Gramophone Dreams 32: RAAL-Requisite SR1a headphones

Tell me now: When you’re there in the scene, watching Lord Voldemort chase Han Solo through the Cave of the Klan Bear, how often do you notice that the sounds you’re experiencing are being pumped at you from five black-painted room boundaries, while the flickering-light images approach from only one? Moreover, in a parallel, more quotidian reality, you’re sitting upright in your seat, noisily chomping popcorn while absorbing—and processing—massive amounts of sensory data: Did you ever consider the sensual, mechanical, and psychological complexity of a moment like this, and how fundamentally unnatural it is?


What I love most about cinema is how easily and effectively my brain lets me experience being there in the bed with Brigitte Bardot in Les Femmes (1969), or there on the platform of the train depot during the opening sequence of Once Upon a Time in the West (1968). My memories of both places remain vivid.


I confess, I do not understand how my mind can convert marginally realistic sounds and two-dimensional flickering-light images into me being somewhere else. But I do have this memory of my 3-year-old daughter putting a cookie in the door of our VHS player. When I asked her why she did that, she looked at me and said, with absolute matter-of-factness, “I’m feeding the Little Mermaid.” It was then I realized: We are wired from an early age to assemble extremely abstract data into powerful conscious realities. This reality-forming process appears to function pretty well no matter how unnatural or abstracted the data it’s working with.


Whether I’m reading a book, watching a movie, or listening to music files, the success of my brain’s reality-construction depends not on the quantity or quality of data, but instead on my ability to focus my attention on the data as it is presented. The more complete my focus, the more complete my experience of a constructed reality.


I remember my college anthropology teacher explaining how, almost a century ago, explorers filmed a tribe of indigenous Melanesians. When they projected the moving images on a screen, no one in the tribe recognized the chief or his wife or anything that resembled their world. Why? Because they had not yet learned to decode the pictographic language of cinema. Because they had never fed the Little Mermaid.


And of course being an audiophile means I’ve spent my life staring at an equipment rack between a pair of wood boxes—watching whole operas, Horowitz at Carnegie Hall, or a sweaty Tina Turner singing “Proud Mary.” I saw all this because I’ve spent a lifetime learning to “see” musicians both inside and outside the speaker boxes.


All this cranial-nerve anthropology brings me to the chief question of this column: Is listening to music with headphones really more difficult or “unnatural” than reading a book? Watching a movie on a flat screen? Or staring at the space between wood boxes? Or rather: Is the art of headphone listening something many audiophiles of a certain age have never learned to do—like Gen Z never learned to sit in a sweet spot staring between giant speakers? Well folks, it’s never too late for old dogs, because I’m pretty sure I’ve found a unique non-headphone headphone—one that will instantly satisfy both headphone connoisseurs and stubborn contrarians: the RAAL-Requisite SR1a’s ($3499). These radical high-tech contraptions sit lightly on your head and neither cover your ears nor put pressure on your pinna. Plus! They image outside and away from your skull—similar to floorspeakers!


Are you ready?


RAAL-Requisite SR1a headphones
I must start by introducing Aleksandar Radisavljević. He’s the founder and chief engineer of Serbian manufacturing company RAAL Advanced Loudspeakers, established in 1995, which manufactures a range of dipole ribbon tweeters (footnote 1). Aleksandar is also co-founder and director of R&D and manufacturing for Requisite Audio Engineering of Ventura, California, which is responsible for the creation of the RAAL-Requisite SR1a ribbon headphones, which the company describes with the trademarked descriptor “Earfield Monitors.”


To the best of my knowledge, the RAAL SR1a’s contain the world’s first and only full-range, pure-ribbon drive-units. To qualify as a pure ribbon, the diaphragm must be a thin, rectangular strip of metal foil, attached only at its narrow ends and energized by rows of permanent magnets at its sides. The diaphragm of a pure ribbon is not attached to a film substrate, as with Magnepan’s quasi-ribbons or various manufacturers’ air-motion transformer tweeters. The SR1a’s design aesthetic relies heavily on laser-cut stainless-steel rectangles and thick buffalo leather. To situate the RAALs properly on my head, I needed to adjust the length of the broad leather top band and the narrower leather back-of-head band. These two bands combine to center the twin 3.77″ × 0.75″ (95mm × 19mm) open-baffle ribbon-drivers on the entrance to my ear canals.


