PhaseNudge
TL;DW: Phase rotator/allpass filter.
Here’s a simple little utility plugin, Airwindows-ized. Except, it seems like this isn’t part of typical DAWs and plugin collections. Can’t see why, it’s a pretty basic tool.
In radio, there was the need for a phase rotator, to make waveforms more symmetrical for loudness maximizing. In reverbs, you get a thing called an allpass filter (a kind of feedback delay at a specific calibration) which diffuses the sound so it can be fed to delay banks and seem more spatial. Turns out these are the same basic thing! It’s also in phase shifters (mixing the phase-shifted part against dry, or inverse dry).
What happens? When you use an allpass filter, what you get is all the frequencies exactly as loud as they were before, but the phases of the frequencies are all different. Specifically, lows get delayed relative to the highs producing an effect where tones are ‘smeared’ across a time stretch, even though the spectral contents are exactly the same. The frequency information’s unaltered (nothing’s out of tune or darkened/brightened) but there’s a blur, possibly a large blur. PhaseNudge is set up to produce delays from really short (normal for a phase rotator) to unusually long, in case you’d like to treat it as a kind of slapback/echo effect.
The calibration of PhaseNudge is finer than you usually find in an allpass: 0.618 is the customary number but when I see that I think ‘golden ratio’, so that’s what PhaseNudge is using, to very high accuracy. Also, PhaseNudge uses a variation on the operating principle of Console to expand and deepen the sound. Though typical allpasses use very short delays, I think PhaseNudge does its thing quite well across a broad range of delays. Anywhere you need a ‘defocus’ or ‘blur’ plugin, PhaseNudge should come in handy, whether it’s diffuse pads, overly pointy percussive elements, or even the effects loop of a lead guitar sound (phase shifters have been used for decades, to make the textures of leads more fluid before they hit the actual amp. You’ve heard this on ‘Eruption’ and may not have even known it, because it’s very subtle there)
This is a real fundamental building-block tool in digital audio, and if DAW makers will not include it as part of standard equipment, I will. ;)
If you’d like someone (me!) to be there filling in these gaps that aren’t trendy enough to light up the ‘plugin market’, support me on Patreon because I absolutely will continue to come up with stuff like this, as I have done for nearly a decade running Airwindows as a commercial plugin shop. There will always be something new, or something overlooked, that’s important. Especially in times when all the big dinosaurs of plugin-land are eating each other in desperate attempts to offer models of a few trendy antique hardware boxes or devices at ever-cheaper prices, somebody needs to be creating the actual tools of the trade and making them available to people regardless of wealth or position.
I’m not the only one, but with Patreon I can be completely immune from fashion. And as I post this, I’m incredibly close to (may already be at) the funding goal where I install Linux and get to work on porting everything to Linux VST! It may become possible to do totally professional mixes and processing on a free computer system! Remember that at my really advanced funding goals I start open-sourcing my actual plugin code. Free doesn’t just mean no monies, it can also mean establishing a community of makers who pool their resources. You could end up seeing whole new DAWs with a look, sound and workflow all their own. I’m prepared to do my part :)
You have a very warm soul Chris! I appreciate your work a lot and I think you’re a hero for trying to give the real musicians a chance. Thanks!
Hello Chris, thank you for the amazing work you are doing and your incredible generosity!
I have several interconnected questions regarding PhaseNudge and would be very happy if you could answer them for all of us:
I guess my main question is what PhaseNudge exactly is, compared to the two different functions a unit/plugin like Little Labs IBP has in order to alter phase relations. Here’s my train of thought, so you know what I mean.
Does PhaseNudge work like a very precise delay to offset signals against each other – because you are talking about delay times in your description? But this can’t just be it, since frequency ranges are delayed against each other right? Then does this work ‘only’ as a phase ROTATOR and not alignment – so ‘only’ like the right knob on the IBP or the PhaseBug plugin? But what would irritate me about that conclusion, is that the scale on PhaseNudge ranges from 0 to 1 and not from 0 to 180 (or 360) degrees, and also that classic phase rotators seemed to include 4 allpass filters in series, but I only hear you talking about one allpass filter. So is PhaseNudge something different altogether or some kind of combination of those concepts?
I hope my questions don’t seem outright ridiculous to you, but I searched the web for more information about all the different ways to handle phase relations and I couldn’t find anything that helped me answer my questions regarding your plugin really.
