Calibrating Input Level for Plugins

[Orvillain]

maximising SNR.

This is simply not true.

Your interface has a fixed noise floor. That's literally what the signal-to-noise-ratio is. When you turn up the preamp, you also turn up the noise. You're not improving anything by recording as hot as you can. Even plugin devs do not suggest that.

 

[MirrorProfiles]

Hello @2dor , @MirrorProfiles and @volkan
I created an account just to ask my question because I share @volkan confusion.
TL;DR question:
- I am quoting @2dor critical information which is the basis of this whole calibration stuff; the plugin author (here for instance Neural DSP) provide a calibration figure based on THEIR audio interface (12.2 dbu in this case). Are they also setting their audio interface gain knob to 0 ?

Elaborated question:
This whole mess of "set your audio interface input gain to zero" started from community, not from plugin devs (to my knowledge), they also recommend (like Scuffhamamps and many) to set their audio interface gain enough to avoid clipping and maximising SNR. If this has started from plugin Dev to ensure the most homogeneous user experience they would have clearly state that we authors of this plugin we set our audio interface gain to zero to have a reference based on the audio interface (used during development) headroom at zero gain, and we recommend you (users) to do the same on your audio interface that we are on the same page.
because of the lack of this statement from plugin dev, I speculate about 2 options:
option 1- they also set their audio interface gain in a way to maximise SNR and avoid clipping but provide the audio interface headroom at gain zero just for (but worthless) reference. Thus our reference point that we consider golden is actually wrong, and we are all mislead by the plugin calibration data.
option 2- that have a special/high-end audio interfaces that allow them to still maximising the SNR ration by turning the gain knob + provide a readout of the headroom (i.e maximum input ) left at that gain setting (essentially an automated way of what @MirrorProfiles is suggesting with the sine-wave method). and then this calibration method at gain set to 0 of us end-users is still valid.


Hope I expressed well my question (English in not my main language, not even the second).
kindly,
LiCoRn

There are no opposing positions on this. Signal to noise is one thing, easily optimised. Calibrating your signal levels for accurate gain staging is another, and also somewhat simple to achieve. They aren’t mutually exclusive.

If you can set your input level to 0, and have optimal levels, SNR, and an easily recallable consistent input level for all your instruments, isn’t that a win?

Read what I’ve posted about a lot recently about signal to noise. So many people who follow the advice about turning up gain as much as possible are ignoring the fact that SNR can only be as good as the loudest source of noise in your chain. You can’t optimise beyond that.

 

[2dor]

@LiCoRn It makes no difference what a vendor has their interface input gain set up like - all that matters is that they reamped a training signal (in case of neural-network based sims; for modelling amps, it's just making sure that whatever your test signal Vrms going into the instrument input, is seen by the amp & they behave the same) from their DAW going into the front end of the amp / gear which at 0 dBFS in the digital domain / DAW, is represented as 12.2 dBU ~ 3.156 Vrms. They could have had an interface with + 30 dBU max output / input but the signal they hit the amp with is 12.2 dBU max.

It's up to the user to leverage the info @MirrorProfiles has pioneered & shared on how to get there.
IMHO there's been a TON of useful examples of how to:

1. get there fast and easy for most folks
2. optimize further once 1. is achieved

I don't know what else there is to say. Vendors actually started quoting and disclosing this info.

For instance:

- Neural DSP themselves: https://neuraldsp.com/getting-start...Ki32LnS-75-VY15MwyOycHuFHS2uUE2Cq_t996NNCI8Id

- Two Notes: https://helpdesk.two-notes.com/portal/en/kb/articles/calibrating-genome-s-input-your-audio-interface

 

[MirrorProfiles]

and UAD:

 

[ChordInversion]

hey folks please let me know
why this is so confusing at 2026 that amp sims as good as real thing but we still confused about adjusting input gain
is there anything that can adjust it for the player
i mean just plug and play
is it hard to do
i am sure that input gain is crucial beacause its gain staging.

Others have provided good advice. I'll only add that it's especially exasperating for IK Multimedia's Amplitube. That's because with their product, you have to re-do the process for every single amp model. That's right. For some reason, they decided to just YOLO the input gains, making them vary from model to model, so even if you get your interface dialed in to a standard, it won't matter. IK tells everyone to dial their interface in as they select each model so that with whatever guitar they have in their hands, the input 'just touches' the red on an arbitrarily strong signal. Which of course means their highly accurate models will respond identically to guitars with pickups of different output, apparently by design. Which is not a thing any amp ever does. They're the modeling company to use for those discerning individuals for whom not actually adequate is sufficient. And they refuse to even acknowledge the issue. It's charming.

