Introduction and acknowledgement
The R1 Zenith is the sophomore outing from UK based IEM manufacturer IMR Acoustics, following on from their well received R1 model. The Zenith is a revision of the original rather than a completely different beast, sporting an improved design and some refinements to the unique tuning and porting system that the R1 was built around but keeping the hybrid driver configuration from the earlier model. This may only be an iterative change, but in raw design terms, the Zenith feels about as close to the R1 as a Porsche does to a VW Beetle.
The Zenith looks and feels more refined, sporting a much more advanced port mechanism, opening or closing with a screw mounted mechanism mounted on top of the driver enclosure. The Zenith actually looks very similar to the higher end models from Japanese manufacturer Acoustune, with an industrial but still attractive vibe. This definitely isn’t an IEM that blends into the background, and for me the revised design held the Zenith position itself as a more serious contender in the very competitive mid-fi market.
These IEMs were kindly provided free of charge by Bob at IMR for the purposes of review – as always, the views expressed here are 100% my own, and there has been no input or incentivisation from the manufacturer for a positive writeup. I would like to thank Bob for his patience, as it has taken far longer than I originally thought to get this review out (real life has a nasty habit of getting in the way of my more fun hobbies at the moment!). Also, it is worth noting for anyone who has been reading the Head-Fi threads about these IEMs, there were some initial QC issues with a small batch of Zeniths that were sent out to the “first adopters” (including myself as a reviewer, although my unit was only sent once all the pre-ordered units had been sent to paying customers). Rather than ask for the IEMs to be returned, IMR have sent out replacement units to all affected users, and implemented a tighter QC check on the relevant issue to ensure that it doesn’t affect any future models. As far as customer service goes, it was a pretty swift and thorough response, so kudos to Bob & Co for turning what could have been a sticky issue for their second release into a good example of how customers should expect to be treated.
The Zenith come in a nicely designed and fairly compact presentation box, with the IMR logo and model name on the cardboard sleeve surrounding the main cardboard box. The rest of the exterior is fairly minimalist – sliding the cover sleeving off reveals a fairly standard black presentation box that opens in a clamshell style to reveal the IEMs in a bed of black foam. Pulling this layer out reveals a further layer containing a large IEM case (with IMR branding), the removable tuning filter in their metal storage block and a selection of silicon and foam tips in various sizes. Peeling the final layer of the orange, opening the IEM case reveals two detachable 2-pin cables, provided in both 3.5mm single ended and 2.5mm balanced configuration.
Overall, while the presentation isn’t quite at the level of some of the high end manufacturers like Astell&Kern or Apple, it definitely gives a nice feel of quality with both the visual appeal and the quality and range of included accessories. The addition of two cables is a definite plus, giving most users the choice of using the stock cable in either format with their favourite sources straight out of the box.
Build quality and design
The Zenith feels like a decent step up in both design and manufacturing quality over the previous model. It sports a more robust anodised gunmetal finish and a much improved aesthetic appeal, replacing the previous flat metal tuning port with something altogether more appealing, adding nice finishing touches like a knurled grip on the opening screw and a more visually striking overall shape.
The tunable nozzle system from the previous model is still here, providing five differently coloured filters to adjust the overall tuning. Each filter has a slightly different venting and damping, and all the filters on my set are nicely machined and solid fitting. From a personal perspective, while this isn’t as many options as something like the FLC8s or LZ A4, I think 5 is probably the sweet spot for this type of IEM. Each filter choice is different enough to merit inclusion, and avoids burying the listener in a sea of sameish sonic choices for the sake of it.
The Zenith maintain a similar size to the original R1, which is somewhere between the coffee been shape of a Westone or Shure IEM and the “pseudo-custom” shell design that is becoming increasingly popular with brands like Ibasso. It has a slightly raised profile on its predecessor due to the new screw mechanism for the porting, making these stick slightly further out of the ears than the original. As such, they aren’t great for laying down on your side in bed and listening, but don’t stick out far enough to be noticeable for day to day use.