Thanks again for taking the time for this and all the best for the next year!
I could do one with four allpasses in series. I never heard that about classic phase rotators. Mine’s just one allpass :)
Hello Chris, thanks for your quick reply!
I took the time to get a little deeper into the subject and found that units like the Little Labs IBP (which stands for ‘In Between Phase’ btw) seem to use multiple (2 in that case) allpasses only when one wants to shift the phase by more than 90 degrees – and I don’t know if the range of your algorithm could be translated into degrees, while earlier phase shifters for radio broadcasting used even more.
But what’s even more important than the number of allpasses, and what’s the real reason for my original confusion, is the different uses allpass filters have in real life because of their function as phase shifters.
They obviously can be used as creative tools to alter the sound of a SINGLE source, smearing the transients and creating more headroom along the way (which is also why they were originally used in radio broadcasting to make the voice of the hosts louder, which became unnecessary with the invention of way faster compressors and limiters).
But another and maybe even more common use today seems to be to make MULTIPLE sources work better together regarding their phase, especially for multitracked instruments like bass or guitar (DI and speaker for example, maybe with multiple mics) and of course, drums, because a simple alignment of two signals by delaying one of them is often not enough to solve phase problems sufficiently, even when done on a sample level.
So what I (and possibly quite a few others) was looking for, is a way to do the latter. And while your plugin already helps a lot with that, I think it would be amazing to do two or maybe even three different things in one plugin, because they are so closely related with regards to solving phase issues:
1)
purely shifting the position of one signal in time forward or backward by up to maybe 500 or 1000 samples, depending on the sample rate used,
MAYBE 2)
doing the same as in 1) on a sub-sample level if that is possible, to be even more precise, because that seems to make a huge difference sometimes,
3) doing a phase shift with allpass filter(s) by up to 180 degrees (or whatever seems useful).
Of course I am not the one to tell if this topic really interests you or how many people exactly may be interested in something like this, but reading a lot of discussions and talking to other engineers about that topic, I get the impression that a) there is a real need for a precise and effective tool to handle phase/time relations between multiple signals, especially for anyone who has experienced what a huge difference this can make for less than already stellar recordings with no phase issues, b) a plugin with the precise functions described above simply doesn’t exist, let alone a free one, and the only way to get close to it exists on the maybe brilliant, but very expensive UAD platform (in form of the Little Labs IBP emulation) and last, but not least c) I think there may be no one beside you, who is skilled, interested and generous enough to pull this off.
Again, I am really sorry if I have wasted too much of your time by writing such a long comment on a topic that may not even interest you enough. But if it does, I think this could make yet another invaluable tool, and possibly for many more people besides me.
Thanks again for all your efforts and a very happy new year,
Dan
PS
I thought about the terms “degrees” and “rotator” (as in phase rotator) some more and now think that you were probably very right from the start in not measuring the phase shift of an allpass filter – at least for real sounds and thus complex waveforms we are dealing with – in degrees at all, although many others do exactly that.
Please correct me if I’m wrong and only if you want to of course, but, although enough of a phase shift also moves the formerly positive parts of a waveform to eventually become negative ones in what is then called a phase shift of ‘180 degrees’, by that time they are not the same anymore, right? If they were, a phase shift of ‘180 degrees’ would be equivalent to flipping the phase of a waveform or, strictly speaking, offsetting it by half its wavelength to itself, but for allpass filters that is only true when there only IS one frequency, like in pure sinewaves. So “degrees” would only make sense for the time-difference of ONE frequency compared to where IT was before OR for the newly generated time-difference between TWO different frequencies, when there are more than one. But since there is always more than one frequency in what we are dealing with (real sounds) and the ‘degree’ of shift is different for each of them in allpass filters, why quite arbitrarily pick one or two of them to be able to describe the shift in degrees, thereby also falsely suggesting that a shift by 180 degrees should just invert a waveform while keeping it the same otherwise or that a shift by 360 degrees should get you back to where you started? Actually, while reading about phase rotators, I noticed that one of the most common questions about them really is, why shifting the phase by 180 degrees doesn’t cancel the unaltered signal like phase switches do.
So – in case i am not totally on a wrong track here – for a plugin like the one proposed above, it would make much more sense to figure out which now abstractly measured amount of phase shift starts to alter the sounds we are dealing with so much, that they don’t feel like the same sound anymore, and make that the maximum, in order to have the most precise resolution for the task of optimizing phase relations between two different signals of the same instrument – be it snare and kick and overheads, bass amp and DI or the different mics on a piano.
