Tags: posts polarity-music Audio-Effects Bitwig Bitwig-5.2b1 Poly-Grid Tutorial FX-Grid

All Pass Filters power everything

Tutorial | May 02, 2024

In this video, I discuss the All-Pass filter module in Bitwig Studio 5.2. While it may not seem like much, this module is actually quite powerful as it allows for phase shifting at specific frequencies without altering the frequency content. This module can be used for tasks such as phase aligning sounds or creating custom filters within the Bitwig Grid.

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In this tutorial on Bitwig Studio 5.2, I explore the All-Pass filter module, which, despite its name, doesn't filter frequencies but rather adjusts phase at specific frequencies. Here's a quick breakdown of its capabilities and applications:

Overall, the All-Pass filter module in Bitwig Studio is a versatile tool for detailed sound manipulation, particularly in phase alignment and the creation of custom filters and modulation effects.

Questions & Answers

Maybe you dont watch the video, here are some important takeaways:

What is the All-Pass filter module in Bitwig Studio 5.2?

The All-Pass filter module in Bitwig Studio 5.2 is a powerful tool that shifts, flips, or inverts the phase at a specific frequency. It does not alter the frequency content of the signal, only the phase at the designated frequency. It can be used to align or offset the phase of different sounds, create filters, and even phase or frequency modulate audio signals.

How can the All-Pass filter module be used to phase align sounds?

The All-Pass filter module can be used to phase align sounds by offsetting the phase of one sound to match the phase of another sound. For example, if the tail of a kick drum does not align well with a bass sound, the All-Pass filter module can be used to shift the phase of the kick drum at a specific frequency to align it with the bass sound. This creates a subtle delay effect, but only at that specific frequency.

Can the All-Pass filter module be used for frequency modulation?

Yes, the All-Pass filter module can be used for frequency modulation. By using an oscillator as a modulator, the All-Pass module can shift the phase of an audio signal, effectively frequency modulating it. This can result in unique and interesting sounds, similar to using a phase modulation input on an oscillator.

How can the All-Pass filter module be used to create custom filters in the Bitwig Studio grid?

The All-Pass filter module can be used to create custom filters in the Bitwig Studio grid by combining multiple All-Pass filters and adjusting their center frequencies and offsets. By using the right combination of settings and blending the signals together, it is possible to create various types of filters, including low-pass, high-pass, notch filters, and even resonating comb filters.


This is what im talking about in this video. The text is transcribed by AI, so it might not be perfect. If you find any mistakes, please let me know.
You can also click on the timestamps to jump to the right part of the video, which should be helpful.

