User manual VELODYNE DF-12SC

[. . . ] Due to the sophisticated nature of this equipment, we highly recommend having an authorized Velodyne dealer perform all installation & setup functions. magnet weight nominal impedance recommended amp power recommended enclosure size * 1. 7 cu. ft. (sealed) * Recommended enclosures : This product has been designed to perform in any type of enclosure, or in an infinite baffle setup. Performance of the subwoofer system may be tailored to your listening taste by altering the type of enclosure used. Power requirements are typically reduced when used in an infinite baffle configuration. Specifications are subject to change without notice. Double check all connections to unit before applying power. [. . . ] q Use only damp cloth when cleaning either controller housing or speaker. q If any part of your Velodyne Servo-Controlled subwoofer or controller should require service, return unit to your authorized dealer. There are no user serviceable parts inside. Velodyne Acoustics, Inc. Suite #101 San Jose, CA 95112 408. 436. 7270 voice 408. 436. 7276 fax 9 2 Servo Technology Velodyne pioneered the use of servo-control technology as a means of reducing distortion over a decade ago. Now, we are the first to offer this revolutionary technology for use in the automobile. In normal music listening, we are exposed to many forms of distortion. Every component in the signal path adds it's own characteristic distortion to the signal. Since most high quality electronics available now have distortion levels far lower than we are able to hear, that leaves your speakers as the worst offenders. While we scrutinize distortion specifications before we buy an electronic component, we rarely see anyone list distortion on loudspeakers. That is because traditional subwoofers (even high quality types) can produce distortion levels around 25% at typical levels. Even at only one watt input power, many subwoofers produce from 8-10% distortion. Traditional speakers produce sound by using a cone which is forced to move by an electromagnetic motor. The motor is connected directly to an amplifier, which provides the necessary increase in power to drive the speaker. If a speaker was functionally "perfect", this method would work fine. The problem arises when the fast moving speaker cone is called upon to stop & change direction quickly. The speaker cone may continue to move, resulting in muddy bass with an increased amount of harmonic distortion. Unfortunately there is no way for this traditional system to "control" distortion. Velodyne's patented servo-control system uses a "motional feedback loop", which corrects for any distortion. The music signal that normally goes to your amp is re-routed to our control unit. This unit monitors the music signal, which should be reproduced exactly without distortion. One accelerometer monitors cone motion, while the other accounts for motion of the vehicle. Now that we can monitor the actual motion of the cone, we can instantaneously compare how well the acoustic output of the speaker matches the music signal. [. . . ] By design, Velodyne speakers are incapable of error. to the amplifier. Forcing the speaker's acoustical output into a true representation of the music. The term "servo" is misused by some manufacturers who use a different motor on their speakers to try and make woofers sound like larger more powerful units. Unfortunately this usually results in a large amount of distortion as well. [. . . ]