Help me understand--HXFX, Kemper, and IRs vs. profiles

[mikezimmerman]

I haven't used a whole lot of effects in the past, but I just picked up an HX Effects unit not to long ago, and joined a band where the guitarist/singer uses IEM and swears by his Kemper...

So, exploring the HX, I see that in addition to the modeling that it does, it also allows you to load IR (impulse response) blocks, which in theory seem an awful lot like the "profiles" that the Kemper uses. Are they essentially the same thing?

However, whenever I hear IRs mentioned with the HX units, they seem mostly to be recreating cabs and mic placements. If they are essentially the same as Kemper profiles, couldn't they also include amps, effects, etc.?

 

[DDXdesign]

I haven't used a whole lot of effects in the past, but I just picked up an HX Effects unit not to long ago, and joined a band where the guitarist/singer uses IEM and swears by his Kemper...

So, exploring the HX, I see that in addition to the modeling that it does, it also allows you to load IR (impulse response) blocks, which in theory seem an awful lot like the "profiles" that the Kemper uses. Are they essentially the same thing?

However, whenever I hear IRs mentioned with the HX units, they seem mostly to be recreating cabs and mic placements. If they are essentially the same as Kemper profiles, couldn't they also include amps, effects, etc.?

Unless I am mistaken entirely, IRs are specifically EQ curves for cabinet emulations - meant to mimic the actual impulse response of the speaker coil and cabinet combos.

 

[mikezimmerman]

Unless I am mistaken entirely, IRs are specifically EQ curves for cabinet emulations - meant to mimic the actual impulse response of the speaker coil and cabinet combos.

Thanks. My initial understand of IRs was that they were cabinet/mic emulation, but the description of how they were created sounded so much like how Kemper was describing their "profiling"process, it got me wondering!

But it sounds like what an IR does is really to record the "acoustic" portion of the signal chain, and then apply it to whatever signal you feed in.

 

[DDXdesign]

Thanks. My initial understand of IRs was that they were cabinet/mic emulation, but the description of how they were created sounded so much like how Kemper was describing their "profiling"process, it got me wondering!

But it sounds like what an IR does is really to record the "acoustic" portion of the signal chain, and then apply it to whatever signal you feed in.

I actually have no idea how it works (it's out of my depth) I just know that it sounds like a very sophisticated EQ curve =0)

 

[Swimming Bird]

Could always try it. Not like you'll break it, right?

 

[jbybj]

My understanding is that an Impulse Response is not limited to cabs and mics. You can easily take an IR of your old tube amp, but, an IR is simply a snapshot of one, static setting. While a Kemper profile is a digital emulation of a circuit or signal flow, with all the parameters available for adjustment. There is a wonderful Reverb plugin called Altiverb, that uses IR to emulate different spaces. All the other reverb parameters are adjustable, but the part of the software that defines the space, is an IR.

In other words, an IR of your amp will sound like your amp, with the settings at the time of the IR capture, and not adjustable. A profile of your amp will theoretically function just like the amp.

 

[jbybj]

I actually have no idea how it works (it's out of my depth) I just know that it sounds like a very sophisticated EQ curve =0)

taking an Impulse Response measures all kinds of stuff, besides EQ. Timing/phase delays, reflections, mechanical or electronic distortion, much more than simply EQ.

 

[DDXdesign]

taking an Impulse Response measures all kinds of stuff, besides EQ. Timing/phase delays, reflections, mechanical or electronic distortion, much more than simply EQ.

Aha, I stand corrected!

 

[MDBass]

Thanks. My initial understand of IRs was that they were cabinet/mic emulation, but the description of how they were created sounded so much like how Kemper was describing their "profiling"process, it got me wondering!

But it sounds like what an IR does is really to record the "acoustic" portion of the signal chain, and then apply it to whatever signal you feed in.

The Kemper models not just the IR of the cab you're using, but the entire signal chain from the pedals to amp,

 

[jbybj]

The Kemper models not just the IR of the cab you're using, but the entire signal chain from the pedals to amp,

You could make an IR of a signal going through 10 pedals, your amp and cab, being close mic’d by an SM-57, mixed with a PZM, at the far end of a gymnasium. One IR, doing its best version of the entire chain.
In layman’s terms, because I am most definitely a layman when it comes to the deep underpinnings, an Impulse Response is taking a known reference source, a tone or noiseburst, passing it through something, and comparing it to the output. It measures the difference induced by the signal chain, and recreates that difference digitally. The IR cares not, whether there is one device in the signal chain, or a thousand.

Commercially available IRs tend to focus on simple combos, like a cab and a mic, because that’s what people want to buy and use. But, I’ve read that making your own IRs is pretty simple and inexpensive. So I have been toying with the idea to check it out. I want to try making IRs of my Traynor YBA-1A through my single 15 EVM-IIL cabinet, with the amp at a few different gains. It would be so cool to have my Traynor rig, perhaps with Apex compression and some Fifth Gear subtle dirt, loaded in my HX FX. And then, and then I’d make IRs of all my dirt pedals at my favorite settings, and various stackings, and then.................

