Munich HIGH END Show Report 2017
Finkteam's Karl-Heinz Fink, a longtime serious designer of advanced loudspeaker technology, showcased their new WM-4 ( €65,000) at HIGH END 2017 in Munich. From its humble beginnings as the WM-2, a working tool used for evaluation and as a design exercise, through to the WM-3. Now releasing a very special WM-4 available in a wide choice of wood finishes, this world-class floorstanding loudspeaker was carefully listened to (and measured) hundreds of times within a variety of rooms. By carefully measuring and predicting the outcome in a variety of situations, this gave the design team a great window to achieving great performance within virtually any listening space.
The key objective was to combine accuracy and realism with fun. Finkteam seeks to create a loudspeaker that is at home being a tool for evaluating system electronics as it was at playing your fave tunes. To achieve this, two elements were critical: good signal to noise and low distortion. Aspects such as flat response wide dynamics, wide bandwidth and low coloration were just a given considering the design heritage. The ratio of enclosure surface area to drive unit radiating area is often huge and given the small movements of all but bass drive units the enclosure panels can move almost undetectably by eye or touch while producing a noise that is completely unwanted. Once of the advantages of a loudspeaker in two cabinets is each can be optimized for the bandwidth it is supporting.
In the case of the WM-4, the bass enclosure can be made stiff and eliminate any significant resonances above the crossover point. Bracing can be dedicated to supporting the section of the panel needing it and not spreading energy where it is not wanted. The mid-high enclosure may be constructed from multiple varying thicknesses of German precision MDF and damped with a very special material than converts kinetic energy to heat.
During Finkteam's development process it became clear that low-distortion drive units and a quiet enclosure expose the fine details of crossover design and also the quality of the crossover components themselves. The improvements to the new Finkteam's 15" bass unit, according to the company, exposed the colorations introduced by steel core inductors which had previously been found to be the best compromise between sound quality, price and mass. Obviously in a loudspeaker design like the WM-4, the team were not focused on price but mass does matter due to fitting securely and shipping considerations. A primary inductor for the LF driver was a humongous Mundorf aircore, which is approximately 150mm cubed.
There is a huge back story to the design of the Finkteam bass driver but to simplify it: Hi-fi woofers generally use half-roll rubber surrounds but the WM-4's is a triple-roll fabric type which, with the paper cone, gives it the appearance of a pro woofer. The difference is that the surround is co-optimised to the stiffness of the surround and spider (suspension) to achieve the linearity of a half-roll surround but without its high hysteresis. Subjectively this ensures 'quick', 'snappy' bass.
Because the diaphragm is planar, the driver is said to not cause the diffraction effects that result when grazing radiation (sound traveling close to the baffle surface) encounters the cavity formed by a conventional cone diaphragm. This removes a distinctive coloration. The wide bandwidth allows optimum choice of crossover frequencies and simplifies crossover design.
As for the tweeter, it is my fave Air Motion Transformer (AMT) operating according to the principles developed by its inventor Oskar Heil. Developed and manufactured in-house by Mundorf, the AMT has a strong, 25μm-thick pleated Kapton diaphragm with 50μm aluminum strips. This material has extremely good internal damping, resulting in particularly low distortion. A special etching process was developed to produce it and the diaphragm configuration optimized through a large number of tests.
Needless to say, the sound was amazingly fast and clean, with highs that extended to the stratosphere. Bass was tight and tuneful while the midrange gave a clear and open aural landscape deep into the music. Wish there was more to listen, yet time is not on my side.