M-Audio Delta 1010 Manual page 46

Problem: I'm getting some pops and clicks in my audio recording.
Possible Cause 1: Input levels are too "hot," causing clipping or input
distortion. Make sure you have the proper signal levels set on the rear of the
Delta 1010 rack-mount unit. "+4" can handle much hotter signals than "-10." If
you find that you are still clipping at the +4 setting, you will need to turn down
the audio at the source.
Possible Cause 2: If you are recording from the S/PDIF input, but you
have the Delta 1010's master clock set to something other than the S/PDIF input,
you are recording an out-of-sync S/PDIF stream. This can result in lost or bogus
samples being recorded.
Possible Cause 3: Your application software may not have the proper
audio buffer sizes set. Each software application handles this differently, but
typically there is somewhere in the software's setup to set the size of the
playback and recording buffers used by the application. Some applications also
require you to run a card calibration (sometimes called "profiling") the first time
you use the software with a new audio card.
Possible Cause 4: Some accelerated graphics cards use excessive
amounts of system bandwidth, preventing the recording buffer of an audio card
from keeping up with demand. This can cause clicks in the recording. Reducing
or turning off the graphics card's graphics acceleration feature often resolves this
problem. In Windows, the level of graphics acceleration is accessed from Start
|Settings | Control Panel | System | Performance | Graphics.
Problem: I'm getting some pops and clicks in my monitoring signal, even
when my system is idle.
Possible Cause: If the S/PDIF input is not muted in the monitor mixer,
and you have the Delta 1010's master clock set to something other than the
S/PDIF input, you are monitoring an out-of-sync S/PDIF stream. This can result
in lost or bogus samples being recorded.
Problem: The sound from the monitor mixer is muffled. It sounds as if it
were running through a mixer with the treble control turned all the way down!
Possible Cause: The current Delta 1010 sample rate is too low. The
monitor mixer is a digital device that runs at the current sample rate of the Delta
1010 board. The frequency response of the mixer is roughly one-half of the
sample rate. There is no way to prevent this lost frequency response while
playing back or recording at a low sample rate. However, it may be prevented
when the system is idle. See the "CODEC SAMPLE RATE" paragraph of the
section 'Hardware Settings Page' for more information.
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