It's all been good news so far, but you'll note that I haven't mentioned the lower frequencies. In my 1996 review of the basic RM7si, I mentioned the generous lows;…
search
And the speakers' imaging was excellent, individual images being precisely positioned within a detailed, stable stage. Peculiarly, the soundstage was arch-shaped, central images being noticeably higher than those at the sides. This generally suggests some frequency-response anomalies that mimic the effect of the listener's pinnae, but the Joseph's response was pretty flat (see the "Measurements" Sidebar). Color me puzzled.
Sidebar 1: Associated Equipment (2000)
Office System
Digital source: Meridian 500 CD transport, Panasonic A-120 CD/DVD player, Musical Fidelity X-24K 24/96 D/A processor.
Amplification: Yamaha @PET RP-U100 desktop receiver.
Cables: Canare interconnects, AudioQuest CV-4 and Symo loudspeaker cables.
Accessories: Pentium MMX 166MHz with Digital Audio Labs CardDeluxe soundcard connected to D/A via 75 ohm S/PDIF link, running Windows 98, WinAmp 2.5, and CoolEdit 2000.
Home system
Digital source: Mark Levinson No.31.5 CD transport and No.30.6 D/A processor, connected with…
Sidebar 2: Signature Measurements
The Joseph's sensitivity was an estimated 84.5dB(B)/2.83V/m, a little lower than specified. However, the impedance (fig.1) was generally high in magnitude, dipping below 8 ohms only in the midrange and reaching a minimum of 6.8 ohms at 184Hz. The phase angle is generally moderate, implying that tube amplifiers rated at 8 ohms would have no difficulty driving this speaker. The saddle at 45Hz in the magnitude trace indicates the port's tuning frequency.
Fig.1 Joseph RM7si Signature, electrical impedance (solid) and phase (dashed). (2 ohms/…
Figs.5 and 6 show the RM7si Signature's horizontal dispersion, both the actual responses (fig.5) and the differences in response (fig.6). It is easier to see from the latter that there is an off-axis flare in the same region where the on-axis output has a depression. In a typical room, these will tend to compensate for one another, resulting in a perceived balance that is closer to flat. In the vertical plane (fig.7), suckouts develop in the crossover region more than 15 degrees above or below the tweeter axis. This is quite a window, presumably due to the minimal overlap between the drive-…
Sidebar 3: Manufacturer's Comment
Editor: We'd like to thank John Atkinson for his review of our RM7si Signature loudspeaker. We were very happy to see that "The '7 Signature laid bare all manner of recorded detail." Perhaps this is why it's been the editing and mastering monitor used by Chesky Records for the last three years.
And JA's vertical-response measurements look superb—most speakers show large response errors within a small 15 degrees window. Thanks to John Atkinson, we can see how little the response changes over a much broader 90 degrees window (45 degrees in each…
Sidebar 4: Specifications
Description: Two-way, stand-mounted, reflex-loaded loudspeaker. Drive-units: 1" (25mm) silk-dome tweeter, 6.5" (165mm) fiberglass-cone woofer (RM7si), 6.5" (165mm) aluminum-cone woofer (Signature). Crossover frequency: 2kHz. Crossover slopes: patented "Infinite-Slope," >100dB/octave. Frequency response: 42Hz-20kHz, ±2dB. Sensitivity: 86dB/2.83V/m. Impedance: 8 ohms nominal. Recommended power: up to 150W.
Dimensions: 15" (380mm) H by 9" (229mm) W by 12" (305mm) D. Weight: 27 lbs (12.3kg) each.
Serial numbers of units reviewed: none (RM7si, first pair); 7…
Chip Stern wrote about the RM7si Signature Mk.2 in October 2002 (Vol.25 No.10):
I have used the stand-mounted, sweet-sounding RM7si Signature ($1799/pair-$1999/pair, reviewed by John Atkinson in August 2000), as my reference speaker because of its realistic timbre and dynamics, spatial depth, precise imaging, high-frequency clarity, and revealing midband. While I remained a big fan of the original Siggie '7, over time I found its highs to be somewhat subdued for my tastes; and when I pushed the speaker hard (as is my wont), certain notes in the transitional zone between the upper mids…
In conversation with Cary founder Dennis Had at a recent audio convention breakfast, I learned that he had a long career in electronics, specializing in military/industrial high-power radio-frequency amplification and transmitters. However, his dream was always the re-creation of single-ended tube amplifiers, especially zero-feedback designs.
He began building these when he was an active member of a high-school band in the 1960s. At that time he used the legendary 300B, a directly heated triode tube dating from the 1930s and already something of an antique. As a young musician,…
Still, this isn't an amplifier you'd leave on all the time. Once run-in, it reached 80-90% of its potential within 30 minutes of cold turn-on. A Standby mode powers the heaters and driver section; the output-tube anode will then warm up in about five minutes. You could leave it powered up for long days or weekends, exploiting the Standby mode to save tube life and power. Otherwise, I'd switch it off completely.
As my ears became accustomed to this affordable power amplifier, it was hard not to be aware of the performance gap between it and the cost-no-object CAD805C reference. As is…
Sidebar 1: Martin Colloms' Associated Equipment
Source components: Krell KPS-20i/l CD player, dCS Elgar D/A processor (both used with and without a control preamplifier). Linn LP12/Lingo turntable, Naim ARO tonearm, van den Hul GLA1V phono cartridge.
Preamplification: Conrad-Johnson ART and P-FR line stages, Conrad-Johnson Premier Fifteen phono preamplifier.
Power amplifiers: Krell FPB600 and FPB650M, Cary CAD805C, Conrad-Johnson Premier Eight A and CAV50, Bel Canto SET 40.
Loudspeakers: Wilson Audio WITT 2, Avantgarde Duo 2, Sonus Faber Electa Amator II, Quad ESL-63, Spendor SP2…