‘Studio Diary’ is an occasional series where I talk about building a home recording setup for hobbyists and enthusiasts like us. I share my personal experiences, and the thinking behind some of the decisions that I’ve made along the way.
Fractal Audio have recently overhauled their amp modelling in the Axe-FX 3 / FM-9 / FM-3. And my recent dive into the Orange Getaway Driver has shown me that I need to revoice my signal chain. I’m taking this as an opportunity to re-evaluate everything about the pedal preset I’ve built for the Axe-FX 3.
Before I get into detail about dialling in each amp and cab, I want to first discuss some more general things I’ve learned about impulse responses (IRs for short), and how that’s led me to some key decisions (or, if you prefer, design constraints) that I’m going to use to guide me as I dial in the amps and cabs.
Series Tracker
This is the fourth post in this series.
You can see the full list of these blog posts over on the dedicated FW 25 Pedal Platform Preset page.
Table of Contents
- Series Tracker
- Acknowledgement
- What Are The Things I Need To Decide On?
- I’m Sticking To Impulse Responses In The Axe-FX 3
- Traditional Impulse Responses vs DynaCab
- To Stereo Pan Or Not, That Is The Question
- Using Low/High Cuts On The Impulse Responses
- Thoughts On The Preamp Functionality
- Discussing The Room Functionality
- Summarising The Decisions
- Final Thoughts
Acknowledgement
I couldn’t have done this without the information available on the Fractal Audio wiki. A huge thanks to everyone who contributes to it.
What Are The Things I Need To Decide On?
There’s two key, overarching things that I need to think about and then make a decision on.
- Am I going with traditional impulse responses, or am I going with the (relatively) new DynaCab impulse responses?
- Am I going with a stereo pan (spanning the impulse responses left and right) or am I going to run all the impulse responses straight down the middle?
After that, there’s a few other things that I should really make a deliberate choice on.
- What low/high cuts do I want to use with the impulse responses?
- Do I want to experiment with the Preamp functionality built into the Axe-FX 3’s cab blocks?
- Do I want to use the ‘Room/Air’ functionality?
(I’m aware that there’s also speaker functionality in the Amp block. I’m going to leave that discussion to the blog posts about dialling in the amps.)
I’m covering these topics in their own dedicated blog post because my decisions are going to apply across every amp that I want to support in my pedal platform patch.
I’m Sticking To Impulse Responses In The Axe-FX 3
There’s one decision that isn’t open for discussion: I’m definitely going to use IRs inside the Axe-FX 3.
- I’m not going to use an IR loader in my DAW.
- I’m not going to use a hardware IR loader like a Two Notes product, the OX Box, and the like.
First off, I want to play guitar without turning on my computer, without having to fire up my DAW software. I simply don’t want that extra step between me sitting down and starting to play.
Secondly, I haven’t seen anything to convince me that a hardware IR loader is going to sound better than the Axe-FX 3 does. Something like the OX Box might, but it’s designed to be connected to a single amp, not a stereo rack unit like the Axe-FX 3.
The decisions today are about how to make the most of the Axe-FX 3’s support for impulse responses. And the biggest decision is which type of impulse response to go with.
Traditional Impulse Responses vs DynaCab
Let’s Revisit Traditional Impulse Responses
I built the very first version of my pedal platform patch to try and mimic my Marshall DSL20HR into a pair of 1×12 cabs. Back then, we only had traditional impulse responses in the Axe-FX 3, so I found the ones that were closest to my real cabs, and never looked back.
I still have that patch on my Axe-FX 3. So let’s throw my beloved Mad Professor Sweet Honey Overdrive onto the pedalboard, grab a guitar, and hear how that sounds:
Granted, I haven’t adjusted this old patch for how Firmware 25 sounds, but still … that’s not a great sound, is it?
Back then, I didn’t understand many of the tools that are in the Axe-FX 3 for adjusting how impulse responses sound. I’m talking about the Proximity and Smoothing controls, playing with the Alignment of the IRs, applying Low and High cuts, changing impedance curves, and (of course) throwing a good ol’ EQ into the signal path too when all else fails.
This is the best I’ve been able to do:
While I think it’s a much better sound that I started with, I don’t think it’s quite there. Every tweak I’ve made to solve one perceived issue has introduced a new problem. I’m especially unhappy with both that low thud that has crept in, and that the end result now sounds quite boxy to me.