Fit and ergonomics
In terms of material, the Zenith is an all-metal affair, with a lightweight aluminium shell that feels solid in the hand but not weighty. The inner edges are nicely anchored and rounded, so there are no notable hotspots or sharp points to dig into the ear, allowing them to be worn for multi-hour listening sessions without any issue.
The nozzle is diagonally angled at about 30 degrees to the main shell body, to allow a more ergonomic fit. This doesn’t quite work for me as I have very large ear canals (and also ears), so the angle is just a few degrees away from being perfect, requiring the use of foam tips to get a solid and stable seal, otherwise the Zenith requires periodic adjustment. As noted, I have particularly cavernous lugholes, so for the average listener I suspect the shape will work better, as the inner face of the IEM should lay flat against the bowl of the ear to provide support.
The supplied cables are a rubber coated affair, with a moderate thickness and an understated right angled jack at the connector end for both balanced and unbalanced. The design is reasonably ergonomic, with the springiness of the previous model’s wires largely eliminated. They are coated in some sort of rubber, but don’t exhibit any particularly bad cable memory, so are easy to despite over the ears. As the cabling is pretty lightweight, you will need to use the neck cinch to “lock” the cables underneath your chin to avoid one of the loops behind the ear working its way loose over time, but given the manageability and quality of the build, that should be a small price to pay.
I have seen some opinions already about people not liking the rubber cables, either from an aesthetics point of view or because of the lack of ear guides or memory wire. Personally, I think the cable design suits the overall vibe of the Zenith very well, and I can’t stand memory wire in any form, so they are a perfectly matched inclusion at this sort of price range for me. I will be testing a few other cables with the Zenith in my follow-up review.
Initial impressions on sound
If you’re still here, you probably want to know how these things sound. Quite simply, these sound excellent. The Zenith take the foundation established by the first model and make some subtle but important tweaks to the sound, pushing it into a new tier quality-wise. I will be diving into the full effect of the various filters and porting system in my follow-up review, but for simplicity here I am basing the bulk of my impressions on the use of the black filters that come preinstalled, as these are my current favourite so tend to get most of my listening time. Likewise, most of my listening was done with the stock IMR balanced cable, my Cayin N5IIs and some Flare Audio “Audiophile” foam wide bore tips.
The tuning is something between a U and a W to my ears with the black filters installed. There is excellent extension in both ends of the frequency spectrum, with the bass staying flat all the way down to sub-audible frequency, and generating some serious home-theatre style rumble on the right tracks. The mids are a touch more present than on the previous R1 model, with a little peak towards the top of the range that pulls the vocals a little further forward on the stage. This can make some vocal tracks sound almost sharp, but it generally steers clear of harshness or unpleasant spikiness, giving the signature a vivid but not overpowering midrange slant. This emphasis also helps the mids cut through the bass cleanly, with the R1Z managing not to swamp the finer detail in the mid area under the bass. Detail is pretty high across the board, and while this won’t approach something more ultra-analytical like some of the Jomo or Empire Ears all-BA models, there is definitely plenty of resolution for the price bracket.
Tonality is more vivid than natural, evoking the feeling of an HD TV set with colour saturation set to maximum. This isn’t a plastic or metallic sounding IEM, but there is definitely a stylised presentation that comes from the big bass and sculpted midrange. Lovers of ultra-realism probably want to look elsewhere, but if musicality and “pop” are what you are after, the Zenith is bang in the middle of your sweet spot.
Bass is big and voluminous, the 14mm beryllium driver moving some serious air in the inner ear. In its “black” configuration, this isn’t a signature for the bass-shy, with some serious low end being presented when called upon in the music. Despite the volume, this isn’t the overblown or boomy sort of bass that can give bass head monitors such a bad name, presenting in a full bodied but tightly controlled manner, with plenty of precision to go with the power.
Compared to the original R1, there is slightly less quantity overall, but the improvement in both texture and detailing is definitely worth it to my ears. There is a sense of scale and fullness to the sub and mid bass coming from the big 14mm driver that gives music a “live” feel, evoking the same sort of feelings I get when I listen to something like the Campfire Audio Atlas. This can of course be flattened out with one of the more neutral filters like the blue, but for me, the full throated roar of these drivers kicking out serious low end makes up some of the unique charm of the IMR range, blending head pounding levels of impact with high quality texture and detail to give a full but musical foundation to whatever is playing.
