Audio Engineering Society

Chicago Section

Meeting Review, February 20, 2007

2/20/07 Meeting Highlights
by Nick Kettman

Tom Danley of Danley Sound Labs presented his SH-50 Synergy Horn design to a group of Chicago area audio professionals on February 20, 2007. Mr. Danley began by giving an overview of the issues surrounding traditional horn-loaded loudspeakers, including the general difficulty of preserving waveshape of the audio signal. He then described how the Synergy design mitigates some of these issues by incorporating a three-way driver configuration in a single horn. The presentation concluded with a demonstration of the Synergy Horn using a variety of music source material.

Most modern loudspeakers do a poor job of preserving waveshape. Some designs, including electrostatic transducers and direct radiators, can preserve waveshape, but often suffer other problems such as reduced low-frequency output. Conical horns exhibit poor low-frequency loading, but this can be mitigated by coupling the low-frequency driver at a point far from the horn mouth. The SH-50 contains seven drivers configured as a three-way system, with a single high-frequency compression driver at the mouth, four mid-range drivers coupled to the horn near the mouth, and two low-frequency drivers coupled to the horn towards the horn opening. With this configuration, the compression driver and mid-range drivers are physically close enough to radiate as a point source. Similarly, the mid-range and low-frequency drivers radiate as a point source. With its specially designed cross-over network, the SH-50 is capable of preserving waveshape over a wide frequency range. Both vertical and horizontal polar response plots show that the polar pattern of the SH-50 does not have lobes which are typical with other speaker systems.

Mr. Danley demonstrated a pair of SH-50 loudspeakers with several types of recorded music, including female voice and acoustic bass. Although the listening environment was not ideal, several attendees commented on the great clarity and imaging produced by the speakers. Mr. Danley demonstrated the system�s ability to preserve waveshape by playing a recording of fireworks, a real-world �test signal� which is difficult to accurately reproduce on typical loudspeaker systems.