CAF 2014: Core Audio Technology, Hawthorne Audio and GIK, take computer audio to eleven

The Core Audio/Hawthorne room sat next to the CanMania showroom, commanding a large and open space. It was also really hard to miss — the charming Melinda Smith was outside, directing traffic for much of the weekend, for one thing, and for another, the amount of sound coming from the demo was enough to give whiplash to even the most profoundly challenged. But what made that sound memorable was its shocking purity. The fact that Chris Jones’ “No Sanctuary Here” was on the seemingly short playlist meant that I heard subterranean bass quite regularly. Being a fan, I took it as a gauntlet thrown. Have at thee!

The first thing I saw in the room, other than the crowd, was a pair of giant-sized open-baffle loudspeakers — the $15k/pair Rainier Mk II from Hawthorne Audio. Hawthorne makes several speakers, but is mostly known for their extremely high-qualiy speaker components, especially their drivers. The Rainiers feature a pair of 15″ “Augie” woofers and a pair of 15″ mid-woofers, with an AMT tweeter sitting between, nestled in a waveguide. 

Specs for the Hawthorne:

• Frequency Response 20hz-40khz +/- 3dB
• Sensitivity: 96dB 1watt @ 1M
• Dimensions: 22″ W x 16″ D x 60″ H
• Recommended Amplifier Power: 2-200wpc into the AMT and midwoofer, Augies powered by included amplifier in its own wooden enclosure.

So, big flat panels with an AMT crossed in around 350Hz, with an active bass and driven bi-amp from … well, that’s where this gets even more interesting.

The amps in question were from Core Audio Technology. Ryan Mintz, the designer, has been working on computer audio for quite some time, but the amplifiers are a bit new and a bit unusual. First, they’re digital, not analog — and no, they’re not Class D. In short, they amplify the native, unconverted digital bitstream and demodulate for the loudspeakers. If you’re taking from this that there is no DAC involved, you’re correct — the sound for the system was sourced from a server, the $6,000 Kryptos Music Server S1. Look, ma, no preamp (or DAC)! The Kryptos sent data directly to the Kratos Fully Digital Amplifiers ($2,500/pair). If this sounds like something from NAD, that wouldn’t be surprising. Where Core Audio Technology diverges is in the use of a fully linear power supply and better clocking, but the “general principle” is the same. All digital, all the way through. Here’s the skinny:

The pristine signal from your source is sent via SPDIF into the amplifier. The SPDIF signal is a PCM (Pulse Code Modulation) signal, which is a type of digital signal transmission. This PCM signal is converted to a Pulse Width Modulation, which is another form of square wave containing amplitude and timing information. As a PWM, the signal is reclocked, amplified in the digital domain, reclocked again, and then demodulated to drive a speaker directly. There is virtually no analog in the signal path all the way up to the binding posts.

I’ve been curious about audio servers since my last one exploded in a ball of fire, and since, have been limping along with scraps and castoffs. Seeing the Kryptos sitting in the rack with its fancy 1080p display almost tempts me from my Mac based addiction, though I will probably be punished for admitting that. PC-based servers are well-known for being wildly upgradeable, but they’re also known for Windows and Windows is Evil. It’s a problem, you see. Anyway, the Kryptos isn’t just an off-the-shelf unit. The box pulls together all manner of computer stuff, but does it with an audiophile’s attention to fine components — the Asus mobo, for example, uses specially selected linear regulators, not the stock switching ones. Yes, Ryan rebuilt the motherboard. The CPU is an I7, fed by a custom “ultra low noise, ultra low ripple, digitally-controlled ATX Power Supply”. On-board storage is via PCIe SSD devices, and output comes courtesy of JCat USB card that can be powered separately.

The sound in this room was polarizing, to put it mildly, but much of the complaints about Day One sound were settled by Day Three. So goes the audio show. What I heard was blazing speed — think “electrostatic” and you’re getting there. Clarity, openness, and transparency were all breathtaking. But, that said, we’re now back at a Frost-ian Crux, standing where two (audio) roads diverge in the woods. Which you tend to prefer says nothing in particular about who you are, but there is a preference most of us have. I haphazardly split the camps by labeling one side as those who appreciate transparency and detail and the other as those who appreciate tone and warmth. Which you might choose, I have no way of knowing, and quite frankly, don’t really care. This is something that goes into that filter of knowing your own aesthetic — just know that this system, here, was very clearly on the “transparency and detail” side of the fence. My take? I was extremely impressed. I personally think that this is what “Class D” technology was supposed to get us, and that we’ll all be seeing quite a bit more designs like this in the future, because that’s what it is. The future.