Multi's, noise floor, front of valve amp (QC/Axe3/Stadium)

Orvillain

Goatlord
Richard Cranium
Messages
11,113
I've made enough noise about this - har har har pun intended - over the years that now I've got these units all side-by-side, I can show clips:


There is a baseline measurement of my guitar plugged directly into the Mark V, with the volume rolled off. Every other unit does not have a guitar plugged into it. I thought this was a reasonable way of showing the base noisefloor of each unit.

You've got the Stadium XL, with all of the levels at unit and set to instrument level where required.
You've got the Axe FX III using output 3 with the front knob cranked, at all of the different boost/pad settings.
Then you've got the Quad Cortex.

All input noise gates turned off. all impedance settings at maximum. Although that should not make much difference given we're not plugging a guitar in. No effects in any of the signal paths at all, and everything only taking the silent input from the 1st instrument input - no multi options. So what you're hearing is the self generated noise of each unit.

Oh, and to clarify - the Mark V is set to the highest gain channel, with a very nice crunchy metal rhythm tone dialed in. That is to simulate the kind of noise you'd be injecting into your rig as a whole; even if it is less obvious on the clean channel for example. I'm tapping the signal at the speaker output of the amp, so you're getting the whole amp here with zero cab colouration.

You can hear that the Axe FX III without the boost pad is noisy. But when you start moving through the boost/pad settings, it does reduce noise as you'd expect. With my setup, there's no real difference between the 12dB and 18dB settings.

The Stadium XL is very slightly lower noise than the Axe FX III is on its 12 or 18dB pad settings. Perceptually, I can definitely hear it being a bit cleaner.

The Quad Cortex is more or less equivalent to the Axe FX III without any boost/pad tweak.

I did not run 4-cable-method. But you can imagine that with twice the amount of digital conversion, you'd get at the very least a little bit more noise. Probably not quite twice the amount, since noise is a perceptual phenomenon just as much as it is a measurable one.

1774791325037.png


Here's an image showing each clip next to each other. Nothing has been gain boosted in the DAW, I've just increased the zoom to maximum so we can see the noise foor.

So... for me Stadium is the winner. Axe III 12dB or 18dB take second position. Quad Cortex and Axe FX III without the boost/pad function are third place; and there's quite a large drop off there in terms of acceptability IMHO.

In isolation, it might not sound like very much. In practice, it is very distracting, and is noticeable even on the clean channel.
 
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I started listening to your clips and was like "i don't hear anything??". Then I'm, "oh yeah, we're listening for noise, duh" so turned the volume up higher. :facepalm

It's just something we've all learned to live with I suppose. Sometimes it can be bothersome.

Good comparisons though. :beer
 
I'd be curious to see what some pedals look like in comparison, e.g buffered pedals or digital pedals with their FX mix turned to zero. Or maybe even if just extra cable length significantly changes the situation with true bypass pedals.

Have you tried messing with the levels from the QC "swipe down from top" view? Or if connecting the XLR outputs to something changes matters?
 
I'd be curious to see what some pedals look like in comparison, e.g buffered pedals or digital pedals with their FX mix turned to zero. Or maybe even if just extra cable length significantly changes the situation with true bypass pedals.
By far the worst pedal for this I ever tried was the Eventide H9 and H90. A damn shame because their algo's are amazing and they're a wonderful company with some truly great people working for them.

Boss digital effects tend to be decent enough. Certainly not as loud as the QC.

VP4 has roughly the same performance as the Axe III btw.

Have you tried messing with the levels from the QC "swipe down from top" view? Or if connecting the XLR outputs to something changes matters?
Yeah you can mess with that, sure. It'll boost signal and noise. So it isn't really a solution. Connecting XLR's no difference, other than a ground loop if you also have the jacks connected to something. The QC's built in ground lifts are quite handy there.



BTW - I tried a "humbuster" style cable as well as a regular TS>TS cable; made very little difference to any of the levels.
 
Have you tried messing with the levels from the QC "swipe down from top" view? Or if connecting the XLR outputs to something changes matters?
This is what I was wondering. In other words, is there any way to simulate boost/pad settings on the QC. (EDIT: already answered.)

I’d also love to hear the results with QCM into the exact same rig… but I get that that’s an expensive data point LOL.
 
Someone please show me where this matters at rowdy shows most of us want to be playing



I've seen so many bands get ppl legit fighting with noise floors that would get the Internets in full on melt down mode


I know it's important and am not trying to be a dick but I think many ppl take this noise thing waaaaaaaay too far. Noise gates set too aggressively really neuter your tone too just keep that in mind.
 
