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Full amp impulse response

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Hi

 

I'm loving the impulse response technology. I'm curious though, can a full amp + cab + mic impulse response be made? Are there such IRs available?

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Are you essentially asking for the Helix to do what the Kemper does? It can’t do that. If not, what you’re proposing might be an interesting experiment.

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Thanks. My Helix arrives on Tuesday so I'm very excited about joining this community.

 

Why aren't there more? Is IR not a good technology for amp modelling?

 

I'm not sure what you mean by more?  More IRs?  There's TONS of them.  More videos and information?  Just google IR and spend the next 20 years reading about them.

 

IRs are fine technology and incorporate nicely into amp modelling, but they do what they do which is to capture sonic response characteristics so they can be applied to a given sound.  So they are a bit static when compared to the dynamic real-time adjustments that can be made to the Helix modeled cabinets, mic and mic placements.  This is why some folks refer to their searches for IRs as "going down the rabbit hole".

 

A typical IR for something like a Mesa 2x12 cabinet may consist of 30 or 40 different files.  Each file has a different variation of that cabinet such as a that cabinet mic'd with an SM57 located on the cap of the speaker, another file with the SM57 2 inches away from the cap of the speaker out toward the cone, and so forth.  For each variation of mic, or mic mixes, and placements there will be a different IR file.  If you don't know what you prefer as far as mic's, mic mixes, and placements you can spend a LOT of time searching through these files to find what you like.  If you know what you like it's relatively easy to choose an IR variation and dismiss the rest.

 

The reason IRs can't be used to model an amp is because they are static.  You send a sound through them and the modify the sound in a static, but consistent way.  Modeling an amp is different altogether because the sound and behaviors of an amp change dramatically when you change things on the amp such as master volume, gain, treble, SAG, BIAS, etc.  You can't dynamically change an IR.  You have to load a new IR to change the sound.

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I'm not sure what you mean by more?  More IRs?  There's TONS of them.  More videos and information?  Just google IR and spend the next 20 years reading about them.

 

IRs are fine technology and incorporate nicely into amp modelling, but they do what they do which is to capture sonic response characteristics so they can be applied to a given sound.  So they are a bit static when compared to the dynamic real-time adjustments that can be made to the Helix modeled cabinets, mic and mic placements.  This is why some folks refer to their searches for IRs as "going down the rabbit hole".

 

A typical IR for something like a Mesa 2x12 cabinet may consist of 30 or 40 different files.  Each file has a different variation of that cabinet such as a that cabinet mic'd with an SM57 located on the cap of the speaker, another file with the SM57 2 inches away from the cap of the speaker out toward the cone, and so forth.  For each variation of mic, or mic mixes, and placements there will be a different IR file.  If you don't know what you prefer as far as mic's, mic mixes, and placements you can spend a LOT of time searching through these files to find what you like.  If you know what you like it's relatively easy to choose an IR variation and dismiss the rest.

 

The reason IRs can't be used to model an amp is because they are static.  You send a sound through them and the modify the sound in a static, but consistent way.  Modeling an amp is different altogether because the sound and behaviors of an amp change dramatically when you change things on the amp such as master volume, gain, treble, SAG, BIAS, etc.  You can't dynamically change an IR.  You have to load a new IR to change the sound.

Thanks that makes sense now...

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I’m confused by this.  I understood that IRs are used to simulate speaker cabinets.  However, I have a friend who recently got a Helix and seemed to download a full AC30 IR with amp, cabinet, mic, etc..  There are found on this page:  http://grgr.de/IR/

 

We’ve tried them with a guitar into the helix and just had the IR loaded by itself.  It sounded very similar to the live amp we had next to it.  

 

Any idea what these are?

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If you feel IRs are enough for capturing amps, go for it. You don't need any amp modeler.
But seriously - classical FIR, IIR technology do not capture any distortion (non linearity). They can capture only frequency ,phase and reverb response.
Kemper impulse technology is brilliant. For so many years it has not been replicated in any other DSP algorithm.

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17 minutes ago, zolko60 said:

If you feel IRs are enough for capturing amps, go for it. You don't need any amp modeler.
But seriously - classical FIR, IIR technology do not capture any distortion (non linearity). They can capture only frequency ,phase and reverb response.
Kemper impulse technology is brilliant. For so many years it has not been replicated in any other DSP algorithm.

That's actually what I DIDN'T like about the Kemper when I tried it. You're very limited to what you can do with EQ/gain adjustments on a profile before the sound is changed negatively. So if you find a profile of an amp you like, but you want lower gain, you have to find a profile of that gain structure instead of just turning down the gain.

