6 - Appendix
Useful Information
E-MU PCIe Digital Audio Systems
117
Grounding
In order to obtain best results and lowest noise levels, make sure that your computer
and any external audio devices are grounded to the same reference. This usually means
that you should be using grounded AC cables on both systems and make sure that both
systems are connected to the same grounded outlet. Failure to observe this common
practice can result in a ground loop. 60 cycle hum in the audio signal is almost always
caused by a ground loop.
Phantom Power
Phantom power is a dc voltage (+48 volts) which is normally used to power the pream-
plifier of a condenser microphone. Some direct boxes also use phantom power.
Pins 2 and 3 of the MicroDock microphone inputs each carry +48 volts dc referenced to
pin 1. Pins 2 and 3 also carry the audio signal which “rides” on top of the constant 48
volts DC. Coupling capacitors at the input of the MicroDock block the +48 volt DC
component before the signal is converted into digital form. The audio mutes for a
second when phantom power is turned on.
After turning phantom power off, wait two full minutes before recording to allow the
DC bias to drain from the coupling capacitors since the bias could affect the audio
headroom.
1
(grd)
3
2
+48V
Balanced dynamic microphones are not adversely affected by
phantom power. An unbalanced dynamic microphone may
not work properly, but will probably not be damaged if
phantom power is left on.
Ribbon microphones should NOT be used with phantom
power on. Doing so can seriously damage the ribbon element.
Since ribbon microphones are fairly specialized and generally
expensive, you’ll know if you own one. Most microphones are either of dynamic or
condenser type and these are not harmed by phantom power.
Appearance Settings in Windows
Adjusting the “Performance Options”in Windows will improve the screen appearance
when moving the mixer around on the screen.
To Improve the Appearance Settings:
1.
Open the Windows
Control Panel
.
(Start, Settings, Control Panel).
2.
Select
System
. Select the
Advanced Settings
tab.
3.
Under Visual Effects, select
Adjust for Best Performance
. Click
OK
.