Diving straight into my demo tracks, listening to something like “The Name Of The Game” by The Crystal Method sounds positively massive on these IEMs, the distorted baselines filling the soundstage with a guttural and glitchy pulse that pins the floating electronica above it firmly to the ground. “Beat It” by Fall Out Boy is similarly weighty, the opening drums feeling thick and solid, each hit placing itself with precision in the ear, the kit feeling like it is attached directly to the back of your skull.
This isn’t a subtle IEM by any means, but that doesn’t mean it is isn’t capable of delicacy when required. The pounding drums of “Bad Rain” by Slash hit HARD in the ear, but the grizzly bassline that accompanies it is packed with texture and clarity as well as raw decibels, resolving tiny textural cues and detailing on the surface of the full-blooded notes underneath. Whatever is there, it will bring out, from the lowest sub bass up to the midrange borders. The additional decibels on the black filter will accentuate any bass present in a track, but it doesn’t conjure up heaps of bass where it isn’t already there in the mastering, keeping enough control to play nicely with more acoustic fare, contenting itself with just warming the underneath of vocal lines and acoustic guitar strums rather than flooding the floor of the sound with omnibass.
Switching up to a more acoustic vibe, “The Wild Swan” album by Foy Vance has plenty of gentle electric and stand up bass peppering the more laid back tracks, and the Zenith does just as well slipping on a smoking jacket and lounge slippers as it does belting out the more grizzly rock beats. The bass lines of “Coco” and “Noam Chomsky” both slide around the ears with a nice blend of richness and thump, picking up the slowly resonating stings and the deliciously smooth texture of each note. Ditto for “Hello, It’s Me” by Sister Hazel, the sumptuous bassline in the intro sounding thick and velvety rich, but remaining viscous in the ear. The texture is palpable, with the strings resonating into the background of the track. This is slightly overlaid with the sheer volume of the bassline, but never drowned out, treading a nice line between detail and density. It doesn’t feel massively detailed in comparison to some leaner all-BA monitors I have listened to, but when you actually compare side by side, the detail is all there in the sound, just wrapper around a more solid body of sound. The clarity is understated, which is quite ironic given the rest of the low end tuning, but this makes a nice surprise when the Zenith beats you over the head with another pumping bassline and then flashes something past your ears you haven’t picked up on your other gear at the same time.
In summary, this is bass for the audiophile bass head – there is plenty of air movement and punch courtesy of the 14mm DD driving things along, but there is also a good amount of detail and control underneath all the quantity. It still has all the classic traits of a DD bass, and definitely won’t match an all-BA setup for raw speed, but the natural feel to the decay and the resonance of the sub-bass notes just feels right in the ear. This is very well done bass for those who like plenty of it, and it may even convert a few who traditionally don’t.
The midrange on the black filter sits just a shade behind the bass in terms of stage position (if not in quantity), sitting at the top of the middle upstroke in the slightly slanted “W” shaped tuning this filter is going for. It isn’t the most natural sounding midrange out there, but it doesn’t aim to be – this is tuned to provide a sharp splash of sound designed to cut through the wall of sound coming from underneath it and introduce some needed air into the stage. Vivid is the word that best describes it – harking back to some of the early models that Bob @ IMR tuned for Trinity Audio, it reminds me in tonality of the Trinity Sabre (their original push/pull dual DD model). It should go without saying that the Zenith is an order of magnitude (or two) more accomplished, and a damn sight smoother, but there is a faint memory of the almost hyper-real tint the Sabre used to give to the sound when I first heard it.
