ICONS accurate input calibration

Ah, so the actual 0 dBFS is more like +17 dBu with Axe-FX without these shenanigans.
The setting for AxeFX (around 17.5dBu=0dBFS) is +18dB. Adding 18dB of gain (think of it like 17.5-18) puts you pretty close to -0.79dBu, doesn't it?
I'm really really happy with that. I've always been wary of integrating audio interfaces because of the level/gain issue.
What's the issue exactly? IMO it's mostly a solved problem these days. The plugin could just as easily calibrate for the most common audio interfaces with gain at 0 and have optimal levels.
 
The setting for AxeFX (around 17.5dBu=0dBFS) is +18dB. Adding 18dB of gain (think of it like 17.5-18) puts you pretty close to -0.79dBu, doesn't it?

What's the issue exactly? IMO it's mostly a solved problem these days. The plugin could just as easily calibrate for the most common audio interfaces with gain at 0 and have optimal levels.
That's a good way of putting it... I wish all plugins that have gain-dependent behavior had a simple dropdown that allows you to select from a list of common audio interfaces (with the instruction that the interface should be set to minimum gain)
 
The setting for AxeFX (around 17.5dBu=0dBFS) is +18dB. Adding 18dB of gain (think of it like 17.5-18) puts you pretty close to -0.79dBu, doesn't it?

What's the issue exactly? IMO it's mostly a solved problem these days. The plugin could just as easily calibrate for the most common audio interfaces with gain at 0 and have optimal levels.
So if I was to run a 1vp sine wave into the preamp on my apollo solo instead of using the hi-z input, what dbfs level should I be targeting?
Also, does it matter which frequency the sine wave is? I.e. 500hz, 1khz, etc.
 
So if I was to run a 1vp sine wave into the preamp on my apollo solo instead of using the hi-z input, what dbfs level should I be targeting?
Also, does it matter which frequency the sine wave is? I.e. 500hz, 1khz, etc.
Why would you use a sine wave, guitar doesn’t produce sine waves, it has transient peaks which affect levels a lot, and in the case of audio interfaces it’s those transients that will cause clipping.
 
Eh, it's probably me.

With a Fractal device as interface, I'm certain that I'm getting exactly the intended gain going into the DAW / standalone app, resulting in expected gain and tone.

With an external interface and DAW, I don't have a clue.
Yeah, if this is the only amp sim plugin you’ll use it’s an easy way to do it. The real fun is mixing and matching plugins and I think most plugin users are quite used to getting things set up right. It’s worth exploring as even using a Fractal interface will require some adjustment for other plugins (my spreadsheet has some common values for other companies).


So if I was to run a 1vp sine wave into the preamp on my apollo solo instead of using the hi-z input, what dbfs level should I be targeting?
Also, does it matter which frequency the sine wave is? I.e. 500hz, 1khz, etc.
In your case, I’d just set your gain to minimum and then set ICONS to 12.87. Your signal will be pretty hot already and it’s easily recallable. No need to measure.

Why would you use a sine wave, guitar doesn’t produce sine waves, it has transient peaks which affect levels a lot, and in the case of audio interfaces it’s those transients that will cause clipping.
You use a sine wave to calibrate because it’s constant voltage and repeatable by anyone anywhere. A guitar is not constant so it’s not good for this purpose. Your guitar voltage is proportional to your calibration signal so it scales accordingly. Imagine you were somehow able to make your guitar isolate at one frequency indefinitely, every time without fail. Every guitar is different, every 1k 1V sine wave should be identical.

You want to ensure you have enough headroom for your loudest peaks. Thats why it’s common to have a 1Vp hit -13dBFS or so - a guitar can output a lot more. Fractal use a lot more headroom than most, but their inputs are also lower noise than most. In reality most interfaces are going to work just fine and any difference in noise (in real world use) is going to be minimal/nothing to worry about.
 
Fractal use a lot more headroom than most, but their inputs are also lower noise than most. In reality most interfaces are going to work just fine and any difference in noise (in real world use) is going to be minimal/nothing to worry about.
Exactly. I think people get way too hung up about trying to maximize signal-to-noise, when its functionally simpler and more consistent to run at minimum gain and just calibrate max input levels across devices (especially when the input gain on interfaces adds noise anyway).

With the peaky behavior of guitar pickups, and for numbnuts like me who have more guitars than sense, its a much faster and more fluid approach than banging the strings to check levels each time an old friend starts making eyes at your from up on the wall.
 
Exactly. I think people get way too hung up about trying to maximize signal-to-noise, when its functionally simpler and more consistent to run at minimum gain and just calibrate max input levels across devices (especially when the input gain on interfaces adds noise anyway).
totally agree. Optimising SNR is table stakes and often interface design is doing this so you don’t have to do anything (much like Fractal have). There some outliers and you obviously need to be aware of things but it’s pretty easily solved and needn’t be a stumbling block.
 
In reality most interfaces are going to work just fine and any difference in noise (in real world use) is going to be minimal/nothing to worry about.
Most interfaces produce way too much noise and don’t have nearly enough headroom for a lot of humbuckers/playing styles.

But there’s typically so much noise that adjusting gain won’t solve much anyway.
 
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when its functionally simpler and more consistent to run at minimum gain and just calibrate max input levels across devices (especially when the input gain on interfaces adds noise anyway).
With very few exceptions, I couldn’t even use most interfaces, including Fractal, with gain set to anything but minimum, and even then half of them clip.

