RAAL-requisite CA-1a Review

The RAAL-requisite SR-1a is an incredible headphone which uses ribbon driver technology to deliver electrostatic-like performance, but with a warmth and body typically lacking from electrostatic headphones. While the sound was incredible, the nearfield earpseaker form factor wasn’t everyone’s cup of tea. Enter the CA-1a, which updates SR-1a’s same ribbon driver tech and puts it in a more familiar circumaural design. Is the CA-1a the next step in delivering a ribbon driver headphone that’s ready for the wider market?

Build and Design

CA-1a comes in fairly simple packaging, and is available either with the headphone by itself (if you already have an amp or interface box that supports ribbon headphones) or with the updated TI-1b interface box. Previously in order to use RAAL-requisite headphones, you needed to either use a specialized amp or connect the provided interface box to a speaker amp. The new interface box available in a bundle with the CA-1a can also be used with high-powered headphone amps. Don’t expect to run this with just any old amp, you’re going to need to be in high gain and pushing past the 50% mark even on powerful headphone amps like the HeadAmp GS-X mini or Burson Soloist 3X GT.

RAAL-requisite CA-1a

The driver and interface tech represents next level, bleeding edge audio, but the physical build and design is more experimental, having the look of a prototype. This isn’t a Meze Empyrean begging to be displayed in your home next to works of classical art. This is a minimalist, functional work of modern design that looks to be more at home in the communications center of a military base than most listening rooms. Whatever you might say about its looks, the comfort level is excellent. CA-1a is relatively lightweight, with soft pads, and an adjustable band that will nicely fit most heads.

The first look we got at CA-1a’s pads certainly raised some eyebrows, but there’s a reason for the design. The design is clearly focused on acoustic qualities and comfort, not aesthetics. RAAL-requisite also provides 2 sets of pads. One with a more open design that vents at the top and bottom, and the other which has a more traditional design. The main difference between the two is that the more open design lends to an airier, more spacious sound, while the more closed off design adds a bit more punch to the bass at the cost of narrowing the soundstage and introducing a small amount of midbass bleed with some tracks.

RAAL-requisite CA-1a


A few minutes with CA-1a will demonstrate that RAAL-requisite has greatly lowered the barrier of entry into the world of ribbon headphones, and this isn’t just true in the physical design and engineering, but also in the sound. While it retains the neutral character of the SR-1a, CA-1a also provides stronger support and extension in the bass into the subbass.

In the bass, CA-1 provides a tight accurate presentation, with a linear extension. While CA-1a demonstrates excellent speed and transient response in the upper registers, the bass doesn’t have quite the same feeling of speed in busy passages. The mids deliver intense detail with excellent vocal presentation. The realistic, personal delivery of vocals was a major highlight of listening with CA-1a. The treble is likewise excellent, with a strong extension and a good balance of strong treble characteristics that are presented in a non-fatiguing manner.

RAAL-requisite CA-1a

If RAAL-requisite’s ribbon driver design delivers a sound that’s in between planar and electrostatic, the SR-1a leaned a bit more to the electrostatic side, while CA-1a provides a sound that’s a bit closer to a planar – particularly in the bass – while still maintaining elements like the vivid imaging, wide soundstage, and out-of-this-world resolution generally associated with electrostatic headphones – though SR-1a still exceeds CA-1a for resolution.

CA-1a puts you in the studio with the Delvonn Lamar Organ Trio on “Get Da Steppin.’” Each instrument is filled with rich detail and texture along with strong positioning and weight in the image. The drums are driving the truck with a steady, tight punch in the kick, and just the right amount of splash and ring in the cymbals in the accents that highlight the other players. The organ weaves in and out of the groove with deep bass tones and a melodic top end. CA-1a gives you the energy of a live performance with the detail and transparency that makes you feel like you’re the one behind the mixboard in the studio.

There’s an incredible emotion in the lead cello in the Berliner Philharmonker performance of John Williams’ “Elegy for Cello and Orchestra.” CA-1a makes you feel as if you’re center stage in the vast connect hall where it was recorded with the cello in your own hands. The orchestra swells around you providing deep layers of dynamic accompaniment. With CA-1a there’s a strong sense of an organic whole and a window into those intricate layers, along with a strong sense of dynamics.

RAAL-requisite CA-1a

CA-1a delivers the smooth, cold rhythm at the beginning of “The Start of Something Beautiful” by Porcupine with a nice impact in the drums, and incredible texture and character in the bass. The cymbalwork is fast and tight, and as layers build on layers, CA-1a maintains the balance of separation and cohesion. It gives you the smooth bass, tight drum groove, and guttural guitars layered with more delicate vocals and ambient synth sounds. Each instrument feels fully present and well developed in CA-1a’s vast stereo image.

I was shocked by the level of depth and impact CA-1a provided to the opening notes of Fiona Apple’s “Sleep to Dream.” The percussion and upright bass is presented in incredible, lifelike, realistic detail, and Apple’s voice rises above it all with her caustic lyrics and the thinly veiled anger behind it. The sparse instrumentation provides accents that demonstrate the width and depth of the soundstage along with the precise imaging that puts the whole song together.

For testing, I used the CA-1a with the Schiit Jotunheim R, and the TI-1b interface with the HeadAmp GS-X mini and the Burson Soloist 3X GT. I found that the Jotunheim R provided a bit more bass, but in a way that could muddy up the mids a bit – probably owing to it being designed for the more bass-lite SR-1a. GS-X mini had a cleaner, tighter overall sound, but could have used a bit more headroom, even on high gain. Soloist 3X GT felt like the perfect match, delivering a transparent, highly resolving sound, without any need to push the volume past the 40-50 range for my ears.

RAAL-requisite CA-1a

The Bottom Line

While the SR-1a provided incredible detail and resolution with a spacious sound, the ergonomics left something to be desired, and the bass was never quite there with music that heavily utilizes subbass ranges. CA-1a provides nearly that same level of detail, resolution, and space with a more accurate, powerful low-end and upgrades to all aspects of the headphones’ usability. While the utilitarian design might still be an issue for some, CA-1a elevates the more mainstream audiophile appeal of RAAL-requisite’s ribbon driver design, and speaks to greater things yet to come.