Setting input levels

[Nos402]

One thing I've never quite known how to with these types of plugins (Pod Farm, Helix Native) is how to set the input levels.

 

Like when you plug a guitar into an amp (or the helix) the input level just is what it is. A Les Paul is hotter than a Strat, etc. 

 

So when using these plugins, I plug my guitar into my audio interface, but how do I know what the "correct" input level is? 

[jabak]

Ditto

[kraley]

You are correct, it is important to have your input level set correctly.

 

Most audio interfaces have an adjustable pad to control this.  If your audio interface has a meter, keep it out of the red range.  Some (most) interfaces might only have a 'clip' red led.  Don't let that go on at all - digital isn't like analog - there won't be good distortion happening, just nastiness.

 

You can record with quite a weak signal - modern daws don't have a noise floor like old tape gear does, so don't push the input volume.

 

Hope this helps!

[Nos402]

Yeah, but then doesn't that negate the characteristics of the guitar output itself? Like for example: normally, a strat isn't going to drive an amp as much as a Les Paul, but if both are recorded with the same input level, then doesn't that normalize the level hitting the preamp and so effectively makes the Strat and Les Paul effectively have the same output?

[kraley]

Yeah, but then doesn't that negate the characteristics of the guitar output itself? Like for example: normally, a strat isn't going to drive an amp as much as a Les Paul, but if both are recorded with the same input level, then doesn't that normalize the level hitting the preamp and so effectively makes the Strat and Les Paul effectively have the same output?

 

Well, it is a bit different I suppose.

 

Remember that you have controls on the input signal in Helix as well, and you can use other gain boosters in your Daw before you hit helix if you want to have a hotter input.  You should be able to drive the Helix as hot as you want to .  

 

 

My observation is that high output pickups are quite likely to produce digital distortion at the input level - so padding it down to an acceptable level at the interface is the way to deal with this.

[sleezye1]

There is a section in the helix native manual that explains exactly what you're asking.

[Nos402]

Oh! I looked for a manual but didn't see one. I'll look again.

[sleezye1]

Oh! I looked for a manual but didn't see one. I'll look again.

http://line6.com/support/manuals/helix-native

[Nos402]

No idea how I missed that! Unless it was just posted! Thanks!

[twpmeister]

There is a section in the helix native manual that explains exactly what you're asking.

The manual has some general guidance but there is still the likelihood of the input gain being significantly different to the helix hardware. Let's put it like this - I want my strat to sound exactly the same on a patch installed to both the hardware and native. I have input pad set to off. How should the input knob in my interface (which is set to instrument but still has adjustable gain) be adjusted to ensure the model on native is seeing the same level input as the helix floor? Likewise if I use the floor input pad where do I then set my interface for that? What is the idiot proof way of doing this? To be clear we are not asking how to normalize input of different guitars we are asking how to match native input to floor input as exactly as possible

Thanks.

[sleezye1]

The manual has some general guidance but there is still the likelihood of the input gain being significantly different to the helix hardware. Let's put it like this - I want my strat to sound exactly the same on a patch installed to both the hardware and native. I have input pad set to off. How should the input knob in my interface (which is set to instrument but still has adjustable gain) be adjusted to ensure the model on native is seeing the same level input as the helix floor? Likewise if I use the floor input pad where do I then set my interface for that? What is the idiot proof way of doing this? To be clear we are not asking how to normalize input of different guitars we are asking how to match native input to floor input as exactly as possible

Thanks.

I see. As long as the guitar sits in the -12 and under zone like the manual suggests then you'll be close enough I'd assume

 

If you record the direct guitar though the helix usb, however, I would think it would match perfectly, no?

[twpmeister]

Not using floor as my interface as the huge selling point of native for me was to be able to use it without needing to transport the hardware with me. The idea of keeping the meter within a certain range doesn't make sense as it would level out the variations between different guitar outputs which is NOT what we are trying to achieve. We are trying to get native to see the same input as helix not the same input from one instrument to another. Thanks for your input all the same.

