Monday, August 3, 2009

New wave


German Physiks Carbon Mk IV driven by Simaudio pre/power amps

Malaysian audiophiles were introduced to a totally different way of making sound at the recent KL International AV Show in the form of the German Physiks speakers.
Malaysians are used to normal cone-shaped woofers, dome tweeters, ribbon tweeters, horns, electrostatic and quasi ribbon/planar-magnetic speakers.
But the DDD (Dicks Dipole Driver) of the German Physiks was quite something else.
The story began in 1978 when Peter Dicks, an engineer, mathematician and sociologist, created a design using mathematical principles that he believed could sound better than the best in the market. In 1980, he had a prototype but the top European manufacturers rejected him.
It was in the 1990s that a German company called Mainhattan Acustik, run by Holger Mueller, became interested and that was because Mueller recognised the DDD as a version of the Walsh Driver invented by American engineer Lincoln Walsh who died before his speaker was launched. Mueller owned a pair of Ohm F speakers which used Walsh drivers.
According to www.soundadviceblog.com, Walsh was a brilliant engineer who was part of the engineering team that developed radar during World War II. He later designed audio amplifiers, and his final project was a unique, one-way speaker with one driver. It was a large cone that faced down into a sealed, airtight enclosure. Rather than move back-and-forth as conventional speakers do, the cone rippled and created sound using a principle known as “transmission line”. The new speaker created a single, perfectly rendered sound wave of remarkable clarity. A new company, Ohm Acoustics, was formed to develop and market Walsh’s new speaker design.
In 1973 Ohm introduced the Ohm F speaker to critical acclaim.
Mueller agreed to license Dicks' design, and German Physiks was born. It took many more years to fine tune the design.


The Dicks Dipole Driver fires downwards

Though the DDD looks like a conventional cone driver, it operates in a totally different way.
According to the German Physiks website, the DDD driver has 4 modes of operation and in essence works as a mechanical 4-way system.
1. The lower frequency end of its operating range can be described with Small/Thiele resonant parameters.
2. In the next frequency band up to the Coincidence Frequency, it works like a pistonic driver.
3. Next an overlapping band follows where pistonic movement is progressively replaced by bending waves until all the radiation is generated purely by bending movement in the cone. Due to dispersion and the cone’s special shape, the Coincidence Frequency is spread over an extended frequency range, rather than occurring at a single frequency like the Dipole Frequency.
From the upper edge of the Coincidence Frequency band, it works like a pure bending wave converter where the velocity of the travelling waves in the cone increases with frequency.
4. The last mode of operation commences above the bending wave band at the Dipole Frequency, when the first standing wave occurs and where modal break-up begins.
it is a nearly ideal point source with an omni directional radiation pattern.
The DDD driver propagates sound in a uniform spherical pattern. The frequency and phase responses are uniform from all listening angles.
An omni directional radiator has several audible advantages:
1. The window in which stereo imaging will be perceived is considerably widened, and “head in a vice” listening constraints are much relaxed.
2. The loudspeaker’s behaviour tends to be much more predictable from room to room, because the reflected sound is timbrally matched to that of the direct sound.
3. The sound of an omni directional loudspeaker has decay characteristics more closely resembling large room reverberation than is the case with the narrowly focused output of typical monopole direct radiators. The sound has a naturalness about it that powerfully suggests the experience of a live musical performance.
Enough of the scientific stuff. What about the sound?
Driven by Simaudio amps, the German Physiks Carbon Mk IV shocked everyone with extremely fast, dynamic and lively music that was totally uncoloured.
It had a peculiar presentation in the sense that the position of the listener was not that vital. When normal cone/dome speakers are used, there is always a sweet spot where everything falls into place and once you step out of it, the soundstage and imaging collapses.
It was not so with the German Physiks. I stood near the doorway because the room was crowded and I could still hear pretty solid three-dimensional images - thanks to the omnidirectionality of the speakers.
The bass went low and was very tight. The speaker uses a 12-inch woofer coupled to a Helmholtz resonator and provides bass down to 28Hz. It sounded and felt lower than that.
Coupled with the sheer liveliness of the presentation was the resolution of details. I noticed a lot of audiophiles nodding their heads, signalling their approval of the sound quality.
In my view, it coupled the delicate resolution of Magneplanars with the bass slam, dynamics and liveliness of Naim speakers.



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