Cesta
0
0,00 €
ACTIVE SUMMING MIXERS IN THE STUDIO PART 3 (Gain Staging)
31.07.2021
Today I'm going to speak about gain staging. How to do the gain staging to use the Mikrosum SMIX32 in your DAW setup, and get the maximum from your audio interface whatever the model or brand it is.
Specifically I'm going to explain how to choose the reference level, setup your DAW, and adjust the VU meters in the Mikrosum SMIX32 accordingly.
THE EBU R68 REFERENCE CHART LEVEL
In Europe this is the chart that correlates the analog signal and its digital level representation in a DAW. In a daw, all levels are presented in dbfs.
As you can see, at the left of the table, is the dbfs level. You want to go well below 0dbfs to avoid distorting the input analog signal. The margin between your reference level and the 0dbfs is called Headroom.
At the center of the table you can see the correspondence in dbu. And at the right the volts (RMS) that correspond to the dbu level.
NOTE: Volts in the chart are RMS (Root mean square).
GAIN STAGING STEP 1
Study the specs of your audio interface.
In my case, I have a Behringer UMC1820. After the manual, reading the specs, it says the following.:
LINE INPUTS: -7 dbfs / +11 dbu / 2.75 volts RMS.
LINE OUTPUTS: -2 dbfs / +16dbu / 4.89 volts RMS.
Ok. So now we know the output level that the OUTPUT LEVEL is : +16dbu.
GAIN STAGING STEP 2
Select the Reference level
The most common reference level is:
REF LEVEL: -18dbfs / 0dbu / 0.775volts RMS.
So, if I choose the REF level to be :
Then the calibration point should be:
-18dbfs + 16dbu = -2dbu / 0.616v RMS(see the chart)
¿What if I choose a different Reference level?
No problem, let's see how it works!
REF LEVEL: -14dbfs / +4dbu / 1.23volts RMS.
So, if I choose the REF level to be :
-14dbfs/ +4dbu / 1.23v RMS and the UMC1820 output level is +16dbu,
Then the calibration point should be:
-14dbfs + 16dbu = +2dbu / 0.976v RMS (see the chart)
GAIN STAGING STEP 3
Setup your DAW levels according to the reference level you have choosed:
REF LEVEL: -18dbfs / 0dbu / 0.775volts RMS.
In your DAW, select a channel and play/run a sine wave. Adjust the TRIM gain of the channel, until the peak meter of the channel reads -18dbfs. Do this with all your channels.
GAIN STAGING STEP 4
Remember that the output level of the UMC1820 is +16dbu. Ok so far.
Then the calibration point for the MIKROSUM SMIX32 vumeters should be:
-18dbfs + 16dbu = -2dbu / 0.616v RMS.
This means that 0VU at the vumeter equals 0.616v RMS. You have to adjust the VU buffer gain trimmers in the Mikrosum SMIX32 VU buffer, till you reach the 0VU point in the Vumeters.