Calibrating Input Level for Plugins

[Sascha Franck]

TLDR: are there issues with using your ears to do gain staging that I don’t understand?

Well, I'm basically always doing just that. And I very often deviate from the "ideal" levels (using Tonex stuff with its intended input levels being all over the place actually forces you doing so). But I do perfectly understand that it's a good idea to have a kinda "common starting point", so amp modeling plugins would in fact sound as they're intended to sound. You can still go from there.

 

[ChordInversion]

Well, I'm basically always doing just that. And I very often deviate from the "ideal" levels (using Tonex stuff with its intended input levels being all over the place actually forces you doing so). But I do perfectly understand that it's a good idea to have a kinda "common starting point", so amp modeling plugins would in fact sound as they're intended to sound. You can still go from there.

Yeah, this. Your ears can tell you what you like, and there's nothing wrong with choosing to guess at it yourself. Unless you have the amp in question handy, your ears cannot tell you if the model is closely matching the amp. I find it hilarious how openly IK is effectively saying "yeah, it might or might not sound like the amp. Just figure it out."

So I do think the "starting point" noted above is a baseline expectation of competently done modeling with competently built software/UI/instructions. But I also don't deny that some players can get results that they like, whether or not they are particularly accurate, by just guessing at it.

 

[contrario]

@MirrorProfiles can we use this knowledge (maximum input level in dBu) to reamp guitars with an audio interface?

Let's say I've tracked some guitars with 12 dBu headroom at minimum gain with my audio interface. If I play a sine wave at 1 kHz, measure the voltage of that signal with a multimeter and set the output level to 12 dBu (3.084 vRMS), can I send the DI guitar signal I've recorded to the amp through the audio interface's line output and successfully reamp my signal?

 

[bikescene]

I decided to set my input gain to match what Helix Native expected after reading this thread a few years back. My digital experience has been pretty seamless since.

I’ve swapped out my DI and my reamp box on my main setup along the way, and have maintain a consistent experience. I’ve been able to use different interfaces interchangeably.

The key for me was determining my reamp levels with a voltmeter, and then adjusting my input accordingly.

 

[theimageofall]

I never used to get on with amp sim plugins. They didn’t sound or feel all that great to me.

Tried the interface at zero and adjusted the plugin input level as per the @MirrorProfiles spreadsheet and bam - started sounding and feeling better immediately.

Since then I haven’t thought too much about it and it works for me.

 

[MirrorProfiles]

@MirrorProfiles can we use this knowledge (maximum input level in dBu) to reamp guitars with an audio interface?

Let's say I've tracked some guitars with 12 dBu headroom at minimum gain with my audio interface. If I play a sine wave at 1 kHz, measure the voltage of that signal with a multimeter and set the output level to 12 dBu (3.084 vRMS), can I send the DI guitar signal I've recorded to the amp through the audio interface's line output and successfully reamp my signal?

Yes exactly - if you know the headroom of one, then you can just match levels to the other (or you can confirm by measuring voltages.

 

[volkan]

I decided to set my input gain to match what Helix Native expected after reading this thread a few years back. My digital experience has been pretty seamless since.

I’ve swapped out my DI and my reamp box on my main setup along the way, and have maintain a consistent experience. I’ve been able to use different interfaces interchangeably.

The key for me was determining my reamp levels with a voltmeter, and then adjusting my input accordingly.

could you tell how to do that voltmeter thing

 

[2dor]

could you tell how to do that voltmeter thing

If you watch the videos @MirrorProfiles linked you'll have a step by step guide on how to do it.

 

[[Nathan]]

I never used to get on with amp sim plugins. They didn’t sound or feel all that great to me.

Tried the interface at zero and adjusted the plugin input level as per the @MirrorProfiles spreadsheet and bam - started sounding and feeling better immediately.

Since then I haven’t thought too much about it and it works for me.

Pretty much the same for me. A regular non nerd guitarist wouldn’t think the levels by different companies would vary so much, but here we are.

It’s a lot better these days at least, most hover around the ndsp levels

 

[bikescene]

could you tell how to do that voltmeter thing

The linked video from @MirrorProfiles is a very helpful resource and demonstrates the procedure very clearly.

