User Manual

User’s Guide OctaMic XTC © RME

9.3 AutoSet

Some preamps include limiters in order to prevent clipping, especially of the A/D converter

stage. Such a circuitry is not feasible for the OctaMic XTC, because it would spoil the mic pre-

amp's excellent technical data.

But as the OctaMic XTC's gain is controlled completely digitally, the device can set it automati-

cally, thus providing perfect protection from overload with no degradation of the audio signal,

which does not have to pass any additional electronic circuits.

Since AutoSet operates as overload protection and not as 'compressor', there is no automatic

gain increase. AutoSet only reduces gain. And with AutoSet activated, the gain can still be

changed manually. The currently highest possible value can not be exceeded, because AutoSet

will reduce the gain in real-time during the manual change.

In practice, there are two possible ways to work with AutoSet:

• Gain of all channels is set to a rather high value, e.g. 60 dB. Then a rehearsal with maximum

acoustic level is performed. Thereafter AutoSet is switched off.

• As above, with AutoSet permanently active.

There are good reasons for both of these alternatives. Thanks to the flexible threshold setting

and easy manual correction of set values, the OctaMic XTC is fit for all applications.

AutoSet can be activated in CHANNEL as well as on the gain pages brought up by the chan-

nel’s SELECT key: a push on encoder 1 and 2 activates AutoSet. The label AS in the display

changes from light gray to black.

With grouped channels the field AutoSet Gain is grayed out, activating AutoSet is then done in

the Groups page.

To avoid shifts in panorama AutoSet should work ganged with stereo channels, so that gain

changes of one channel are also applied to the other one. This function is part of the groups

and thus available for up to 8 channels simultaneously. This also means that for using ganged

AutoSet a stereo pair (like Mic1/2) has to be defined and activated as group.

As soon as AutoSet reduces the gain the label AS, shown in the front display, changes its color

from black to blue.

9.4 Instrument

The 1/4" TS instrument input of channels 5 to 8 allow to attach both line signals as well as in-

strument signals. It handles standard line sources like keyboards, mixing desks, effects devices

or consumer-type units perfectly well. With its input impedance of 800 kOhm it also serves

perfectly as instrument input. The maximum input level is +21 dBu unbalanced. PAD is not

available here.