Is This Intermodulation Distortion?

Aja

Aja

Inspired
I've been absolutely in love with the tones I have been getting. Certainly because of the amazing new update, but mostly just because I've been meticulously tweaking and experimenting. Probably because the update sounds so good....It's a perfect circle.

Anyway, as I have been noodling with my highest gain lead tones I have noticed a certain harmonic "swoosh" sound buried deep in the background. I was wondering if this is the intermodulation distortion that this particular amp would produce in a real world scenario too.

I also remember John Mayer talking about (this was a few years ago and a lot of updates have happened since) this digital "whoosh" sound when two notes rubbed together as an indicator that digital was JUST on the brink of being perfect, but not there yet to him.
I wonder if this sound is what he may have been referencing?

I am using the Double Verb Normal with a compressor and Suhr Riot. I think I read somewhere (probably the Wiki) that the early Fender amps tend to do weird things with distortion. If I remember correctly mostly in the low end.

Here is a sound example, hopefully you can hear what I am talking about.
It's really present in the very first note. Sorry for the annoying sounds lol.

 
The Wiki and Tech notes talk about Intermodulation distortion and ghost notes. I didn’t like it the first time I noticed it and, somewhat like Mayer, thought it was a digital artifact.

Then I noticed it on my tube amps and realized it wasn’t digital, it’s accuracy, and at that point was totally sold on Fractal’s products.

Mayer seems to have moved beyond that thinking since he has at least two FX3 in his studio, and used them for one of his albums IIRC.

Also, “WHOOSH” was a terrible word to describe something, but whatever. I immediately thought he was talking about power-supply sag, which is very easily dialed in or out using the Amp block. It’s another characteristic of a tube amp and indicator of the accuracy of the modeling.
 
It takes two or more notes sounding at the same time to generate intermodulation distortion. You won't get intermod with just one note.

I don't hear anything I'd call a "swoosh" in your recording, but what's the definition of "swoosh," anyway? :) I do hear a pulsating thing going on. That sounds like a vibrating string that's just barely brushing against a fret. Try raising the action a bit or adding a touch of relief.
 
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Greg Ferguson said:
The Wiki and Tech notes talk about Intermodulation distortion and ghost notes. I didn’t like it the first time I noticed it and, somewhat like Mayer, thought it was a digital artifact.

Then I noticed it on my tube amps and realized it wasn’t digital, it’s accuracy, and at that point was totally sold on Fractal’s products.

Mayer seems to have moved beyond that thinking since he has at least two FX3 in his studio, and used them for one of his albums IIRC.

Also, “WHOOSH” was a terrible word to describe something, but whatever. I immediately thought he was talking about power-supply sag, which is very easily dialed in or out using the Amp block. It’s another characteristic of a tube amp and indicator of the accuracy of the modeling.
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Oh man I actually LOVE the sound it makes. It makes the whole thing feel like a cooking amp! I was just wondering if that was the intermodulation distortion or something else.
I have never been able to crank a Twin Reverb to 9 and throw a Suhr Riot in front! So hearing all of that extra "noise" just adds that extra bit of character that makes this stuff so addicting, in my opinion.
 
Rex said:
It takes two or more notes sounding at the same time to generate intermodulation distortion. You won't get intermod with just one note.

I don't hear anything I'd call a "swoosh" in your recording, but what's the definition of "swoosh," anyway? :) I do hear a pulsating thing going on. That sounds like a vibrating string that's just barely brushing against a fret. Try raising the action a bit or adding a touch of relief. relief
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There is a lower fundamental frequency that almost sounds like a ring modulator under the note. That's what I am referring to. My action is butter.
 
Aja said:
There is a lower fundamental frequency that almost sounds like a ring modulator under the note.
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I'm not picking up on a lower frequency. Maybe if you followed it with another note a half-step removed, I'd be able to hear it.

Aja said:
My action is butter.
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You're describing how your action feels. That's only half of the equation. The other half is how it sounds.

