Sascha Franck
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What if you just found out the truth?
Helix Amp Models Producing DC
- Thread starter MirrorProfiles
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What if you just found out the truth?
Lele
Roadie
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GTR37
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Are you on an IPhone 7??
EOengineer
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Let’s not forget that reproducibility is a part of the scientific verification process. This thread is science. We’re all scientists now.
Dom Mcsweeney
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Helix Boomer Box confirmed:What a boomer comment! Phones are perfcetly usbale foenwirtsing
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Count me as one of the Winstons in this thread, nodding and smiling with all you Peter Venkmans with your wit and intellect.
MirrorProfiles
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Igor said they're looking into it but that it shouldn't be negatively affecting the models. I do think the XTC model sounds broken though and not how it's supposed to. I can't really prove it in any way though unfortunately. And with it being remodelled in Agoura I don't see the old version being changed at all.
Lysander
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Yeah - digital DC shouldn't really affect a model's fidelity. It will impact how the digital signal (USB, for example) interacts with other devices, mostly in the form of reduced S/N ratio.
Lele
Roadie
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Even if I'm not using it a lot, just because the EV Panama Blue is keeping.me busy in a happy way, the Helix Blue Channel of XTC model is -imho - very good, too, even if I never tried the real amp.
Could you tell something more about what isn't right in your opinion?
MirrorProfiles
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Suppose I better make some clips. I’ve described it a few times, it’s REALLY fuzzy and does weird stuff like there is a lack of headroom (even when the bias and MV are low).
TheTrueZoltan!
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I did some tests today to compare Helix Native to my Axe-Fx III and was quite shocked how much low frequency ghost notes the HX power amp modeling created with the standard Ripple settings compared to the Axe-Fx and all my other amp sim plugins. And at the gain settings I usually use, these ghost notes create very strong harmonics that can actually get quite unpleasant. For example, With a 200 Hz sine wave, the HX models produced a very strong ghost note around 80 Hz, with corresponding harmonics at 160 Hz and up.
Even with the exact same preamp settings I could get the HX model of the Peavey Invective to sound (and feel, yes) almost indistinguishable from the 5150 BL model in the Axe-Fx. But I had to reduce the Ripple setting to a maximum of 2.0 or lower to achieve an acceptable result. 0.0, on the other hand, seemed almost sterile to me.
Even with the exact same preamp settings I could get the HX model of the Peavey Invective to sound (and feel, yes) almost indistinguishable from the 5150 BL model in the Axe-Fx. But I had to reduce the Ripple setting to a maximum of 2.0 or lower to achieve an acceptable result. 0.0, on the other hand, seemed almost sterile to me.
TheTrueZoltan!
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Axe-FX III
Helix Native (Ripple 5.0)
Helix Native (Ripple 0.0)
With Ripple at standard settings (5.0), the HX model creates pretty significant low frequent ghost notes which, due to the gain of the amp model, result in very messy harmonics in the actual frequency range of the guitar. I wonder what the intention of Line 6's sound design team was for this and why they have deliberately set the default value for Ripple so high.
@MirrorProfiles BTW, in my tests the Axe-Fx III models show the same (sometimes even more) low frequency content you described as DC offset. I was also surprised to see that the Axe Fx III adds harmonics to a supposedly unprocessed (directly from input to output, without any additional block in the chain) 200 Hz signal. Is that the so-called “secret sauce”?
Axe-Fx III unprocessed 200 Hz sine wave
RME UCX II unprocessed 200 Hz sine wave
Helix Native (Ripple 5.0)
Helix Native (Ripple 0.0)
With Ripple at standard settings (5.0), the HX model creates pretty significant low frequent ghost notes which, due to the gain of the amp model, result in very messy harmonics in the actual frequency range of the guitar. I wonder what the intention of Line 6's sound design team was for this and why they have deliberately set the default value for Ripple so high.
@MirrorProfiles BTW, in my tests the Axe-Fx III models show the same (sometimes even more) low frequency content you described as DC offset. I was also surprised to see that the Axe Fx III adds harmonics to a supposedly unprocessed (directly from input to output, without any additional block in the chain) 200 Hz signal. Is that the so-called “secret sauce”?
