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Down with Dynagroove! Page 3

33 critics CAN be wrong (from Vol.1 No.5, May-June 1963)
We have watched with avid curiosity the reactions of the other hi-fi publications to the new RCA Victor Dynagroove system and, up to the time of this writing, we have yet to see any of them raise any serious questions about it (footnote 2). As a matter of fact, record critics appear to be almost unanimous in their praise of it, judging by the reviews we have seen, and by the critical accolades quoted in a brochure that RCA Victor is circulating.

RCA Victor's pamphlet cites reviewers in High Fidelity, Hi-Fi/Stereo Review, the…

Down with Dynagroove! Page 4

More dope on Dynagroove (from Vol.1 No.8, August 1964)
The April 1964 issue of the Journal of the Audio Engineering Society carried a detailed article by RCA's Dr. Harry F. Olson (footnote 3), which shed considerable new light on the controversial RCA Victor Dynagroove system. On the basis of this, plus some other recent articles on the subject, The Stereophile is now obliged to retrench on one point with which we originally took issue, but we are even more firmly convinced that most of the other aspects of the system represent a giant backward step in the recording art.

The…

Down with Dynagroove! Letters

Letters on Dynagroove & JGH's Diatribe

Dynagroove denigrator
Sirs:
I have read the Dynagroove ads; I have heard the commercials; I have read the press releases (and the counter-press releases); I have tuned in FM stereo broadcasts of these discs; I have watched their effect on a pair of matched and calibrated 4½" VU meters.

I have listened carefully and with an open mind. And I have formed my conclusion.

So long as this process remains in use by RCA Victor, I will never, repeat, never buy another of their records.

I am sorry for my local record store…

Meridian DSP8000 digital active loudspeaker

Nestled south of the North Downs in England's southeast, the Kentish dormitory town of Sevenoaks is about as sleepy a place as you can imagine. Yet 20 years ago, in the unlikely circumstances of the back room of a Sevenoaks pub, I witnessed the world of consumer loudspeakers changing. Meridian's Steve Hopkins was showing a pair of the company's active M2 loudspeakers connected directly to a 101 preamplifier.

The idea of integrating the power amplifier into the loudspeaker was not new in the pro audio world even then—in my days as a musician in the 1970s, I had become used to seeing…

Meridian DSP8000 digital active loudspeaker Page 2

All of the digital adjustments are available from the Meridian System Remote. The processed digital datastreams for each speaker's drive-unit feeds are sent to four 24-bit/192kHz delta-sigma D/A chips, the outputs of which drive the power-amplifier modules. Five separate bipolar amplifiers are used in each speaker: three 150W amps each drive a pair of woofers, while two 100W modules drive the tweeter-and-midrange unit. According to Meridian's downloadable literature on the '8000, these low-feedback amplifiers offer "extremely low noise, high detail, and fast bass" due to "the combination of…

Meridian DSP8000 digital active loudspeaker Page 3

"Wait a minute," I hear you say. "Doesn't the Technics downsample/truncate to 16/48 from its digital output?"

Well, no. The DSP8000's front-panel display unambiguously showed "PCM 96kHz," and I checked the data format with RME's DIGICheck software. It appears that it is not the player but the disc, and therefore the content provider, that controls the presence or absence of a hi-rez digital output. Put a Classic or Chesky DVD-V disc in a DVD player and, provided the manufacturer has included the necessary double-speed interface hardware—Technics, Panasonic, Pioneer do; Toshiba, Onkyo,…

Meridian DSP8000 digital active loudspeaker Specifications

Sidebar 1: Specifications

Description: Remote-controlled, powered, three-and-a-half-way, floorstanding, sealed-box loudspeaker with two Meridian Comms ports (5-pin DIN), 9-pin D connector for RS-232 PC setup and control (null modem, 9600 baud, 2N1, no handshake), two digital (S/PDIF) inputs, and one digital (S/PDIF) output mirroring selected input. As supplied, handles input sample rates of up to 96kHz; FIFO buffer locks at 44.1, 48, 88.2, or 96kHz, ±150ppm (LPCM or MHR encoding); 176.4kHz or 192kHz supported with special firmware and cabling. Drive-units: 1" (25.4mm) composite-dome…

Meridian DSP8000 digital active loudspeaker Associated Equipment

Sidebar 2: Associated Equipment

Digital sources: Meridian 800 DVD-V/CD/CD-R player; Apple Macintosh 8100, 80MHz, fitted with two Sonic Solutions SSP3 digital audio workstation NuBus cards, connected via 15' TosLink optical link; Technics DVD-A10 DVD-A player; Accuphase DP-100 SACD transport and DC-101 D/A processor (this used from its balanced analog outputs and redigitized at 24/96 with a dCS 904 A/D converter).
Equalization/format conversion: Z-Systems rdp-1 digital control center (updated to handle 96kHz sources).
Cables: Datalink: AudioQuest SVD-4, Meridian S/PDIF. AC:…

Meridian DSP8000 digital active loudspeaker Measurements

Sidebar 3: Measurements

Performing acoustic measurements on a speaker that has only a digital input posed some problems, as the DRA Labs MLSSA system I use for all of my loudspeaker tests outputs only an analog signal. I therefore digitized the MLSSA stimulus at 24 bits/88.2kHz with a dCS 904 A/D converter, and converted the AES/EBU datastream to S/PDIF using a Z-Systems rdp-1, this set to do nothing but convert formats. The peak level of the digital signal, measured with a Dorrough digital-domain meter, was -6dBFS.

The second problem involved the sheer bulk of the DSP8000—it was…

Meridian DSP8000 digital active loudspeaker Measurements part 2

But before you jump to any conclusion about the subjective effects of this behavior, look again at fig.1: The midrange unit narrows its dispersion in the exact region where the on-axis response is a little "hot." Similarly, the tweeter's lower-octave flare occurs where the on-axis response begins to plateau down. In a typical listening room, the '8000's on- and off-axis behaviors will tend to balance each other, resulting in a neutral perceived balance.

However, the use of a short horn surrounding the tweeter dome does increase that drive-unit's directivity above 11kHz or so. In all but…