Manufacturer's Specifications
System Type: Three-way, tower-style, vented-box system.
Drivers: 10-in. cone woofer, 6-in.
cone midrange, and 1-in. aluminum-dome tweeter.
Frequency Response: 36 Hz to 20 kHz, ± 1 dB, on axis; 36 Hz to 10 kHz, ± 1 dB, 30° off-axis horizontally.
Sensitivity: 88 dB at 1 meter with 2.83 V rms applied.
Crossover Frequencies and Filter Slopes: 250 Hz (18 dB/octave, Butterworth) and 2.2 kHz (24 dB/octave, Linkwitz-Riley). Impedance: 4 ohms nominal.
Recommended Amplifier Power: 10 to 250 watts per channel.
Dimensions: 13 1/2 in. W x 4 41/2 in. H x 14 3/4 in. D (34.3 cm x 113 cm x 37.5 cm) excluding pedestal; pedestal, 15 3/4 in. W x 2 in. H x 17 in. D (40.0 cm x 5.1 cm x 43.2 cm).
Weight: 95 lbs. (43.1 kg) for single system.
Price: $2,000 per pair. Available it premium dark oak, black oak, or light oak.
Company Address: 633 Granite Court, Pickering, Ont., Canada L1W 3K1.
The Stratus Gold is the top of Canadian manufacturer PSB's loudspeaker line, which also includes models from $225 to $1,400 per pair. The Stratus Gold is a large, floor-standing tower system with a vented-box low end designed around a high-excursion 10-inch woofer.
PSB was the first Canadian loudspeaker company to take advantage of the advanced testing facilities and scientific staff of Canada's National Research Council. The NRC, as pointed out in my review of the Paradigm 7se loudspeaker (see sidebar, "Testing at Canada's NRC," Audio, September 1989), is a government-funded Canadian operation whose mandate is to help Canadian manufacturers be competitive in world markets. PSB has made extensive use of NRC facilities, including controlled listening tests in NRC's International Electrotechnical Commission (IEC) Standard listening room (after which both Audio's New York listening room and my own were patterned), to optimize the Status Gold's performance.
PSB has emphasized minimizing resonances, which "cast a muddy veil over every sound," according to their design white paper. The large cabinet of the Stratus Gold employs an innovative scheme of internal bracing and damping to minimize resonances, and weighs in at 95 pounds! The Gold's tweeter (source: Vifa of Denmark) uses a high-stiffness, low-mass, aluminum-alloy dome with a polyamide suspension. To make the tweeter's off-axis response in the top octave more uniform, PSB adds a phase plug in the form of a 1/2-inch diameter rigid disk held about 0.050-inch above the center of the dome by six thin plastic spokes. The disk and spokes are an integral part of the tweeter's molded mounting ring. In addition to modifying the directional response, the disk has the very practical benefit of protecting the dome from roving fingers and other objects.
The 6-inch midrange uses a very large, 28-ounce ceramic magnet, mounted in a cast-magnesium frame, which provides high efficiency and control of its low-end response.
The cone is made from a mineral-filled polypropylene material, which provides the proper stiffness and a high degree of internal damping. A soft-rubber dust cap and long-excursion rubber surround complete the design. The midrange is mounted in its own closed-box sub-enclosure, which is damped with loosely packed soft fibers, and is located in the top of the cabinet. The bottom wall of the sub-enclosure, which is attached to all four walls of the larger enclosure, also serves as a brace to strengthen the main cabinet. The smaller size of the midrange allows a higher crossover frequency, thus keeping high-energy fundamental tones out of the tweeter and allowing cleaner operation at higher levels.
The crossover between the woofer and midrange, at 250 Hz, is a third-order Butterworth design, which provides both flat on-axis response and flat sound power through the crossover frequency range.
The 10-inch woofer has a massive, 54-ounce magnet and a 2-inch diameter, long-throw voice-coil. Its cone is made of felted paper fiber, treated for increased stiffness, and is held on its periphery by a rubber surround. In a phone conversation, PSB's founder, Paul Barton, stated that the spider of the woofer has been designed with deliberate nonlinearities to essentially eliminate the dynamic offset problems that many high-excursion woofers exhibit (see sidebar, "The Oil-Can Effect," in the previously mentioned review of the Paradigm 7se). The Stratus Gold's cabinet has three shelf braces, strategically placed to provide maximum strength and minimize side-panel resonances. The cabinet is of furniture quality, with oak-veneered side panels and solid hardwood on the top and bottom. For maximum rigidity, the major joints at the top and bottom of the cabinet are locked into place by tongue-in-groove aluminum extrusions.