The mids are slowly tilted upwards as they travel, reaching up to form a peak somewhere near or just over the treble border. This peak adds a dash of sharpness and emphasis near the sibilants in a track, but are sufficiently warmed by the bass underneath not to sound harsh. This definitely isn’t a monitor that will be ultra-forgiving to poorly mastered or overly hot tracks due to this tuning, but feed it good quality sound and it puts out a sweet and slightly spiky midrange sound. Vocals hold the high ground here, pushed just slightly in front of the other instrumentation, impressing themselves on the forefront of the listener’s soundstage. Guitars and other midrange instrumentation flare out backwards from the singer across the large stage the R1Z constructs, with plenty of crunch around the edges and a meaty undertone to everything as the bass fills in the gaps.
As mentioned previously, this isn’t the most accurate IEM in terms of timbre, but what it lacks in realism of tone it makes up with with energy and a decent dose of detail (3D, anyone?). There is still an organic tint to the sound (mainly due to the warmth imparted by the bass), so it doesn’t feel overly metalllic or processed, but you definitely know you are listening to a set of earphones and their own interpretation of the sound. This style of tuning lends itself particularly well to rock and guitar based music, putting down some seriously chunky riffs and crunchy edged guitar breaks without breaking sweat. Feed it “Dude (Looks Like A Lady)” by Aerosmith, and the jangling Perry and Whitfield guitar breaks fizz around the edge of the stage, full of energy and snap. Flick over to something a little more downtuned, and “We Die Young” by Alice In Chains practically oozes out of the nozzles, the guitar feels so sludgy and thick.
The Zenith treads a careful line between weight and crunch, maximising both for an energetic and crisply detailed sort of sound. There is an almost sweet tint to the way acoustic guitars are rendered, swapping some of the bludgeon for a thick and weighty tone that works really well with more melodic acoustic fare. Play something like “Dimming Of The Day” from the Alison Krause and Union Station collaboration, and the mixture of Krauss’ ethereal vocals and the layers of hand-picked guitar almost make me drift away, the sound is so inviting. The dynamic shifts in the song between the quiet and loud guitar phrasing and the lilting vocals highlights the control that is in play with the huge 14mm beryllium driver, keeping a tight and very musical grip on the song that fills the ear but doesn’t overpower the listener. Background detail is noticeable here, with scuffing and plucking of strings and the breath and the formative sounds of the singer as she phrases each line are clearly heard in the back of the presentation.
The Zenith is rated with a theoretical extension up to 40KHz, with the high ranges being taken care of by the ceramic plate that forms part of the hybrid driver array. This gives the R1Z impressive extension on paper, and while it doesn’t necessarily sound like the most treble-heavy IEM you will ever hear, there isn’t a noticeable roll off as the sound rises, remaining stable all the way past normal hearing (or mine, anyway). Ceramic drivers aren’t always known for their smoothness, but the plate in use here blends extremely well with the main DD, produces a seamless and buttery smooth tone right up into the highest registers. Listening to “Chi Mai” by Duel, the solo violin is surrounded by a flickering sea of high synth notes and sparkling little flashes of sound. The Zenith paints these with delicacy, subtle cymbal taps and other incidentals hanging in the air above the rich sound of the violin as it hits the high notes. Notes sit somewhere between thin and average in terms of size, but are presented solidly rather than with a jagged or edgy tonality. There is a subtle sense of weight to the underneath of the notes that stops the notes from sounding too crystalline or sparkly, but adds heft to the cutting edge above rather than blunting the sound. I think the phrase “crunch” sum is it up best for me – there is a sense of fizz and anima to notes that clearly defines the edges without losing the sense of body.
For the black filter, the treble sits a little behind the mids and bass in emphasis, adding a little breathing space to the top end of the sound but not feeling overly sharp or emphasised. If the treble on something like the Andromeda feels like a highly polished rapier as it slashes about a track, the black-nozzles R1Z feels more like a battle axe, adding a finely-honed cutting edge to the boom and bluster underneath as it cleaves through the thick air underneath. Guitar harmonics have bite and weight at the periphery of the notes, lingering just long enough to open out in the ear. “Starlight” by Slash opens with its customary dissonance, the harmonics of the guitar lines hanging thick and fat in the air. Myles Kennedy adds his multi-octave vocal to proceedings, and again the sound feels thick and edgy, but never hot, his helium-tinged vocals holding ground against the fat bass and chugging guitar without crowding the track.