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Of course Kemper technology has its drawbacks. It can not predict how circuts will behive outside the impulse range.

I am experiencing a lot of companies and guys claiming that eg. IR should be made with tube amp because it adds that "tube feeling". Their IRs are almost useless for me - captured with impedance curve affected frequency response and distortion converted to IR noise. :(

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5 hours ago, Mattlcook said:

I’m confused by this.  I understood that IRs are used to simulate speaker cabinets.  However, I have a friend who recently got a Helix and seemed to download a full AC30 IR with amp, cabinet, mic, etc..  There are found on this page:  http://grgr.de/IR/

 

We’ve tried them with a guitar into the helix and just had the IR loaded by itself.  It sounded very similar to the live amp we had next to it.  

 

Any idea what these are?

 

It's a good question, and if you're just wading out into the world of modeling and impulse responses it's justifiably confusing.

 

You can make an IR of anything - and it will do what an IR can do, no more, no less. Including an amp. However, generally speaking an IR of an amp - particularly with the Helix - is seen as a step - or steps - backward, not a step forward. 

 

The keyword when it comes to an amp is CONTROL.  Ask yourself this:  How often do you tweak the settings of your cabinet (answer: never)? How often do you tweak the settings on your amp (answer: a lot).

 

The trick is to realizing what each piece of the signal chain DOES to your sound.  What is more important for creating that Vox 30 sound?  The amp or the cabinet?  It may surprise you to realize that in terms of the actual unique sound you have come to love with the Vox 30, it's the CABINET you like, not the amp. The amp has far more to do with the control of the sound (volume, drive, presence, etc.). That's not to say the amp has zero influence, only to say that the cabinet of the Vox is arguably more important to its uniqueness.  In fact, swap the real Vox cabinet with your favorite real Marshall amp and you would notice that it starts to sound a lot like the Vox sound you've always loved BUT with the Marshall controls. So you could control the Vox sound in a Marshall way, which is kind of cool when you think about it. However, perfectly capturing those sounds with the perfect microphone in EXACTLY the way you want it is an absolute pain in the butt, and this is where the joy of IRs come in. Once you, or somebody else has done it in a way that does exactly what you need, you can capture the IR of that, slap it on the end of your amp sim, and walla, now you have it ready to go whenever, or wherever, you need it.  It's beautiful.  

 

Okay, so back to the Helix.  Yes, you could make an IR of the Vox amp - and combine it with the IR of a Vox cabinet . . . but think about what you're losing. You're only getting a teeny snapshot in time of the settings of the amp WITHOUT any distortion/compression (because the IR can't capture that among other things), and you have diddly squat in the away of control over it.  Do you want to tweak the drive to get more grit?  Yeah, can't do that.  Do you want to modify the sag or hum response like you can in the Helix amp sim?  Good luck with that.

 

Furthermore, what EXACTLY are you gaining when you give up that control? The amp sim already simulates the stuff the IR does extremely well. So you lost the control . . . you didn't gain any unique sound . . . ummm . . .

 

There's a reoccurring discussion in the Helix group over whether or not stock cabs are as good as IRs. So far it seems like the IR group has largely won (by the way, I'm a person who still tends to prefer stock cabs - frankly I find the complete and 100% allegiance IR love a little baffling but I do respect how easy they are once you find them - but then again, once you find the settings on your stock cab you're set too), but there's not contest between the Helix amp sims and an amp IR.

 

There is a reason nobody . . . or almost nobody . . . is doing it, and until there is some technological breakthrough, that's not about to change. Control is better when you are simulating control (amps), and less important when you are simulating outputs (cabs). When all you're simulating is an output that once you've found you never need to change again, a simulation of that output is divine (cab IR).

 

Still, at the end of the day, sound is sound. By all means, download those amp IRs.  Maybe there is an amp you really love that isn't in the Helix, and you want to layer an IR over a Helix amp sim because it sounds really good.  Hey, If it causes you to rock the world more power to you.  Cool sounds are cool sounds, no matter how they're done.