I aim for a different voltage as reference, but the concept is basically the same.

I have a sine generator plugin (js tone generator in Reaper) routed to a hardware output. My reamp box input is connected to a line output of my interface. I connect a cable into the output of the reamp box.

I want to target 11.5dBu=0dBFS. I want to measure 0dBu on my meter, so I lower the level of the js tone generator plugin to -11.5dB. I place the multimeter (AC Voltage mode) leads onto the tip and sleeve of the reamp output. I adjust the output pot of my reamp box until I measure 0.775V, which is 0dBu.

I just got used to setting it this way.

 

[volkan]

The linked video from @MirrorProfiles is a very helpful resource and demonstrates the procedure very clearly.

I aim for a different voltage as reference, but the concept is basically the same.

I have a sine generator plugin (js tone generator in Reaper) routed to a hardware output. My reamp box input is connected to a line output of my interface. I connect a cable into the output of the reamp box.

I want to target 11.5dBu=0dBFS. I want to measure 0dBu on my meter, so I lower the level of the js tone generator plugin to -11.5dB. I place the multimeter (AC Voltage mode) leads onto the tip and sleeve of the reamp output. I adjust the output pot of my reamp box until I measure 0.775V, which is 0dBu.

I just got used to setting it this way.

Thank you very much sir
Please could you explain
Firstly
Why target 11.5 dBu.
Secondly
the coming signal from reamp box could measure with voltmeter as V "voltage" then how did you convert that V thing to the dBu

 

[Richard_G]

 

[Nathan Explosion]

I read all this like

And went back to "fuck it I'll do it by ear."

 

[bikescene]

Thank you very much sir
Please could you explain
Firstly
Why target 11.5 dBu.
Secondly
the coming signal from reamp box could measure with voltmeter as V "voltage" then how did you convert that V thing to the dBu

I went for 11.5 because that is the nominal level for Helix hardware and Helix Native. I’ve seen 11.4dBu quoted, but measured 11.5dBu on my HX Stomp and went with that value.

The value of 0.7746V is the voltage that produces 1mW of power across a 600ohm resistor, which defines 0dBu. My reference of 0.775 is a rounded value based on what my multimeter can support.

I think it’s a convenient value to use for calibration because the numbers are easy to remember. If I want to go for 12dBu=0dBFS, I’ll see my tone generator plugin for -12dB and adjust the reamp box output pot until K measure 0.775V.

 

[volkan]

Ok firstly we will target what we want on the tone generator due to the specs of the plugin
i will study to understand the other steps in my free time : )

 

[volkan]

I went for 11.5 because that is the nominal level for Helix hardware and Helix Native. I’ve seen 11.4dBu quoted, but measured 11.5dBu on my HX Stomp and went with that value.

The value of 0.7746V is the voltage that produces 1mW of power across a 600ohm resistor, which defines 0dBu. My reference of 0.775 is a rounded value based on what my multimeter can support.

I think it’s a convenient value to use for calibration because the numbers are easy to remember. If I want to go for 12dBu=0dBFS, I’ll see my tone generator plugin for -12dB and adjust the reamp box output pot until K measure 0.775V.

i successfully got the dry guitar signal out of sono interface "to amp"(reamp) output
i mean as the sine wave thing going through the daw the signal comes out from "to amp" (reamp) output.
i can use the multimeter for my guitar signal now?
And there is two steps last for me (sin wave and multimeter adjustment)
What should be the values here wet dry what is meaning
What should be in multimeter

 

[FuzzyAce]

I read all this like

And went back to "fuck it I'll do it by ear."

I know, I wish I could say I think really hard about it, but I don't and just do it by ear.

 

[bikescene]

i successfully got the dry guitar signal out of sono interface "to amp"(reamp) output
i mean as the sine wave thing going through the daw the signal comes out from "to amp" (reamp) output.
i can use the multimeter for my guitar signal now?
And there is two steps last for me (sin wave and multimeter adjustment)
What should be the values here wet dry what is meaning
What should be in multimeter
View attachment 58485

When I am trying to measure the 0.775V on the output, I’ll drop the Wet Output level. For example, I’d set that to -12dB if I am trying to calibrate the output for 12dBu.