Similarly with violin, the haunting “Chi Mai” by the new-classical duo Duel (try saying that after a few drinks) feels rich but pointed, the violin cutting through the swirling soundscape and giving an almost vinegary tang to the track as it brings the notes to a focus in the ear, without pushing undue unpleasantness or harshness into the ear. There is a synth and triangle style accompaniment to the track that is delicately presented across the top of the soundstage, sitting behind the more prominent violin strokes and adding delicacy and froth to the heavy notes of the bass and sweeping orchestral movements beneath. I’ve heard darker and smoother renditions of this track, and also lighter and more ethereal versions with other gear – the R1Z strikes a bolder and more muscular path, giving the treble weight and edge enough to resonate but not enough to become the dominant frequency range. Like the bass, there is detailing and nuance aplenty if you listen out for it, allowing the Zenith to push out plenty of more subtle audio cues like room reflections and scuffed micro-details in your well known tracks, without pushing the emphasis way up in the mix.
There are certainly filters that certainly make the most of the treble capabilities of this unusual hybrid driver, so for the treble-heads out there, something like the blue filter will probably be a much better selection. That said, even with the black filter, the Zenith never feels undercooked or lacking up top. The capability of the ceramic transducer to push some seriously weighty volume without harshness is a testament to the thought and capability that has going into tuning these IEMs, and for me, sits pretty close to ideal for the overall signature of the black filters.
Stage, separation and layering
The original R1 was famous for having a stage that was about as large as you can get with the limitations of an in-ear device. This was helped in part by the semi-open nature of the construction, so it is no surprise to find out that the Zenith has inherited the staging capabilities of its predecessor. I find soundstage very difficult to accurately assess in terms of exact difference between different IEMs, but to me, the Zenith has a slightly smaller stage than the R1, but only marginally. This is likely caused by the relatively closer positioning of the mid-range in the stage in the newer model, which just pulls a little of the original scale back towards the listener. Either way, the Zenith stage is still huge in IEM terms, and the slight boost in the midrange adds a little size to the instrumentation as a trade off, so the sound feels just a little “bigger” in my mind. In fact, the R1Z evokes comparison with the Campfire Audio Atlas in this regard, throwing an audio image out where all the component parts seem a little larger than life compared to other IEMs in my current collection. The tuning port also helps in this regard, with the open setting letting out a little of the bass heft, airing out the stage a little more in all directions and giving a slight expansion to my ears. This is still an in-ear monitor, so the difference isn’t night and day – those expecting the same sort of transition you get going from closed to open back headphones will be somewhat underwhelmed, but as an additional piece of tuning flexibility, this will definitely help the R1Z appeal to more listeners.
Separation and layering are both highly technically proficient, with the Zenith throwing a wide and clearly defined stage, relying on imaging rather than artificial width to keep the instruments from blurring into each other. As mentioned, the note size is quite large here, so there isn’t a huge amount of black space between each musician – there is noticeable room around more delicate notes, but with busier tracks the Zenith feels more like a high-def wall of noise than a sparse jazz club in terms of how it presents the stage to me. “Coming Home” by Sons Of Apollo has all the sweep of the drum fils moving across the back of the skull in easily distinguishable sections, building all the layers of sound up cleanly while still keeping that “at the gig” sense of hugeness and cohesion that really blasts the song into your eardrums. Playing something more sedate, “Trouble” by Ray Lamontagne resolves the hard panned instruments into the outer reaches of your eardrums just like the track is designed to, the bass sitting fully in the right ear, and the bass drum and rimshots feeling like they are coming at me diagonally from behind my left ear. The size of the notes really helps the song come alive on the Zenith – on some IEMs I own, the hard-panned instruments can spread the track out to thinly, feeling like a widescreen but very flat art print. With the Zenith, there is more of a spherical sense of space and placement, painting a big but more realistic sonic picture of the band as they recorded the track in the studio.
