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Sonus Faber Guarneri memento loudspeaker Measurements

Sidebar 3: Measurements

The Sonus Faber Guarneri memento's voltage sensitivity was a little below average, at an estimated 86dB(B)/2.83V/m. However, its plot of impedance magnitude and electrical phase against frequency (fig.1) indicates that it is not too demanding an amplifier load, though a minimum value of 4.35 ohms at 197Hz and a combination of 5.7 ohms and –38° phase at 124Hz suggest that tube amplifiers be used from their 4 ohm taps.

Fig.1 Sonus Faber Guarneri memento, electrical impedance (solid) and phase (dashed). (2 ohms/vertical div.)

Though difficult…

Chord Choral Blu CD transport & Choral DAC64 digital audio converter

I was stumbling through the Denver Convention Center at CEDIA 2006 when I spotted John Franks, of Chord Electronics, and Jay Rein, of Chord's US importer, Bluebird Music, stranded in the basement purgatory for "niche" products. I couldn't resist asking, "What sin relegated you guys to this little hell?"

"Practicing two-channel without a license," riposted Rein, before going on to describe Chord's new 6TB Media Engine music server. "But we didn't bring it. We brought—this."

He'd been blocking my view of Chord's table. Now he moved aside and made a flourish toward the Blu,…

Chord Choral Blu CD transport & Choral DAC64 digital audio converter Page 2

"We'll get to the buffer, but first I need to expand upon that 64-bit DAC environment," Franks said. "A 16-bit input multiplied by a 16-bit coefficient gives you a 32-bit output. By using a 64-bit filter and architecture we avoid having to throw away information by truncating the output—something that becomes important if a digital volume control is used.

"Now we get to that buffer. Because we use all-digital data extraction, we can employ a RAM buffer to sequentially accept all the data, re-time it, and then output it. It gives us a jitter-free local clock, without requiring us to send a…

Chord Choral Blu CD transport & Choral DAC64 digital audio converter Page 3

. . . yes and how he kissed me under the Moorish wall and I thought well as well him as another and then I asked him with my eyes to ask again yes and then he asked me would I yes to say yes my mountain flower and first I put my arms around him yes and drew him down to me so he could feel my breasts all perfume yes and his heart was going like mad and yes I said yes I will Yes.

I think I need a cigarette.

Tierney Sutton's "Sometimes I'm Happy," from her On the Other Side (SACD, Telarc 63650), is far more closely miked than either of the other discs, but engineer Robert Friedrich…

Chord Choral Blu CD transport & Choral DAC64 digital audio converter Specifications

Sidebar 1: Specifications

Choral Blu: Digital transport with upsampling. Digital outputs: 1 coaxial BNC, 1 Dual Data 176.4kHz twin coaxial BNC, 1 optical TosLink, 2 AES/EBU XLR or 1 Dual Data AES twin XLR. Wordclock input: 1 coaxial BNC, 44.1kHz. Dithers: 16 or 24 bits. Sampling frequencies: 44.1kHz, 88.2kHz, Dual Data 176.4kHz.
Dimensions: 13.1" (335mm) W by 4.1" (105mm) H by 6.6" (170mm) D. Weight: 15.4 lbs (7kg).
Serial Number Of Unit Reviewed: 9933.
Price: $10,400.

Choral DAC64: Multi-input digital-to-analog converter with 64-bit filter. DAC chips: Chord-specified Gate…

Chord Choral Blu CD transport & Choral DAC64 digital audio converter Associated Equipment

Sidebar 2: Associated Equipment

Digital Sources: Ayre C-5xe universal player, Nagra CDP CD player, Logitech (Slim Devices) Transporter network player.
Preamplifiers: Ayre K-1xe, Krell Evolution 202.
Power Amplifiers: Ayre MX-R and Krell Evolution 600 monoblocks, HeadRoom Max Balanced headphone amplifier.
Loudspeakers: Dynaudio Confidence C4, AKG K 701 headphones.
Cables: Interconnect: Kimber KCAG, Krell CAST, Shunyata Research Altair Helix, Aries & Antares. Speaker: Shunyata Research Lyra, HeadRoom balanced headphone cable.
Accessories: Ayre L-5xe line filter; Furutech…

Chord Choral Blu CD transport & Choral DAC64 digital audio converter Measurements

Sidebar 3: Measurements

Chord's Choral Blu offers a surprisingly large number of output options for a CD transport. To examine what it did, I connected its data output to the digital input of the RME soundcard fitted to my PC and looked at the data in the digital domain using Adobe Audition and RME's DIGICheck program. Fig.1 shows the statistics of the Blu's output data while it was set to upsample those data to 88.2kHz and increase the word length to 24 bits. The test signal was 16-bit "digital black" on a test CD. DIGICheck indicates that bits 1–16 are indeed permanent zero, shown by…

The Final Word: Yo Yo Ma Live

I sometimes do crazy things to experience live music. In my late teens I met a woman—a friend of a friend of my girlfriend—who was a flautist attending the Mannes School of Music in New York City. She was a classic New Yorker, from a classic New York family. Though apparently demure and retiring, she had fearlessly ridden the city subways since childhood, taking the Broadway line at any hour of day or night (her stop was Dyckman Street, above 200th). All of her parents' money and energy, such as it was, had gone into their daughter's musical career, and I was so inspired by this level of…

RealTraps MondoTrap room acoustics treatment

For a hobby based on science and technology, audiophilia has more than its share of unscientific elements. That's not necessarily a bad thing; not all of those elements are obvious snake oil, and there's more than science to creating—or re-creating—a musical experience. Still, for the more technical-minded it's a little disconcerting that even the most basic distinctions, such as why two CD players sound different from each other, are hard to explain using technical measurements and simple scientific concepts.

So it's reassuring to now and then review a product whose mechanism…

RealTraps MondoTrap room acoustics treatment Page 2

But we get along well, and I like our new digs. I love the view, the good restaurants, the excellent bakery just down the street. But the stereo now occupies the apartment's main living space, which is adjacent to the single bedroom (our son sleeps there). This puts some restrictions on the stereo's use. I can't listen seriously while dinner is being prepared—too many clanking pots. I can't listen above minimal volumes late at night. And I can't fill the room—at least, not permanently—with eight objects that, in shape and scale, resemble those obelisk thingies floating around in 2001: A…