 

[LiCoRn]

I (hopefully) understood that:
- the only/loudest noise that matters for guitar is the pickup noise. so the gain knob here will multiply this external noise. So if the guitar has quiet pickup then .... you can't do much about it (apart from noise gate) ?
- Internal audio interface conversion (or from pcb) noise is low enough not to be considered (for modern audio interfaces). is this where SNR maximisation when dealing gain knob is to be understood ?
Thank you very much for quickly answering my question and correcting my outdated knowledge.

 

[MirrorProfiles]

- the only/loudest noise that matters for guitar is the pickup noise. so the gain knob here will multiply this external noise. So if the guitar has quiet pickup then .... you can't do much about it (apart from noise gate) ?

Not exactly, but most of the time this will be the case. You have to ensure your interface noise is below that of your guitar signal - usually that’s taken care of because of how manufacturers design their products. All of the noises matter, and you should be aware of them (even if they’re solved problems). Even the quietest pickups will have noise, guitar signals are very weak and prone to outside interference. Amps and pedals and power supplies etc also have noise.

- Internal audio interface conversion (or from pcb) noise is low enough not to be considered (for modern audio interfaces). is this where SNR maximisation when dealing gain knob is to be understood ?

Often it is, but again, not always. It just needs to be below your other noise.

You can roll your guitar volume down to compare the noise of the interface vs the noise from your signal chain. The noise from the guitar should comfortably mask the interface noise.

 

[volkan]

Others have provided good advice. I'll only add that it's especially exasperating for IK Multimedia's Amplitube. That's because with their product, you have to re-do the process for every single amp model. That's right. For some reason, they decided to just YOLO the input gains, making them vary from model to model, so even if you get your interface dialed in to a standard, it won't matter. IK tells everyone to dial their interface in as they select each model so that with whatever guitar they have in their hands, the input 'just touches' the red on an arbitrarily strong signal. Which of course means their highly accurate models will respond identically to guitars with pickups of different output, apparently by design. Which is not a thing any amp ever does. They're the modeling company to use for those discerning individuals for whom not actually adequate is sufficient. And they refuse to even acknowledge the issue. It's charming.

i am user of tonex software and thats the same for me
some profiles have too much gain i have to decrease the gain on interface
but some profiles doesnt have enough gain even its high gain amp so i have to maximize gain on interface to get proper high gain sound

 

[volkan]

and UAD:

View attachment 58214

so it means that
you will only adjust the input level on plugin as we know (if its red you will reduce if its low you will increase) ?

 

[2dor]

so it means that
you will only adjust the input level on plugin as we know (if its red you will reduce if its low you will increase) ?

This is how I do it if I need to optimize SNR as well as ensure calibration is in place:

1. I get a guitar with hot pickups and strum really hard
2. I watch for clipping or how many dB are left until clipping occurs
3. I increase the slider on my interface, I start from minimum gain / at 0, and hit hard again until clipping occurs
4. I take note of the dB increase I applied via the input knob on my interface (ie. let's say 7 dB)
5. I roll the input gain slider on the interface down by approximately 1 dB (so instead of boosting by 7 dB and clip, I boost by 6 dB)
6. I subtract the boost amount I applied with either the plugin input knob or a standalone gain plugin first thing in the chain
7. I use the calibration info that applies to my interface and adjust accordingly per my interface's max. input gain and the plugin / profile calibration info.

I rarely do this since I get very little benefit & I prefer to have safe headroom so I don't accidentally clip if I introduce a boost pedal going into my interface etc.

Hope this helps.

 

[ChordInversion]

i am user of tonex software and thats the same for me
some profiles have too much gain i have to decrease the gain on interface
but some profiles doesnt have enough gain even its high gain amp so i have to maximize gain on interface to get proper high gain sound

It's unavoidable with captures, because its impossible to know the conditions of every single capture that's been done. But with modeling, there's no reason whatsoever for it. They just YOLO it at IK.

