Planar, dynamic, electrostatic drivers. We all attribute various traits to each technology and are biased in our own ways in how we expect them to sound, what technical achievement they are capable of and yet we’re always hoping to be proven differently to get out of our expectation bias zone and while sometimes we are proven wrong and are succinctly happy about it we mourn the fall before perfection yet are also happier than ever. We can really be a bunch of hard to please crazies, but the diversity of today has left us in a better place than ever before. There’s a top of the line headphone for basically every acquired taste.

Over the years, each of these driver technologies spawned contenders who emerged into a superclass and have all qualities that are not easily found in their competitors or even absent. The Utopia for its speed and resolution, the Abyss Phi TC for tactility, slam and the sensation of almost “being there”, the Susvara for timbre, tonality and the pursuit of complete euphony and among them juggernauts like the SR009S and of course the ever so marble stoned HE-1.

From time to time, different driver technologies or ideas of projecting sound into our ears appear like a flash and are gone as fast as they entered the stage, went EOL, into the unknown or simply stayed rare and absent. Piezo electric systems like the Taket H2+ for instance. The AKG K1000 or a few hybrids like the Dharma. Though to be fair, the K1000 wasn’t a flash of an appearance and had a fair run but simply wasn’t pursued as a concept for a long time only making a “comeback” in the form of its lead engineer releasing the MySphere.

Ideas and concepts always come and go, there’s still plenty to innovate and to explore thankfully as understanding and utilising human hearing is a vast, wonderful space of many exciting things to come. Yet after all these years, wouldn’t it be nice to have a technology to enter the headphone game and potentially shake it up quite a bit? Something more radical than just a bit better resolution, slam and imaging?

Well, enter the RAAL-requisite SR1A. A headphone that will surely change the landscape for both its bold design and its excellent and absolutely unique performance.

RAAL-requisite, based in Serbia and California respectively, is very well known for their world-class aluminium based ribbon tweeters and over the course of the last few years they managed to mold a headphone driver out of exactly that renowned design, deep in the fires of their forge. Requisite has been building professional recording equipment for top producers and engineers for over 30 years now.

RAAL-requisite actually calls them earfield monitors and like the AKG or MySphere these immediately do away the usual difficulties of headphone design like reflections, resonances, acoustic impedance of earpads etc etc. Sure, they all come with their own weaknesses, especially shared at one common point, but we will find that out later in this review how these are minimised here more than ever before.

Like the AKG and the MySphere, these earfield monitors are not resting on the sides of your head but instead angled nearby, hanging in the air, and boy, what they do with the air is something really special. No, not special as in being “just” another TOTL that rests among its equal peers to serve a different taste.

No, the SR1A are actually game changers that present and render music in a way that no other headphone does today. Far and away from any post honeymoon period, their initial shock and awe did neither wear out nor did it shake off through brain burnin. Whenever I came back to them from other headphones, their biggest strength: all-encompassing sensation, tactility, speed, clarity, precision and reference class resolution took me immediately over and hooked for hours and hours. Is it this perfect? Yes, and no.

Let’s get the build, looks and ergonomics out of the way so we can go to the meat of this review and find out.

Looks, build, ergonomics:

If the dark side was to build a headphone, it would look and feel like the SR1A. Bold, menacing, durable, sturdy and easy to service if a part would need a replacement. In fact, this quality aspect of the SR1A is a very welcome change in the age of glued pads, headbands attached with far too delicate screws and similar hard to self-service parts. You can even change the drivers themselves in case of blowing one entirely on your own by just replacing the existing cartridge with a newer one. You might even stitch, cut your own material to replace the existing headband by just poking appropriate holes into them. How great is that?

The overall design isn’t hung up on the last artistic detail or the last word in terms of material perfection through employing automobile design craftsmen like certain manufacturers do but it makes up for it through robustness as they don’t feel like breaking easily or falling apart. Something a lot of high end headphones lack.

Not that you should throw them around anyway and even if you wanted to, you would first need to get them off your head, which at the point of running music through them would be quite the herculean feat.