Sorry for using so many words again,
Cheers,
Dan
Hello Chris. I’ve just read Dan Raphael’s comments and it’s kind of funny that I reached your website (and the specific PhaseNudge plugin) because I’m just looking for what Dan described above. I know that the Little Labs IBP plugin might help me but I don’t own the UAD hardware. Basically, I’m trying to get the optimal phase relation between 3 guitar tracks that were reamped from the same performance with 3 different rigs. I don’t want to do it automacally, the I idea is to use my ears and I confess that a correlometer (specially if it’s a multiband one) is also going to be very handy. ;) I will download PhaseNudge as soon as I finish typing this comment and give it a try. It’s really good and rare to find someone with your mindset. Thanks so much.
If you could just create an allpass filter with selectable center frequency, and poles, it would be awesome.
I often use one before compression or saturation. It adds a vintage smear that compressors just love on the kick and snare. It actually accents the transients in a round way. (Tchad Blake’s mixes all sound like this, cause he uses a multiband limiter at the end of his chain, and at crossovers it introudes those phase shifts)
My go to settings are around 200-1500Hz 42dB/oct 0.7Q
It looks like this on a phase analyzer: http://prntscr.com/ivk6ij
Tchad’s setting is like this: http://prntscr.com/ivk6ij, so it would be great to have a control over the filters Q.
Hi Chris, i have been watching almost tons of your videos, of the plugins to know in Depth, or almost in the way you have created it for a purpose, so its neccesary because sometimes i need audio examples to understand the purpose of certain plugin you have made, and also take the freedom to combine them in weird manners, and are so cool anyways. well, the lead motif of thhis message is to write if you could do a phase alignment tool, a phase shifter not similar or to mimic certaian hardware but just with certain parameters adjustment of phase angle, resonant frequency, gain
mirror and flip modes speed stereo setting selection
δr mode for modifying stereo in midside or whatever you consider usefull , What.txt get me here all the time. THANK YOU SO MUCH Mr Chris Johnson!
Merry Christmas!
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Hello Chris,
How do I simply rotate all frequencies by 90 degrees? What is the “magic” number?
My application involves spoken word only. I am using plug-ins for short-wave radio (amateur radio) hobby.
Currently using a 64 bit VST Host.
Thank you!
Juha Jussila
i went to find this plugin of yours after looking at this product: https://www.kludgeaudio.com/500/rotator.html because I was very curious to hear what it does to audio. PhaseNudge was doing things to audio, but, apparently it does different thing that the mentioned 500-series module.
my further research found following documents of interest (in no particular order):
https://static1.squarespace.com/static/58f8d954b8a79b4ccf726c3b/t/5996dc63d7bdceeb0f5bc325/1503059043905/The+Truth+about+Audio+Processing+in+Radio.pdf
http://www.w3am.com/SymmetraPeakPatent.pdf
http://www.w3am.com/SymmetraPeakBrochure.pdf
http://www.w3am.com/8poleapf.html
http://tonnesoftware.com/downloads/11-12-2017-Tonne-All-Pass.pdf
I would be very curious to hear your take on this “method”.
Hello Sir
Just found your blog and I would love your plugs-in (VST or AU) for Mac? Any chance?
Cheers
PhaseNudge is just….WOW. It actually beat out some really expensive bus comps for me last night! Thanks Chris. To call a genius would be…..accurate. :)
Btw for anyone looking for “standard” phase rotation there is a module inside Variety Of Sound’s “preFIX” plugin. It’s free and 64bit:
https://varietyofsound.wordpress.com/downloads/
I am not even sure if this will help me fix the issue I am seeing with one of the recordings I have (Quicksilver Messenger Service live at the Filmore 1968) The Semetry is off i cant show the image to make it clearer to you but what I see is from baseline up is much higher goes from infinity to -3 Db the bottom goes from infinity to roughly -6Db I am not a big time DJ I only do a 3 hour show once a week for my local FM radio station and am not even paid so no one seems to care as long as I keep playing the music I grew up with and love still. BUT I have been putting these shows together for 5 years now and the more I learn the more I realize I do not know LOL. I have two versions of AU one is old and is 3.0 and the other is version 22.3.0