discrete music

music/electronics

+4 dBu / -10 dBV

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+4 dBu / -10 dBV:  These values are typically used to represent ‘Pro’ and ‘Consumer’ audio signal levels – some gear even has a switch to scale the output, or to adjust input gain.  So what do these values mean on a common scale?

First we need to know how to get from dB to volts.  For linear measures like volts, we defined the measure in dB to be 20*log10(volts/reference).  To go backwards we’ll need volts = reference*10^(dB/20).

You’ll recall from a previous post that the reference for dBV is 1 volt, and the reference for dBu is 0.775 volts.

Let’s convert 4dBu to dBV, via volts:

0.775*10^(4/20) = 1.228V

20*log10(1.228/1) = 1.8dBV

So +4dBu=+1.8dBV, and the difference between +4dBu and -10dBV is really about 12 dB.

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Written by jeffvautin

2009.06.12 at 4:00 pm

Posted in Audio/Electronics Theory

Tagged with , , ,

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