Overall, this isn’t an IEM that will immediately blow you away with how far to the left and right it can push a note, but when you sit and listen, you appreciate just how well it positions everything on the stage, and just how natural and precise it feels.
Synergy and power requirements
The R1Z isn’t an overly thirsty IEM, given the relative size of the dynamic driver it sports. Reasonably unsafe listening levels can be achieved from a mobile phone or other bog-standard audio device, so amping isn’t strictly necessary from a purely volume-based perspective. That big ol’ driver does mean that the Zenith can happily suck up any spare juice that gets sent its way, however, so plugging it in to sources with a higher power output will usually result in a slightly grippier feel to the low end, with the extra voltage allowing the driver to reach its full capability. It also isn’t a particularly forgiving IEM, despite the heavy bass presence, so the cleaner the audio signal, the more your ears will appreciate the output.
In terms of gear matching, the R1Z seems fairly agnostic to source, not exhibiting noticeable hiss with any of my equipment and retaining a similar tuning across the gamut. My favourite pairing so far has been the Cayin N5IIs running balanced, the clean but weighty notes of the Cayin complementing the general tuning of the Zenith to provide a detailed but rich sound, with plenty of life and musicality. The DX200 / Amp 8 combo runs it close, but the slightly more spacious Ibasso actually makes the R1Z sound a little more diffuse to my ears, taking the already large stage and pushing it just a little further out in all directions – this might be just the ticket for fans of large sound stages, but I don’t think the Zenith benefits massively from the extra help in that regard for me. I also wouldn’t pair this IEM with particularly thin or treble-heavy source, purely as this will bring the high-mid push a little closer to harshness, but again, that’s just my personal preference.
This is usually the section where I compare the IEM in question to other gear in my current inventory and try and draw some comparative notes out. Given the chameleonic nature of this IEM and its multiple tuning filters, that will follow in more detail in part two of this review, as I need more time to match the right comparison to the right R1Z filter and port setup.
As an initial knee-jerk, the R1Z has comfortably gone toe to toe with both the AKG N5005 and Dunu DK-4001 in terms of both sound quality and technical ability, placing itself firmly in the running for the sub-$1000 bracket. It won’t be everyone’s ideal tuning, even with the multiple options on board, but the simplest thing I can at this stage is that I don’t feel I am missing anything when I switch from other IEMs I have in my rotation, but when I switch back the other way, I do get pangs for that delicious bass and vivid midrange. Time will tell if it can sit at the same table as IEMs a little further up the chain like the Campfire Audio Atlas or Solaris, but initial impressions are that it won’t be a million miles away for my preferences (certainly to the Atlas).
The Zenith is marketed as an improvement of the original R1 model, and when compared side by side, I think that generally holds true. It has toned down the bass a little from the frankly insane capabilities of the original, but the trade off of quantity for a markedly higher level of detailing and control is definitely worth it. Similarly with the midrange, there is a different tone to things there, and some may pine for the old smooth as butter R1, but again for me, the increased engagement and detail is worth the slightly edgier tone. This isn’t a harsh or spiky IEM when you keep it well fed, and the additional touch of sweetness really helps to create a balance to the sound.
Add in the much improved machining and design of the vent mechanism and an overall uptick in build quality, and the Zenith definitely punches its weight when looked at in the current marketplace. The cables will be a bone of contention for some, but again, they are markedly less awkward than the first iteration, and the fact that a balanced AND a single ended cable are included as part of the standard package should definitely be commended.
Looked at purely on its own, the Zenith would certainly be an IEM I would be happy to recommend to people looking for a bassy but sweet sounding dynamic driver style sound. Add in the multiple tuning options and accessory package, and the fact that it manages to improve on almost all aspects of the well-received original model, and it becomes even more of a no-brainier. The specific sound choices and style of this IEM won’t be for everyone, but if you get a chance, your ears may seriously thank you if you do decide to give these beasts a listen. As mentioned, I will be delving further into each of the filters in part 2 of this review, so I will post my final conclusions along with the usual Audio Primate ratings and specs there, but as far as initial impressions go, these are a pretty big statement of intent from IMR, and a definite step up into the next league of sound reproduction.