Audacious Audio

This is an electrostatic column speaker, 6' tall and costing $6000/pair. An integral, fan-cooled amplifier is located in the base. The 2SW is said to cover almost the entire frequency range and is based on a patent, number 3,668,335, issued to manufacturer/designer Harold Beveridge on June 6, 1972. Internal acoustic lenses in front of the electrostatic panels widen the speaker's dispersion: In the Beveridge literature, it says "This 6-foot high device consolidated the entire frequency range into a vertical line source, and uniformly disperses it over a horizontal pattern, 180 degrees wide. The beaming characteristics of the high frequencies are ingeniously translated into the same dispersive pattern as the low frequencies, creating a perfectly balanced cylindrical sound wave front."

The top-of-the-line model from America's leading headphone manufacturer, these are bulky, heavy, very business-like in appearance, and very, very good.

The ESP-9 is dual-powered: from the AC line, or from the input signal itself, The power supply is rather large and heavy, and appropriate in appearance to the phones. Amplifier connections are via wires with spade lugs attached, and speaker connections are made to the rear of the power supply. A front-panel switch selects speaker or headphone operation, and terminates the amplifier outputs with 10 ohms in the Phones position.

Construction is typically top-of-the-line Koss: Rugged, nicely finished, and apparently very durable, and the phones are easy to handle. (Many headphones are so loosely pivoted on their headbands that they swing into impossible positions whenever you pick them up.)

I have lost track of how many loudspeakers I have measured with DRA Labs' MLSSA system since Stereophile started accompanying its reviews with measurements in the late 1980s, but it must be close to 1000. Most of those speakers have long since faded from my memory, but there are some whose excellent measurements stick in my mind. One such is the Magico S5 Mk.II I reviewed in February 2017.

In ancient times, when I first ventured beyond playing files stored on a USB stick or NAS to streaming from Tidal and Qobuz, I ran a USB cable between a MacBook Pro and my DAC. For playback software, I alternated between Amarra, Audirvana, and—sometimes with a dCS DAC—dCS Mosaic.

"Panel speakers that do bass? Sign me up!" That was my reaction when I first heard a pair of Diptyque Reference loudspeakers, at AXPONA 2023. The Reference is a 6'-tall, French planar magnetic speaker whose designers, Gilles Douziech and Eric Poix, make no secret of their love for Magnepan, the Minnesota company famed for its dipole panels. The French duo has improved on Magnepan's pioneering technology by addressing the number-one shortcoming of such designs: a lack of low-frequency extension.

It takes audacity for a company that already builds one of the finest DACs on the planet, which is already expensive, to set out to build one that's so much better that it warrants an extra digit in the model number and a much higher price tag. But then CH Precision has never lacked audacity.

A first for German manufacturer Octave is the Jubilee Class A mono ($85,000/pair), a push-pull class-A monoblock with a self-regulating autobias pentode circuit that can also run in "high power" class-AB mode. The Jubilee Class A monoblock uses KT120, KT150, or KT170 output tubes.