# How (not) to use Impulse Files - tutorial



## Leec (Feb 20, 2008)

Basic guide to using Impulse Files for cabinet simulation.

Ok, first off, here's what I'm using and a note about them: Cubase SX 2 as my DAW, Line 6 Pod Pro XT as my pre-amp, Sir1 Deconvolver, bunch of impulses. (SIR: SIR1). 

Cubase SX 2 is the DAW I use, but there are obviously many others. This tutorial only deals with the how-to's of that program. Probably many of the operations are very similar in other DAW's, so just use this as a basic guide if you don't have SX. SX 1 is virtually the same, and all these operations will work in it, and probably in 3, too.

Sir1 is free to download and simple to use. You can use it any DAW that will support VST plug-ins. There are others that are free and will do the same (and possibly more), but I happened upon this one first and it serves my purposes (read: limited knowledge) very well. You'll need to download and install it to your DAW's VST folder. Once this is done, you may need to launch the DAW and have it scan through the plug-ins directory in order to find and use it. Hopefully not. ;-)

The Pod XT Pro can be replaced with virtually anything that'll simulate amps, like a GNX, a Pod 2.0, an XT Live, a GT8, etc. We're turning off the cab simulation, so it's not necessary to have something that simulates cabinets.

Lastly, download some cab impulse files. You can find them online. Just google "guitar cab impulse" and you'll find lots. There are many out there. Andy Sneap's forum is a good place, so is noisevault.com. I've added a couple to this post, just to get you going.

Next, a little prep work that can pay off later down the line:
With your cabinet simulation turned on, create several patches with your favourite amps, using stomps if you want. This applies to clean as well as heavy sounds. 
Save these patches with cab simulation TURNED OFF demonstrative names, i.e, Diamondplate_TubeScreamer_nocab.***, Criminal_nocab.***, etc. (***=whatever your patch file extensions are, .l6t for Line 6).
The purpose of this is so you can record takes with them each in turn, trying them out through the impulse files until you find ones you like - some amp models work better than others.


Ok, now on to actually using them. 

1. Load up your DAW, in my case, SX 2.

2. Start a new project, and choose a "Empty" project template for now, just to go through this tutorial with the basics.

3. With your new project loaded, right click in the track pane and choose "Add Group Track", choose Stereo configuration when asked (not important for this tutorial, but it will be when you want to pan tracks routed to this Group track).




4. Double click the new group track name field and name it something suitable, like Rhythms (again, not essential, but it's good practice to keep your recording projects tidy.




5. Right click beneath the folder this just created (or anywhere in the track pane) and choose "Add Track".


 

6. This track you just added should be selected, but if not, left click on this track to select it (click somewhere like the dark blue area to the left of the M and S buttons). Now to the left of the track pane, you should see the Inspector pane. This pane allows you to edit the selected track's mixer properties. If you don't see it, click this button.




Got the Inspector pane open? Cool, now we want to route this track to the Rhythms group track before it goes to your main out. So, with the newly created track selected, click the dropdown menu called Out.


 

You'll see listed at the bottom the group track we made. Had we made more group tracks, we'd see those listed here, too.

7. Back over in the track pane, right click somewhere on the track we just made and choose "Duplicate Track". 


 

Do this as many times as you have patches. I.e, if you made 7 patches, do this 6 times to create a total of 7 tracks. With this done, rename each track using the patch names you made earlier. If you made a patch called Diamondplate_TubeScreamer_nocab.***, call this track something like "Dplate_TS". If you also made a patch without the TS stomp on called something like "Diamondplate_nocab", call this track "Dplate" or Dplate_noTS". You can leave the "nocab" portion off now, as none of these patches should have cab sim turned on. In fact, you could have left it off when creating the patches, but you might find it helpful like I do; sometimes I want the patch with AIR turned on when I'm jamming at home, for rehearsals and live I want the same patch without AIR...

8. So now you should have something that looks like this: 


 

In this pic, I have 4 tracks. I made 4 patches; one Dplate amp with TS turned on, one with it turned off, one Criminal amp with TS turned on, one Criminal amp with TS turned off. Each of these tracks are being routed to the Rhythms Group Track.

9. Select this track by clicking somewhere on the Group track, like the turquoise area to the left of the M, S, R and W buttons. Now, with this track selected, in the Inspector pane, locate and expand the Insert tab by clicking the little + sign on the right edge:




This should now give you this view:




10. Left click somewhere in the first narrow black field and a dropdown doth appear! From this list, point to Sir1011 > Sir1 and choose it.




11. Sir1 should now launch, presenting you with this view:




12. Now we load an impulse file into Sir1. To do this, you obviously need to have some impulse files. Sir works like any windows app, so just click the Open File button in the top right hard corner and navigate to an impulse file:




Sir1 will load an entire directory, so if you have a folder with all your impulses in, and you open a file in that folder, it'll list everything in that folder. It'll list it like so:


 

Personally, I only use a handful of impulses, so I have a directory with just 3 or 4 in it, and load up that one - just to keep things tidier. You can specify a default directory in Sir1 so it'll load that directory every time you start up Sir1, and indeed, that's what I've done with my 4-file directory.

13. So now we have our impulses loaded into Sir1. Like many effects, Sir has Wet and Dry controls (Wet being processed, Dry being unprocessed). This is in the form of two indepedent sliders. Since the dry signal sounds pretty horrible (if you haven't found this out yet, play a little of your patch without the pre-amp's cabinet simulation turned out; it's a horrible, brittle mess with no sustain), we want to turn the dry signal off. To do this, click the On button below the Dry slider so it changes to Off:




14. Now, select the first track (in my case, that'd be Dplate_TS) by left clicking on it somewhere, hit Record (use the * key on your numeric keypad just to be a super-awesome super-rad villain) and administer some metal! As stated already, it's going to sound pretty awful as you play, 'cause you're hearing the sound with no cab simulation. This can take a little getting used to, especially with lead parts. But I think the results are well worth it.

