Gradient Helsinki 1.5 Speaker
Scandinavian design is often highly unusual. Case in pointthe Helsinki 1.5 speaker from Finnish Gradient, which made the cover of the August 2010 issue of Stereophile.
This 3-way design features a 0.75-inch aluminum-dome tweeter described by the company as "waveguided," which I assume refers to the horn-like structure surrounding it. A 5-inch paper-cone midrange driver fires at an upward angle from its own enclosure/baffle in a cardioid radiation pattern.
Mounted sideways in the base is a 12-inch paper-cone woofer open on both sides, resulting in a dipole radiation pattern. Reviewer Art Dudley surmises that the glass "dorsal fin" behind the frame is intended to reduce dipole cancellation from the side-firing woofer.
As Dudley notes in his review, "Gradient describes their latest loudspeaker as room-independent. Well, yes and no: yes in the sense that, when optimized, it performs in such a manner that the room contributes far less to the sound output than it does with most other speakers; but no in the sense that, to achieve such an optimum, one must take tremendous pains in selecting the Helsinkis' positions within that room."
He also reports that he never quite got the bass performance he wanted, which might not be surprising given the specified frequency response from 200Hz to 20kHz (±1dB) with the –6dB point at 35Hz.
In the end, Dudley concluded, "The Gradient Helsinki 1.5 is a remarkable product whose execution seems to lag only slightly behind its conceptionand its conception is both original and, in its way, ingenious. Though I was skeptical at first, I came away thinking that the Helsinki 1.5 is a must-hear for anyone with a taste for hi-fi adventure, and quite possibly a must-own for anyone for whom clarity of presence can tip the scale toward ecstasy." Not bad for $6500/pair.