected a more premium build from both the headphones and its cable.

But, what about the sound? Ollo claims that the S4X are “Reference Headphones;” indicating that they are relatively neutral and could be used in mixing and mastering applications, in addition to audiophile ones. However; after hearing them, I think this is a bit of a stretch, for a number of reasons.

To begin with, on solid-state amplification, this isn’t the most resolving set. There is significant grain, and that grain is significantly amplifier dependent. While it was the best for solid-state off the THX AAA 789, I still expected better performance in the clarity department for a reference set. And, oddly, after trying the S4X on a number of different sources, I found that the resolution of the S4X was surprisingly best on tube amplification in comparison. As most reference level gear used in mixing and mastering applications will generally be of the solid-state variety, I consider this finding to be both concerning and counter indicative of this headphone’s intended purpose.

In further contradiction to the intensions of its designers, I found the S4X to be too thin in its presentation, slightly too bright in its tonality, and too far forward in its upper mid-range and other areas of its frequency response to be considered reference or used effectively for mixing and master applications, especially over the course of the day. In consideration of the latter, this is a problem as it pushes vocals, electric guitars, and brass instrumentation too far forward in the mix. Vocals and instrumentation of this type could come across as pretty shouty, harsh, and strident on occasion; and if one was mixing with this set, they would most likely lower these parts of the mix too much in the final product, that is, if the S4X was used as their reference.

So, while I don’t think this is actually a headphone that has been designed well for its intended purpose, due both to its build and sound, I do not necessarily think that it is a bad headphone either. I actually quite enjoyed the S4X off of my DarkVoice 336. I preferred it most with a Japanese Raytheon in the pre-tube slot. This tube mellowed it out just enough to increase enjoyability, and like I’ve already said, it also actually increased the S4X’s resolution overall.

With further regard to timbre, I do not want to give the impression that the S4X is overly bright, as it does come across as a relatively flat signature for the most part. My issue with calling it holistically flat, is that there are some dips and peaks, here or there (mostly in the upper regions of the S4X’s frequency response), which do come across as aggressive when they occur, and are on the brighter side of neutral. I think whoever is tuning this set, is mistaking mid-forwardness and treble extension for detail, and allowing things to go a touch overboard for a neutral or reference set. For instance, on well-recorded hair metal tracks, the S4X was exposed at times, and came across as overly hot in its delivery. Instead of turning things up to 11, the S4X kind of takes them to 12, at least.

Needless to say, I did not really find a problem with treble extension here, and there is decent treble detail, even if it is somewhat harsh, aggressive, or grainy in its nature, at times. There is good air on this set thanks in part to this extension and its seven-and-a-half-K dip, which seems to result in a certain sense of spaciousness in combination with its slight elevations in other mid and treble regions.

So mids were also mostly articulate and representative, but there is a dip at around 3K, which may also contribute to some thinness in the mid-range as well. Particularly in the lower mid-range. So, male vocals in the lower ranges were less forward than female vocals in the upper ones. The takeaway here is to be aware these do present in a leaner fashion, especially in comparison to what I would expect from a reference set. With specific comparison to Sennheiser HD560s, both headphones have rather leaner presentations in the mid-range, but the S4X is even leaner, and somewhat more forward than the 560s.

If I appreciate anything about this set, it is its bass performance. The bass here is relatively linear, and extremely coherent. It is never overdone, and blends extremely well into the rest of the mix, while also having enough presence and control to express bass detail and articulation to its listener. While I did find the mid-range and treble presentation of the S4X to cause listening fatigue over the course of long listening sessions, the bass never contributed to any weariness. Having said that, it is not the tightest or fastest bass, and there is some mild diffuseness to be aware of. Sub-bass representation is decent, but it does roll off. And, neither transients, nor micro or macrodynamics are class-leading, but I do find them to be sufficient for mixing and mastering purposes. They won’t wow you on rap music or hip-hop tracks, but they are more than sufficient for rock-and-roll, blues, and jazz genres. To tie it together, regarding the low-end of the S4X, I find its bass representation to be relatively well-distributed, and extremely coherent in its character, even if it isn’t the fastest and lacks the slam and impact necessary for some genres.

Stage width, is slightly about average for a monitor, which is nice. Depth of field isn’t spectacular, but again, for a monitor, there is decent depth to this set, and the image is somewhat 3D in its general presentation. The S4X also images fairly well, tracks smoothly, and accurately represent instrumentation for both placement and distinction. Separation isn’t striking, but it is better than a lot of other monitors. Decay was not a particular strength of the S4X, but peripheral decay was better than the rest, which added some much-needed ambiance here or there on particular tracks. Peripheral detailing was also, at least, on par with the rest, but again, this was somewhat source dependent.

So, let’s tie a bow on this one. The Ollo S4X is a boutique product with a boutique price. Unfortunately for Ollo, at this price, I don’t think the S4X is really worth it, even for a boutique item. If I were assigning a price to this set, I would say it’s probably worth approximately $300 USD, given both its build and sonics; especially considering that one can obtain an Sennheiser HD560s for $200 or less at this point in time. While the 560s can’t really keep up with the S4X in terms of the type of quality materials used, it’s certainly more comfortable, and during my testing, whenever I thought the S4X might beat out the 560s, I would A/B the two, and I always preferred the 560s between them- no matter their source.

So, the cheaper headphone is, at least, on par with S4X in terms of its performance. After some thoughtful consideration, the microphonic headband, limited cup size, on-ear discomfort, and fatiguing sound profile suggest going with another set as a more capable natural reference, unless you’re in the market for a flawed boutique headphone at a boutique price. And with that, I’m out… for now!

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