[Nos402]

My total guess as to a good way to do this would be to set the input level of Native based on your hottest guitar (for me, probably the Lester setting in my Variax). Set that to be within the "optimal range" while also using your ears (and your DAW to record samples) to make sure it sounds approximately the same as it does when plugged into your Helix. Then once you've set it for your hottest guitar, just leave it alone and all the rest *should* have the same relative differences. I think. This is all just theoretical.

[twpmeister]

Maybe what I instead need to figure out is where on my interface input gain knob unity gain lives. Unfortunately it is not labelled

[Triryche]

Maybe what I instead need to figure out is where on my interface input gain knob unity gain lives. Unfortunately it is not labelled

What interface do you have?

One approach may be to pass the dry guitar signal, unaffected (no gain adjustment) to your DAW.

[bc05]

What interface do you have?

One approach may be to pass the dry guitar signal, unaffected (no gain adjustment) to your DAW.

Personally using Helix hardware. To get an IDENTICAL sound to that, do I record a stereo DI via USB 7 and 8 or just one mono track via USB 7? Why this is so nebulous escapes me

[adamqlw]

I have had exactly this problem since forever every VST that I have used. Not clipping is one thing, but having the input stage of the VST see something that is “calibrated†to a known real-world constant still remains elusive. The thing about gain staging is that it the order matters. The unity gain idea twpmeister mentioned would solve this. It’s been utilized in the Axe FX 2 (input gain only optimizes signal to noise levels, so the amp inputs react appropriate to pickups with different output levels), and in a way in the ElevenRack as well, which had a fixed input so you there was no question of how much gain to apply.

 

I was quite excited when I first saw DigitalIgloo mention that the input gain settings would be discussed in the manual, but looking at the details, all this will do is make sure the guitar isn’t clipping the interface input. I’m still looking for a way to find out how much gain to use to bridge the gap between what my DAW receives and what the dry out of Helix (hardware) delivers. Ideally, we want a way to zero our DAW input to the Helix DI output.

 

Some thoughts I had earlier on this, if anyone is interested.

 

“ I don’t mean to generalize that single coils have output of 100 mv and humbuckers have output of 300 mv, but rather something less specific. For example, according to the DiMarzio

• DiMarzio’s “standard strat†single coils have an output range of 130 to 200 mV.
• Hum-cancelling Dimarzio strat pickups have an output range of 90 mV to 325 mV (the 90 mV being the unusual low-output Malmsteen pickups).
• DiMarzio vintage output humbuckers range 178 mV to 285 mV
• DiMarzio medium power humbuckers range 250 mV to 352 mV
• DiMarzio high power humbuckers range 325 mV to 510 mV

If we take 90 mV to 510 mV to but the lower/upper bound of what the input should be receiving, and convert that into zones on the input meter, then we could reliably adjust input gain by aiming for those zones on the input metering (which can be done independent of setting input gain to optimize signal to noise ratio on the hardware), and not by ear, to match up accordingly with the pickup being used. This would take a large part of the guesswork/â€use your ears†out of the equation, and brings the modeler closer to a real-world plug-and-play solution. As I understand it, there is no standardized way to measure pickup output. How hard one hits, the type of pick, etc, all confound the process of measuring output. But even without that precision, the broad buckets could be effective in making modelers more accessible to the average guitarist.

As you say, backing off the input trim can emulate the lower output guitar hitting an amp, but the question that has stumped me is just how much to back off. While I can use my ears, part of what I like about using different guitars is how simply changing guitar has a generally predictable impact on tone, which is a function of both the overall response of the pickup as well as the output level. Maintaining as much of that framework in the virtual world seems like a net benefit.

Basically, it feels to me like modelling is pretty accurate but the question mark is how to calibrate input to mimic “real world†application. This seems to have been solved in hardware on the ElevenRack and Axe FX, because the input sensitivity is known and can be compensated for. Hopefully there can be a way to come close to mimicking this by indicating certain known values (i.e. pickup type) to calibrate the input to.â€

[bjnette]

In the old days of tape you recorded as hot a signal as you could to lessen any noise floor and tape hiss.

We could in fact hit the meters into the red and the tape would saturate (soak up)the magnetic particles on the tape.