The crossovers use all air-core inductors, wound with 14-gauge wire, and high-voltage capacitors bypassed with small polypropylene capacitors. The crossover between midrange and tweeter is a sharp-cutoff, fourth-order, Linkwitz-Riley design. Its steep, 24-dB/octave slope ensures that only treble energy reaches the tweeter and minimizes lobing problems by keeping the acoustic outputs of the midrange and tweeter in phase.
Measurements
Fig. 1--On-axis frequency response for an input of 2 watts into 4 ohms (2.83
V rms); measurement made at 2 meters and referenced to 1 meter.
Fig. 2--On-axis phase response and group delay, corrected for tweeter arrival
time.
Fig. 3--One-meter, on-axis energy/time curve, measured with grille off.
Fig. 4--Horizontal off-axis frequency responses, taken from the front, around
the side, and to the rear of the speaker.
Fig. 5--Vertical off-axis frequency responses, taken from below, up the front,
and to the top of the speaker.
Figure 1 shows the equivalent, 1-meter, on-axis, anechoic frequency response curve, smoothed with a 10th-octave filter, for an input of 2.83 V rms (2 watts, at the rated 4-ohm impedance). The curve was taken at 2 meters and referenced to a distance of 1 meter, with the microphone normal to the enclosure's front surface, midway between the midrange and tweeter. This point is 36 inches above the bottom of the enclosure and corresponds to the ear height of a seated listener. The figure also shows the effect of the Stratus Gold's grille, which added a ±2 dB roughness in the response above 2 kHz. The remaining measurements were taken with the grille off.
The curve fits within an admirably flat envelope of about ± 1.5 dB from 40 Hz to 20 kHz, which is only a bit off the manufacturer's rating. The curve exhibits some roughness in the response between 3 and 7 kHz and a slightly rising response above 8 kHz. Averaging the axial response over the range of 250 Hz to 4 kHz yielded a sensitivity of 86.9 dB, only about 1 dB below the manufacturer's 88-dB rating.
The systems were very closely matched, within ±0.5 dB, from 100 Hz to 17 kHz. However, at higher frequencies, one system exhibited a narrow, high-amplitude (12-dB) ultrasonic peak at 22.8 kHz, which made its 20-kHz response 6 dB higher than the other system's. That other system's response, by contrast, was fairly flat up to 25.3 kHz, where it exhibited a slight peak and dip.
A call to Barton revealed that the high-frequency peak was not typical and was due to the tweeter's metal-dome breakup resonance occurring too low. He promptly sent me two new matched tweeters, which I ultimately installed, and I did further listening tests. Before installing them, however, I carefully compared the speakers subjectively, side-by-side, and could not detect any differences. Fortunately, the response differences were exhibited only above 17 kHz, where I could not hear their effects with normal program material. I did do a high-level, ultrasonic sine-wave sweep comparison of the tweeters and could not detect any audible subharmonic distortion in the bad tweeter. I used the unit with the good tweeter for all subsequent tests.
Figure 2 shows the axial phase and group-delay measurements of the system, corrected for the tweeter's time arrival. There is a total phase rotation of about 250° between 1 and 20 kHz. The group-delay curve exhibits oscillations between 3 and 7 kHz, which correspond to the roughness in the axial response noted earlier. These group-delay oscillations are not significant because they result from minimum-phase aberrations in the response, i.e., the oscillations would go away if the axial response were carefully equalized flat with a minimum-phase equalizer (which most equalizers are!). A separate measurement indicated that the midrange lags the tweeter by about 0.25 mS (250 µS). This is little more than one-half wavelength at the 2.2-kHz crossover point.
Figure 3 shows the 1-meter, on-axis, 2.83-V rms energy/ time curve (ETC) of the Stratus Gold, for a test signal swept over the range from 200 Hz to 10 kHz. The main arrival, at 3 mS, is fairly compact and well behaved, with some broadening at levels 20 dB below the peak. A broad lower-level group of returns between 3.5 and 4.2 mS is seen, but I did not take the time to investigate the source of these returns. A perfect energy/time curve would appear as a single sharp spike centered at 3 mS, with a width of about 1 mS at the base (the 50-dB line) and tapering to a rounded point at the top.
