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Let's take a look at the vocoder aspects of the EVOC 20. So we'll take a look at how to bring in audio through the Side Chain input, analyze it, and re-synthesize it through the Synthesis filter bank to get a variety of the vocoded sounds. So the place to start is our audio that we have in the range here. So this is our -- (Male speaker: I have nothing to say.) Nothing to say, yeah. (Male speaker: I have nothing to say. I have nothing to say.) So I want to vocode that and be able to play around of it in the EVOC 20. So the first thing that I am going to do is set the Output here to No Output.
That's because I don't want to hear it playing on top of the vocoded signal. So then in EVOC 20, what I am going to do is go to the Side Chain menu up here and choose Audio 1 - NothingToSay. So now it's routed through here. But I don't hear anything. (music playing) And when I play the synth part, it just sounds like a synth. So what I've to do is change my Signal Monitoring here to vocoder, this Voc. So now what happens is when I play back and I play notes, and it's vocoded.
Here it's I have nothing to say, but it's not all that intelligible and it's a little bit rough around the edges. So there is a lot we can do to address that. But first it's good to get a sense of what's actually happening with this whole process. What do these lines and things mean and all that? So, let's go through that. So essentially, what's happening is the Side Chain input, that's where the audio files coming through, and you have to imagine that's going up here and it's coming down through the top and it's being split into these five different frequency bands here, and it can actually be more than five.
I could have it be all the way up to 20 bands. And so this top part, this blue area, is the analysis filter bank. So what that's doing is it's taking our audio file, I have nothing to say, and it's splitting it into these different frequency ranges. And then there's an envelope follower on the end of each of these band pass filters that's in these frequency ranges. So that's going to track the shape of the volume of the sound. Then what it's going to do is it's going to send that down to our synthesis filter bank. That's here, that's in the green. And then the synthesis filter bank will take that volume information from the different bands and apply it to the synthesizer and then you end up getting the synthetic reproduction of our input sound.
So what happens is here's frequency from left to right, so 80Hz to 8000. So let's say this band right here, maybe this is 200Hz to 500Hz, so it's going to track the volume in that range and then in this next range and so on. So the more bands that I have then each of these slices of the frequency spectrum is smaller, and it's tracking the volume in a smaller slice and therefore you get a more accurate representation, because basically there's just more of little slices that are here where it's tracking volume.
So what happens when I've got more bands, like 20 here, is it's going to sound a little bit more intelligible. So I'll play the sound. (music playing) All right! So you can hear pretty clearly what he is saying, and then I'll bring this down, less bands. And you can still hear it, but it's a little bit more grungy less distinct. (music playing) So another thing that's going to really make a difference in terms of the sound is if we adjust the attack and release on the envelope followers that are part of our analysis filter bank.
So here is our analysis filter bank and so when I adjust the release, you'll hear that really makes a difference. (music playing) All right! So I get a longer release and it's less distinct. (music playing) And when I get down to about six milliseconds or so, you can hear it's a pretty accurate representation. It's pretty clear. When I go lower, it gets a bit more grainy because it's really short release. I can also adjust attack too. That's going to make more of a difference on a more percussive sound, where it's going to just make the transient softer on it.
The other thing that's kind of neat that I can do is if there's a certain portion of this sound that I like, like a certain vowel or something, I can just freeze the analysis and then I can play that shape and just play the synthesizer part, so that's kind of cool. The other aspect we've got here is I can set the low and high frequency for our filter bank here. So-- (music playing) if I set the low-frequency, that's basically acting as a high-pass filter.
420Hz is the lowest frequency. So I can make that really extreme. And I can do the same with this highest frequency here too. This acts as a low-pass filter, so it's cutting out the high-frequencies. And I can actually move this as a unit. If I just click in the middle and drag, I can move the spectrum around, which is kind of neat. And then the other thing I can do is if I don't want these to work as a high- pass and a low-pass filter, I can have the lowest bands, so from here to here, and the highest band, just be band-pass filters.
So if I make the rest of this very narrow, you can hear there are still low frequencies from this lowest band, because it's just a band pass, and there are also high frequencies in the highest band, but the rest of them are all kind of squished together. (music playing) So as you can see, all these parameters here with our analysis and synthesis filter bank really make huge difference to the vocoded sound. So in the next video we'll take a look at how we can stretch and shift the formants of this synthesis filter bank to get even more interesting vocoded sounds.
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