How to Convert dBv to dBu

dBv-to-dBu conversion is a fairly straightforward process.

The conversion of dBu to dBv is a simple process made easy with simple mathematical calculations. Firstly one must understand what each unit is mathematically. A decibel is given by the mathematical equation "Lv = 20log(V/Vo)," where V is the applied voltage, Vo is the reference voltage, and Lv is the voltage level. A dBv is a logarithmic ratio having a reference voltage of one volt. A dBu is a logarithmic ratio having a reference voltage of 0.7746 volt.

Things You'll Need

• Scientific calculator with logarithmic functionality

Instructions

1. Get your calculator ready. For our example we will say that our theoretical dBv unit is 4 dBv. Based on the equation "Lv= 20log(V/Vo)," and the fact that we know that "Vo = 1" we can determine our applied voltage level "V." Do this by rearranging the equation and isolating for "V." The result after rearranging should read: "V = (Vo)(10^(Lv/20)." The result for "V" for our example should be: "V =(1)(10^(4/20)) = 1.585 volts."

2. Plug your result of your applied voltage level "V" into the equation for dBu, which is "Lv = 20log(V/Vo)," where "Vo = 0.7746 volts." In the previous step our theoretical value for our applied voltage was "1.585 volts." Therefore our expected result is "Lv = 20log(1.585/0.7746) = 6.220 dBu."

3. Check your answer by converting your answer in dBu back to dBv. This can be done by trying out the free dB conversion calculator listed in the References section of this page. Our result of 6.220 dBu, once plugged into the free calculator, converts back to our original 4 dBv.

Tips & Warnings

• Mathematical process:

• Lv(dBv)= 20log(V/1)

• V = 10^(Lv(dBv)/20)

• and

• Lv(dBu) = 20log(V/0.7746)

• therefore:

• Lv(dBu) = 20log((10^(Lv(dBv)/20)/0.7746)

References

• Sengpielaudio: Conversion Voltage V to voltage level Lu and Lv