Sigma Horn Introduction
The new Sigma design language takes from the success of the ES-Biradial technology and employs some new geometry tricks to further refine the off-axis performance of our proprietary horn technology. The changes focus on creating the holy grail of measurements: true constant directivity along with an an ultra wide coverage angle. There are many constant directivity designs but few that achieve textbook perfect frequency response flatness, or ultra-wide coverage patterns. Most commercially available constant directivity horn provides a listening window of only 90 degrees. This is great for pro-sound applications where you can array speakers strategically for a specific venue, but for consumer audio listening in the home, it has been my observations that a 120 degree listening window offers a best balance of primary reflected energy vs direct energy ratio. In contrast, a 90 degree listening window is too direct, causing the speaker to sound somewhat shouty and aggressive. While the 120 degrees takes on a more relaxed presentation, where the sound exists as a presentation in front of you stretching left and right as a large canvas of sound. I feel that many early horn speaker adopters appreciate the added clarity that a 90 degree offers, especially compared to non-horn speakers (direct radiating), however long term listening suffers. The goal is the ability to listen for six hours, for example, without fatigued, as the sound is simply presented in the room rather than thrown at your listening chair.
The New Sigma Horn
Designed with the self-assured restraint of a “sigma male” archetype, the product rejects excess, trends, and unnecessary ornamentation in favour of quiet authority and uncompromising function.
After extensive development I've been able to provide consistent, wide, and constant directivity across the frequency spectrum.
In contrast, our standard ES-800 Biradial Horn No.3073 offers a slightly narrowing directivity, with some increased irregularity in the off-axis smoothness compared the Sigma.
The horn profile uses my ES-Horn Flare curvature, however I've omitted the wrap-around geometry of previous designs in order to maximize the horn size for the given cutoff frequency. The horn flare still progresses to a wide flare at the mouth, rather than an abrupt transition into a baffle.
The vertical coverage and height are kept to a minimum in order to keep close driver spacing between the woofer and high frequency which is critical for proper integration and coherency of sound.
In addition, the design offers a lower frequency cutoff point for the same physical size. This particular Sigma Horn No.3323 has a 700Hz cutoff frequency (Fc) and uses a 1" throat.
Where is the Sigma Horn Currently used?
We first implemented the Sigma horn on our Speaker System No.3154. The overall listening impression is that the speaker sounds much larger than its actual size, a virtue of the large horn mouth area and wide coverage. The soundstage is presented as a wall of sound, a function of the 1" throat (vs. 1.40") and dipole radiation (driver runs open-back).
The new Sigma Horn requires special setup fixtures for our CNC machines, along with special cutters and machining cutter path techniques and strategies. As a result, we only offer the Sigma Horn on our built-to-order finished speaker systems.
Crowe is a Canadian high-end audio atelier designing fixed reference loudspeaker systems, built to order in Picton, Ontario, with curated finish options and direct client guidance.
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