Lessons

Lesson Info

Making an Impulse Response

So uh when we recorded this album um called uh painted with light I think uh oh I'm sorry I don't know the name of the album just yet there they've been talking with labels itself so they'll be putting out a really soon I'm sure so we use the same guitar that a day remember used it was the strat with mgs in it uh what I did for the base was we used trillion um which I'm actually gonna be showing you that a little bit later um which it was just one the one main track of trillion and then we also had another track of just really low end base oh yeah and this was this was also my impulse response just going to remind you of that so talk about that a little bit because I know that initially with your axe facts you were kind of struggling to get the right tone and that the impulse response that's there's a turning point for you that's a great point I actually was pretty frustrated with the vax effects to be completely honest whenever I first got it and I was on the phone act two actually re...

turn it to be totally honest but they told me about the feature with impulse responses and as soon as I made my own impulse response which is the one that I'm giving you guys a switch went off I was like, okay, this this is all at once so if you guys if you guys get this impulse response you can put on the axe effects if you have one and it will make a world of difference um so I was pretty excited when that happened so as soon as I fear that I still have it today I absolutely love it um and I can't wait to use it more later, okay, so what is an impulse response? I kind of feel like I should have explained this ah long time ago but let's read the official definition in signal processing that the impulse response or impulse response function I ref of a dynamic system is its output when presented with a brief input signal called impulse now that probably doesn't it cleared up for anybody but an impulse response and we're just going to talk about impulse responses for a second because I think they're absolutely incredible. Um this is what it means for you for you guys uh in terms of guitars in terms of guitars it means you're capturing sonic characteristics of a microphone preempt cabinet, et cetera. Okay, so an impulse response basically it's monitors how different frequencies react in a certain environment and that khun b a speaker of a cabinet uh it could be a room, for instance, so let's say uh the way the way you make on impulse response is and I'll show you with the axe effects which is really cool um where is that? Okay that's a little bit later but it will play a sine wave from twenty hertz to twenty kilohertz and it's just a sign sweep that goes through every single frequency that we can hear that you use in recordings and it monitors how each frequency is affected want it when it hits that frequency so let's say you're in a room that is, you know, ten feet wide and you have some weird frequency that's bouncing around in there and you think it's cool you like it for instance so what you do is you would play the frequency response the sine wave over a speaker and you'd have a microphone in the room and it would record that sign sweep and then you would put it in what's called a deacon volver which I'll explain in a second what it analyzes that sign sweep and it says it's basically like, hey, what did what did this frequency do at once you know at one kilohertz it it sustained, for instance, so it would mimic that whatever you apply the impulse response through convolution, reverb or some kind of convolution plugin which is also what you guys might know is a cabinet uh simulator so um convolution is the technical term, so as soon as you put it on anything that you play through there when it hits one hurts our one kilohertz it's going to sustain its goingto have river, right? It'll have the same properties so you can use this technique with, um, modeling uh, excuse if you have any qu love uh, you can actually you can run, run it through, run the sine wave through the q and as you adjust it, it will monitor the difference. The difference is that you make and waves makes a plugin called q clone and you can actually take if you buy one expensive e q you know you don't have money to buy a bunch, you you run this plugging, it will put a sign sweep through it continuously, and as you make the changes on the knobs, it will also make the same changes in the plug in in the program, so you can use that q, which is a hardware unit as many times as you want. So when someone says impulse response, they're not just talking about a guitar cabinet. Sound on impulse response is how on acoustic environment, whether it's an e q or room or speaker, how it reacts to different things that are put through it, and the best way to figure that out is to put a sign sweep through it. So that's what we do with the cabinet and I'll show you that it sounds weird the axe effects has the kemper as as it's wobbling it's going through a bunch of free basically did just what you just described and then what it's doing that the kemper is a little more specific with what it does because it's going through more things than just the speaker it's ah it's also analyzing what's happening specifically in the low what's happening in the ladies you hear separate it sounds like maybe there's three different stages you know it's it's got kind of a mid range thing kind of the die and lying and then and then lows exact so it does kind of seem to treat you know specific properties differently but you know in the end you you know you just use that refine option and actually that you know the actual audio then is modeled right now so it does the same type thing I think that's that's basically what that is this is an impulse you know it's it's sending sending a signal through and it's being captured it is it's making an impulse of your entire signal it's also making impulsive different volumes that's why it's fading fading in like that so I'm fascinated by impulse responses you could make them in stereo you could make them mano whatever you want to do I think they're absolutely incredible okay by the way that was an excellent explanation of impulse responses I have been reading about him for a long time and I think that you just summed them up to me better than anything do you understand them? No, she was she wasn't paying attention she was on something I was not on facebook