RAAL-requisite's circumaural ribbon headset, the CA-1a

RAAL-requisite's co-owner Danny McKinney

As audiophiles, we strive almost obsessively for a low noise floor and no distractions, only to be spectacularly thwarted when we evaluate equipment in a retail or show environment. Around us, people are entering and exiting, and often talking up a storm. The air conditioner is set to a low drone. Bass notes leak in from the next room over. AXPONA's cavernous Ear Gear space, where more than two dozen manufacturers of headphones and related equipment were demonstrating their wares, was awash with buzzing, excited people—the best kind of noise, really, even if you have to turn the demo cans way up to block it.

I had come to pay RAAL-requisite a visit, hoping to audition a first for me: a recently-launched ribbon headphone called the CA-1a. The Serbian-American company previously made waves with another ribbon headset, the SR-1a. SR stands for studio reference, suggesting an elevated standard, and reviewers have tended to agree. Stereophile's Herb Reichert wrote about the SR-1a in Gramophone Dreams #32, calling it "both revelatory and revolutionary" and assigning it class-A+ status. At $3499, the product is up there in price, and given an ultra-low impedance of 0.2 ohms, the SR-1a requires an amplifier of at least 100Wpc to make it sound its best.

The CA-1a is much the same beast, but fundamentally different at the same time. The SR-1a, in Herb's words, "sits lightly on your head and neither covers your ears nor puts pressure on your pinna . . . [It] images outside and away from your skull—similar to floorspeakers!" The CA-1a uses essentially the same ribbons; slender strips of foil, attached only at their short ends and energized by an array of small magnets alongside their flanks. But the newer 'phones retail for a much more affordable $2000, have traditional circumaural cups (made from polycarbonate) with interchangeable foam pads, and can be driven by an amplifier as humble as the Schiit Jotunheim ($299). In fact, that's how I listened to the CA-1a: via a $1299 German-made RME ADI-2 DAC, plugged into a Jotunheim.

On "The Incredibles" by Gordon Goodwin's Big Phat Band, a complicated, spy-themed, large-ensemble jazz piece, it was remarkably easy to follow each instrument to the exclusion of all the others. I delighted in the same quality on Stevie Wonder's "Sir Duke," and even heard it on a favorite 1960s mono recording by Johnny Barfield and the Men of S.O.U.L called "Mr. Starlight"—a spooky, Lynchian doowop song with Barfield's pained, piercing falsetto at its core. The RAAL-requisite CA-1a kept leading me deep into the music, thanks to a presentation that was agile, fast, superclean, and revealing to a T.

When it comes to headphones, I'm partial to the purity of planar magnetics. The HifiMAN HE1000se and the Audeze LCD-4 are my favorite cans for serious home listening. Considering what I heard in the RAAL-requisite booth, I'm guessing that in a side-by-side shootout, the CA-1a could rival and perhaps surpass them.

jimtavegia's picture

They don't even come close to the Harman curve and have a very low HF output, but if you like them that is perfectly fine. Sadly these would sound to me very soft and unexciting with my 75 year old ears.

I am beginning to think that it is very hard to make recommendations on speakers and headphones anymore as one's personal hearing flaws(?) and rooms are too critical to make judgements on value to the possible purchaser. I would think that with the price of everything these days, auditions are a must.

The HE-1000's I would have an easier time living with as closer to the Harman target.

JRT's picture

In addition to reference grade DA conversion, RME ADI-2 DAC FS includes five bands of parametric EQ plus two tone controls, all useful in correcting some significant problems in playback frequency response. It also includes excellent amplifiers for headphones exhibiting more conventional load impedance, such as your 35_Ohm Hifiman HE-1000.

As the show report article mentions, these current hungry 0.2_Ohm RAAL ribbons are being powered by the Schiit Jotunheim R headphone amplifier, which was designed with the explicitly expressed purpose of powering RAAL ribbon headphones.

jimtavegia's picture

Spending more money to fix a problem on a pair of cans that are hard to drive and need EQ seems to be a tough sell. Seems like there is a disconnect between marketing and good engineering. We've seen this in the last issue of Stereophile.

Sure RME is happy to oblige.

JRT's picture

...and what sounds right through a set of headphones to some will not sound right to others.