[00:00:00] In this video I want to talk about the All-Pass filter module inside of Bitwig Studio 5.2
[00:00:07] and it doesn't look like much but this module actually is very powerful.
[00:00:12] And it's called filter but it's actually not filtering frequency content.
[00:00:17] It only shifts or flips or inverts the phase at this frequency.
[00:00:24] That's all it does.
[00:00:25] It doesn't lower frequencies or push frequencies or anything like that.
[00:00:30] It only affects the phase at this sender frequency.
[00:00:34] And I have this here inside of an FX grid and before the FX grid I have an EQ curve
[00:00:38] analyzer here sending out some kind of test signal and after the FX grid I'm using here
[00:00:43] also an EQ curve analyzer and you can see here in green the frequencies.
[00:00:50] So you can see there's no filtering applied to the frequencies but in purple you can see
[00:00:55] here the phase.
[00:00:57] So the phase basically shifts at this frequency here completely to the opposite.
[00:01:04] So everything that's positive goes negative and vice versa.
[00:01:09] And when we change the sender frequency you can see we shift basically here the phase
[00:01:13] at different frequencies.
[00:01:17] So this is all it does basically.
[00:01:20] So no frequency content is altered with this.
[00:01:24] So that's important to know.
[00:01:26] If we increase or decrease here the steepness of the filter you can see it affects kind
[00:01:31] of how the phase shifts at certain points.
[00:01:35] So here we have now multiple phase shifts at higher frequencies and only one frequency
[00:01:42] shift here at the lower frequency but you can also shift this here around.
[00:01:46] So at 2p you basically do only one flip at this kind of sender frequency.
[00:01:54] And if you pull this down here the effect is not that drastic.
[00:01:58] You can go down to 20Hz but the shift only is applied here barely above 1k.
[00:02:06] So this is kind of roughly how this works only to explain to you what's happening inside
[00:02:12] of this module.
[00:02:14] So here I have a pulley grid in there I have basically a sine oscillator and the sine
[00:02:21] oscillator sounds like this.
[00:02:23] It's just a bass.
[00:02:29] And here with the all-pass filter device in there we can basically offset the whole signal.
[00:02:34] So the red one is the dry signal coming out of the sine and the blue one here is the shifted
[00:02:39] one from the all-pass filter.
[00:02:42] So you can use this sometimes if you want to to phase align certain sounds.
[00:02:49] So let's say you have a kick drum and you have a bass sound and you want to align the
[00:02:53] tail of the kick drum with the bass sound and it doesn't fit very well.
[00:02:57] You can put this here maybe on the bass or on the kick drum itself and then use here
[00:03:03] the sender frequency to offset the phase of the kick drum.
[00:03:10] And this is kind of then like a delay but it's only on this frequency.
[00:03:17] So you apply only this shift on this frequency.
[00:03:20] If you change the frequency of the bass right if you go higher then the frequency offset
[00:03:27] or the shift here is different.
[00:03:30] So that's the idea about it right because the sender frequency is down here and if we
[00:03:37] play higher frequencies of course the shift is different than up there.
[00:03:43] So here we have multiple, I showed you right if you pull this up to 3p you have then multiple
[00:03:48] phase shifts at certain points and I think 1p it only shifts the lower part of the frequency
[00:03:56] spectrum.
[00:03:57] So here we have let's say lower frequencies and then you can shift it a bit and then if
[00:04:02] you go higher kind of is already still a complete phase flip or phase inversion.
[00:04:18] So if you want to apply a small little sub millisecond offset to your signal then you
[00:04:25] can use the R-pass module here with 1p and then just slightly offset some bass frequencies
[00:04:31] or some mid-range frequencies and align it with different signals.
[00:04:36] So that's the most easy the most simple use case for this because it doesn't alter the
[00:04:43] frequency at all.
[00:04:46] What you also can do is you can phase modulate signals with this.
[00:04:51] So let's say you have some kind of sound some kind of melody or a sample and you want to
[00:04:58] phase modulate this or FM a signal with another signal.
[00:05:04] So you can do this because you do basically a phase shift which is the same thing as using
[00:05:08] here the phase input on a sign because the phase input also only just alters the position
[00:05:16] or the offset of the signal.
[00:05:18] So you can do this here with the all-pass device now on audio signals.
[00:05:24] So we can use here another oscillator.
[00:05:29] Let's use another sign oscillator here.
[00:05:35] Use a modulator out.
[00:05:36] You can't just go into here and do this a phase modulation with this because we have
[00:05:42] here an oscillator.
[00:05:43] But let's imagine that you don't have an oscillator here with a phase modulation input.
[00:05:47] Let's say you have a sample on audio track or some recording and then you put an all-pass
[00:05:53] on that audio signal and then you can use an oscillator here and then just modulate
[00:05:59] basically here with an audio rate and then you get a different sound out of it.
[00:06:09] Let's pull up here the volume.
[00:06:23] So you can use the all-pass device or all-pass module to phase modulate or to frequency
[00:06:29] modulate all kinds of audio signals.
[00:06:32] You don't need oscillators for this now.
[00:06:35] You can use a sampler.
[00:06:36] You can use an audio signal like I said from a different channel.
[00:06:39] You just put an FX grid on this audio channel and then you use a sign oscillator and then
[00:06:44] you modulate this and then you can phase modulate or FM any sound inside of Bitwig
[00:06:50] with this.
