John Atkinson

The problem confronting the magazine reviewer when organising the necessary listening tests to accompany/reinforce the measured behavior of a device under test is complex. There has never been a problem with the measurement aspect; as long as someone has access to the same test gear—and full knowledge of the test conditions—then he should be able to replicate the critic's findings exactly (assuming an infinitely narrow spread of behaviour from sample to sample—a rasher assumption with some manufacturers' equipment than of others). However, when it comes to determining reliably the audible (or inaudible?) effects on music program by an amplifier/cartridge/loudspeaker etc. then the going gets tough.

Back in May 2014, I reviewed NAD's Masters Series M50 Digital Music Player ($2499) and M52 Digital Music Vault ($1999 with 2TB storage). At the 2017 Consumer Electronics Show, NAD announced the M50.2, which is almost identical to the original M50 but now incorporates two 2TB hard disks, arranged as a 2TB RAID array, to ensure data integrity, and adds TosLink and coaxial digital inputs, Bluetooth with aptX for streaming music from a smartphone or tablet, and two single-ended analog inputs—all for $3999, or $499 less than the combined cost of the two earlier products. Like the M50, the M50.2 offers WiFi and Ethernet connectivity, and has a CD drive, accessible via a slot on the front panel under the color TFT touchscreen, that can be used to play CDs, or rip them as FLAC, WAV, or high-bit-rate MP3 files.

Introduced in 1985 as the smallest model in JBL's "Ti" range, the 18Ti ($590/pair) shares with its larger siblings, like the JBL 250ti (recently reviewed by J. Gordon Holt), a high-tech tweeter that uses a one-piece ribbed titanium-foil dome/surround just 25µm thick. This is both rigid and of very low mass, pushing its first-breakup mode up to the region of 30kHz. The tweeter is mounted above the polypropylene-cone woofer, offset a little to one side to make room for the 45mm diameter port (though the speakers are not supplied as a handed pair). The 10-liter internal volume box is well-constructed from 20mm chipboard, covered in real-wood veneer.

Kentucky manufacturer Thiel has acquired a reputation for the coherence of sound presented by its range of distinctive, sloping-baffle, floor-standing loudspeakers. Designer Jim Thiel gives a high priority to linearity of phase response; as a result, he chooses to use phase-linear, first-order crossovers in his designs, the target response being the combination of electrical and mechanical filtering. As the out-of-band rejection is then only 6dB/octave, it places demands on his chosen drive-units to be well-behaved, not only in their passbands, but also outside of them. In effect, the loudspeaker has to be designed as a whole system, the interaction between the drive-units and crossover being considerable.