PAG/NAG Feedback Calculator

Calculate Potential Acoustic Gain (PAG) and Needed Acoustic Gain (NAG) to predict feedback margin.

PAG:-20.5 dB
NAG:1.9 dB
Margin:-22.5 dB
FEEDBACK RISK
Distances

Closer = better gain

Further = better gain

The gap to fill with amplification

Farthest listener from speaker

Results

PAG

-20.5

dB

NAG

1.9

dB

Margin

-22.5

dB

FEEDBACK RISK

Insufficient gain before feedback. Adjust setup.

Suggestions to Improve Margin
  • • Move microphone closer to the talker (reduce D1)
  • • Increase distance between loudspeaker and microphone (increase D0)
  • • Use directional microphones and/or loudspeakers
  • • Consider acoustic treatment to reduce room reflections
What is PAG/NAG?

PAG (Potential Acoustic Gain) predicts the maximum amplification a sound system can achieve before feedback occurs. NAG (Needed Acoustic Gain) is the amount of amplification actually required to reach the farthest listener.

If PAG exceeds NAG by at least 6 dB, the system has a safe operating margin. If not, the system will likely produce feedback before reaching adequate volume.

Formulas

PAG = 20log(D1) - 20log(D2) + 20log(Ds) - 20log(D0) - 10log(NOM) - 6dB

NAG = 20log(Ds) - 20log(D2)

Margin = PAG - NAG (need ≥ 6dB)

Setup Diagram
TalkerMicrophoneSpeakerListenerD1 = 0.6D0 = 4D2 = 8Ds = 10D1 = Talker→Mic | D0 = Speaker→Mic | D2 = Speaker→Listener | Ds = Talker→Listener

Disclaimer

These tools are provided in beta and are subject to change. All calculations and results may contain errors and should be independently verified by a qualified professional before use in any design, installation, or safety-critical application. AV500 accepts no liability for decisions made based on these outputs.