 

[MDBass]

My understanding is that an Impulse Response is not limited to cabs and mics. You can easily take an IR of your old tube amp, but, an IR is simply a snapshot of one, static setting. While a Kemper profile is a digital emulation of a circuit or signal flow, with all the parameters available for adjustment. There is a wonderful Reverb plugin called Altiverb, that uses IR to emulate different spaces. All the other reverb parameters are adjustable, but the part of the software that defines the space, is an IR.

In other words, an IR of your amp will sound like your amp, with the settings at the time of the IR capture, and not adjustable. A profile of your amp will theoretically function just like the amp.

A Kemper profile is a snapshot as well: you can’t go back in and tweak the settings on a specific pedal in the chain after saving, and although you can adjust the EQ and overall gain it’s not relative to the EQ and gain on the amp you’ve modeled.

 

[MDBass]

You could make an IR of a signal going through 10 pedals, your amp and cab, being close mic’d by an SM-57, mixed with a PZM, at the far end of a gymnasium. One IR, doing its best version of the entire chain.
In layman’s terms, because I am most definitely a layman when it comes to the deep underpinnings, an Impulse Response is taking a known reference source, a tone or noiseburst, passing it through something, and comparing it to the output. It measures the difference induced by the signal chain, and recreates that difference digitally. The IR cares not, whether there is one device in the signal chain, or a thousand.

Commercially available IRs tend to focus on simple combos, like a cab and a mic, because that’s what people want to buy and use. But, I’ve read that making your own IRs is pretty simple and inexpensive. So I have been toying with the idea to check it out. I want to try making IRs of my Traynor YBA-1A through my single 15 EVM-IIL cabinet, with the amp at a few different gains. It would be so cool to have my Traynor rig, perhaps with Apex compression and some Fifth Gear subtle dirt, loaded in my HX FX. And then, and then I’d make IRs of all my dirt pedals at my favorite settings, and various stackings, and then.................

Right.

But, as the OP mentioned, the vast majority of those commercially available IR’s (loadable into the Helix/HX or other platforms) are for cabs and mic placements only.

The options certainly are almost limitless, though an IR isn’t designed to model distortion/clipping.

 

[jbybj]

A Kemper profile is a snapshot as well: you can’t go back in and tweak the settings on a specific pedal in the chain after saving, and although you can adjust the EQ and overall gain it’s not relative to the EQ and gain on the amp you’ve modeled.

I’ve never been face to face with a Kemper before. I assumed it was capable of making the kind of amp models like we find in Zoom or Helix devices, where each control is emulated.
My bad. Nevermind.......

 

[SirMoak]

I’ve never been face to face with a Kemper before. I assumed it was capable of making the kind of amp models like we find in Zoom or Helix devices, where each control is emulated.
My bad. Nevermind.......

Yep, the Kemper can do that. It makes a profile of the amp, cab, mic, etc, then you get the usual controls for the amp like gain, eq.
IRs on the other hand are static. I am not even sure if you could model compression with an IR, never mind distortion. You are right about the time and phase part of IRs though. The first time I saw IRs was in recreating room reverberations.

Helix effects and amps are component modelled, which is why they react so well to dynamics. Kemper can react just as well, but it's a different approach.
Basically if you want to model an amp, you need some sort of amp simulation. I could never get as close to a fake guitar sound (octaver into overdrive pedal into IR) on my HX Effects as I can by running the octaver into an amp sim on my HX Stomp.

 

[MDBass]

Yep, the Kemper can do that. It makes a profile of the amp, cab, mic, etc, then you get the usual controls for the amp like gain, eq.
IRs on the other hand are static. I am not even sure if you could model compression with an IR, never mind distortion. You are right about the time and phase part of IRs though. The first time I saw IRs was in recreating room reverberations.

Helix effects and amps are component modelled, which is why they react so well to dynamics. Kemper can react just as well, but it's a different approach.
Basically if you want to model an amp, you need some sort of amp simulation. I could never get as close to a fake guitar sound (octaver into overdrive pedal into IR) on my HX Effects as I can by running the octaver into an amp sim on my HX Stomp.

He’s saying he thought the Kemper modeled each part of the chain individually (amp, cab, pedal, etc.) making them interchangeable after the fact.

It doesn’t do that.

 

[TrevorOfDoom]

Of note, if OP does have the HXFX, he doesn't have access to amp models.
Amp models are only available on the Helix, Helix LT, and HXStomp.

 

[mikezimmerman]

Yep, I know there's no amp modeling in the HXFX. The IR capability in the HXFX just made me wonder if you could use an IR to accomplish that, hence my question...

Of note, if OP does have the HXFX, he doesn't have access to amp models.
Amp models are only available on the Helix, Helix LT, and HXStomp.

 

[micguy]

Impulse responses can model a lot of things in a system, but strictly speaking, they don't model non linearities (distortion). So long as the system is linear, impulse responses work - could be electronics, speakers, rooms, whatever. But an amp (or pedal, or speaker) going into overdrive/overload requires more sophisticated modelling techniques.