FM3 vs HX Stomp - very nice comparison from John Cordy with poll!

Which is which?

  • A is Helix

  • A is Fractal


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SwirlyMaple

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1,845
The A/D converters have 114 dB of dynamic range and are probably the same converters used in the Stomp. The instrument input on the FM-3 uses a dynamic range enhancement technique which boosts the dynamic range to 123 dB.
Considering that your own product documentation says 114dB with no qualifier here, page 118: https://www.fractalaudio.com/downloads/manuals/FM3/FM3-Owners-Manual.pdf , then I doubt Phil's comment about the Stomp being higher was made in bad faith. I searched the whole doc and see no reference to 123dB anywhere. I don't see it on the wiki either.
 

Gearzilla

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6,992
The one thing that does differ on the inputs, though, is the FM3 has a fixed 1MOhm input impedance. The Stomp (and Axe FX 3) have variable input impedance which is pretty important for the tone and feel of certain pedals. :munch
Do you mean like running a fuzz box into a modeler? Is the variable impedance important for anything else?
 

SwirlyMaple

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1,845
Do you mean like running a fuzz box into a modeler? Is the variable impedance important for anything else?
Yep, modeling a fuzz box within a modeler ;) It can probably be faked pretty well if the modeling itself is built around a fixed high-z input, but if you're trying to make a digital recreation of specific real-life hardware, the input impedance of that real hardware has a big effect on how your pickups sound. Old fuzzes in particular got a significant part of their feel and tone from having low input impedance. Other classic pedals like the CE-1 chorus also had significant coloring from low impedance inputs. Tone-suck from low input impedance is generally seen as a negative thing in modern pedals, but again, if you're trying to make a 1:1 re-creation of real hardware in the digital realm, the input impedance is an analog interaction with the guitar's pickups that can't be neglected.
 

Gearzilla

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Messages
6,992
Not the first time and probably not the last. I like Fractal products but it’s always something that’s kept me at arms length. It probably could have just been explained from the start like a professional.
Fortunately Nicolas is around to help out with those types of communications.

Yep, modeling a fuzz box within a modeler ;) It can probably be faked pretty well if the modeling itself is built around a fixed high-z input, but if you're trying to make a digital recreation of specific real-life hardware, the input impedance of that real hardware has a big effect on how your pickups sound. Old fuzzes in particular got a significant part of their feel and tone from having low input impedance. Other classic pedals like the CE-1 chorus also had significant coloring from low impedance inputs. Tone-suck from low input impedance is generally seen as a negative thing in modern pedals, but again, if you're trying to make a 1:1 re-creation of real hardware in the digital realm, the input impedance is an analog interaction with the guitar's pickups that can't be neglected.

So the dynamic impedance switches with the first block in the modeler? I was under the impression that it was set relative to the first block whether the block is on or off—at least with the Helix.
 
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SwirlyMaple

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1,845
So the dynamic impedance switches with the first block in the modeler? I was under the impression that is was set by the block whether the block is on or off—at least with the Helix.

I'm not sure I'm fully understanding what you're asking, but yes, the first block in the Helix sets the input impedance via an analog circuit that it switches. Same for the Axe 3, as far as I'm aware, though I don't own one so I'm not an expert there. On the Helix, in Auto mode, the input impedance seen by your guitar pickups is equal to the input impedance of the first block in the chain, whether it's bypassed or not. You can override the value manually or set it to be controlled via snapshot. On the Axe FX 3, as far as I'm aware, it changes the input impedance based on the first non-bypassed block in the signal chain.

Regardless of how it's done, though, it's still important to have it for matching the sounds of some pedals. That's what I was explaining in my previous reply.
 

guitarobert

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Messages
543
Input dynamic range has very little to do with the ability to handle low level signals. Audio CDs max out at 96dB of dynamic range, and that is still far beyond the dynamic range needed for an electric guitar signal. Whether one is more than the other likely doesn't make any difference given what dynamic range and SNR a guitar signal actually has. Case in point, look at a noise gate setting. It's usually set far above -96dB to remove the noise floor.

What actually matters is what happens inside the black box of signal processing algorithms employed by each unit. It's almost not worth trying to debate from a factual point of view, since we don't have access to the algorithms themselves. Those that have knowledge of how they actually work won't end up comment on them here. Best we can do is comment regarding what we hear subjectively, or get into running and posting test signal outputs. However, what the ear hears is what matters most even relative to that latter exercise. If people hear artifacts on one system or superior performance on the other system, that's what matters at the end of the day.

I've also seen comments made regarding X modeler being superior to Y modeler because it has a faster core DSP or more cores of DSP. This doesn't mean anything either. The techniques used to create the nonlinearities that we all enjoy (or don't enjoy) are what really matter. Those may or may not be processor intensive. Then there can be optimizations within them that determine how many MIPS are actually needed.
 

dk_ace

Member
Messages
3,041
The one thing that does differ on the inputs, though, is the FM3 has a fixed 1MOhm input impedance. The Stomp (and Axe FX 3) have variable input impedance which is pretty important for the tone and feel of certain pedals. :munch

Wow I didn’t realize that. I’m on the list for one to put in the loop of my helix. It will definitely have to stay in the loop now that I know this...