Along the front edge of each SR1a baffle is a 0.65″ × 4″ roll of red-orange memory foam wrapped in Italian lambskin suede. That foam-and-suede roll keeps the SR1a off the head and away from the ears. The back part of each earpiece features a gusseted pentagonal wing made of what appears to be lenticular gray-black carbon fiber. That “wing” serves as a waveguide while increasing the area of the ribbon’s baffle, allowing for deeper bass.


The SR1a’s weigh 15oz (425gm) and come packed in a Pelican case. The RAAL ribbon’s natural impedance is a near-dead-short 0.018 ohm. Therefore, they need to be driven by a 50–150Wpc loudspeaker power amplifier (not included) via an impedance-matching interface box (included). This 2″ × 5″ × 7″ ventilated black box contains banks of power resistors that bring the SR1a’s apparent load up to approximately 6 ohms (fig.1, footnote 2). The output of this interface box must be connected to the SR1a headset via a 7′ Y-cable with a female XLR connector (use of which prevents the owner from accidentally connecting the RAAL headphones directly to the output of a headphone amp, with guaranteed bad results). Also included are two 2′ pairs of banana-to-banana cables for connecting the output of your power amplifier to the input of the interface box.


Fig.1 RAAL-Requisite SR1a headphones, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.).


The RAAL-Requisite SR1a’s, which come with a 5-year warranty, are not only the world’s first full-range pure-ribbon transducer; as far as I know they are also the world’s first headphones that are repairable by the user. The SR1a ribbon drivers are encased in a unique “cartridge” that simply slides in and out of the headphone shell. No tools are required, it takes just a few minutes, and electrical contact is made automatically. These field-replaceable ribbon cartridges cost $199 each or $350/pair.


Cupping and chambering
Beyond their unprecedented full-range ribbon-ness, the RAAL-Requisite SR1a headphones are distinguished by their off-the-ear-ness. This is important: It means their sound character is not manufactured or controlled by a circular padded acoustical chamber surrounding the listener’s pinna—like virtually all other over-ear headsets. This is important because all circumaural over-ear headphones have one unsubtle, unnatural, and unavoidable listening component: They mechanically cup our ears, and we can feel them doing this cupping the whole time they’re on our heads. (If you cup your hands right now and place them snugly over your ears, you’ll experience the resonant seashell-like sounds that result from this cupping.) This air-tight pressurizing is also called “chambering,” which is how over-ear headphones make bass. The problem is, this audible circumaural cupping and chambering mask detail and compress lower frequencies.


Cupping is what tells my brain that sound is being pressured into my ear canals. Even when I close my eyes, my awareness of cupping shuts me in and encourages me to imagine the band is playing inside my head. (Headphone-haters hate when that happens.)


Off-the-ear headphones like the RAAL-Requisite SR1a’s and the JPS Labs Abyss AB-1266 Phi’s do not cup or chamber: Instead, they hover near the listener’s ear, which means they deliver free and open reproduction that requires very little brainwork to reconstruct.


Amp requirements
Aleksandar Radisavljević explains why the SR1a headphones need a 100Wpc amp:


“Since there is already a 10:1 (or higher) ratio of cable to ribbon resistance, this means that the ribbon will not be controlled by amplifier damping. (It was clear from the beginning that ribbon excursion and damping control must be accomplished by passive means: using small amounts of acoustical resistance.)

Footnote 1: RAAL Advanced Loudspeakers d.o.o., Djordja Simeonovica, 419000 Zajecar, Serbia. Tel: (381) 64 144 1111. Web: raalrequisite.com, raalribbon.com. Requisite Audio Engineering, 2175 Goodyear Ave, Suite 110, Ventura, CA 93003-7761. Tel: (818) 437-0779. Web: requisiteaudio.com.


Footnote 2: Using the Dayton Audio DATS V2 system, John Atkinson measured the impedance magnitude and electrical phase angle of the RAAL headphones with them plugged into their adapter box. The load seen by the amplifier varies between 5.8 ohms below 300Hz and 9.8 ohms in the high treble. It is almost a pure resistance, however, the phase angle measuring close to 0° across the audioband.