If I can’t get it “right” for one guitar, how am I going to successfully support three different voicings?!?
In the past, the solution was to switch to different IRs, and keep switching until you found the sound you were looking for (or, at least, the sound you could live with). If you couldn’t find what you wanted in the Axe-FX 3, you could load your own IRs and keep going. Or (more likely) you’d buy a pack of IRs from someone, and try those instead.
Enter The Next Contestant: DynaCabs
Then, at the end of 2023, Fractal Audio added DynaCab IRs to the Axe-FX 3. We get a lot less speakers than before, but in return we get the ability to move the virtual mic in two different axes: position (left and right across the speaker) and position (distance away from the speaker).
This is a game-changer. Just listen to this:
That’s a demo I’ve made with DynaCab IRs, and I think it’s no contest. To my ears, the DynaCabs deliver a sound that’s bigger (more top-end, more lower-frequencies), more detailed, and lacking the boxiness and low-end thud that I got when using two traditional impulse responses.
On top of that, they’re so easy to work with. All I have to do is grab the DynaCab(s) that I want, and then tweak their position and distance until I’ve found the sound that I want. I say “all”, but it still takes me hours to dial them in. But the point is, I can dial them in. They’re not just a static take-it-or-leave-it snapshot of a speaker.
And that’s why I’m going with DynaCabs for the new pedal platform patch.
To Stereo Pan Or Not, That Is The Question
Let’s go back to that old preset that I started with above. Seeing as I had two cabs in the preset, I panned them hard left and hard right. I was trying to mimic my experience of hearing my two real speaker cabs here in the room.
Was it a good idea though?
Stereo Panning IRs Prevents Me Blending Them Together
The first problem with panning IRs is that I lose the ability to blend them. (Blending is where you take two or more IRs and reduce the volumes of one of them to find a combined sound that works for you.) Each ear is only hearing one IR, and I have to make sure that they’re roughly the same volume, otherwise the guitar is off to one side.
Do Mono Guitar Tracks Sound Better?
Then there’s the question of what happens if I want to record tracks for songs? I’m going to want to record mono guitar tracks, because they’re easier for a novice like me to mix. While the Axe-FX 3 makes it easy to sum to mono (plus I can do that in my DAW), I think I’d be happier if the guitar track was already in mono to begin with. That way, I’d be recording the sound that I’ve already dialled in and am used to.
Do demos for the blog sound better if the speakers are hard-panned?
To try and answer that one, I’ve taken that old preset of mine and panned both speakers down the centre this time. Here’s how that sounds:
Just as a reminder, here’s how the same preset sounded with the IRs hard-panned left and right:
Listening back through speakers, I hear a difference. We’ve definitely lost something by panning the IRs dead centre. Thankfully, that’s easy to fix. All I’ve got to do is move the delay and reverb to go after the IRs and make sure that they are in stereo. Here’s how that sounds:
Still not as wide-sounding as having the IRs panned left and right, for sure. But I think it’s easier to listen to (the stereo field is more forgiving; I don’t have to be exactly dead centre to hear the full sound), and I think it sounds more like one guitar.
Overall, I’m hearing no reason to pan the IRs hard-left and hard-right. Plus, there’s one other reason why it makes sense to run the IRs straight down the middle …
One Eye On The Future
Although it’s something I don’t do, I am interested in creating captures or profiles of my signal chain. Which approach do I need to adopt for that?
The four leading tools for this (Kemper Profiler, Neural DSP Quad Cortex, IK Multimedia Tonex and Neural Amp Modeller) all seem to be built to make captures or profiles of mono input signals.
Using Low/High Cuts On The Impulse Responses
What Are The Low Cut & High Cut Controls?
This is a tip from Leon Todd (Ragdoll’s guitarist, and one of the best Axe-FX 3 educators on YouTube).
In the Axe-FX 3, we can apply both a low-cut and a high-cut to each individual IR in a preset. Leon explains how and why in this video for G66.eu:
Should I Apply A Low Cut?
I think the answer here is a resounding ‘yes’.
I’ve been applying a low cut at 80 Hz right from the first pedal preset that I made, and there’s never been a problem about it removing too much low end from the signal.