Removing the woofer reveals a well-constructed box with tight fit. An internal partition separates the top of the enclosure to make a housing for the midrange. All panels are made from medium-density fiberboard (MDF), 3/4-inch thick.
The top and base of the cabinet are solid, 3/4-inch oak and look very handsome. The cabinet is braced internally with MDF panels that divide the cabinet into separate compartments but have four large, square holes for air circulation.
To damp internal reflections, gray woolly fiber is used inside the box rather than fiberglass. Unfortunately, most of the system's damping fiber was placed rather loosely inside the cabinet, with many loose particles, and had a tendency to shoot out the port under high-level excitation at low frequencies! A high-level, low-frequency sine-wave sweep revealed no significant cabinet side-wall resonances except for a front-panel resonance in the area at the bottom of the woofer, in the 130- to 180-Hz range. This resonance caused a moderate, internal vibrating sound at high-level excitation (both systems had this problem). A comparison of the woofer's excursion with the port open and closed (covered by hand) revealed that the port reduced the woofer's excursion about 50% at the Helmholtz box resonance of about 28 Hz. The woofer did not exhibit any detectable dynamic offset effects (a rare trait). Wind noises were minimal at high drive levels.
The woofer's linear excursion capability was a healthy 1/2 inch, peak to peak, with a very high excursion limit of about 1 inch, peak to peak. The woofer overloaded gracefully at high levels, with no objectionable noises. The effective piston diameter of the 10-inch woofer was about 8 1/4 inches (measured from the middle of the surround on one side to the middle of the surround on the other). The crossover of the Stratus Gold consists of 13 parts: Four inductors, five capacitors, and four resistors. All inductors are air-core. The crossover is hand-wired on a piece of hardboard and mounted on the rear of the cabinet, behind the woofer. Film and nonpolarized electrolytic capacitors are used. All internal wiring is stranded 14-gauge, with push-on terminal clips for driver connection. A notable feature is the hand selection of inductors and capacitors to meet a very tight, ± 1% tolerance (according to the supplied schematic). Resistors are held to a ± 2% tolerance.
The lower, 250-Hz, crossover is a third-order (18-dB/ octave) Butterworth design with the woofer connected in reverse polarity from the midrange and tweeter. I verified this by noting the inward movement of the woofer cone with application of a positive d.c. voltage to the positive inputs of the system. The crossover schematic also confirmed the reversed-polarity connection to the woofer and that there was no polarity inversion in the signal going to the midrange and tweeter.
Fig. 6--Mean horizontal responses, derived from data of Fig. 4.
Fig. 7--Mean vertical responses, derived from data of Fig. 5.
Fig. 8--Magnitude of impedance.
Fig. 9--Complex impedance, showing reactance and resistance vs. frequency.
Fig. 10--Three-meter room response, showing both raw and smoothed data.
The phase response of the upper crossover was investigated by noting the change in axial frequency response with the tweeter connections reversed. A Linkwitz-Riley crossover design dictates that the drivers be exactly in phase with each other at all frequencies throughout the crossover region, thus yielding no lobing error (i.e., aiming the main crossover directional lobe directly ahead). If the polarity of either driver is reversed, a very deep null should result in the axial response at the crossover frequency. With the tweeter reversed, the on-axis response null was only about 15 dB deep, which indicates that the individual responses are about 20° to 25° (rather than 0°) out of phase when connected normally. Further investigation revealed that the main crossover directional lobe, rather than being aimed directly ahead, was aimed somewhat upward, which caused the slight out-of-phase condition. This optimizes coverage for seated to standing listeners, at the expense of listeners below axis.
The horizontal, "3-D," off-axis curves of the Stratus Gold are shown in Fig. 4. Unlike the "3-D" curves in my previous reviews, these are not normalized to the on-axis response.
For a system with perfect off-axis response, all the off-axis curves would have the same shape as the on-axis curve (including any axial aberrations). The on-axis response curve is shown as the bold curve at the rear of the graph.
The curves are well behaved and indicate good, wide horizontal coverage. Not clearly shown on the right side of the graph is an increase in the off-axis, high-frequency response between 15 and 18 kHz, which indicates an abrupt widening of the coverage in this range.