[00:06:53] I showed you this basically in some of my recent videos with the FM modulations where
[00:06:59] I used a delay.
[00:07:01] So now you don't need to use a delay.
[00:07:03] You can use an all-pass which is much more precise with this because I showed you right.
[00:07:08] You have this sub millisecond offset you can apply.
[00:07:12] You don't need to use milliseconds anymore.
[00:07:17] So that's that.
[00:07:19] Then we can also do some interesting frequency stuff with this.
[00:07:26] If you maybe already know most of the filters you get here let's say a low pass filter here
[00:07:35] is consisting of all-pass filters in there.
[00:07:39] So you can build with some all-pass modules a filter.
[00:07:44] So I try to do this here.
[00:07:49] You can see here the sine wave in the EQ but we can also switch this here to let's say
[00:07:54] a saw.
[00:07:55] We have some overtones and we also want to change the resolution here.
[00:08:03] So yeah we have a nice little saw there.
[00:08:06] So now we can just say we want to use a blend and the blend actually just blends two sounds
[00:08:14] together right.
[00:08:15] So we can use the all-pass here go in there and then create a kind of a shifting signal
[00:08:25] so we delay the signal here with the all-pass or we flip the phase at a certain point and
[00:08:31] sounds like this.
[00:08:43] So here the thing is we mix basically let's go back into the oscilloscope and that is
[00:08:49] the pitch.
[00:08:50] We mix basically here the original signal and shift the signal together like this and
[00:08:56] then you can see here it basically kind of counters the original drive signal so we have
[00:09:03] a phase cancellation.
[00:09:09] But because this has a center frequency I showed you before that the offset is different
[00:09:15] at different frequencies because we have your center frequency right.
[00:09:18] We have a full phase flip at this frequency but all the other frequencies have a different
[00:09:23] offset number or different offset value.
[00:09:28] So we shift at different frequency differently which you can see here.
[00:09:34] Here is then basically no phase flip and then we have here a lot of phase cancellations
[00:09:39] and so on.
[00:09:40] So we create basically some kind of low pass filter with this and we can increase this
[00:09:45] effect by just using multiple of these here.
[00:09:49] Let's use here this we go in here and that another one in there and then in here.
[00:09:58] Let's push this here together.
[00:10:02] Duplicate this.
[00:10:09] So now you can see we remove a lot of content here and all we have to do now is more or
[00:10:14] less use a macro here and modulate here all the all-pass center frequencies and you can
[00:10:22] bring in here all the overtones.
[00:10:24] So it sounds like this.
[00:10:39] So this is the whole magic of these all-pass filter devices.
[00:10:42] Create changes or offsets the phase at different frequencies differently so we can create phase
[00:10:50] cancellations in different frequencies with different amounts.
[00:10:54] So it creates basically filters.
[00:10:57] So here we have now a low pass filter, a Jennifer Lopez filter.
[00:11:02] We can also create let's say let's use a blend here and push this up.
[00:11:12] So this is Lopez filter with multiple with different of the same techniques here and
[00:11:18] we increase basically with the more we add to this here we increase the steepness of
[00:11:24] the filter.
[00:11:25] So we can also add your more if you want to.
[00:11:32] So the filter gets steeper the more you add.
[00:11:35] We can also create some kind of high pass filter.
[00:11:40] It's the same technique basically but I think you need to flip the phase.
[00:11:45] Yeah, let's actually use this new module called invert.
[00:11:54] So this is now inversion so it phase flips the signal again but that all frequencies
[00:12:02] not only at certain frequencies at all frequencies and you get with this here.
[00:12:09] Some kind of high pass.
[00:12:13] You can see I remove now the lower frequencies and we can do basically the same.
[00:12:18] We can duplicate this here.
[00:12:27] And we get steeper and steeper with every iteration in there.
[00:12:40] So now we have kind of a high pass with this.
[00:12:51] Maybe do one more here.
[00:12:55] So if you are 1234512345 that's okay.
[00:13:03] So high pass filter and Lopez filter just with a few are pass devices here.
[00:13:09] We can also blend these two together.
[00:13:14] And then you can see we have here a certain kind of dip at the center frequency because
[00:13:23] we add the low pass and the high pass filter together but they not really have unity gain
[00:13:31] at this crossover frequency.
[00:13:33] This is always a problem with also with frequency splitters and so on.
[00:13:38] So you have to balance this out and maybe change at the offset frequencies differently.
[00:13:43] But what we also can do here is we can do exactly the opposite.
[00:13:48] So we can use another macro here and just say we want to offset here the all-pass frequency
[00:13:55] to this direction right up on the positive direction and here in the negative direction.
[00:14:04] So we want to spread the frequencies apart on each of these things.
[00:14:10] So now if we increase here the frequency right so we offset this in one direction and we
[00:14:15] offset this one in another direction we basically create some kind of notch filter with this.
[00:14:36] So what I want to say is you can now create your own kind of filters inside of the grid
[00:14:42] with a few all-pass modules here and get creative.
[00:14:47] So you can basically create high pass filter, slow pass filters, combine these filters to
[00:14:51] create notch filters and make different resonances at different frequencies.
[00:14:56] So you can create your own filters inside of the grid now with this.
[00:15:01] So it's pretty interesting actually.
[00:15:03] Oh yeah I need to push this there.
