Audio Optimum FS62E
Product information "Audio Optimum FS62E"
The FS62E is a slim, fully active floor-standing speaker with dimensions H=106cm x W=23cm x D=30cm and can be considered the first true two-and-a-half-way system. "True" in the sense that a precisely phase-parallel analog active crossover allows for the first time a complete alignment of theory and practice, fully realizing the advantages of the principle.
In a two-and-a-half-way system, two mid-woofers of the same size are used, with both diaphragms working in parallel in the bass range, while the midrange is radiated only by the upper mid-woofer. The musically important midrange reproduction corresponds to a classic two-way system, and at low frequencies, the double diaphragm area provides significantly increased bass dynamics. When both mid-woofers and the tweeter are driven correctly, a two-and-a-half-way system is the most effective method for achieving the best possible sound quality and high maximum volume with the smallest number of speaker drivers.
The difficulty in design is that the two mid-woofers require different low-pass filters with completely different cutoff frequencies. As a result, both low-pass filters also have completely different phase frequency responses, meaning that in the upper bass range, the sound contributions of the two mid-woofers do not add properly. The phase behavior becomes more problematic the steeper the slope of the low-pass filter for the lower mid-woofer. In passive two-and-a-half-way systems, a first-order low-pass filter with a 6dB per octave slope is usually the only option to keep the ripple in the amplitude frequency response from becoming too large. However, a first-order low-pass filter has little attenuation for higher frequencies, causing the lower mid-woofer to extend into the midrange, which it should not do. The increased bass dynamics from the second mid-woofer come at the expense of midrange reproduction and spatial imaging.
The FS62E is different. Not only are both 18cm mid-woofers and the 30mm tweeter driven by their own 200W SINCOS full-bridge amplifiers, but a precisely phase-parallel 3-way active crossover divides all frequency ranges with active fourth-order Linkwitz-Riley filters, ensuring that the lower woofer is no longer audible in the midrange. The two different LR4 low-pass filters are cross-compensated with a second-order analog all-pass matrix, and the acoustic transfer function of the tweeter is integrated into the LR4 high-pass function of the active crossover via a Linkwitz transform. The phase frequency responses of the three diaphragms are exactly matched at both crossover points, making them behave like a single diaphragm with ideal acoustic properties.
Thanks to the low crossover frequency to the tweeter, the FS62E behaves like an ideal full-range system and simultaneously like an ideal point source with homogeneous sound dispersion.
The naturalness of music reproduction, the musical detail resolution, and the precision of spatial reproduction are unmatched.
In the bass range, the FS62E operates as an actively filtered bass reflex system with a lower cutoff frequency of 33Hz (-3dB). The large forward-facing bass reflex tunnel is aerodynamically optimized at both ends, ensuring no wind noise even at low frequencies and high volume. Combined with amplifier power of up to 400Wsin per channel, the FS62E delivers an unparalleled combination of precise and deep bass reproduction for its size, previously expected only from much larger speakers.
To avoid microphonic effects, the electronics are externalized from the speaker cabinets. The speakers are connected to the SINCOS MonoAmps via 6-core special cables HS4-SO8-TTP250-BA, included in a 1.6m length.
The combination of phase-parallel analog active crossover, SINCOS full-bridge amplifiers, the absolute best speaker drivers for this application, and a precisely tuned, highly efficient bass reflex system makes the FS62E one of the best floor-standing speakers ever built, regardless of size or price. You are welcome to experience this firsthand in a listening session.