I keep reading people saying they use interfaces with like 12 dBu maximum input level, and it puzzles me profoundly.
 
Most interfaces produce way too much noise and don’t have nearly enough headroom for a lot of humbuckers/playing styles.
Are you using pedals? I can just about clip 13dBu but I don’t think i’ve come across a guitar that’ll clip 14dBu.

Pedals like a TC integrated preamp/Dirty Tree can add a lot of level and they need way more headroom. 12dBu is fine for most situations though, pickups significantly louder than that are edge cases.

It’s been a long time since I had to deal with signal to noise being an issue with guitar recording, there’s a lot more to gain by optimising environmental noise into the pickups+electronics.
 
Are you using pedals?
No, god forbid. I hate pedals, always have. :)


I can just about clip 13dBu but I don’t think i’ve come across a guitar that’ll clip 14dBu.
My Les Paul Custom with stock 498s clipped 14 dBu Duet all the time, it was unusable.

Right now the only guitar I have with me is a Traveler Guitar with who knows what rail humbucker, it clips the Duet as well, I have to play very carefully to avoid that.

On the FM3, the input pad is set to 16 dB, I can’t play with anything lower, and this setting works all right. I can still clip it if I want to, but I don’t play like that normally. So even Fractal devices don’t have enough headroom I’d say.

With hotter humbuckers and Axe-FX, I used Input 2 on the back, it’s better spec’ed than the front input which was sufficient for me most of the times but at gigs I clipped it every once in a while, too. :)
 
I find I clip Apollo high-z inputs and Tonex inputs with some of my guitars. Oddly, on spec the Tonex should have less headroom than the Apollo but the Apollo seems to clip more?

Most conventional documentation has guitar pickups putting out way lower voltages than the stated max inputs on those interfaces. What gives?

I also exacerbate the issue by cranking my bridge humbuckers close to the strings while backing off the neck pickup as a "channel switcher" way of playing the two pickups
 
Most conventional documentation has guitar pickups putting out way lower voltages than the stated max inputs on those interfaces. What gives?
I suspect that the documentation you’re referring to states RMS voltage, while clipping is caused by peak to peak transient spikes.

It’s also very unclear how that is even measured. It depends a lot on the guitar - where exactly the pickup is placed. On pickup height as well, of course - how close it is to strings. New strings will give higher output.

And the elephant in the room is technique, of course, how exactly you’re playing and what. I believe that the maximum output is produced by very fast string motion perpendicular to the pickup, so palm muting with some pick angle/hand position may produce more voltage than another with the same guitar and pickup.

And manufacturers, they just don’t care about instrument inputs.

Also, when you say that one device clips more than the other one, how do you know? Are indicators working the same way? :)

Sometimes there is no clipping indication for a fast transient, while you’ll see it in the recorded waveform, and probably hear that something’s off, but too late…
 
I suspect that the documentation you’re referring to states RMS voltage, while clipping is caused by peak to peak transient spikes.

It’s also very unclear how that is even measured. It depends a lot on the guitar - where exactly the pickup is placed. On pickup height as well, of course - how close it is to strings. New strings will give higher output.

And the elephant in the room is technique, of course, how exactly you’re playing and what. I believe that the maximum output is produced by very fast string motion perpendicular to the pickup, so palm muting with some pick angle/hand position may produce more voltage than another with the same guitar and pickup.

And manufacturers, they just don’t care about instrument inputs.

Also, when you say that one device clips more than the other one, how do you know? Are indicators working the same way? :)

Sometimes there is no clipping indication for a fast transient, while you’ll see it in the recorded waveform, and probably hear that something’s off, but too late…
Tbf, a lot of those transients are going to get clipped by whatever you have first in your chain. That may be an amp, or it may be a pedal or buffer.

It’s obviously best to avoid clipping but context is really the most important aspect and you factor in a lot of things about what the best decisions are in how you record. If all my guitars were crazy high output, I’d use a DI and A/D that can handle it. If I recorded low output stats, I’d likely track hotter. Just being aware is the important part
 
Tbf, a lot of those transients are going to get clipped by whatever you have first in your chain. That may be an amp, or it may be a pedal or buffer.

It’s obviously best to avoid clipping but context is really the most important aspect and you factor in a lot of things about what the best decisions are in how you record. If all my guitars were crazy high output, I’d use a DI and A/D that can handle it. If I recorded low output stats, I’d likely track hotter. Just being aware is the important part
Well, digital clipping is always bad, I don’t think there’s any context where it’s beneficial. And we’re talking about interface specs, exactly where this digital clipping occurs.

DIs were brought up recently in one of these conversations, they have their own issues and most often are even worse than interfaces. And mic preamps will bring more noise and distortion.

I don’t have crazy high output guitars either, none of them ever had x2ns or such stuff.
 
It’s been a long time since I had to deal with signal to noise being an issue with guitar recording, there’s a lot more to gain by optimising environmental noise into the pickups+electronics.
That’s another puzzling thing I hear so often and can’t understand where it even comes from.

Guitars are dead quiet when properly shielded. Interfaces produce noise which, when going through a higher gain amp/ampsim, gets boosted with compression and you can only defeat it with a gate which in turn kills the attack unless you use some lookahead stuff.

I even recorded this and posted on this forum some years ago. The interface noise is obvious and absolutely abhorrent, and there’s a HUGE difference between a decent and a crappy input.
 
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