INDUSTRY COMMENTARY

Ribbon Loudspeakers by Newform Research.

Robert Greene’s commentary on linesource loudspeakers (page 104, The Absolute Sound February/March 2004 Issue 146) reprinted with permission from The Absolute Sound Commentary on Dali Megalineloudspeakers ($40,000)

"All of us who’ve lived with point-source speakers - and that must be almost all of us at one time or another - have come to terms with the sound bouncing off the floor and combining with the direct sound from the speakers. My own solution is to sit very close to my Harbeth Monitor 40s and the get the speakers quite high off the floor. This maximizes the direct sound and makes the floor bounce relatively small. But line sources like the Megalines are intrinsically devoid of floor bounce (or more precisely they integrate the floor reflection into the direct sound by design, although at higher frequencies the Megalines have so much vertical directivity there’s very little floor bounce to integrate).

The absence of early reflection has the effect of making the speakers clearer, more neutral, and less apparent as the acoustic sources. People often say that some speaker or another "disappears", but point-source speakers, unless listened to under the conditions mentioned above, disappear only side-to-side. They always let you know where they are because the floor bounce gives the ear/brain an ineradicable cue to their front-to-back position. The Megalines "disappear" sideways. But they also disappear front-to-back and let one hear the true depth of recordings, not the distorted depth perspective of floor-bounce corrupted sound.

The Megalines’ smooth and flat balance isn’t just a matter of "anechoic" response - it’s actually delivered at the listening position. No matter how flat and neutral a point-source speaker is anechoically, you have to take considerable care- usually involving the close-up, "monitoring" listening position - to hear the neutrality the speaker promises in principle. But line sources by nature reach out into the room with their actual frequency response unaltered by floor reflection.

The floor-bounce problem is the reason that point-source are so difficult for room-correction systems - it’s not clear what to correct. Viewing this the other way around, they are both a design problem and a listening problem. Which frequency response at the listening position ought to be flat? The direct sound or the combines direct and floor reflected sound? Which balance is one supposed to hear? These problems simply go away with speakers like the Megalines, and they are thus capable of flat frequency in an unambiguous sense and a truer kind of neutrality.

Of course, most of what I have just been saying applies to all line-source speakers."

** Newform Research note **. Robert mentions here specifically floor bounce. In most rooms, ceiling bounce would be as much of a problem and a large linesource deals equally well with both.

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