If you lower your action, it'll feel even more buttery. But the fret buzz will drive you crazy.
 
Aja said:
There is a lower fundamental frequency that almost sounds like a ring modulator under the note.
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Cliff's Tech note article about ghost notes and his quotes in the Wiki will cover it well. If it's what I suspect it's a result of the note being played and the power-supply's ripple, so there are two frequencies interacting which is the basis of a ring modulator.

You can control that…
[303] Another option is to change the supply type to DC. This will eliminate any ghosting and give you a more "ideal" response. Most modelers use a DC power supply model but I've found that an AC supply model is key to achieving that last few percent of realism. The supply ripple is a big part of why old amps sound the way they do.

Most guitar players actually like a percussive attack so that's why about 10ms has become a de-facto standard.
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Rex said:
You're describing how your action feels. That's only half of the equation. The other half is how it sounds.

If you lower your action, it'll feel even more buttery. But the fret buzz will drive you crazy.
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It sounds fine to me, I play mostly clean and have never had anyone tell me my guitar sounds buzzy or anything close to that.
Greg Ferguson said:
Cliff's Tech note article about ghost notes and his quotes in the Wiki will cover it well. If it's what I suspect it's a result of the note being played and the power-supply's ripple, so there are two frequencies interacting which is the basis of a ring modulator.

You can control that…
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I think this is exactly what I am hearing! And I would 100% agree with this bit:
I've found that an AC supply model is key to achieving that last few percent of realism. The supply ripple is a big part of why old amps sound the way they do.
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I haven't ever messed with the B+ Time Constant control or the Power Type so I'll be messing with those now.
Although I can't imagine my tone or the feel of my rig improving too much.
Thanks for the link to that thread, very interesting stuff.
 
@Greg Ferguson Whoa changing the power type to DC COMPLETELY removed that sound. Fascinating. And just goes to show you the level of accuracy and detail Cliff has put into these models. Just outstanding.

BTW Im leaving it on AC, I like it. I also like that being a bit different than most modelers that use DC which makes me happy. Even if it's all under the hood.
 
Aja said:
It sounds fine to me, I play mostly clean and have never had anyone tell me my guitar sounds buzzy or anything close to that.
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I didn’t say your guitar sounds buzzy. Let’s go back a step...

Rex said:
I do hear a pulsating thing going on. That sounds like a vibrating string that's just barely brushing against a fret. Try raising the action a bit or adding a touch of relief.
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Aja said:
I haven't ever messed with the B+ Time Constant control or the Power Type so I'll be messing with those now.
Although I can't imagine my tone or the feel of my rig improving too much.
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Cliff is always listening and comparing his models with the originals and tweaking things. He wrote those articles and made those comments a long time ago, measured in firmware revisions, and the modeled sound is SO much more dynamic and realistic now than it was then.
 
Aja said:
@Greg Ferguson Whoa changing the power type to DC COMPLETELY removed that sound. Fascinating. And just goes to show you the level of accuracy and detail Cliff has put into these models. Just outstanding.

BTW Im leaving it on AC, I like it. I also like that being a bit different than most modelers that use DC which makes me happy. Even if it's all under the hood.
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Then it's a "ghost note". It actually IS intermodulation distortion but it's intermodulation between the note your playing and the power supply ripple.

You can also change the "flavor" a bit by altering the AC Line Freq. An amp in Europe will sound different because the line frequency is 50 Hz.
 
FractalAudio said:
You can also change the "flavor" a bit by altering the AC Line Freq. An amp in Europe will sound different because the line frequency is 50 Hz.
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That makes sense, the 50 Hz vs. 60 Hz is not a lot but it'd affect the notes that result.

Cliff, it's so educational and fun to watch the growth of your algorithms and the gear. I don't want to sound like a suck up, but I am really happy to see the growth of your code and the products. I've watched for modeling to occur for years, and seeing it happen is way cool.
 
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