4 - The PatchMix DSP Mixer

Mixer Strip Creation

5.Each analog input pair has its own Input Pad (-10dBV or +4dBu) which controls the input signal range. Changing the I/O settings can add or subtract 12dB. Check these settings if you cannot set the proper input level. See I/O Settings.

Making the Best Possible Recording

Making a good digital recording is easier than ever thanks to the high resolution 24-bit A-D converters on your Digital Audio System. These converters are much more forgiving than the 12-bit or 16-bit converters of the past. Even so, to get the best performance possible, you'll need to follow a few basic guidelines.

First, whenever you input an analog signal to the Digital Audio System, make sure that you're feeding the A-D converters with an optimum signal level. The quality of a digital recording is directly related to the signal level you feed into the A-D converters. If the analog input level is set too low, you lose resolution—if it's set too high, the A-D converters will clip.

To measure the input level, simply add an insert meter to the channel strip in PatchMix DSP. These meters are accurately calibrated to display 1dB for each bar on the meter. You can enlarge the meter view by clicking on the insert meter in a strip and selecting the “Effect” button at the top of the TV screen.

The “I/O Settings” in the Digital Audio System allow you to set the input levels to

-10dBV (consumer equipment level) or +4dBu (professional equipment level) for each analog input. This control sets the overall input level to match your other gear, but to get the best possible recording you need to fine tune the level further.

In order to supply the correct input level, you’ll need to adjust the output of your analog source (electric instrument or preamp) so that the input level comes close to 0dB without ever going over.

Play your input source signal while watching the insert meter in the strip. The signal should go into the yellow area frequently, but never into the red. Adjust the level of your source until you have a good level. If the signal is way too strong or too weak, you may have to go back and adjust the I/O Settings. Choose “-10” if the input signal is too weak and “+4” if the signal is too strong.

Digital audio has NO headroom past 0dBFS (FS = Full Scale) and will “hard clip” if the signal exceeds 0dB. Hard clipping sounds bad and will ruin your recording. Hard clipping occurs because at 0dBFS, all 24 bits are turned on and the A-D cannot measure any higher level. Analog tape, unlike digital, can be driven past 0dB, although with some degradation of the signal.

The Digital Audio System includes Insert “Trim Pot” controls, but they adjust the signal level after the signal has been digitized and will not recover any lost resolution. It’s far better to set the input level correctly in the first place. Trim Pots can be used in emergency situations if there's no other way to get a hot signal in, but they were designed to adjust levels feeding effect plug-ins.

E-MU Digital Audio System

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Creative 1212M, 1820M owner manual Making the Best Possible Recording