As compared to the engineering problem set associated with loudspeakers and small room acoustics, headphones on individual heads bring a different set of problems more closely tied to each individual listener's HRTF, head related transfer function.

Simple EQ isn't going to solve all of the issues associated with differences among individual HRTFs, but some of it is a difference in the perceived frequency response, and for that I would not dismiss the use of EQ with very good headphones.

The added difficulties in driving ribbons or electrostatics are separate from this.

jimtavegia's picture

The Harman curve is an average of a sample set of people who preferred a certain EQ curve. My issue is that when the HF response of "cans" looks like a saw tooth wave form, (very uneven) with tremendous peaks and valleys, that is a lot to correct for.

My only contention is that for more money, many times significantly more money, the better performance may not be there, depending upon what the listener needs from his headphones base on hearing inaccuracies. In some cases, a product needs more work before being brought to market.

It would not bother me if someone liked what he owns if it makes the music seem more real, like real instruments and singers in a real space, and they feel it is recorded well. That is my goal.

yyz's picture

I have the SR1a | CA-1a | Schitt JR | RAAL VM-1a tube amp | Star8 headphone cable | old RAAL adapter box and new TL-1b adapter box

I use a Lumin X1 DAC and a Benchmark DAC3B as my digital sources to the RAAL phones. I also use fibre optic streaming. So this is a hi-end setup I have.

I am a 2-channel guy and tended to hate headphones. However, the SR1a was right at the top of the very best sound I have heard from ANY system. Including massively expensive 2-channel systems. The SR1a is for 2-channel fans. The CA-1a is for headphone folks however, I have to say that I also love the CA-1a now. The sound is way too good.

If the Schitt JR is 30/100 in terms for where it fits in the RAAL headphone amp hierarchy. The VM-1a a 100/100 with an excellent DAC such as the Lumin X1. The new RAAL TL-1b adapter box is being used by me with a CODA #16 amp (a great amp). I would say that is an 85/100. I am also using that TL-1b with a modded Peachtree GAN1 (and Lumin X1 SPDIF streaming and volume) and this is also 85/100. That is the mods and the design of the GAN1 that is blowing up there.

Even though I rate the JR a 30/100 that is still a very nice sound and very enjoyable with the new Star8 headphone cable. This just some great gear.

The CA-1a is my rock-and-roll headphones and my SR1a is my best 2-channel system.

yyz's picture

I should add that I am getting a new PlayBack Designs Dream DAC late in 2023. Between the Dream and Lumin X1, the 'better' DAC will go with the RAAL VM-1a, and the lesser DAC will go with my upcoming Livingroom 2-channel system.

The VM-1a is in my office as are all the other gear mentioned in the prior post.

Alex RAAL-requisite's picture

Hello gentlemen,

Please allow me the opportunity to explain a couple of choices we made for Axpona show.

We use RME DACs at Shows only because they sound really good and are easy to carry at the same time due to their small form factor.

We never use any RME EQ capabilities in presentations and anyone that wants to see that at the Show can go into the Menu and check.

Schiit Jotunheim R was there because it's a good sounding amp and it's also small, easy to fly-in to the Show.

We also had a small battery powered iFi iDSD DIABLO pocket amp as well as Ampersand Centrance battery powered amp.
Our headphones were not of the radar of designers of those two amps, yet they worked great with our Amp-Ribbon Transformer Interface box that converts 0.25 Ohms or our headphones to 32 or 16 ohms.

At our dealers, Moon Audio, there was our VM-1a and other expensive amps that could be listened to with our headphones, on completely different DACs, so we have covered all the variety of systems that one could use with our headphones, deliberately emphasizing the fact that it doesn't take a dedicated amp to drive our headphones.

Sure, power is welcome, but not more so than with other low-sensitivity headphones. Whatever drives well the 1266TC, Sus and Hedd, will drive RAAL-requisite, no problem there.

On both Shows in Munich this May, we will have a few High-End headphone amps (tubes and S-S, up to $30k) and a couple of DAC that are not RME, so we will show a variety of amps that can be used successfully with our headphones...



Jason Victor Serinus's picture

Sorry I missed you, Alex. Ms. Doven, now 14, sends love and licks.

Send a press release if you'll be in Munich, Warsaw, Santa Ana, or Seattle.