I was in the chat room. Okay, lee ok, cool. Um all right, well, I tried my best and you didn't listen so now I'm just kidding ok, cool so you have it you have an impulse response um I don't have any we should listen to what an impulse response sounds like it's it's not a sign sweep when in the end after the sign sweep but whether it's on the axe effects or on your computer and I'll explain how you can do this yourself it puts it through what's called a deacon volver and that that just changes the sound into a tiny little pinprick of sound and that holds all the characteristics of that sign sweep and it's sometimes it might just sound like something that it's very strange and I'll play that but that's what it ends up being that's that's all on impulse responses but it makes a world of difference whether using itfor reverb q actual an actual amp or a cabinet so how do you use an impulse response so you take that tiny little sound the pinprick of sound? Usually if it's reverb it'll have a longer trail but for specifically talking about cabinets it's just gonna be a tiny little pinprick of sound but it has all the characteristics of of the cabinet okay, so you're gonna load it into uh you know, it might be called an I r loader or a cabinet part of a plug in and we have uh okay um or convolution plugin convolution reverb convolution loader look for the word convolution memorize that um so the way the eyes it whether it's separate from the plug in or if it's part of the plug in these are two examples um you can load it in so whenever I use them I have to turn off the cabinet. You really have to do that. You turn off the cabinet in the plug in and then load up something separate. We have the poland which is a free lee cat les cab too. I think that's the official name that you khun load into impulse responses you can load in two different ones if you want. Ah, a good example of that is if you took if you remember our mike technique from earlier if you have a new impulse response from your d six and you have an impulse response from your fifty seven you can mix them together in ways that are pleasing to you and you can get the same kind of cool tones that we got with dual miking techniques here some good info for matt at fractal in the chat room which is says acts effects I our capture and kemper profiling are both creating impulses so that is confirming what we thought hey says twenty, forty eight points for the fractal and two fifty six for the camper I believe so that would refer to, you know, the number of points that air captured within those I ars on he said some great a third party libraries are available from own hammer and red wires I have used some of the red wires wants and I liked him a lot of not filling with own hammer do those come with impulse responses what's that red wires is a third party impulsive or I don't know what I don't know about own hammer but he says the new own hammer pack rocks so if there's anybody on the planet that knows about I ours, it is mr matt from fractal. So listen to this man and check this stuff out cool. Um okay, so for instance, I think right here yeah, on the right we have revolver, which is a plug in by pv that bunch of cool amps in there. I haven't been well extensively used that, but that's an example of a spot where you would be able to load it in you can't always loaded meant like in amplitude you're not able to do that unless there's a something. I don't know that that's. Not possible. Just kidding. Okay, next step, let's make one, shall we? All right. So, so first step before you do any of this, you get your aunt plugged in, whether you're doing with the kemper or you're doing with the ax effects you plug in your amp, you play through it, you make sure that you like what you're getting the sound that you're getting through the microphone. Um and from, well, actually, from the amp doesn't matter for the expects so, but just make sure that you're getting the sound that you like through the microphone. What before you make an impulse response? If you see the diagram, you're just going to be going from the the interface, uh, out into that actually, lets start start with the expects. Ok, you have the ax effects. You're going out of the ax effects where the sign sweep is coming from into the amp input, which I should talk about this for a second. The amp is a power and it's, not a guitar. A um, um the best sound that you're going to get when you're making an impulse response is gonna be through, not using like any kind of too power and pretty things that you want to be solid state because it doesn't color the sound it doesn't add distortion it's absolutely clean and that's what you want if we did run it through the amp, for instance, you would be picking up characteristics of the amp and the cabinet, but, um, it's not really made to do that, so I've never done it, maybe school, but probably not. I was recommended to not do that. So anyway, after it goes to the power amp that's going into the cabinet and the cabinet is playing out into the microphone, so what's happening is that my microphone is plugged into the interface the prince so whenever you're capturing an impulse response, you're not just capturing the cabinet, you're capturing the microphone and any settings that you have on the pre empt. So if you do have a pre empt with the accused on anything like that, you want leave those turned off almost you're setting sounding good with him turned on you can leave him on. So anyway, that's what you're capturing, catherine the cabinet, the microphone and the sound of the pre empt. And so whenever you're on the axe effects, you're just gonna hit utility and, uh page over to I r cap pretty simple, make sure everything's hooked up right and hit the test signal go in and test, make sure is cool, that's what it sounds like. All right, so what we're gonna do is hit capture, and here we go. This is what it does work, one, one, one, one, all right, and that's, uh, that's. How captured the thing. All these devices are making all these crazy noises, but in the end, it sounds really awesome. Um, so all you do to use that is you save it to wherever I'll save this one. Actually, I would like to hear this. I'm going to use this later. If it's cool, maybe I'll share it on somewhere. I don't know, we'll see. All right, so save it, ok, done. All right. So that's, how you make an impulse response of a guitar cabinet with the axe effects.