Figure 5 shows the vertical off-axis curves, also in non-normalized form. The on-axis response (the bold curve in the middle of the graph) is somewhat obscured by adjacent curves. The raised responses at the rear of the plot, which unfortunately have been visually emphasized by the chosen "3-D" view angle, are at extreme down angles and thus not too important. In general, the off-axis curves are well behaved and indicate fairly smooth vertical response, particularly for angles of 0° to 15° above axis (not clearly shown in the graph), which correspond approximately to the heights of a sitting and a standing listener.
Figures 6 and 7, respectively, show the NRC-style mean horizontal and vertical on- and off-axis response curves.
The mean axial (+ 15° to-15°) horizontal response curve in Fig. 6 is reasonably flat and extended except for a slight depression in the range from 2.5 to 8 kHz, coupled with some response roughness and a general rising trend above 8 kHz. Up to 7 kHz, the 30° to 45° mean response is surprisingly close to the axial curve, both in shape and level.
The response starts falling above about 7 kHz but exhibits a high-frequency peak, at about 18 kHz, that indicates the abrupt widening of the coverage seen in Fig. 4. The 60° to 75° off-axis response is fairly flat up to 7 kHz but, like the 30° to 45° mean response, rolls off above that point and exhibits a high-frequency peak above 15 kHz.
Figure 7 shows the mean vertical responses of the Stratus Gold. The mean vertical axial-response curve is very similar to the mean horizontal axial-response curve shown in the previous figure. This signifies that the sound of the Stratus Gold should change very little in the primary listening window, for both lateral and vertical movements. Examination of the individual curves that comprise the mean axial response (not shown) indicates that the up curves are significantly smoother through the crossover region than the down curves. This is a direct result of the slight out-of-phase condition and lobing noted earlier. The 30° to 45° mean response shows narrowing-coverage directional effects of both crossovers, which result in response dips at 400 Hz and 2 kHz. Both vertical off-axis mean curves exhibit the same high-frequency roll-off and peak phenomena that the horizontal off-axis mean curves exhibit.
Figure 8 shows the Stratus Gold's magnitude of impedance plotted over the extended range from 5 Hz to 20 kHz.
The system had a low of 2.9 ohms at 100 Hz and a high of 13.4 ohms at the subsonic frequency of 15 Hz. The very low impedance in the bass and upper-bass range between 55 and 350 Hz make the Stratus Gold a demanding load for any amplifier. Only amplifiers with high current capability should be used with the Stratus Gold. The impedance's 2.9-ohm minimum and 3.4:1 variation (from 9.8 to 2.9 ohms) in the audio passband make the Stratus Golds quite sensitive to cable resistance. To keep cable-drop effects from causing response peaks and dips greater than 0.1 dB, cable series resistance should be limited to a (low) maximum of about 0.050 ohm (50 milliohms). The Stratus Gold's complex impedance plot, over the range from 5 hz to 30 kHz, is shown in Fig. 9. The smooth nature of the spirals indicates that there are no problems.
The phase angle of the impedance (not shown) reached a maximum of +39° at a subsonic 7 Hz and a minimum of-53° at the bass frequency of 48 Hz.
Fig. 11--Harmonic distortion products for the musical tone E1 (41.2 Hz).
Fig. 12--Harmonic distortion products for the musical tone A2 (110 Hz).
The system's 3-meter room curve, with raw and sixth-octave smoothed responses, can be seen in Fig. 10. The Stratus Gold was located in the right-hand stereo position, aimed at the listening location, and the test microphone was placed at ear height (36 inches) at the listener's position on the sofa. The system was swept from 100 Hz to 20 kHz with a sine-wave signal of 2.83 V rms (corresponding to 2 watts into the rated 4-ohm impedance). The parameters of the time-delay spectrometer's sweep were chosen so as to include 13 mS of the room's reverberation along with the direct sound. The curve is well behaved and extended except for some room-effect response roughness below 1.5 kHz. Above 2.5 kHz, the curve is very smooth and flat, the best I've measured in my listening room.
The distortion of single-frequency tones versus power level, for the musical notes of E1 (41.2 Hz) and A2 (110 Hz), are shown in Figs. 11 and 12. Distortion products for A4 (440 Hz) were below the measuring capability of my equipment. These measurements indicate the level of harmonic distortion generated by the system with the application of a single-frequency sine wave at power levels from 0.1 to 100 watts (10 to 20 dBW, a 30-dB dynamic range), in steps of 1 dB. The power levels were computed using the rated system impedance of 4 ohms (20 V rms = 100 watts, etc.). The E1 (41.2-Hz) harmonic distortion data is shown in Fig. 11. The full-power distortion, at 100 watts, only reached a moderate 8.9% second harmonic. At 41 Hz, 100 watts generates a loud 101 dB SPL at 1 meter. The A2 (110-Hz) harmonic data is shown in Fig. 12. The second harmonic reached only 0.9% at full power, and the third was even lower, at 0.5%: At 110 Hz, the system generates a loud 104 dB SPL at 100 watts at 1 meter.