I never figured out what the Dry Output does in that plugin.

If you know your output, you can take an additional step and adjust input gain so that it matches your output levels.

You could put ReaInsert after the tone generator plugin, and adjust the input gain so that the return level matches the output levels. You’d basically be using your in/out as a unity gain hardware insert at this point. One benefit of this additional step is that you can record a DI, then also patch in pedals as a calibrated hardware insert, that you can run in front of a digital amp.

 

[volkan]

When I am trying to measure the 0.775V on the output, I’ll drop the Wet Output level. For example, I’d set that to -12dB if I am trying to calibrate the output for 12dBu.

I never figured out what the Dry Output does in that plugin.

If you know your output, you can take an additional step and adjust input gain so that it matches your output levels.

You could put ReaInsert after the tone generator plugin, and adjust the input gain so that the return level matches the output levels. You’d basically be using your in/out as a unity gain hardware insert at this point. One benefit of this additional step is that you can record a DI, then also patch in pedals as a calibrated hardware insert, that you can run in front of a digital amp.

so the value " wet" in tone generator will be adjusted to the plugin manufacturer input specs (for neural dsp plugins it's 12.2)
so we will set the value -12.2 on tone generator
as the sine wave going we want to see the 0dBu on multimeter 0.7746V
is that right ?
@MirrorProfiles
@bikescene

this procedure is right ?

@2dor​

​

@James Freeman​

did i misunderstood the things ?

 

[volkan]

hey there, long time listener first time poster here. just wanted to say how great it is that i found this forum thread. im sure there many people like me using plugins who have said 'i just can't get it to sound right'. they've gone onto read user manuals, watched youtube videos (full of misinformation) and tweaked and tweaked until they're blue in the face but no closer to fixing their problem let alone understanding it.

For me im a career IT guy (now in my late 40s) so bits & bytes are home and im not scared of code & electronics. i took up guitar in 2015 and been (trying) to use guitar sims since not long after that but since forever (as my guitar teacher can attest) ive never been able to get it to sound right. FINALLY i found this thread and i've read every goddamn post in it (over the course of 3 days). The lightbulb moment was:

'1 Vp = 0.707 VRMS = -0.79 dBu equals -13 dBFS in the digital domain' regarding the neural amp model.

i bought the Fortin NTS amp sim a few years ago but as i mentioned it was never able to get it to sound even close to all of the vids that i saw online. I followed the process on calibrating my audio interface to -13dbfs that all of the sudden it sounded perfect. not even just close but PERFECT.

just wanted to say thanks to James Freeman & MirrorProfiles (i assume you're EdS on YT). so anwyays i wanted to try & help in my own way. i've done the calibration thing with an Irig HD2 (my first ever audio interface purchase) as well as an an apogee jam+. I calibrated them against -13dbfs as I have a few of the Neural plugins so that just seemed like a natural choice.

i used my hx stomp to produce a 1khz sine wave with a voltage of .707v RMS (it's a bit out but is close enough)
View attachment 34693


i then plugged that into my irig hd2 (on minimum gain) and looked at how many dbfs that is on 0 gain (it was -13.6dbfs). turns out it needs +0.6db of gain to bring it to -13dbfs (i dont have a screenshot offhand but if people want it i can repro).


View attachment 34695

This is for the apogee jam+. it has a cool feature where you can see the amount of interface gain in the audio/midi app. 0.707v RMS on the apogee jam+ -is -21dbfs. so needs +8 db of gain to bring it to where the Neural amp sims expect it. i hope my understanding of whats needed (and how to measure it) is correct and this info helps someone.
View attachment 34696


You may see it above but i also have an FM3 but ill leave that to another post. its got killer tone once you get it right but holy crap was it unneccesarily hard.

There are two values
Neural DSP =12.2dBu for input gain adjustment.

'1 Vp = 0.707 VRMS = -0.79 dBu equals -13 dBFS in the digital
For the multimeter reading?