Someone please show me where this matters at rowdy shows most of us want to be playing



I've seen so many bands get ppl legit fighting with noise floors that would get the Internets in full on melt down mode


I know it's important and am not trying to be a dick but I think many ppl take this noise thing waaaaaaaay too far. Noise gates set too aggressively really neuter your tone too just keep that in mind.

1) Noise floor compounds in real rigs​


What I’m measuring here isn’t “can you hear it in a bar,” it’s:


  • guitar pickups
  • cables
  • pedalboard
  • modeller
  • amp gain stage

All stacking.


So if your modeller is already injecting noise before you even hit the amp, you’re starting in a worse place. By the time you hit high gain, that noise is multiplied, not just added.

2) It absolutely matters outside of live chaos​


A few real-world scenarios where it does matter:


  • Recording (obvious, but huge)
  • Rehearsals at sane volumes
  • Clean / edge-of-breakup tones
  • Stops, chugs, tight rhythm work
  • Ambient / delay / reverb tails

That last one is the killer. Noise sitting under long tails is gross. You can’t unhear it once you notice it.

3) Noise gates are not a free fix​


This is the big misconception.


Aggressive gating:


  • kills sustain
  • messes with pick dynamics
  • clamps transient detail
  • feels unnatural under the fingers

So yeah, you can hide noise… but you’re trading away feel and tone to do it.


A quieter rig = lighter gating = better playing experience.

4) Gain staging actually matters here​


What I’m showing with the pad settings isn’t nitpicking, it’s basic gain structure:


  • Axe FX III without pad = worse SNR
  • Add pad = improved SNR
  • Stadium XL = slightly better baseline SNR

That’s not cork-sniffing, that’s just correct level matching inside the box.

5) “You won’t hear it live” is the wrong bar​


That’s like saying:


“You won’t notice bad mic pre noise in a noisy club”

Cool… but:


  • front-of-house might
  • recordings definitely will
  • you will on in-ears

And more importantly, why accept worse performance when better exists?

ottom line​


Yeah, in a chaotic venue you can get away with a noisy rig.


But:


  • it still affects feel
  • it still affects recordings
  • it still affects quieter moments
  • and it forces you into heavier gating

So no, this isn’t overthinking it.


It’s just building a rig that isn’t fighting you before you even play a note.

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help write this response — not because I couldn’t be bothered to think it through myself, but because that’s roughly the level of effort I feel your point warranted.And just to be completely transparent, I actually used ChatGPT to help write this response — not because I couldn’t be bothered to think it through myself, but because that’s roughly the level of effort I feel your point warranted.And just to be completely transparent, I actually used ChatGPT to help write this response — not because I couldn’t be bothered to think it through myself, but because that’s roughly the level of effort I feel your point warranted.And just to be completely transparent, I actually used ChatGPT to help write this response — not because I couldn’t be bothered to think it through myself, but because that’s roughly the level of effort I feel your point warranted.And just to be completely transparent, I actually used ChatGPT to help write this response — not because I couldn’t be bothered to think it through myself, but because that’s roughly the level of effort I feel your point warranted.And just to be completely transparent, I actually used ChatGPT to help write this response — not because I couldn’t be bothered to think it through myself, but because that’s roughly the level of effort I feel your point warranted.And just to be completely transparent, I actually used ChatGPT to help write this response — not because I couldn’t be bothered to think it through myself, but because that’s roughly the level of effort I feel your point warranted.And just to be completely transparent, I actually used ChatGPT to help write this response — not because I couldn’t be bothered to think it through myself, but because that’s roughly the level of effort I feel your point warranted.And just to be completely transparent, I actually used ChatGPT to help write this response — not because I couldn’t be bothered to think it through myself, but because that’s roughly the level of effort I feel your point warranted.And just to be completely transparent, I actually used ChatGPT to help write this response — not because I couldn’t be bothered to think it through myself, but because that’s roughly the level of effort I feel your point warranted.And just to be completely transparent, I actually used ChatGPT to help write this response — not because I couldn’t be bothered to think it through myself, but because that’s roughly the level of effort I feel your point warranted.And just to be completely transparent, I actually used ChatGPT to help write this response — not because I couldn’t be bothered to think it through myself, but because that’s roughly the level of effort I feel your point warranted.And just to be completely transparent, I actually used ChatGPT to help write this response — not because I couldn’t be bothered to think it through myself, but because that’s roughly the level of effort I feel your point warranted.
 
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