The IM on a 440-Hz (A4) tone, created by a 41.2-Hz (E1) tone of equal input power level, is shown in Fig. 13. At full power, the distortion only reached 3.6%. The distortion specs of the Stratus Gold are among the lowest I have measured.
The short-term, peak-power tone-burst input and output capabilities of the system are shown in Figure 14. The peak input power was calculated by assuming the measured peak voltage was applied across the rated 4-ohm impedance. At higher frequencies, where the Stratus Gold's impedance is near 8 ohms, this results in higher than actual power levels, and vice versa when the impedance is below the rated 4 ohms.
The lower curve of Fig. 14 shows the maximum power-handling capacity of the Stratus Gold. At all frequencies above 125 Hz, the output limit of my power amplifier (a Crown Macro Reference) was reached before the speaker's limit was reached! The jump in input power between 400 and 500 Hz is a result of my changing the amplifier from parallel-mono to bridged-mono operation. The parallel-mono mode is used for loads below 4 ohms (like the Stratus Gold's impedance from 50 to 400 Hz), while bridged mono is best for loads of 4 ohms or more. Above 800 Hz, the system could handle peak voltages in excess of 200 V, which is 10 kW into a 4-ohm load or 5 kW into 8 ohms, and still provide somewhat clean output and not be harmed.
("My speaker can handle 10,000 watts, nyah nyah nyah!!") The mid- and low-frequency power-handling capacity of the Stratus Gold was also very good, more than 100 watts at 20 Hz. The power levels were so high that the lights in my lab were keeping time with the test bursts! The upper curve in Fig. 14 represents the peak sound pressure levels the Stratus Gold can generate at a distance of 1 meter on axis for the power levels shown in the lower curve. Also shown on the upper curve is the "room gain" of a typical listening room at low frequencies, which adds about 3 dB to the response. at 80 Hz, and 9 dB at 20 Hz.
Above 500 Hz, the peak output rises to nearly 126 dB. With room gain, a single Stratus Gold can generate peaks in excess of 110 dB SPL above 26 Hz, and 120 dB above 60 Hz! Of course, these figures will improve for two systems operating in stereo with bass signals that are common to both channels. The Stratus Gold definitely does not require a subwoofer! Its maximum output in the low-frequency range from 30 to 150 Hz exceeds that of most of the speakers I have evaluated with this test.
Fig. 13--IM distortion on 440 Hz (A4) produced by 41.2 Hz (E1), mixed in one-to-one
proportion.
Fig. 14--Maximum peak input power and maximum peak sound output vs. frequency
at 1 meter on axis. The power-handling capabilities are extremely high; see
text.
Use and Listening Tests
The Stratus Gold systems have been designed for flat response without the aid of any nearby reflective boundaries that may provide bass reinforcement. This made them very suitable for use in my usual speaker positions, a significant distance from any reflecting surfaces. All listening was done in my listening room, which measures 15 1/2 x 27 x 8 feet, with the Stratus Golds 8 feet apart and canted in toward my listening position on the sofa, about 10 feet away. This location placed them about 6 feet away from the short rear wall and 4 feet from the side walls.
Driving equipment included the Onkyo Grand Integra DX-G10 and Enlightened Audio Designs (EAD) "Ultra" modified Rotel RCD-855 CD players, along with the Jeff Rowland Consummate preamp and Model 7 power amplifiers, all connected with Straight Wire Maestro interconnects and speaker cables.
I did most of the listening before the measurements, although some listening was done after I had replaced the tweeters with known good units. It turned out that only one of the original tweeters was not typical. None of the after-the-fact listening tests changed my original impressions of the systems.
Connection to the Stratus Gold is through a pair of heavy-duty double-banana jacks on the bottom of the system. Two pairs of jacks are provided, to facilitate bi-wiring the system.
