I am still confused about audio interface input gain and NDSP plugin input gain - please help

Plugins
1

I just set up a new RME Fireface 802

I was looking at this Google doc list re: amp sim input gain and it lists RME as having max 13dBu

However, RME lists two separate max instrument input levels: "Maximum input level, Gain +6dB; +21dBU’ and also “Maximum input level, Gain +60dB; -33dBu” (these numbers are very different than the Google doc list stating 13dBu)

I have NeuralDSP Petrucci and am very much unsure how to calculate the input gain with the RME Fireface 802

Any help would be appreciated

Thank you

2

Can you elaborate - What does the manual say exactly when it mentions those two separate instrument input levels? How does it differentiate them from each other? Are they different physical inputs on the device?

3

I just received this from RME tech support:

000188
0001881504×388 24.4 KB

4

The Google doc doesn’t list your interface as +13. It reads “RME (most devices but check specs as some vary)”. The +13 doesn’t apply to your 802. From the 802 manual, +21 dBU should the correct spec for that device’s instrument inputs as far as I understand the issue. So the correct input gain for NDSP plugins should be +8.8 dB.

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5

Also, you may already be doing this, but just to make sure: Setting the gain to 0 on your interface is not the way to go, as explained here by Ghost Note Audio. The Google sheet wants you to set the interface gain to 0 and go from there, but that’s losing out on a bunch of signal-to-noise ratio.

I wrote down instructions for myself, strictly based on Ghost Note Audio’s video:

  1. Set interface gain to 0.
  2. Measure peak levels by playing hard. Let’s say it’s -10,3 dB.
  3. Increase interface gain until you’re as close to clipping as possible, without clipping. Measure that peak value. Let’s say it’s -1,9 dB.
  4. Get the difference between those two values. For these ones, it’s 8,4 dB.
  5. Get your own gear-specific value from the Google sheet. For me, it’s SSL2 + NeuralDSP, which is 2,8 dB.
  6. Set your Petrucci X plugin input gain to that value (2,8 dB), then from that value, subtract the difference you got in step 4 (8,4 dB), getting us to a final value of -5,6 dB.
  7. Optional: If you want to keep the plugin input gain at unity (handy for switching between presets; NeuralDSP please make a Lock Input Gain button… :folded_hands: ), insert a utility gain plugin before Petrucci X and set its gain value to -5,6 dB.

I’m happy to be corrected if I got anything wrong there, so if anyone spots anything, please let me know.

6

I was just about to post a link to that excellent video from Ghost Note Audio. You beat me to it.

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7

I think in the OP’s case it would be simplest to just set the interface’s input gain to +8.8 dB (relative to minimum/”zero” interface gain) even if it’s not totally optimal. Unless that starts to clip of course. That way you could leave the plugin’s input gain at 0.

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