This is now considered a desirable and missed artifact in recording with digital and there are plugins and FX that

simulate the soft compression that tape did.

Now with digital especially at 24bit depths zero is the max headroom you can get and in gain staging leveling this is\

equivalent to hitting your VU meters hard to the pin.

Now if you are using outboard gear like an analogue mix console which operates at -18dbv or the like you gain staging runs out

recorded at near zero on the peak meters and you will have to attenuate the level at mixdown.

You will have to do this in your DAW as well and here is the adverse effect. You amplify your guitar to make the sound but in your DAW

you'end having to turn it down on the input trim or fader. In other words the opposite; quelling it.

What you really want is to open your tracks up with some EQ and get some sense of amplification.

The way to do it is to record averaging -18db Full scale on your peak meters and peak about -12db. There is no possibilty of digital

overs ruining your recording and when you go to mix the trim doesn't have to come down much if at all.

This is especially an advantage to mixing down out of the box when you go back to analogue spec'd gear. It still applies in your DAW.

Now you could record at just below peak on your meters and as long as it stays out of the red. Never clips, ice picks.

you should be okay but your mixes run out of head room from the get go and you then once recorded lower the trim or insert a trim plugin

to bring the volume down to get some headroom for your EQing, fader moves group buses and of course plugins like Hx Native.

If you record at 32bit depth you wont hear the ice pick clips until you mixdown is listened to.

This applies to Axe FX or Eleven Rack as well; like the HD500 and the Helix they can sense the input impedance before it processes it adjusts.

In the box, plenty of plugins apply limiting trickery to their inputs to save their plugins from sounding bad

and betting a bad rap. If you apply this standard approach to your recordings you will get better sound out of all plugins you use.

It will sound more open, have more depth (genre depending) and gone will be the harshness of maximum digital bit processing thru your gear and DAW.

Most interfaces have fairly high tolerence for various input impedances but you might have to manually trim them as needed for higher output guitars

Some auto match your guitars impedance or you could use your Eleven Rack or Axe FX DI out.

[adamqlw]

This is really a problem of gain staging. If one completely ignores the signal to noise ratio, the question is: how much gain should be applied prior to the helix input stage so that the signal is calibrated to a known level.

 

This matters because distortion is non-linear, so the order gain is applied is critical. Pre-distortion adjustments have dramatic impact on tone, while post distortion adjustments affect only volume. Even clean tones are affected if they rely on compression from the amp.

[adamqlw]

The most useful indicator would probably be peak levels for singlecoil/humbucker/high output humbucker.

 

It's not a precise solution to the problem, but it would help narrow the range of error significantly. Someone with a helix could actually measure this by recording the DI signal for those categories and noting peak levels. Alas, I only have native...

[bjnette]

If you are talking about gain as in like from an amp before Native then yes

you might only need to run a cab in Helix or the like.

Otherwise it is simple,

How much gain on audio equipment is how much headroom does a piece of gear has before it distorts.

And a little of this might be desirable if you run your guitar thru a 1073 preamp.

If not a high end preamp but more like a preamp on an interface it will be called gain,

trim or output level or a combination of these.

 

All you really need to do is make sure your output level going to you DAW is

as described. Select a track in your DAW. Set it to record on the input channel

your coming in on and look at the meters.

Usually the input level on the track will be as it is coming in in your DAW also

reflected in Native's input meter.

Raise or lower the preamp gain/volume so your level hits the input meters at no more than -12.

 

OUTPUTS PLUG INTO INPUTS

[adamqlw]

Raise or lower the gain/volume so your level hits the input meters at no more than -12.

 

 While this is important to ensure that there is no harsh clipping at the input of the sound card, it does not solve the problem. To clarify, I am referring to pre-Helix native input *linear* gain, i.e. pure clean volume adjustment, absolutely no distortion/compression. This discussion can take place *entirely* in the digital domain, after any A/D conversion on the interface, which means the headroom before distortion is not relevant to the discussion.