Not sure I’m going to purchase it anymore, but would have hoped to have flexibility about where to put it. Variable impedance is a must for me though.

D
 

rumbletone

Silver Supporting Member
Messages
8,941
I just listened to the Andy Timmons clip - it sounds great to me. Yes it has that strat ‘quack’, but the way the breakup/overdrive is happening is to my ears totally different from the OP. In other words, the tone from the guitar is very similar, but the way the amp responds to the guitar when pushed sound completely different to me.

And to be clear - I don’t know whether the sounds in clip A that I don’t like are something that could be dialled out - they quite possibly could.

Did you listen to that Andy Timmons clip I posted above? To me it's got that exact sort harshness to the attack - at least that's how I hear it.

To me the challenge is people always try to conclude that tone is inherent to the technology/brand/etc.

Nope...not in my experience. What you hear coming out of the speaker is what the person using the gear did with it. Not much else to it...

My favorite folks to listen to are the ones who make stuff sound good. And that is a totally subjective evaluation on my part.
 

mousepunk

Member
Messages
1,345
The Helix pales in comparison as far as dynamics are concerned IMHO. I've noticed that with many of the amp models the Line 6 emulates (esp higher gain models with or without drive pedals) when you roll off the volume on your guitar they don't respond anything like the real thing and below volume 4 (at least on the single coil guitars I play- fender strats/teles) the signal comes and goes and sounds weak at times if not disappears completely.

besides the noise gate on/off option there is input impedance which can dramatically change the feel and reaction of the amp in HX. Did you try to tweak it?

btw is there a similar option letting control the input impedance in FM3?
 

phil_m

Trying is the first step towards failure.
Gold Supporting Member
Messages
14,734
Considering that your own product documentation says 114dB with no qualifier here, page 118: https://www.fractalaudio.com/downloads/manuals/FM3/FM3-Owners-Manual.pdf , then I doubt Phil's comment about the Stomp being higher was made in bad faith. I searched the whole doc and see no reference to 123dB anywhere. I don't see it on the wiki either.

My comment actually had very little to do with the FM3 other than I was using those input specs to point out that the input on the Stomp doesn’t “cut out” at a certain point as the poster was claiming. There isn’t anything in the input or modeling that makes the signal cut out at low levels (other than the noise gate doing its job).
 

Fractal Audio

Member
Messages
1,282
Input dynamic range has very little to do with the ability to handle low level signals. Audio CDs max out at 96dB of dynamic range, and that is still far beyond the dynamic range needed for an electric guitar signal. Whether one is more than the other likely doesn't make any difference given what dynamic range and SNR a guitar signal actually has. Case in point, look at a noise gate setting. It's usually set far above -96dB to remove the noise floor.

What actually matters is what happens inside the black box of signal processing algorithms employed by each unit. It's almost not worth trying to debate from a factual point of view, since we don't have access to the algorithms themselves. Those that have knowledge of how they actually work won't end up comment on them here. Best we can do is comment regarding what we hear subjectively, or get into running and posting test signal outputs. However, what the ear hears is what matters most even relative to that latter exercise. If people hear artifacts on one system or superior performance on the other system, that's what matters at the end of the day.

I've also seen comments made regarding X modeler being superior to Y modeler because it has a faster core DSP or more cores of DSP. This doesn't mean anything either. The techniques used to create the nonlinearities that we all enjoy (or don't enjoy) are what really matter. Those may or may not be processor intensive. Then there can be optimizations within them that determine how many MIPS are actually needed.
Input dynamic range has everything to do with the ability to handle low level signals. The normalized gain of even a medium gain tube amp can be over 60 dB. If your input dynamic range is only 96 dB and you leave 6 dB of headroom your noise floor is now a paltry -30 dB. There's a reason modeling products use various techniques to improve input dynamic range including dual-range A/D techniques, channel doubling, companding, pre/de-emphasis, etc.

Algorithms are extremely important. However usually the quality of the algorithm is proportional to its complexity. The higher the complexity the more powerful the processor required. One of the main reasons today's modelers sound so much better than they did just a decade ago is the increase in computing power allowing more advanced algorithms.
 

Lele

Member
Messages
2,007
One of the main reasons today's modelers sound so much better than they did just a decade ago is the increase in computing power allowing more advanced algorithms
and in real time!
I remember an excellent pitch shifter that a guy used in a Mac (or other workstation, I don't remember) in a studio many many years ago, when I didn't even know what a pitch shifter could really do, but we went out to have dinner while that machine elaborated the pitch shifted song part!
 
Messages
10,843
Input dynamic range has everything to do with the ability to handle low level signals. The normalized gain of even a medium gain tube amp can be over 60 dB. If your input dynamic range is only 96 dB and you leave 6 dB of headroom your noise floor is now a paltry -30 dB. There's a reason modeling products use various techniques to improve input dynamic range including dual-range A/D techniques, channel doubling, companding, pre/de-emphasis, etc.

Algorithms are extremely important. However usually the quality of the algorithm is proportional to its complexity. The higher the complexity the more powerful the processor required. One of the main reasons today's modelers sound so much better than they did just a decade ago is the increase in computing power allowing more advanced algorithms.

Weird, it says you quoted me, but that’s a different guy you quoted. Glitches in the Matrix. :)
 



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