 

If you're down for a cool read, this was one of the best reads I found:

 

https://www.premierguitar.com/articles/The_Working_Guitarist_All_About_Impulse_Responses

 

 

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39 minutes ago, Kilrahi said:

In fact, swap the Vox cabinet with your favorite Marshall amp and you would notice that it starts to sound a lot like the Vox sound you've always loved BUT with the Marshall controls. So you could control the Vox sound in a Marshall way, which is kind of cool when you think about it. However, perfectly capturing those sounds with the perfect microphone in EXACTLY the way you want it is an absolute pain in the butt, and this is where the joy of IRs come in. Once you, or somebody else has done it in a way that does exactly what you need, you can capture the IR of that, slap it on the end of your cab sim, and walla, now you have it ready to go whenever, or wherever, you need it.  It's beautiful.  

What IR technology are you talking? What IR (except Kemper) technology can reproduce Marshall or Vox overdrive?
Have you ever swapped amps/cabs and could not recognize your amp behavior?

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Awesome answer Kilhari. That makes a lot of sense. 

 

1 hour ago, Kilrahi said:

 

It's a good question, and if you're just wading out into the world of modeling and impulse responses it's justifiably confusing.

 

You can make an IR of anything - and it will do what an IR can do, no more, no less. Including an amp. However, generally speaking an IR of an amp - particularly with the Helix - is seen as a step - or steps - backward, not a step forward. 

 

The keyword when it comes to an amp is CONTROL.  Ask yourself this:  How often do you tweak the settings of your cabinet (answer: never)? How often do you tweak the settings on your amp (answer: a lot).

 

The trick is to realizing what each piece of the signal chain DOES to your sound.  What is more important for creating that Vox 30 sound?  The amp or the cabinet?  It may surprise you to realize that in terms of the actual unique sound you have come to love with the Vox 30, it's the CABINET you like, not the amp. The amp has far more to do with the control of the sound (volume, drive, presence, etc.). That's not to say the amp has zero influence, only to say that the cabinet of the Vox is far more important.  In fact, swap the Vox cabinet with your favorite Marshall amp and you would notice that it starts to sound a lot like the Vox sound you've always loved BUT with the Marshall controls. So you could control the Vox sound in a Marshall way, which is kind of cool when you think about it. However, perfectly capturing those sounds with the perfect microphone in EXACTLY the way you want it is an absolute pain in the butt, and this is where the joy of IRs come in. Once you, or somebody else has done it in a way that does exactly what you need, you can capture the IR of that, slap it on the end of your cab sim, and walla, now you have it ready to go whenever, or wherever, you need it.  It's beautiful.  

 

Okay, so back to the Helix.  Yes, you could make an IR of the Vox amp - and combine it with the IR of a Vox cabinet . . . but think about what you're losing. You're only getting a teeny snapshot in time of the settings of the amp WITHOUT any distortion/compression (because the IR can't capture that among other things), and you have diddly squat in the away of control over it.  Do you want to tweak the drive to get more grit?  Yeah, can't do that.  Do you want to modify the sag or hum response like you can in the Helix amp sim?  Good luck with that.

 

Furthermore, what EXACTLY are you gaining when you give up that control? The amp sim already simulates the stuff the IR does extremely well. So you lost the control . . . you didn't gain any unique sound . . . ummm . . .

 

There's a reoccurring discussion in the Helix group over whether or not stock cabs are as good as IRs. So far it seems like the IR group has largely won (by the way, I'm a person who still tends to prefer stock cabs - frankly I find the complete and 100% allegiance IR love a little baffling but I do respect how easy they are once you find them - but then again, once you find the settings on your stock cab you're set too), but there's not contest between the Helix amp sims and an amp IR.

 

There is a reason nobody . . . or almost nobody . . . is doing it, and until there is some technological breakthrough, that's not about to change. Control is better when you are simulating control (amps), and less important when you are simulating outputs (cabs). When all you're simulating is an output that once you've found you never need to change again, a simulation of that output is divine (cab IR).

 

Still, at the end of the day, sound is sound. By all means, download those amp sims.  Maybe there is an amp you really love that isn't in the Helix, and you want to layer an IR over a Helix amp sim because it sounds really good.  Hey, If it causes you to rock the world more power to you.  Cool sounds are cool sounds, no matter how they're done.

 

If you're down for a cool read, this was one of the best reads I found:

 

https://www.premierguitar.com/articles/The_Working_Guitarist_All_About_Impulse_Responses

 

 

 

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4 minutes ago, Mattlcook said:

Awesome answer Kilhari. That makes a lot of sense. 

It makes no sense. IRs are not even remotely any "amp sims".

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9 minutes ago, zolko60 said:

It makes no sense. IRs are not even remotely any "amp sims".

 

I didn't say they are, which means you didn't understand what I said. That may be on me, but considering how hard it is to decipher your stuff sometimes, that is probably somewhat on you too.

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