Is aliasing a problem?

I have written several articles about aliasing. And recently I noticed that even on the High setting the Neural DSP Archetype: Cory Wong still generates a bit of aliasing. Listen to my (very annoying example):

Yuk! But admitted: the aliasing is not a major problem here. In the mix I don’t think anyone will notice it. Neural DSP uses 4 times oversampling for the High setting. Some amp sims I use offer 8 times oversampling and I will use that setting, even on the more crunchy and clean tones.

Too neurotic?

Maybe I am a bit too neurotic when it comes to sound quality. I have tested many devices using a pure sine wave and checking its frequency spectrum with a spectrum analyser. On other days I felt like “WTF it just sounds great!” There’s no such thing as perfect sound. It’s totally subjective in my opinion.

Today I stumbled upon the thread ‘Testing Aliasing of Plugins (measurements)’ on Gearslutz. The person who started the thread, Fred vom Jupiter, uses Plugindoctor to measure aliasing.

Although he has a point, aliasing can be problematic, only your ears can tell you if it’s really a problem. We should make judgements based on how it sounds.

So I left this comment:

Be careful with this. Always do a listening test to make sure whether or not this is a problem. A plugin with some aliasing might sound better than another plugin without aliasing. Aliasing is having a small factor on sound.

Aliasing can even sound okay. Sure, those are complex harmonics, not your normal odds and evens, like intermodulation distortion. Intermodulation distortion also happens in the analog world. So these kinds of harmonics which are not even and odd also happen in the analog world. You might call them unmusical but you can also think of these as nice side effects. It’s saturation. It might add extra spice to your sound.

And be reasonable. We can measure all things that doesn’t LOOK good but sounds great. Data might not give us the right story. We can fool ourselves with data.

Over the years my opinion about aliasing has shifted like an on and off-switch. It’s hard to say if it’s a huge problem. It depends on the amount of aliasing and since aliasing is only a part of the sound a plugin produces we might accept it as side effect. The solution to aliasing also gives us a new problem: much higher CPU usage. There are new ways though to tackle the problem, as Jatin Chowdhury mentions in his super interesting article ‘Practical Considerations for Antiderivative Anti-Aliasing’.

When it sounds wrong it might be good

In the early 60s The Beatles found out that distorting the mixing desk of the EMI Studios sounded cool. The EMI engineers disagreed. This was not the way music should be recorded. They were very dogmatic about it. These engineers were trained. But sometimes training and doing things ‘as it should’ can kill creativity.

In short: The Beatles were right. At least in my book.

Many of the plugins which were tested by the Gearslutz-guy Fred vom Jupiter show signs of aliasing. However those plugins are used by many well known and respected mixing engineers. So are these engineers tone deaf?

I don’t think so. Mixing engineer Tchad Blake has influenced my style of mixing in a great way. I consider him the Saturation King. Some of the plugins he has used a lot over the years, the Soundtoys Decapitator, Radiator and Devil-Loc, are also used by many others, including myself. These plugins can be heard on many popular records although they might show a bit of aliasing on your spectrum analyser. But somehow both the engineers and the public don’t mind. How come? Because these productions sound fantastic.

Data might fool you

I am not saying aliasing is not a problem because it (sometimes) is. I noticed it for the first time in the early 90s when I bought a Peavey Pro-Fex 19″ effects-unit. For the first time I noticed weird ghost notes when bending strings. I still own this device so I created this short example using it (be warned: it’s an annoying example):

Why did I buy it? Well we didn’t have YouTube or the internet at the time… so written reviews was all we had. I regret buying it, the Pro-Fex has like the most ugly and digital sounding amp sim ever. Sucks big time.

Lofi & Hifi

There’s no reason to turn yourself in a neurotic person. Nowadays I believe people, including me, are too much busy testing and comparing the tools which are available. Simply because we can and because we are interested in what sounds best. But I think there’s no such thing as best in music and sound. It’s all relative and a matter of making the best out of what you’ve got. Be glad your tools are not the same as everybody else is using. Be glad your tools have artefacts. Mistakes are great for art. Since blues players started to overdrive their amps, populair music is all about imperfections. If it sounds too hifi, no good. If it sounds too lofi, no good either. But in my opinion something in between sounds best. Because then it has that edge.

If it sounds good, it is good. However if it doesn’t look good, it still might sound good.

UPDATE: changed ‘tone death’ into ‘tone deaf’

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4 Responses to Is aliasing a problem?

  1. Dan November 14, 2020 at 5:55 pm #

    “tone death”. Lol. Small typo but it makes a great band name. Just found this blog and it’s right up my alley! I was really confused as to why I was getting weird artifacts when playing a tone sweep through my amp. My search for info brought me here.

    • Marco Raaphorst November 14, 2020 at 6:16 pm #

      Haha, thanks! Fixed the ‘tone death’ mistake 🙂

  2. Ritch Flynn December 1, 2020 at 2:58 pm #

    Stumbled on your article after seeing that same thread a few days ago! While I do agree that it’s not an issue which should be obsessing over at the cost of our music, I’ve come to a slightly different conclusion…

    Throwing a vinyl of Zeppelin on the stereo, and following it up with Image Dragons on iTunes…. in the comparison, it seems as if rock is now packaged – quantized, pitch corrected and sterilized. Mixes are clear and punchy but, to some extent, at the cost of lacking character, depth and feeling. It just doesn’t quite have that same intangible ‘magic’ quality. (and loads of factors play into this…)

    What we know for sure is this: music has evolved as technology has. It’s why that 80s sound is the newly intented digital reverb, and synth guys sold off their Moogs and Oberheims for pennies to get that digital sparkle of FM synthesis. And these day’s it’s all about bringing out enough head turning analog emulations as to give you whiplash.

    The tools we had even a decade ago have been radically improved & are getting better and better. Digital is getting closer to the analog world when it comes to sound generation, effects and quality. So whats next? For me it’s achieving a more natural and old school sounding mix in the box. So I’m reducing aliasing to get closer to analog. Switching out plugins for stuff like like Chris at Airwindows, and removing those bad actors that’ll muddy my mix with aliasing. Hopefully it’ll give my highs and mid range less masking and more smoothness in time. Selective saturation/distortion is key for me now as well, using it more to bring out mids than anything else, since distorting highs is just asking for trouble. Selective high and low cuts too to clean up the mix.

    So yeh, in a nutshell I think we can optimize it, without obsessing over it. And while many people used the more limited tools they had available to them, now we have better tools so we have a bigger responsibility to do the best we can with them instead of only repeating the past… Anyways thats my (long!) 2 pesos on how I’m improving my mixing, and eventually perhaps getting closer to those classic sound that I love!

    • Marco Raaphorst December 1, 2020 at 10:19 pm #

      I don’t think analog is better than digital. In fact I hated analog tape back in the day. The noise and the dropouts. Digital in my opinion is way more convenient. I love being able to save things, quit and work on it some other time.

      Sure, aliasing can be annoying. I use 8 times oversampling with my amp sims all the time. Then, aliasing is no longer an issue. But when I need just a little saturation, aliasing often is not a problem. In most cases you won’t hear it. And in some other cases it can be nice. It sounds like ring modulation. The old samplers all had aliasing which is now considered as a nice side effect.

      I guess rock and pop music sounds good because it has these “wrong” side effects like distortion.

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