IR’s - Who, What, Why, Where?

[King Tut]

Could some of you kind people explain IR’s to me please?

 

For context, I’m in the process of transitioning from Zoom to Line 6 and I’m finding my way around a Stomp XL.

 

So, what are they, how do you use them, where do you get them, can you tweak them and are they worth bothering with?

 

Thanks in advance!

[Machines]

I loaded a few IRs onto my Zoom B6, and my limited understanding is they are generally used for recording - to create a representation of using a specific type of cab, mic placement etc. 

 

I haven't found them useful yet, as I feel like they're effectively just 'EQ patches', that don't seem to sound good on their own (and I haven't recorded for a while).

[Wombat]

I use Impulse Responses on my Stomp live. They are basically bits of code to sound like Cabs or amps (and other things like Acoustic Guitar body sizes). Generally they are ‘third party’ to the maker of the device so a ‘standard’ (think vhs/betamax) was developed.

Some devices, like Kemper, can ‘make’ an IR by recording white noise played through an amp/cab.

I use the Celestion Berantino IRs a lot. I can put them in almost any preset (often with another cab) and mix my post amp ‘bits’ to get a great sound (that goes to FOH, not my amp).

Just needs tweaking like any preset.

[fretmeister]

 All cab sims in the Stomp are actually IRs. When you buy external IRs you often get hundreds of files - all with different mic types and placements even for just 1 type of cab.

 

Line 6 have a great UI process where it says "Cab 1, Mic at 2 inches away" type thing, and then "Cab 1 mic at 3 inches away" but when you move from one to the other all that has happened is that the Stomp has loaded a new file that was made with the mic being 3 inches away. It's a very nice system of letting us navigate by what we want to happen rather than file names.

 

I've had a Helix since they launched and to start with I did use quite a few external IRs including some Ownhammer ones and Celestion's own ones.

 

Then in a firmware release about 2 years ago now Line 6 completely revamped the included Cab Models and they massively improved them. Since then I use them 99% of the time. There are only 2 external IRs I use now - a specific Mesa 4x12 one and a Celestion 4x12 that uses the G12-65 cone because that sounds quite different to the usual V30 and Greenbacks etc and at the moment there isn't a G12-65 in the Helix.

 

So - you can't really tweak an external IR because it is a set file. But you can't really tweak an internal Cab Model either - it just seems like you can. You are loading a new file for each control change. As a result there are hundreds of thousands of them hidden away in the Line 6 gear.

 

When I record, I tend to record without any cab sims or IRs at all because then I can listen in the mix and change them after the recording.

 

If I hadn't already bought the IRs I do own I would not have bothered now. The latest version of the L6 cab sims is excellent. 

A lot of bass is recorded direct as well - so no cab sims, no IRs, not even any real physical cabs either. Just straight in with EQ and compression. Some times when I record I don't use any cabs at all, just compress it, and then EQ to taste. Or sometimes mix a cab with a direct signal. 

 

If you use the Stomp with a real amp and cab then you'll want to turn off the cab sims anyway - a cab running into another cab is usually a dull mess. But then again, there are no rules.

 

Within the HX system you can do what you like. Even build a patch completely backwards if you want. Bass into the Cab > FX > Amp last > output to speaker / headphones.

Whatever you like!

 

 

[Skybone]

Currently have the Celestion Pulse 10 IR's on my POD Go, quite happy with the results. 

 

Although the standard cab models are good, they didn't really quite hit the mark. Did a bit of research and found the Celestion site, who had loads on offer, took a punt at the Pulse range, and glad I did.

 

What are they? WAV files.

How do you use them? Load 'em into your box via your computer

How do they work? Electronic Wizardry

Where do you get them? https://www.celestionplus.com/

Are they worth bothering with? Yes if you want to play about trying to find something that sounds a bit "better".

 

[MartinB]

Essentially just an EQ curve that matches the sound of putting a specific microphone in a specific position in front of a specific speaker cabinet.

 

The green wiggly line is a Helix Cab > Single block for an Ampeg 4x10 cabinet, which uses a built-in IR.

The blue smooth line is a Helix EQ > Parametric block with an approximation of the same overall frequency response.

They should sound broadly similar - they're just different tools for the same job. IRs can be a bit more characterful because they've got all those little peaks and notches at different frequencies. An EQ-based "cabinet" can give you a bit more fine control. Settings for both blocks are below if you want to try them out:

 

 

Edited February 24 by MartinB

[BigRedX]

29 minutes ago, MartinB said:

Essentially just an EQ curve that matches the sound of putting a specific microphone in a specific position in front of a specific speaker cabinet.

 

The green wiggly line is a Helix Cab > Single block for an Ampeg 4x10 cabinet, which uses a built-in IR.

The blue smooth line is a Helix EQ > Parametric block with an approximation of the same overall frequency response.

 

Goes some way to explain why I think a lot of the bass cab models make my sound worse. There's a fairly hefty dip in the mid-range just where I like to boost the EQ without a cab model being present.

[King Tut]

Well - as I don’t use cab sims live I very much doubt I’ll be messing with IR’s but thanks for the pointers peeps!

[Quatschmacher]

Just want to leave this here for anyone who is interested: this is a great FREE set of bass IRs by Shift Line. (Their B15 is the stock can sim in the Ampeg SGT-DI.)