 

[volkan]

This is how I do it if I need to optimize SNR as well as ensure calibration is in place:

1. I get a guitar with hot pickups and strum really hard
2. I watch for clipping or how many dB are left until clipping occurs
3. I increase the slider on my interface, I start from minimum gain / at 0, and hit hard again until clipping occurs
4. I take note of the dB increase I applied via the input knob on my interface (ie. let's say 7 dB)
5. I roll the input gain slider on the interface down by approximately 1 dB (so instead of boosting by 7 dB and clip, I boost by 6 dB)
6. I subtract the boost amount I applied with either the plugin input knob or a standalone gain plugin first thing in the chain
7. I use the calibration info that applies to my interface and adjust accordingly per my interface's max. input gain and the plugin / profile calibration info.

I rarely do this since I get very little benefit & I prefer to have safe headroom so I don't accidentally clip if I introduce a boost pedal going into my interface etc.

Hope this helps.

sir thank you very much
i want to learn also the waveform on daw during the recording how should it be is there any proper shape for that
i know we should avoid clipping on the waveform
i know that the waveform affects the headroom and dynamic range but
otherwise is there other benefits on sound we hear

 

[2dor]

sir thank you very much
i want to learn also the waveform on daw during the recording how should be i mean is there any proper shape for that
i know that it affects the headroom and dynamic range otherwise is there other benefits

If you see a straight line / square / cut peaks, then you've clipped. There's usually a red indicator on the channel so you should be able to tell very easily.

 

[AlbertA]

This is simply not true.

Your interface has a fixed noise floor. That's literally what the signal-to-noise-ratio is. When you turn up the preamp, you also turn up the noise. You're not improving anything by recording as hot as you can. Even plugin devs do not suggest that.

Umm it does improve things

Post in thread 'Rumor mill: John Mayer plugin coming soon?'

Dec 19, 2025

I can't watch this video at the moment but the thumbnail seems to suggest that turning the gain down isn't the right idea. I thought you said the guy who said to turn the gain up is wrong

Simple life?
- Just keep the gain all the way down, use the database here and it'll be fine for the most part.

If you really want to go down the rabbit hole...

There are two separate issues here at play

1. Accuracy

An amp responds to the strength of the incoming signal, shaping the tone differently at lower versus higher input levels. This is why single-coil pickups typically sound...

• AlbertA

• 
• 

 

[volkan]

Düz bir çizgi / kare / kesik tepe noktaları görürseniz, kırpma işlemi gerçekleşmiş demektir. Kanalda genellikle kırmızı bir gösterge bulunur, bu nedenle bunu çok kolay anlayabilirsiniz.

Otherwise if we hear good sounding with invisable waveform we should consider the waveform shape? Because sometimes encounter that everything perfect sounding but waveform invisable

 

[2dor]

Umm it does improve things

Post in thread 'Rumor mill: John Mayer plugin coming soon?'

Dec 19, 2025

I can't watch this video at the moment but the thumbnail seems to suggest that turning the gain down isn't the right idea. I thought you said the guy who said to turn the gain up is wrong

Simple life?
- Just keep the gain all the way down, use the database here and it'll be fine for the most part.

If you really want to go down the rabbit hole...

There are two separate issues here at play

1. Accuracy

An amp responds to the strength of the incoming signal, shaping the tone differently at lower versus higher input levels. This is why single-coil pickups typically sound...

• AlbertA

• 
• 

The simple life is beautiful

 

[2dor]

Otherwise if we hear good sounding with invisable waveform we should consider the waveform shape?

If you can't see the waveform but you clip the converters, you'll probably know for sure - it sounds like a$$.

 

[volkan]

If you can't see the waveform but you clip the converters, you'll probably know for sure - it sounds like a$$.

No i mean there is no clipping and sounds good for you but waveform invisable

 

[2dor]

No i mean there is no clipping and sounds good for you but waveform invisable

I mean at the end of the day, if it sounds good it is good.

There are essentially 2 ways to go about using sims:

1. "sounds good" like you just said
2. tweaking the chain to match what the plugin was calibrated for

 

[aldunk]

otherwise is there other benefits on sound we hear

I just wanted to chip in to say that I used to do the "set gain just below clipping" and often struggled to get clean amp sims to sound clean.
When I changed to the zero gain on interface method I noticed that as well as getting clean tones more easily I also found my tone to be clearer for whatever reason. There was less apparent "mud" to the sound at least to my ears.