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NHT Xd active loudspeaker system Measurements

Sidebar 3: Measurements

Their active, digitally crossed-over and equalized nature meant that I could examine the intrinsic behaviors of the NHT XdS satellite and XdW subwoofer in some detail. However, it is important when looking at the graphs that follow not to assume that any problems and idiosyncrasies that are revealed in the measurements of the raw drive-units are indicative of problems in the overall Xd system's behavior.

With that warning out of the way, fig.1 shows the impedance magnitude and phase for the XdS satellite's woofer and tweeter. With the speaker intended to…

 

NHT Xd active loudspeaker system John Atkinson January 2006

John Atkinson wrote about the NHT Xd system in January 2006 (Vol.29 No.1):

When Kalman Rubinson reviewed NHT's $6000 satellites+subwoofer loudspeaker system in the November 2005 issue (pp.105–115), he was very impressed, concluding that "The NHT Xd is the best thing to come down the pike in a long time....Because the Xd's performance is competitive at the highest levels, anyone interested in high-quality music reproduction must hear it." I was also impressed enough by the Xd's measured performance that I decided I would do a Follow-Up.5

A Follow-Up would also allow me to…

 

NHT Xd active loudspeaker system Follow-Up Measurements

Sidebar: Follow-Up Measurements

Fig.1 shows the response of the Xd satellite (black trace) and the XdW subwoofer (green), as well as the individual responses of the Xd tweeter (red) and woofer (blue), with the XdA crossover running the original digital filters. The crossover points lie at 110Hz and 2.3kHz, and the Linkwitz-Riley filter slopes are a very steep 48dB/octave. A touch of excess energy can be seen in the mid-treble, and the top octave is a little shelved off both on axis (red) and in the 30° averaged response (black). It also looks as if the tweeter's ultrasonic dome resonance…

 

Two Days in August: <I>Stereophile</I>'s First Jazz Recording

The genesis of this project goes back nearly 17 years, when my wife, Joan, and I moved into a brownstone floorthrough in Brooklyn. As we were about to sign the lease, our soon-to-be landlord said, "Oh, one more thing: your upstairs neighbor is a musician." This did not exactly discourage us from signing the lease, however, and soon I began to see a steady stream of musicians trudging up the stairs outside our apartment: Oliver Lake, Sonny Rollins, Pheeroan akLaff, Bob Moses, Marty Ehrlich, and a whole bunch of other people I was reading about in the jazz press. Just who was this guy?

…

 

Two Days in August: <I>Stereophile</I>'s First Jazz Recording Page 2

By early afternoon everything was in place, and everyone was warmed up enough that we could run a sound-check. Things sounded pretty good—the studio has a marvelously warm acoustic, and the right wires seemed to be connected to the right microphones. We adjourned for lunch while John remained behind to reroute cables, recheck channels, zero out any DC offset on the Manley A/D converter's outputs, and do some eleventh-hour worrying.

By 3pm we were ready to roll tape, starting with "Followthrough." Neither John nor I had heard any of the tunes Jerome had written for the sessions,…

 

Two Days in August: <I>Stereophile</I>'s First Jazz Recording The Music

The Music
"Decision Point": Pulsing bass guitar sets the scene and occupies the core of this opening cooker, which juxtaposes two types of improvisatory play: loose-jointed multidimensional collective interaction over a relatively fixed bass "pedal point," and the weaving of lines through a progression of chords with walking bass. Each of the three soloists—Steve Nelson on vibraphone, Marty Ehrlich on alto sax, and Art Baron on trombone—joyfully explores the open musical terrain; Billy Drummond makes the drums dance throughout.

"Sway Low": I have the good fortune of working with…

 

Two Days in August: <I>Stereophile</I>'s First Jazz Recording Blue Heaven Studios

Blue Heaven Studios
Mail-order retailer Acoustic Sounds—www.acousticsounds.com, (800) 716-3553—was founded by Chad Kassem in the early '80s to sell LPs and CDs. One thing led to another, and Chad got into reissuing his favorite recordings, as well as original blues recordings, on his Analogue Productions label. To help with this, he opened his own mastering facility, AcousTech, with LP pressing company Record Technology Inc. Then came Blue Heaven Studios.

Chad acquired the First Christian Church in Salina, Kansas to use as offices and warehousing, but, struck by the beautiful…

 

Two Days in August: <I>Stereophile</I>'s First Jazz Recording Multitrack Madness

Multitrack Madness
Recording Rendezvous, Stereophile's first nonclassical album at the deconsecrated downtown church Chad Kassem has transformed into Blue Heaven Studios was a challenge. It's a great-sounding space, but I was concerned that a purist microphone technique would result in balance problems with the particular ensemble Jerome Harris had chosen for his compositions. While the coincident-stereo microphone technique I've used for previous Stereophile classical recordings would faithfully capture the delicious acoustic of what everyone was starting to call the "First Church of…

 

Two Days in August: <I>Stereophile</I>'s First Jazz Recording Multitrack Madness part two

Accordingly, I prepared several four-channel submixes. The first featured the drums and bass guitar, with some digital equalization provided by a Z-Systems RDP-1. For the bass guitar, I mainly used the DI track, adding a bit of presence-region bite with the RDP-1. (While Jerome had liked the recorded sound of his bass, he wished for a bit more "woody" character to its sound.) I also experimented with some reverberation for his bass guitar solos. As well as the stereo drum tracks, I kept the spot snare drum track separate, to allow some flexibility in balancing the final drum sound.

Half…

 

Two Days in August: <I>Stereophile</I>'s First Jazz Recording Multitrack Madness part three

To drive the Manley, the sax and trombone tracks were converted to analog by connecting the Sonic Solutions' optical digital output to a Wadia 27i D/A processor via a Sonic Frontiers UltraJitterbug. The Wadia had a sufficiently high balanced output voltage to drive the Manley fully into limiting, if that's what I wanted. The Manley's output was redigitized using a dCS 904D A/D converter running at 24-bit resolution, and to ensure word-clock synchronization, the dCS's reference clock input was driven by another of the Sonic Solutions' digital data outputs, this time dejittered by a Meridian…

 

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