Ergonomics and general fit leave nothing to be desired honestly. You can wear these for hours and hours and not get any hotspots, pressure points or any other banes from the headband world.

Now the fit is a whole different game. These being earspeakers that do not touch your head at all, requires a bit more experimentation than your usual headphone experience taught you so.

The RAAL driver enclosure swivels up to 360° giving you plenty of possibilities to project the sound towards your head. Now:

Carefully choose the angle of each side relative to your head to give the imaging the best space to expand and stretch and try to find the sweet spot between the extremes of blurred, blended imaging when the drivers are to close to your head and the oval, very wide-stretched stage similar to the K7XX AKG headphones, just without the hole in the middle of the image.

Give yourself all the time in the world to find exactly that spot and get rewarded with the best staging and imaging in the business. I just mildly spoiler’d the review a bit, yes, but getting the right fit will make sure you can reap all the benefits this headphone is ready to unleash.

sound impressions:

Do you remember the moment when you put on a great headphone for the first time and what it did to you and all your senses? Remember the smiles, the joy, being impressed, the tapping of toes, the strange sounds you might have made out of sheer happiness? Everybody reading this had such a moment. Sometimes it wore off after a few hours, days, weeks as more or less glaring issues came up like overly excited treble, mid-bass bumps that give you a headache, too thin mids, lower mid dips, strong upper mid dips, etched treble and so on.

Now, if you‘re at a point when you listened or know most of the headphones I mentioned at the beginning, you’re far less likely to impress than compared to your earlier days. No, you’re not getting old. You’re just not easily tricked anymore and time flies faster than ever before, so you are pickier than ever and less likely to impulse buy or follow flavors of the months or general hype. Yet here I am kinda hyping all this up, but it is really worth it, I promise.

First things first:
soundstage, imaging, placement of objects in the space

The SR1A’s soundstage is second to none in size and depth and especially how it is created around your head encompassing you with the music, the instruments, the air, the positioning of every object, the vocalist’s breathe and vibrato and all the tiny stuff that you might want to hear or not but is there in the recording adding to the live quality, the “being there” or presence. Everything is there, stable, not fuzzy, not warbling, solid center image. Compared to usual headphones the “speaker-like” moniker is much more at place here than say the Abyss 1266 Phi TC or similar staging wonders. All are not only dwarfed in terms of sheer size, height but also in how everything is illuminated, placed and rendered in precision and sharpness. It truly is a remarkable achievement and this is thanks to the absolute speed of these headphones due to the ribbons being able to start and stop almost immediately, leaving no trail behind – the advantage of having very low mass and also tight control. Transient speed, transient attacks and decays happen so quick and yet so tactile you get a physical sensation of this experience. It is hard to describe.Think CRTs vs LCDs where the superior stop and start of the CRT is still superior for motion resolution and clarity. Sure, an LCD can pack 4K now but CRT technology has just been discontinued and the speed difference still stands. Now think of the gap being even wider. That’s where the SR1A resides. They kinda make other headphones feel slow and almost sluggish.

It is both extremely fast and yet doesn’t blur the tiniest detail or texture. It‘s all there, drawn as if a lightning bolt would draw into the night sky, sharp and illuminating. It really is impressive how it can be so fast without any blur yet also be tactile and far from any softness or smear.

Now as for how the stage is drawn for the listener, think of a blend of a pair of speakers that is kinda infront of you and the usual headphone experience of top of the line contenders like the HD 800. There is a good amount of frontal projection giving you plenty of believability of having a speaker like experience. The illusion is not quite there yet, but it is closer than ever. There are very few headphones being able to deliver that frontal projection, but they all fall short of the SR1A.

tonality, frequency response, timbre:

