Jamo Concert II Speaker System Review

The Danish-made Jamo Concert II speaker is a fairly conventional two-way system with a 6-1/2-inch woofer operating in a bass-reflex enclosure. The cabinet, suitable for shelf or stand placement, measures 16-1/8 inches high, 9-3/8 inches wide, and 9-7/8 inches deep, and each speaker unit weighs about 20 pounds. The crossover, at a nominal frequency of 2,000 Hz, is to a 1-inch soft-dome tweeter. The rated system impedance is 8 ohms, and the system has no controls or adjustments.

The cabinet of the Jamo Concert II is finished in mahogany or stained black ash. Gold-plated binding posts, recessed into the rear of the cabinet, accept stripped wire ends or banana plugs, but are spaced too widely for dual banana-plug connectors. The woofer port is in the rear of the cabinet. The black perforated-metal grille is retained magnetically, with its edges fitting into slots along the sides of the speaker panel. The unusual design allows the grille to be removed and replaced with exceptional ease, and the absence of protrusions on the sculptured panel makes the Concert II much more attractive than most speakers are when operated without a grille.

Beyond the Concert II’s physical specifications, crossover frequency, and impedance, the only ratings provided in the owner’s manual are its frequency range, given as 40 to 20,000 Hz, and three distinct power ratings: “Operating Power 6.3 watts, IEC Input Power 40 watts, and Rated Power 80 watts (120 watts music).” These numbers, like all speaker power ratings, derive from nonstandard measurement methods and are not easily correlated with real-world operation. Price: $798 a pair.

Lab Tests

For our measurements and listening tests, we installed the Jamo Concert II speakers on 26-inch stands and placed them about 2 feet from the wall behind them. The room-response measurements indicated a notably flat and smooth response, with the usual floor-reflection peak and dip between 250 and 500 Hz, and a strong output between 50 Hz and our 20,000-Hz measurement limit. The close-miked woofer and port response curves combined for an unusually flat response from about 35 to 200 Hz, falling gently at higher frequencies to —10 dB at 2,000 Hz. When this was combined with the room curve, the result was a composite frequency response of ± 3 dB from 25 to 20,000 Hz.

Although the composite curve seems to suggest a remarkable bass extension for a 6-1/2-inch woofer, the 25-Hz figure should not be taken too literally. The actual low-frequency limits of the speaker are defined by its power-handling and distortion characteristics rather than by an artificial low-level measurement.

The system’s sensitivity was 88.5 dB sound-pressure level (SPL) at 1 meter with a standard input of 2.83 volts of pink noise. Our reference level for the distortion measurements was 3.36 volts, corresponding to a 90-dB SPL. The woofer distortion was about 1 percent at 100 Hz, 2 percent at 80 Hz, and 7 percent at 50 Hz. The effective crossover between the cone and port radiation was at about 75 Hz, and between 20 and 50 Hz the system’s actual distortion with a 3.36-volt input was in the 10- to 30-percent range.

The impedance of the system was 7 to 7.5 ohms at 43 and 180 Hz, with another dip to 5 ohms at 3,500 Hz. There were impedance peaks of 21 ohms at 27 Hz, 27 ohms at 80 Hz, and 30 ohms at 1,000 Hz. The horizontal dispersion was good, with little divergence between the response measured on-axis and 45 degrees off-axis below 8,500 Hz and only about 6 dB difference at 12,000 Hz. Quasi-anechoic FFT response measurements with our IQS signal-analysis system confirmed the smoothness and uniformity of the system in the audible range, showing only ±1.5 dB variation from 180 to

16.000 Hz. The overall group-delay variation of 0.2 millisecond from 3.000 to 20,000 Hz was consistent with our other measurements.

High-power tests with one-cycle tone bursts showed that the Concert II was no midget in its power-handling abilities. Our amplifier clipped before the speaker rattled, reaching inputs of 490 watts at 100 Hz (into 14 ohms), 250 watts at 1.000 Hz (30 ohms), and 790 watts at 10,000 Hz (8 ohms).

Comments

The measured performance of the Jamo Concert II indicated that it should be a very listenable small speaker, but we knew that before we made any measurements. The Concert II had a balanced spectral response and unmistakable smoothness that were instantly apparent. In A/B comparisons it showed itself to be in the same class as some highly regarded speakers of comparable size but much higher price. It was not even badly outclassed by some much larger, as well as more expensive, systems. There are no miracles in audio, however, and although the Concert II had a pleasing frequency balance, its bass output could not compete with that of systems using larger drivers in larger enclosures.

Of course, each speaker has special characteristics that make it more or less attractive to any given listener, and no two speakers (including pairs of the same model) are truly identical. I would not presume to rank one speaker above or below another merely because their individual colorations differ slightly, but I have no hesitation in ranking the Jamo Concert II as one of the better contenders in the under-$1,000-a-pair price class.

Read all

Jamo reviews

Read all