[00:15:07] And the more you add to this the more steepness you get and you can create more precise filters
[00:15:15] this way.
[00:15:16] So it's pretty interesting, pretty fun to do this.
[00:15:31] And as I showed you before if you increase here the steepness of these all-pass filters
[00:15:36] we create more base inversions at upper frequencies.
[00:15:41] So if we do this here let's go up to 6.
[00:15:47] You can see here we create some kind of comb filtering there.
[00:15:52] Let's see how this sounds.
[00:16:20] So yeah it's basically a different kind of filter.
[00:16:22] It's more like a comb filter or a notch filter with multiple notches or it's kind of a flanger.
[00:16:29] I don't know you can call it like you want to.
[00:16:32] So this is how you set up this stuff here inside of the grid.
[00:16:37] I think if you just use here let's say one blend, one all-pass device, let's remove this
[00:16:46] here.
[00:16:48] One all-pass device, one blend.
[00:16:50] You kind of create some kind of I would say phaser maybe.
[00:17:00] So you put an LFO on that probably.
[00:17:02] So you can also create phasers with different notches or you can experiment with filters
[00:17:11] and phasers and combine these two.
[00:17:14] But usually phasers and filters and all that stuff is more or less the same thing.
[00:17:21] It just called differently because they sound different.
[00:17:26] This one hurts maybe.
[00:17:30] [Music]
[00:17:36] [Music]
[00:17:43] [Music]
[00:17:50] [Music]
[00:17:56] [Music]
[00:18:01] [Music]
[00:18:07] So yeah, this is also possible.
[00:18:10] I found it also quite interesting to create some kind of resonating comb filters with this.
[00:18:17] So let's say you have a noise signal and a very short one.
[00:18:27] And then what you usually do is you go into a comb filter which is also just a bunch of all-pass filters here with the feedback loop in there.
[00:18:39] Let's see how this sounds.
[00:18:41] So we increase the resonance.
[00:18:44] [Music]
[00:18:55] But with the comb filter you have some kind of feedback here that you can change.
[00:19:01] Also here the feedback polarity so you can flip the polarity of the phase on the feedback signal that goes back right into the input here.
[00:19:13] But you can't change the internals like how the all-pass filters are set up and what kind of center frequencies they use and so on.
[00:19:21] So this was kind of missing.
[00:19:24] But now you can kind of do it with an all-pass here.
[00:19:28] So we can do something like let's say using a long delay.
[00:19:33] So it's the only way to do basically feedback inside of the grid.
[00:19:38] Use your long delay and go down with the delay time.
[00:19:45] And then we go back into a blend here.
[00:19:48] Mix these together.
[00:19:53] And then let's use here gain knob.
[00:19:58] Increase the gain a bit.
[00:20:01] [Music]
[00:20:20] But the problem here is this is not 0.02 milliseconds because this long delay is limited by the sample rate right here.
[00:20:35] So it's at minimum we can go down to 10.67 milliseconds.
[00:20:43] That's the buffer size right.
[00:20:45] So even though we go lower you can see it does change the signal.
[00:20:49] [Music]
[00:20:52] Only above 10.
[00:20:53] Then it starts to change because that's the lowest amount here.
[00:20:57] 10 milliseconds.
[00:20:59] [Music]
[00:21:02] Right.
[00:21:03] So what we can do now is we can change here the buffer size.
[00:21:06] So we can go down to let's say 32 samples.
[00:21:09] So we have now here 0.67 milliseconds.
[00:21:13] So it's probably not a good sample size or buffer size of...
[00:21:26] We can go lower than 10 milliseconds.
[00:21:31] [Music]
[00:21:38] So we can create kind of a comp filter with this here.
[00:21:43] But now instead of using delays we can also bring in let's say our pass here at a certain point.
[00:21:52] [Music]
[00:22:09] So with this we can...
[00:22:11] You have to be very careful here with this.
[00:22:14] With the feedback.
[00:22:15] [Music]
[00:22:20] You can create kind of nice bell sounds or some atonal sounds with different frequency overtones distributions.
[00:22:30] [Music]
[00:22:37] So I really hope we get in the future inside of the grid at some point a better feedback kind of device.
[00:22:46] Because this feedback is really interesting and you can create a lot of interesting things with feedback.
[00:22:52] So maybe we get something to get down to lower buffer sizes at some point would be really nice to have.
[00:23:00] I know it's very nerdy for some people but you can create a lot of nice devices with this.
[00:23:06] [Music]
[00:23:09] You can see how we shift basically all the overtones around just because of this all pass device.
[00:23:15] [Music]
[00:23:44] Yeah, so that's basically it.
[00:23:49] For now there's a lot of more stuff you can do with all pass filters just by offsetting the phase at different frequency by different amounts.
[00:24:00] Like I said here feedback is interesting just combining dry signal and offset all pass offset signals.
[00:24:08] If you do phaser sounds flanger sounds you can create filters not filters low pass filters high pass filters.
[00:24:14] It's probably also interesting for reverbs distortion.
[00:24:18] So there's a lot of stuff you can create with all pass filters.
[00:24:22] It's basically a component of most modern audio effects in any form.
[00:24:31] So it's a very nice addition to the bit we grid but I wish we get lower values for the feedback buffer sizes.
[00:24:42] But we're very nice to have in the future.
[00:24:44] Maybe the next update I don't know.
[00:24:47] So that's the all pass filter for you.
[00:24:49] I hope it gave you some interesting inspirations to try this out and create some of your own devices inside of the grid.
[00:24:58] That's it for me.
[00:24:59] Leave a thumbs up if you like the video.
[00:25:01] Subscribe to the channel.
[00:25:02] Thanks for watching and I'll see you in the next one.
[00:25:04] Bye.