In general the RAAL is dead serious in being neutral and flat and consistently so, to the utmost end of the treble especially. Combined with the consistent delivery of energy or should we call it barrage (in a good way) it is not a relaxing headphone at all. The treble while not elevated to the point is ruler flat and can potentially cause issues for listeners who are used to rolled off treble like Audeze LCD-2, Empyreans, HD 650 or generally warmer gear. In any case pairing with amps that are not ruler flat or dead neutral is advised for long term listening and to counter the slightly leaner, whippier character. While not thin or lacking the overall tonality is not an experience full of meat and bones, more athletic, highly agile and especially reactive.

micro and macrodynamics, transients:

Tiny volume variations and gradiations and large variations of the whole musical context are essential in how we perceive and “absorb” music it’s what makes us move and connect with the music or let’s say dig into it as the dynamisms involved there define the emotions the music creates. What sounds like a lot of poetic words is in the end one of the most important traits you should look for in a headphone.

Given the good run the RAAL already has during this review, I’ll just let you know how absolutely great it behaves in this regard. The SR1A never subdues or even suppresses tiny variations into the background and is always up to the task in resolving them fully, giving them space to breathe and fade out. And given the larger picture, it can slam on point and slingshot hard into the space with tactile, snappy transients, like a fiery whip lightening up the darkest of nights with loud cracks, highly dynamic and in high contrast.

Bass quality, quantity and character:

As for the entire frequency spectrum, these ribbons do not lose grip on the technicalities and control they bring and unleash into the sound space on any part of it. Only from around 30Hz on downwards does the bass lose the battle of physics.

Bass goes down to around 28-32hz and rolls off from there, reminiscent of the legendary HD 800. And in similar ways to the Sennheiser, yet superior in every way all bass until that point is marvellous, clean, hard hitting, of high resolve and draws every bass line, every subtlety and corpus without a faint, quick, nimble, lightning fast. Absolutely impressive.


These ribbons simply never stop. Again, plenty of ruthless resolve, texture, speed and cleanliness. The SR1A clearly takes no prisoners and instead hijacks you while simply being impossible to catch for speeding tickets or any arrest. This headphone really needs some adjustment and brain burn-in to realize what’s happening and how it happens.

If you’re a friend of legendary midrange stars like the HE-500, HD 650, HD 600, prepare to potentially get disappointed at first because romanticism and dreamy and honeyed seduction is not the way the SR1A plays. Is it the dreaded “cold and clinical”? Not quite.

It’s just that the stop and starts are happening so fast, the blur and slowliness you are perceiving which gives the aforementioned headphones their romantic vibe is non-existent. The advice of being careful in finding a matching amp naturally especially applies here, where our hearing is the most sensitive.


Gobs of detail, resolve, texture, finesse and, most of all: a natural timbre.

The SR1A’s treble never loses composure in any instance. It will never be brittle, splashy, grainy or even remotely lose focus or fall apart at higher volumes, however it will, as I mentioned a lot by now, be full of energy, speed and attack. An all out attack on the senses in the most neutral way.

Amp pairings:

I’ve been building amps for years, among them the Nelson Pass/First Watt designs are one of my absolute favorites. Back when the HE-6 got released and their (still) legendary power requirements made a few enthusiasts start using power amplifiers it was the defining moment that drove me away from dedicated headphone amps, thus from there on I powered everything through my amps up until the Susvara and now the SR1A.

Unfortunately, lack of space at home makes it hard to keep all the amps I built and own in one place. Making me scatter them around the family to share all the joy and, of course, also all by myself.

Pass Labs XA30.8:

Pass amps are designed with a lot of overhead in mind, it’s why they are able to drive loads beyond what’s on paper while unleashing that special magic Nelson imbues onto the design. The XA30.8 is, despite the mismatch on the spec sheet, a great pairing with the SR1A. Perfectly matched 24 MOSFETS per channel with the right amount of 2nd order harmonics add a slight euphony to the ruthless laser sharp precision and neutrality and enrich the experience effortlessly with both cleanliness, clarity and yet unrestrained bass reproduction. There is zero distortion or limpiness to hear and, of course, given the “physical” nature of the RAAL, to be felt.