 

Consider the -12 dB peak INSIDE the Helix plugin. Does this represent the peak output of a high output pickup? If I am using single coils and I adjust the gain so that Helix Native sees -12dB, then when I utilize an amp model with a bright cap, the gain settings will be lower than they are in the “real worldâ€, which also means the tone will be brighter than expected. Cliff Chase describes it as such:

 

 

“On a real amp this is implemented using a variable resistor called a potentiometer. Many amps include a "bright cap" on the drive control which is a small value capacitor placed across the terminals of the pot that bleeds treble frequencies through as the gain is reduced. Sometimes this bright cap is switchable via a switch on the amp. Sometimes it is fixed.â€

 

Cliff also provided some insights into levels one might need to pay attention to, although these are only relevant if there is a known constant at the input stage of the model to calibrate to…

 

“… is 24 bits. This is 144.7 dB of dynamic range. Full-scale is about +20 dBu. So even if your guitar is -20 dBu (-40 dB re. FS) you still have over 100 dB of dynamic range.

 

A typical single coil pickup can easily exceed -20 dBu. A humbucker can easily exceed 0 dBu. Full-scale of 20 dBu gives you a few bits of headroom in case of very hot pickups.

 

The self noise of a guitar pickup and associated electronics limits its dynamic range to less than 100 dB typically.â€

 

 

One can of course ignore all of this and “use your earsâ€, as we have always done. But if modelling is truly that accurate, then it seems a waste to throw away decades of real-world experience that most guitarists brings to modelling units, instead of translating real-world paradigms to their digital equivalents.

 

 

 

[aleclee]

Personally using Helix hardware. To get an IDENTICAL sound to that, do I record a stereo DI via USB 7 and 8 or just one mono track via USB 7? Why this is so nebulous escapes me

 

 

Record mono from 7.

[bjnette]

Perhaps what is missing is what are you using as an interface. How are you going in and what instruments are you using. Really you should be able to go in and just set your interface gain so it is around -18db or so. You can make a high or low impedance pickup whatever you like this way. This is normal to adjust the gain as needed. Using the Helix input level to push the level up will mean your actual level recorded on the track will be low. You want to use half of those bits at least. Helix Native is not an input device. It is a plugin. It doesn't care what the pickup strength is. All you need to know is the optimum level into the DAW and Native input level (think of it as a trim) to set the gain to on your interface. That is -18db FS and peaks about -12db FS. decibel figures are only meaningful when referred to a known constant. It could be dbu, dbrms, dbv, dbfs or others A pickup is minute in electrical value and needs pre-amplification. Nothing to do with a plugin or a DAW except the value recommended as it's input. I hope this clears it up for you. Cheers

[bjnette]

How to translate an interface so that it will respond predictable when back on the Helix

The manual has some general guidance but there is still the likelihood of the input gain being significantly different to the helix hardware. Let's put it like this - I want my strat to sound exactly the same on a patch installed to both the hardware and native. I have input pad set to off. How should the input knob in my interface (which is set to instrument but still has adjustable gain) be adjusted to ensure the model on native is seeing the same level input as the helix floor? Likewise if I use the floor input pad where do I then set my interface for that? What is the idiot proof way of doing this? To be clear we are not asking how to normalize input of different guitars we are asking how to match native input to floor input as exactly as possible

Thanks.

That is indeed a good question as Helix also has auto impedance detection. There are some interfaces(expensive) that will also do it but plenty

do have Hiz inputs for guitar.

Another way is to use an amp with a DI out or a line level out into your interface.

But I guess if you check the Helix input on the DAW channel meters when you disengage any FX and Amps.

or via s/pdif into an interface or Helix DI out and note the levels. Also record a Helix patch that works for you via s/pdif on a track in your DAW

Then dry s/pdif into another track with Native loaded with the very same patch and increase s/pdif output till it matches the level recorded from the Helix track.

This will then be your reference for setting interface for Native without using Helix and should translate back as needed. Hopefully.

There might be a better way;

Use the s/pdif from Helix into your DAW and note the patch level reached.

Deactivate any FX and amps. Note the level on the DAW track. Load Native with the exact same patch and note the track output level or Native out level.

Trim NAtive so it matches.