JMLab Daline 3.1 Floor standing speakers

The JM Lab Daline 3.1, manufactured in France, is a recent addition to the American audio scene. It is a slender columnar speaker housed in an attractively finished cabinet. The system's name is derived from its internal construction, described as a "decoupled anti-reso-nance line." This is a variant of the well-known (but relatively costly and rarely employed) transmission-line enclosure, which has the reputation of producing a notably clean and extended low-bass response.

The Daline 3.1 is a two-way system with a 5.25-inch long-throw woofer and what the manufacturer calls a Tioxid tweeter, an unusual design featuring a 1.125-inch inverted titanium dome coated with a 7-micrometer-thick layer of titanium dioxide. The two drivers are close together near the top of the speaker's front panel, about 3 feet above the floor.

The upper third of the enclosure serves as a single cavity that loads the rear of the woofer. Instead of being a simple enclosed or ported volume, however, this cavity opens into a folded transmission line, whose length appears to be about 6 feet, terminating in a port at the lower back of the cabinet. It is also apparent that the partitions forming the line provide exceptional bracing for the cabinet walls.

The woofer has dual voice-coil windings, which the manufacturer says are operated in parallel. The rationale for this configuration is that one voice coil handles the middle frequencies and the other the bass range. The woofer's suspension does clearly allow an impressively long cone excursion for its size. The crossover to the tweeter is at 4 kHz with slopes of 12 dB per octave.

The system's bandwidth is specified as 40 Hz to 23 kHz at the -3-dB points on-axis and to 20 kHz at 30 degrees off-axis. Sensitivity is rated at 89 dB sound-pressure level (SPL) at 1 meter for an input of 2.83 volts. The impedance is nominally 8 ohms, with a minimum value of 4 ohms.

The speaker's input connectors are near the bottom of the rear panel, just below the port. There are two pairs of multiway binding posts, normally paralleled by metal jumpers, which connect to the tweeter and woofer crossover sections. With the jumpers removed, the system can be biwired or biamplified.

The 3.1 weighs a solid 34 pounds, which seems considerable for an enclosure of its modest size. But a cutaway drawing of the cabinet indicates that in addition to its internal partitions, the lower portion is filled with sand, which the manufacturer says damps cabinet resonances as well as weighting the system's bottom to improve its stability. The cabinet bottom is also equipped with short, conical feet, which can be removed if desired.

JM Lab recommends that the Daline 3.1 be placed with its back panel at least 1 foot from the wall behind it. For our listening tests and room measurements we placed them about 3 feet in front of the wall and slightly more than that distance from a side wall.

The averaged room response from the left and right speakers was exceptionally flat from 350 Hz to 20 kHz, with a variation of only +/-2 dB over that range. The lower frequencies were also unusually uniform, though unavoidable room-boundary effects resulted in a considerably greater variation in output. The output between 200 and 400 Hz was somewhat elevated relative to the rest of the range.

Quasi-anechoic MLS response measurements at distances of 1 to 2 meters confirmed the outstanding flatness of the system's response, which was within +2.5 dB from 300 Hz to about 18 kHz (there was a sharp drop of about 4 or 5 dB at that frequency, although the output returned to the reference level at our upper measurement limit of 20 kHz).

The system's horizontal directivity - the change in its high-frequency output as one moves off the tweeter axis - was as notable as its frequency response. At 45 degrees off - axis, output in the octave between 10 and 20 kHz was down an average of only about 5 dB relative to the on-axis output (most tweeters we have tested have shown variations of 10 dB or more in this measurement). And, though probably less important to a speaker's audible performance than the other characteristics we measure, the Daline 3.1's group-delay response (a measure of phase linearity) was among the flattest we have measured, with an overall variation of less than 500 microseconds from the lower audio frequencies to 20 kHz.

The system impedance agreed exactly with the curve printed in the manufacturer's literature. There were peaks of 32 ohms at 60 Hz and 18 ohms at 1.3 kHz, a minimum of 4 ohms at 200 Hz, and a constant 12 ohms between 6 and 20 kHz. In view of that and the system's measured sensitivity of 90 dB, it is clear that the Daline 3.1 should be an easy speaker for any decent amplifier to drive.

One of our major concerns was how much distortion the Daline system's relatively small woofer would generate at low frequencies. It proved to be a giant killer, however. At a constant drive level of 2.83 volts, the distortion was about 9 percent at 30 Hz, falling to just over 1 percent at 60 Hz and varying between 0.6 and 2 percent from there to its rated crossover frequency of 4 kHz. We have tested a number of far larger speakers that did not match that performance.

The woofer's size also prompted caution in measuring the speaker's ability to absorb large peak power inputs. At 100 Hz, the diminutive driver absorbed single-cycle bursts of 275 watts into its 6-ohm impedance without damage, although it had obviously reached its suspension limits. At higher frequencies the amplifier clipped before the speaker was at risk, at peak levels between 600 and 1,000 watts.

If you guessed that a speaker with the Daline 3.1's performance characteristics probably sounds pretty good, you would be correct. From the beginning, it was obviously a very flat, smooth, clean-sounding speaker, and nothing in our testing diminished that judgment in the slightest. One of its most striking characteristics is what I call, for want of a better term, "acoustic invisibility." The soundstage was simply "there," occupying the front of the room, and without any apparent relationship to the two slender columns at either side. This effect was confirmed by playing the test tracks of the Chesky JD37 CD - the stereo positioning of the noise-burst test signal was as nearly perfect as I have yet heard.

My initial reaction to the Daline 3.1 was one of surprise, tinged with disbelief when I realized that most of its sound was generated by a single, rather small driver. While (like most speakers) the 3.1 can benefit from a good subwoofer, it doesn't really demand such assistance. The bass was solid and clean down to below 50 Hz (it was room-filling at that frequency), and, though at a considerably reduced level, it could still deliver a clean output at 30 Hz.

All too often I hear or test speakers claimed to achieve improbable feats, only to find them falling well short of their touted performance. The JM Lab Daline 3.1 is distinctly not in that category. It seems to do exactly what is claimed for it and is a real value at its price.

JMLab Daline 3.1 Floor standing speakers photo