Evo test subwooferja firme Eminent Technology TRW 17, ki gre do O Hz v eni najstarejših undeground revij IAR, kjer je zelo obširen ?lanek o tem kaj je pomembno pri subwooferjih ter o tem, da je to edini pravi subwoofer- toda pripravite se na dolgo branje:
http://www.iar-80.com/page142.html
ter za pokušino, kako deluje subwoofer, ki gre do O Hz:
----------------------------------------------------------------------------
Part II: How the TRW Works
The design concept of the TRW is radically new for a subwoofer, and radically different from conventional subwoofers, indeed so different that doubting Thomases can't see how the TRW could possibly work as an audio subwoofer.
But the basic technologies employed by the TRW are actually old, well established, and well proven.
A. Proven Technologies
The engine that provides the airflow, hence the bass energy, in the TRW is simply a fan, directly powered by an electric motor, which in turn is directly powered by the powerline. Electric fan technology is very old, in fact several decades older than the moving coil loudspeaker driver employed by conventional subwoofers. And the electric fan has been very well established and well proven, for over a century, as a very effective and efficient mover of large quantities of airflow. The electric fan is used almost universally, for small applications like venting your computer case, for medium applications like ventilating or exhausting your domestic room or attic, and for large applications like power station cooling and wind tunnels. If any doubting Thomas thinks that fan technology cannot move enough air to create thunderous bass in a domestic room, let him try to stand upright in a wind tunnel.
The second engine in the TRW, which tracks the audio signal and modulates the airflow in accurate sympathy, is simply variable pitch for the fan blades. This variable pitch blade technology has been employed and proven for nearly a century, for example in airplanes, where the propeller blade pitch is varied to suit varying conditions. Airplane propeller blades even reverse their pitch, thereby providing negative airflow, to very effectively brake the airplane after landing touchdown (even more effectively than the old fashioned technology of wheel brakes can do). If any doubting Thomas thinks that variable pitch blades cannot effectively modulate airflow, to reproduce a positive and negative audio signal waveform, let him try to stop a heavy airplane, after landing touchdown, with old-fashioned wheel brakes alone.
Doubting Thomases will be further reassured by the fact that these two old technologies have already been successfully combined in a loudspeaker (though not a subwoofer), over half a century ago, a loudspeaker that can play extremely loud and put out huge amounts of acoustic energy. The moving vane loudspeaker, used extensively in World War II, used one engine to move air, and a second engine to modulate the airflow via a variable pitch blade, just as the TRW subwoofer does. And this moving vane loudspeaker, using the same basic technologies united together as in the TRW subwoofer, could generate such huge acoustic energy and loudness that it was used to communicate between warships that were located far (perhaps miles) apart! If these same technologies as used in the TRW have long ago been proven to be able to generate this kind of acoustic energy and loudness over the open air space above the ocean, then doubting Thomases can be reassured that the TRW can generate all the acoustic bass energy you could possibly want within the confines of a domestic room space.
The TRW drives its rotating fan directly by an electric motor, working straight off the powerline, at constant rotational velocity. The TRW modulates the fan blade pitch with a voice coil, which is mechanically linked to the variable pitch blades, and which is driven by a conventional power amplifier responding to the bass audio signal input.
As the blade pitch is modulated in response to the bass signal, the blades push more or less air forward, or more or less air backward (for the negative portions of an AC bass signal waveform). Note that the TRW fan can happily and effortlessly thereby reproduce bass signals of arbitrarily low frequency (as discussed above, this is the complete opposite of conventional subwoofers, which get into progressively worse trouble, in many ways, as the bass frequency to be reproduced goes lower). The TRW can even happily, effortlessly, and accurately reproduce DC (zero Hz), by simply holding the blade pitch fixed while the fan continues to rotate.
IAR
---------------------------------------------------------------------------------
Za tiste, ki ne boste brali in se le smejete: osnovni princip je še iz 2. svetovne vojne- ventilator ustvari tok zraka, ki ga modulirajo gibljivi deli ventilatorja, ki ustvarijo zvo?no valovanje nizkih frekvenc.
Skratka ni? novega!?!