Velodyne Acoustics FSX-12 owner manual Velodyne servo-control solution, Volume control

woofers actually add to the bass spectrum making it appear louder than recorded. This is due to the additional and unwanted harmonics (distortion) of the fundamental signal. While conventional subwoofers offer little to combat distortion products, we at Velodyne have developed another way. . .

The Velodyne servo-control solution

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The Velodyne FSX-12 produces sound in the same manner as conventional loudspeakers: a cone-shaped piston is forced to move by means of a linear motor composed of a coil situated between the poles of a very strong permanent magnet. In our F-series products however, a feedback mechanism is provided to link the driver to the amplifier creating a control system loop.

At the heart of this control system is a low mass accelerometer rigidly attached to the voice coil. The accelerometer continuously monitors cone motions, providing us with a feedback signal for the servo control circuitry. This high-gain system is designed to improve linearity and reduce distortion approximately 30 times over conventional non-servo systems. While the input signal is being sent to the class AB amplifier which powers the driver, a continuous signal representing cone motion is sent back to a comparator circuit. This circuit constantly adjusts for any deviation between the input signal and the subwoofer's output. This self regulation results in extreme control over cone movement, and very accurate low distortion sound.

At typical listening levels, these servo controlled units produce less than 1% harmonic distortion with input signals extending to 20Hz and below. Far better than conventional designs currently on the market. This combination provides you with the best combination of clean, deep, accurate bass, without making any sacrifice to distortion.

Important!!!

Do not use both LINE LEVEL and SPEAKER LEVEL connections simultaneously!

Volume control

This control allows you to balance the output from the subwoofer to the main speakers/ amplifier in your system. This control should be set to achieve similar output level from both the main speakers and subwoofer when listening to music. The remote may then be used for minute/temporary adjustments, such as increasing the volume for home theater usage. A good starting point for the volume control is 3 or 4 dots from minimum.

Low-pass crossover- 40 to 120Hz

All inputs sum the left and right channels together, with the resulting signal passing through an adjustable low-pass crossover before being amplified. The crossover control allows you to adjust the upper limit of the subwoofer's frequency response from 40 to 120Hz. The subwoofer's response will begin rolling off above the frequency you set this control to. You should set the crossover frequency to obtain a smooth and seamless transition from the subwoofer to the main speakers in your system. If your main speakers are smaller units with limited low frequency output, you may wish to choose a higher frequency (such as 100-120Hz) than you would with larger speakers which have greater low frequency output. With larger speakers, you might start with this control set lower, such as 80Hz.

A bypass switch is also provided if you wish to use an external crossover. If you are not using an external crossover, we recommend that you use the one provided within the unit for optimum performance!

Phase adjustment- 0˚/180˚

This control allows you the "reverse" the phase of the subwoofer's output signal 180˚ to correct for any possible mismatch & resulting cancellation between the subwoofer and your main speakers/amplifier. To adjust, simply listen to the system with music playing. Then move the switch from one position to the other and listen for a change in low frequency output. The correct position will have a greater amount of apparent low frequency output.

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