PreSonus FireStudio Tube - Manual (Page 31)

CONTROLS AND CONNECTIONS
28 | PreSonus 2008
NOTE: Active instruments are those that have an internal preamp or a line-level output . Active
instruments should be plugged into a line input rather than into an instrument input. Plugging a line-
level source into the instrument inputs on the front of the FireStudio Tube not only risks damage to
these inputs but also results in a very loud and often distorted audio signal.
Therefore, don’t plug a line-level source into the combo jacks of channels 15 or 16.
 LED Meters. Each SuperChannel features two 6-LED level indicators. The indicator on the left meters
the input signal. The meter on the right meters the amount of gain reduction through the limiter.
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VU indicator. The VU indicator meters the input signal. The first three green LEDs will light
up when your input signal from either the XLR (Mic) or ¼” (Instrument) input reaches -40
dBfs, -20 dBfs, and -12 dBfs, respectively. The two yellow LEDs will light up when the
channel’s input signal reaches -6 dBfs and -3 dBfs, respectively. The red clip indicator LED
will illuminate when the channel’s input signal reaches 0 dBFS. At this level, the signal will
begin to overload the converters and exhibit signs of clipping, an undesirable type of distortion.
Use the gain controls to keep the signal below 0 dBFS.
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Gain Reduction indicator. This meter shows the amount of gain reduction implemented by the
limiter. As you turn the Limiter knob to the right, the input gain will be reduced by a lower
amount.
 80 Hz Rumble Filter. A rumble filter is available to eliminate low-frequency noise. This lets you greatly
reduce background noise from air conditioners, wind noise, and so on with the flick of a switch. The
button will illuminate when the 80 Hz filter is engaged.
 Limiter. This button is used to engage the Limiter. The button will illuminate when the limiter is
engaged.