Axe-Fx III unprocessed 200 Hz sine wave
RME UCX II unprocessed 200 Hz sine wave
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MirrorProfiles
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The Helix DC thing was separate to the side effects of dialling in ripple, it was producing DC with ripple at 0 on several amps. I agree though that ripple can quickly sound bad, and IMO, quite often it's not a very realistic approximation of the sound of amps.
Lele
Roadie
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Imho it doesn't make sense to use the standard Ripple settings. My default settings for both Ripple and Hum are always zero in my Helix presets.
I think that Fractal is on the same page:
"Ghost notes are a form of amplitude modulation . The cause of ghost notes is excessive AC ripple on the B+. The ripple modulates the gain of the output stage. Ghost notes are especially undesirable because they are harmonically unrelated and occur even when playing single notes. The cure is improved power supply and/or screen grid filtering. Some modelers model ghost notes. It is the opinion of this designer that any amp exhibiting ghost notes is poorly designed and/or needing repair and hence I don't model them."
That's right about where I'd been saying there was some extra 'phatness' in some of the older Axe tones - around the 200HZ area lower mids area!
I don't know how it is in the newer amp software but I definitely heard something that made the tone nice and fat but not present in the original amps....but that I feel isn't actually there in the real amps.
Regarding ripple, I feel you need a real amp signal in there for comparison. I do hear quite a bit of cross-over distortion in many real amp tones as well. At the end of the day, it's the harmonics that give the tone their accurate, authentic and unique character - but yes, we do need the right set of harmonics.
James Freeman
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I wonder what is the standard way to remove DC from digital signal, maybe high-pass filter at some low frequency like 3Hz?
Lysander
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It's just averaging all samples in a window, then subtracting it from each sample.
If you do it with a moving average (i.e. last X samples) you're effectively implementing a high-pass filter, too
KingsXJJ
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I get that these items being discussed are measurable. I also get they may not be ideal. I guess my honest non-crap stirring question is are they audible? If so, only within critical listening sessions involving headphones or references monitors in a controlled studio environment? While I appreciate and, if it mattered to those involved, encourage the exploration… would it help to put it in context? I use a variety of gear from top to bottom and while I have favorites, I no longer hear the absurdities apparent in early modeling. I read discussions about whether folks could pick out a sound clip between current Helix versus Stadium, and. I get that experienced listeners may be able to pick out a “signature” tell on some brands, like @MirrorProfiles and @Orvillain state about Helix and high frequency content. I fully believe them. I consider myself a discerning ear but I may be sensitive to other factors entirely and this may be true for others as well ala the Kemper discussions. I’d truly like to hear opinions on this whether subjectively or objectively based. I’ll give one vulnerable example to show an instance of an observation I recently made (kept to myself until now). Among other gear, I have a Hotone Stage that relatively introduced Sound Clone. It can capture on it’s own and “convert” NAM files to store and play. I did the whole grab a ton of highly regarded NAM files and auditioning them. I found some that were IMO outstanding. I found one of a Chupacabra Amp that was just outstanding. Last night I played it for hours honestly wondering if things could be any better. Now this is on a “sub-prime” brand that many here will never even try or invest in for a variety of reasons… true or not. Using a file no longer in it’s native format and having been converted to run on the Stage. Whether you believe me or my ears or not, it was stunning and as close to a spiritual experience as music can get. For me. So it begs the questions, am I deaf? Have no taste? Is it an inferior technology using a stellar capture on a one of a kind amp? What is actually going on? I have a ToneX big boy too and while it can offer some nice tones too it wasn’t and never has been quite like this. I’m not saying it can’t be. Does my Fractal gear sound great absolutely. So does my $200 Nux Amp Academy under the right conditions. I’m throwing out a lot and likely rambling at this point but it’s an honest dump. Do any or some of these measurements actually matter? If so, when? What’s the cutoff? I could go on but bright folks should no by now what I am asking. Share please.
TheTrueZoltan!
Shredder
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@KingsXJJ I don‘t think many people are really able to hear a thing like DC offset. But the ghost notes and their harmonics caused by ripple? Yes, that can be audible. We are of course counting peas here, but if that leads to the constant improvement of already great gear, then more and more people will have spiritual experiences playing it, just like you had playing your favorite capture.
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