 

https://shift-line.com/irpackbass

[Hellzero]

Maybe this review of the Headrush Flex Prime by Nate Navarro might help a bit understanding what those new "multi effects" can do, including the IR's and the Revalver (Super) Amp Cloner technology.

 

 

 

To be clear: I'm not affiliated with Headrush at all.

[King Tut]

On 24/02/2025 at 23:18, King Tut said:

Well - as I don’t use cab sims live I very much doubt I’ll be messing with IR’s but thanks for the pointers peeps!

I may have sounded a bit glib here, apologies if I did. I never realised IR’s were just about cab sims, I thought you could maybe sample an effect and recreate it on another unit - what a donut!!🍩 Anyway, really appreciate all the responses and probably will download some and have a play!

[Hellzero]

@King Tut The 3 new Headrush units can "sample" an effect or even a software to recreate it on their own devices.

 

It's in the video above. 😉

[King Tut]

5 hours ago, Hellzero said:

@King Tut The 3 new Headrush units can "sample" an effect or even a software to recreate it on their own devices.

 

It's in the video above. 😉

That sounds pretty cool - I'm well into the process of learning my Stomp XL after swapping over from Zoom so I don't see myself investing time into another system at the moment - I will check the vids out though - thanks!

 

[Wombat]

1 hour ago, King Tut said:

That sounds pretty cool - I'm well into the process of learning my Stomp XL after swapping over from Zoom so I don't see myself investing time into another system at the moment - I will check the vids out though - thanks!

 

I think the point is that you can get IRs for a lot of things other than Cabs. I have some for acoustic guitar body shapes that I think helps the sound of mine on the odd occasion I’m lured in to playing 6 strings.

But also that there is tonnes of stuff thats great on the Stomp so you don’t need to get bogged down with it. I like the Eden cab that’s on the Stomp. Sounds great with the GK800!

[LukeFRC]

On 24/02/2025 at 18:22, MartinB said:

Essentially just an EQ curve that matches the sound

With a time dimension too- so that it models that eq curve over time.

 

a small bit of time for a cab sim, a big bit for a reverb 

[MartinB]

Yeah for sure. For the OP's Stomp XL, it's pretty short at maximum of 2048 samples (< 50ms) - which is probably why the Line 6 docs only describe it for use as a cab sim, although people do routinely use it for acoustic instrument captures as well. It's just not going to be much good for a cathedral reverb
😄

[JPJ]

I’ve been successfully using 3Sigma double bass IR’s loaded into a TC Impulse pedal to make my NS EUB sound more like a double bass when playing live. As others have said, there is a whole lot more than cab sims available in the IR world, and it’s well worth getting up to speed with the various options out there.

[Hellzero]

@JPJ Which IR's do you use?

 

https://www.3sigmaaudio.com/items/category/upright-basses/

[Hellzero]

56 minutes ago, Hellzero said:

@JPJ Which IR's do you use?

 

https://www.3sigmaaudio.com/items/category/upright-basses/

Found the answer here:

 

 

[JPJ]

11 minutes ago, Hellzero said:

Found the answer here:

 

 

Yep, I use the German bass & Czech bass models, German darker sounding, and Czech bass more open and airy 

[Baloney Balderdash]

It's basically an advanced and very detailed EQ snap shot, that also reacts somewhat dynamically because it is also a snap shot of the EQ over a, albeit ultra short, time window span.

 

Edited 10 hours ago by Baloney Balderdash

[Hellzero]

1 hour ago, Baloney Balderdash said:

It's basically an advanced and very detailed EQ snap shot, that also reacts somewhat dynamically because it is also a snap shot of the EQ over a, albeit ultra short, time window span.

 

It's not that at all, otherwise you could reproduce it easily with a full parametric EQ, a compressor and a reverb, which is absolutely not the case.

 

There are way more parameters in an Impulse Response sampling, and these last 3 words are way more closer to what it really is than your definition attempt.

[Baloney Balderdash]

12 minutes ago, Hellzero said:

It's not that at all, otherwise you could reproduce it easily with a full parametric EQ, a compressor and a reverb, which is absolutely not the case.

 

There are way more parameters in an Impulse Response sampling, and these last 3 words are way more closer to what it really is than your definition attempt.

I think that would be discussion about semantics, which never leads to anything productive, but whatever.

 

Can you give a better simple basic one sentence explanation?

 

Edited 8 hours ago by Baloney Balderdash

[Hellzero]

Just now, Baloney Balderdash said:

Can you give a better simple one sentence explanation?

Already did : Impulse Response sampling.

[Baloney Balderdash]

20 minutes ago, Hellzero said:

Already did : Impulse Response sampling.

There you got you answer OP!

 

 

On a different note, perhaps I should have used the word "frequency response" instead of "EQ" (though both words are commonly used for the same term/concept), which was what I meant.

 

Again a discussion about semantics though.

 

But I do I think it was obvious what I meant from the context, unless you insist on misinterpreting it.

 

I mean, from the context, what did you even imagine I meant by EQ @Hellzero, it doesn't even make sense in other sense of the word?

 

Did you imagine I meant EQ settings, how do you imagine that would even be possible from capturing sound alone?

 

Edited 8 hours ago by Baloney Balderdash