I'd like to implement the clip LED indicator for the SEND outputs of my module. This schematic from «Elliott Sound Products» seems to be sufficient.

What is the PRO line levels voltages that I have to use as +/-Refs for comparators?

enter image description here

  • \$\begingroup\$ It depends on what level your signal clips, and that's dependent on your output device or input device, and what range of input and output voltages they support. There is no level we can give you as an answer. \$\endgroup\$
    – Justme
    Jul 22, 2022 at 12:15
  • \$\begingroup\$ @Justme ! It is Eventide H9. The H9s inputs are optimized for instruments but will accept line-level signals up to 4dBU before clipping. \$\endgroup\$
    – Roman
    Jul 22, 2022 at 12:23
  • \$\begingroup\$ If you know it clips at 4dBU, why can't that be used? \$\endgroup\$
    – Justme
    Jul 22, 2022 at 12:31

1 Answer 1


The true clip level is call 0 dBFS depends on your amplifier and supply voltage. You can choose "your clip" level or calibrate it to the control console standard reference level then calibrate it to see how much headroom you have.

Choose the exact +/-peak voltage for your thresholds.

0 dBu = 0.7746 Vrms = 1.095 Vp = 1.00 mW (600 ohm)
+4dBu = 1.228 Vrms = 1.737 Vp (= US analog ref level)
+6dBu = 1.55 Vrms = 2.192 Vp (= German broadcast standard -9dBFS)

0 dBV = 1V (RMS)
US home equipment level (USA) with -10dBV (0.3162Vrms)

What you choose for clipping level depends on your headroom goal or the required rms or peak output.



  • \$\begingroup\$ I use my hearing as a clipping indicator because I hate hearing distortion. I built an electronic clipping indicator for the TV my wife frequently watches. \$\endgroup\$
    – Audioguru
    Jul 22, 2022 at 16:02
  • \$\begingroup\$ my wife got a hearing aid after menigitus but won't wear it. \$\endgroup\$ Jul 22, 2022 at 17:19

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.