For the non-bi-wired state, the pairs are connected with large gold-plated straps. Because the jacks are on the bottom of the system, attachment of the cables is difficult unless the system is lying on its side. Since I had to make and break connections several times during these tests, I took a shortcut, doing a balancing act by tipping the system slightly forward, reaching under the rear of the system with plug in hand, and making connection by feel. But this really is not the way to do it, because the system could fall forward! I did not bi-wire the Stratus Golds for my listening evaluations.
The appearance and the fit and finish of the Golds are excellent. My wife and family really liked the oak finish. Particularly handsome are the beveled top and base of the system; it's quite obvious that they are made from solid pieces of oak, because the wood grain maintains continuity all around the edge and along the bevels.
The Stratus Golds produced a very clean, balanced, wide-range sound that competed with my reference systems (B & W 801 Matrix Series 2) on nearly an equal basis. The PSB systems were slightly more bright than the references, with a very open, revealing character. With the grilles off, they were noticeably brighter than the reference systems, but with the grilles on, the high-frequency differences were much smaller. Overall, however, I preferred the system's sound with the grille off, and all the following listening was done in that condition.
Andrew Rangell's piano playing on J. S. Bach's The Goldberg Variations (Dorian DOR-90138, a great piano CD) demonstrated the Golds' good balance, presence, and smooth upper bass. Orchestral climaxes on Igor Stravinsky's Petrouchka and Rite of Spring (Chesky CD 42, one of Chesky's excellent CD re-masterings of early '60s analog recordings) were reproduced very cleanly and demonstrated the Golds' excellent dynamic range. The organ pedal notes played by E. Power Biggs, on the Saint-Satins "Organ" Symphony (CBS Odyssey MBK 38920, another good remastering from an old analog source) were handled very well, but the upper harmonics of the strings on the same selection were emphasized a bit too much for my taste.
With the Consummate preamplifier in mono mode, the center image of the Gold loudspeakers was very stable with frequency and was of minimal width. Imaging and sound-staging were both top-rate.
The Stratus Gold passed the pink-noise, stand-up/sit-down test with excellent results. Hardly any noticeable tonal changes in upper-mid response were noted at any position, sitting or standing. The systems' low-frequency output on third-octave band-limited pink noise equaled that of the reference systems at all frequencies from 31.5 Hz on up. However, in the two lower third octaves, at 20 and 25 Hz, the Gold's output was diminished and was accompanied by significant chuffing sounds in the vented-boxed ports. The third-octave low-frequency test signal is very demanding because the signal causes high woofer displacement (and resulting high port velocities), but it does not have any higher frequency spectral components that can mask the air-rush noises. Typical program material having high low-frequency energy levels always has some higher frequency content that usually masks these types of noises.
The bass notes between 3:41 and 3:44 on track 15 of Dorian's very demanding organ version of Pictures at an Exhibition (DOR-90117), when the organ is played all-stops-out during the finale, made my reference systems stumble.
But the Stratus Golds handled the difficult passage without a whimper (and even at higher playback levels!). Track 2, however, at times 0:50 to 1:02, contained some program information that triggered the front-panel vibration in the lower area of the woofer, noted in the "Measurements" section. (I searched for such a passage after I had done the measurements.) The dynamic range of the Stratus Gold was nicely demonstrated by playing the heavy-metal track "Rock and Roll Animal" from the CD The Final Frontier by Keel (MCA Records MCAD-5727) at near concert levels. (I'll bet you didn't know that the lead singer of this group, Ron Keel, is my twin brother-just kidding!) For those Audio readers who like to play music (?) at these levels, the Golds will do it very nicely.
The solo electric bass passage starting at time 3:04 from "The Chain" on Fleetwood Mac's Rumours CD (Warner Bros. 03010-2) could be played loud and clean, with a low end that could be felt! The hand-claps and cymbal crashes on track 9, "I Don't Want To Know," were particularly effective through these PSB systems.
At $2,000 a pair, the Stratus Golds provide considerable performance and first-class looks for the money. They should appeal both to the audiophile crowd, for whom accuracy, balance, and imaging are important, and to a wider audience that likes loud rock 'n' roll, for whom the ability to play loudly and cleanly is important. The low impedance of the Golds through the upper bass range, however, means that higher quality, more expensive amplification is required along with low-impedance cabling.
D. B. Keele, Jr.
(Source: Audio magazine, Nov. 1991)
Also see:
MB Quart 280 Speaker system (Dec. 1988)
Quart 490MCS Speaker (Equip. Profile, Feb. 1992)
Celestion UL-10 Loudspeaker (Jan. 1977)
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