Signals - Adding Decibels

Calculate total signal level in decibels from multiple signal sources. Supports both equal signal levels and different signal strengths.

Signals - Adding Decibels

The decibel (dB) is a logarithmic unit used to express the ratio of two signal values - like power, sound power or pressure, voltage, intensity etc. - where one value is a reference value.

Adding Equal Signal Levels

The total signal level in decibel from equal signal sources can be calculated as:

Lt = Ls + 10 log(n)

Where:

  • Lt = total signal level (dB)
  • Ls = signal level from each single source (dB)
  • n = number of sources

Note: Adding two identical sources (doubling the signal) will increase the total signal level by 3 dB.

Calculator

Inputs

Results

Total Signal Level (Equal Sources)-- dB
Number of SourcesIncrease in Signal Level (dB)
23
34.8
46
57
1010
1511.8
2013

Adding Signals from Sources with Different Strengths

The total signal level from sources with different strengths can be calculated as:

Lt = 10 log((S1 + S2 + ... + Sn) / Sref)

Where:

  • S1, S2, ... Sn = signal values (signal unit)
  • Sref = signal reference value (signal unit)

Alternatively, if you have decibel values and a level difference:

Lt = Highest Level (dB) + Correction (dB)

Calculator

Inputs

Results

Total Signal Level (Different Sources)-- dB
Level Difference (dB)Decibels to Add to Highest Level (dB)
03
12.5
22
32
41.5
51
61
71
80.5
90.5
100.5
>100