Pass Labs XA30.5:

Similar to the XA30.8 but drier, a bit more stoic and technical if there was a word of lesser euphony. Still a great match.

Pass Labs XA25:

Not far from the power of the XA30.8 the XA25, potentially giving out up to 80Ws @ 8 Ohms or 120W @ 4 Ohms did not quite reach the elegance and effortlessness of the bigger brother. I felt there was something lacking and didn’t pursue the combo any further.

DIY F4 Monoblocks:

With 2 F4’s you can achieve around 100 Watts per 8 Ohm load. As the F4s are buffer amplifiers, they take on what the preamp characteristics are. In my case, they currently give more neutrality, a bit more clinical and less euphony overall. While their specs speak of more power and drive, the XA30.8 combo gave out a more holographic and dynamic experience and gave the overall onslaught of energy a good touch of musicality. 


This amp, also or especially designed for the Susvara in mind, is a dream to listen to and quite the well engineered effort of HIFIMAN, yet not cheap though, mind you. At 110W @ 8 Ohms, they are officially up to spec. A very clean, neutral sound with an abundance of details and resolution, paired with 6×6922 tubes to enhance the flavor is must-hear experience. Together with the XA30.8 these were the favorite pairings except for the XA30.8 edging the EF1000 out in the delivery of vocals and the more relaxed counter effort. Other than that the holographic stage, the imaging within the space was a common trait both shared. This amp makes switching between the Susvara and the SR1A so easy.

Upgrading the experience: The RAAL Requisite 728 and 1028 silver cable.

Aftermarket headphone cables are always just a matter of time and RAAL fully aware of it took no prisoners with their own take and released the 728 (7 feet) and 1028 (10 feet) full silver cables for those whose mindset is to maximize upon every part of the chain.

A headphone so sensitive and “aware” of changes and competence in the chain absolutely needs a high performing cable.

Where it improves upon the stock cable is is mostly on transparency, micro-dynamics, transient speed and especially in the sharpness of the imaging qualities. It’s quite a good transformation and not just a small step to fill the last gap. Personally, I recommend getting everything else in the chain in place before taking on cable matters. Afterwards, the 728/1028 cable will definitely be the icing on the cake and further reward your efforts.


The SR1A earfield monitors are not the easiest headphone to pair with or integrate into your existing headphone setups or collection. They simply do away with any dedicated amps you might have sitting on your shelf. They require more real estate, overall heat dissipation, and cabling matters. They need more focus, effort and attention to placement and finding the perfect spot to illuminate your aural experience. Once you are deep into their territory though they grab you hard and relentlessly and take you onto a journey that even the most experienced headphone enthusiast hasn’t experienced yet.

Are they an all out assault on your senses? Yes, they are, yet in a good way, in an exciting way, in a way you have never heard before. The RAAL can be everything if you want it to be due to its technical prowess and perfect tonality, but it will never be a warm, smooth and creamy LCD-2 experience or a HD 650 on a top of the line tube amp. They can be cozy, warm, dreamy if the music is, yes, naturally, but the technicalities will always underline the overall picture.

They certainly take getting used to at first. You will find yourself trying to grasp the whole picture and presentation at once since the delivery of information has never been so clean, bare and clear yet so full, dense, packed at such a enormous speed. And you might even find yourself standing on the seat metaphorically but over time you will have found out when to be ready for such a listening session.

The SR1A definitely is the starting point where the headphone experience takes a new and exciting turn and the SR1A is there to collect you, put you into the seat and drive away.

Oh, and if you’re from the UK like me, RAAL-requisite just setup a new camp at Hifonix, right in Birming Rd, Sutton, Coldfield. There you have the chance to listen to the SR1A personally with a few different amplifiers, also RAAL-requisite’s very own.


396 Birmingham Rd, Wylde Green, Sutton Coldfield B72 1YJ, United Kingdom

+44 121 382 5444

Contact: Aseem

Thanks for reading

Visit RAAL-requisite over at and don’t hesitate to give them a call (818) 437-0779