Now rewind and listen back to your tone, and see if you like it through the cab impulse you selected. And that's it! 

Don't like it too much? Try selecting another cab impulse and see if you prefer it through that.

As I alluded to above, to save yourself some time, record a take of you playing the same riff with each patch you made. Then solo each track to hear it through the impulse and find one you like (make sure you're soloing the Group Track as well as the actual track; if you're soloing only the track you recorded on, you'll hear it without the impulse). If none grab you, load up another impulse and try soloing each through that one.

This is by no means a definitive guide to using cab impulses and also by no means a guide to using impulses in general. For cabinet emulation, I don't touch any of the controls on Sir1 other than muting the Dry channel and chaning level of the Wet channel. 

There are many uses for a deconvolver; it's great for reverbs (obviously), and great for adding warmth to vocals, for bass cabinets, for effects...all sorts of stuff. Noisevault.com is great for this.

Another tip is if your computer's not too hot on CPU power, you can try adding Sir to the input channel, so your audio is printed to disk through Sir, meaning you can unload it once all your recording's done. Obviously this means you can't change impulses late, but if you hit upon a sound you like, there's no reason this would be a problem.

As with anything, play around and experiment. Try recording with your cab simulation turned on. I find you can get lovely watery lead tones with it.

I hope this tutorial is useful to someone; my first attempt at writing one, so I hope it makes sense.

"Go and do likewise, gents"

Lee


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## theunforgiven246 (Feb 20, 2008)

Here is an effect that uses impulses with zero latency so you can hear it as you play instead of recording with no cab simulations on.


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## Harray 18 (Feb 20, 2008)

i dont think they have enough crunch

plus with impulses it sounds like im using a really bad reverb

im staying pod


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## Leec (Feb 21, 2008)

theunforgiven246 said:


> Here is an effect that uses impulses with zero latency so you can hear it as you play instead of recording with no cab simulations on.



I'm pretty sure this can be achieved with almost any plug-in. It depends on your hardware, though. Cubase SX can monitor inserts as you play, but if you're hardware's not up to it, you get bad latency. I might be wrong on this, though.



Harray 18 said:


> i dont think they have enough crunch
> 
> plus with impulses it sounds like im using a really bad reverb
> 
> im staying pod



This isn't a problem of impulses. If you create a great patch with your Pod with AIR turned on, then turn it off and run it through a good impulse, there's no reason why you'd lose crunch. In my meagre experience of using them, pound for pound, a great impulse knocks 7 shades of shit out of AIR modelling on the XT, and makes the patch sound fuller, warmer and heavier.
As for the reverb problem, I don't know what's going wrong there.

I can only guess you've got some bad impulses. Check out the ones I uploaded, they're pretty nice.


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## Coryd (Feb 21, 2008)

Good tutorial!!! Thanks for the info


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## cow 7 sig (Feb 21, 2008)

thanks for that,been after a good how to for this awhile now


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## smueske (Feb 21, 2008)

> This isn't a problem of impulses. If you create a great patch with your Pod with AIR turned on, then turn it off and run it through a good impulse, there's no reason why you'd lose crunch. In my meagre experience of using them, pound for pound, a great impulse knocks 7 shades of shit out of AIR modelling on the XT, and makes the patch sound fuller, warmer and heavier.
> As for the reverb problem, I don't know what's going wrong there.



That's what an impulse file is. An impulse file is just a reverb simulation loaded into a convolution reverb. In the above case, it's either because the wet mix was too loud or the impulse itself was bad. Personally, I don't like impulse files on guitar, but it's all a taste thing. I don't use Cubase (which I think the tutorial is), but I think posting tutorials of any kind always helps somebody.

Nice work!


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## Drew (Feb 21, 2008)

Hmm. Based on that description, smueske, you could probably do some pretty warped sounding things with impulses if you WEREN'T trying to make them sound like a cabinet. 

Interesting... Gears are turning...


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## Leec (Feb 21, 2008)

smueske said:


> That's what an impulse file is. An impulse file is just a reverb simulation loaded into a convolution reverb.



Yeah, I know. I allude to this at the end of the tutorial, as well as some other uses for them; again, anyone who's only heard of impulses being used for cab simulation, check the wiki entry for a decent explanation of the principle and check noisevault.com for some interesting applications.



smueske said:


> In the above case, it's either because the wet mix was too loud or the impulse itself was bad.



I think he has a bad file, because pushing the wet mix up too high results in clipping. Either that or he's having some bizarre latency issues.


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## theunforgiven246 (Feb 21, 2008)

But there are some deconvolvers that have latency no matter what, or at least from my knowledge of daws and plugins and shit (which is limited) haha


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## smueske (Feb 22, 2008)

> Hmm. Based on that description, smueske, you could probably do some pretty warped sounding things with impulses if you WEREN'T trying to make them sound like a cabinet.



Oh, I totally agree. Convolution reverbs are a very interesting addition to the pallet. I like them on pianos and strings and such, but I do think there can be applications for general sound design (including guitar). It's cool, too, that some companies are starting to come out with impulse creation software, where you can create and model virtual spaces (including obstacles, wall shapes, etc.). The problem, right now, is that most of the convolution reverbs are very CPU intensive. I don't really start to play with them until mix time (or when I'm just goofing around). For my uses a traditional reverb (Lexicon, Waves, etc.) does exactly what I need and is already tuned for performance. Hopefully, the next generation of convolution reverbs will more optimized for tracking.


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## theunforgiven246 (Mar 9, 2008)

We really should have a sticky about impulses and how/how not to use them!


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