Input Master Levels

Macros: InMstL, InMstR, Atten_dB?, Atten_G?

These controls may not be present on all cards. Where present, they operate in tandem with the Line Level controls and simply extend their range.

As with the Line Level controls, the default units are steps, changing to dB if the card is calibrated and the dB button is active.

Macro Notes:

InMstL=3 sets the Left Input Master Level to step -3 if the Input dB button is off, or to the setting that gives the attenuation nearest to -3 dB if it is on. InMstR operates similarly for the Right Input.

Use an In_dB command before InMstL or InMstR to be sure the dB button is in the desired state.

Note that in dB mode the InMstL or InMstR value you use only applies to the Master control. There is no single command that adjusts both Line and Master Levels to achieve a specified overall dB value for that channel, as there is for the Generator Volume. The total dB value is, however, displayed next to the dB button.

Atten_dB?0 is a read-only variable that returns the total attenuation, in dB, for channel 0. You may use channels 0-3 here, given as a single digit; variables are not allowed:

    0 = Left In
    1 = Right In
    2 = Left Out
    3 = Right Out

The return value is always given in dB, regardless of the state of the dB button.

For input channels 0 or 1 the return value takes into account whether your sound card has separate input lines and if so which one is selected, as well as whether you have separate attenuation or gain due to Input Line or Master levels.

(The return value for output channels 2 or 3 takes both Master and Wave volume settings into account, if these controls are available on your system.)

If you have not yet performed an auto-calibration, the return value will always be 0 dB.

Atten_G?0 is similar to the above but instead of dB it returns the attenuation as a linear gain factor. For example, Atten_G?0 would return 0.5000 where Atten_dB?0 returns 6.02 dB, or 1.000 instead of 0.00 dB.

See Macro Data Unit Conversions for a discussion of how to use Atten_G? to obtain actual volts or User Units from ADC or DAC values returned by certain macro math and macro array functions.

See also Input Control Dialog