It’s working for me, so I don’t see any reason to reconsider this.
Should I Apply A Mix-Ready Low Cut?
If I’m going to be applying a low cut anyway, should I go further and use a larger low-cut so that the guitar tone can drop straight into a mix? (i.e. avoid having to do further EQ when mixing a song)
No, I shouldn’t do this.
Most of the time, I’m not recording anything – I’m just playing guitar on my own for fun. And it’s a lot more fun when the guitar tone has some low-end in it.
Plus, I don’t know what low-cut to add to make the guitar tone mix-ready. Won’t it vary from guitar tone to guitar tone? Seems to me that it’s a decision best deferred until mixing a song.
Should I Apply A High Cut?
Until now, I’ve been applying a high cut to the impulse responses that I use. It’s set at around 8 kHz. Do I want to carry on doing that?
There’s some additional information to consider:
In the video above, professional music producer Henning Pauly shares some of his tips for recording guitar tones. At the end of the video, he talks about guitar treble frequencies (the frequencies that would be affected by adding a high cut to the IRs in the preset that I’m building).
He doesn’t advocate for cutting them, he advocates for boosting them.
Leon Todd is applying a high cut to the Cab Block because that’s what he needs for live performances. And Henning Pauly is applying a boost to guitar treble frequencies (and snare drums, he said) because that makes a recording mix sound better.
Turns Out, I’m Already Doing This! Well, Sort Of …
The Cab block in the Axe-FX 3 has a section called ‘Air’. This is a filter that mixes in part of the original signal (ie before the IR has been applied).
The controls are very simple:
- what frequency we want to mix in (in this case, 5 kHz and above)
- and how much we want to mix in (as a percentage).
I’ve been doing this for a long long time. Again, probably a tip that I learned from Leon Todd’s YouTube videos.
I’m Sticking With The Axe-FX 3’s Air Feature
The ‘Air’ control isn’t exactly the same as adding a 5 db shelving boost at 5 kHz.
- With the ‘Air’ control, we’re blending in treble from a different signal.
- With the shelving boost, we’re accentuating the treble that comes out of the Cab block.
I’ve experimented with both, and I found that I prefer the sound of using the ‘Air’ feature. Bear in mind, this is for playing, recording and listening to a guitar in isolation. In a mix, the shelving boost might well be the better choice.
So I’m going to hedge my bets a bit, and (hopefully!) make it easy to switch between the ‘Air’ feature and a 5db shelving boost in my pedal platform patch.
Giving Some Help To The Treble Content
Now that I’ve decided that I want that treble content, I think I have enough information to make a decision on applying a high-cut to the IRs in the Cab block.
Going forward, I am not going to apply a high-cut to the IRs in the Cab block.
For what I do – clean and vintage-sounding low-gain overdrive recordings at home – I can’t hear a benefit when I apply the high-cut. If I don’t like how the top-end sounds, I found that adding a high-cut doesn’t solve that problem for me.
Thoughts On The Preamp Functionality
What Is The Preamp Functionality In The Axe-FX 3?
Buried in the Cab block, the Axe-FX 3 has the ability to emulate how different classic recording preamps affect the sound.
- I can choose from a long list of preamp types (11 as of fw 25.00).
- I can dial in some Drive for additional gain.
- I can dial in some Saturation for additional harmonics.
All very cool. But not well documented, either in the manual or on the wiki.
I’m Going To Use My Preamp Plugins For This
This one’s an easy decision:
- I’m not going to use the preamp modelling in the Axe-FX 3.
- If I want to emulate preamps, I’ll do that with my collection of Universal Audio UAD Unison preamp plugins on the Apollo x6.
When I’m recording pedal demos for the blog, I don’t want any preamp modelling anywhere in the chain. The audio demos are there as proof to back up the words that I write. I don’t believe that preamp modelling helps me do that.
When I (finally!) get around to recording music, I’m going to want all the audio sources to go through the same preamp modelling / emulation. That makes it impractical to rely on the Axe-FX 3 for this modelling.
Finally, as I understand it, the circuits in classic hardware preamps affect the tone in more ways than just gain and saturation. (Plus many of them have additional features, which also leave a sonic footprint of some kind.) The UAD plugins model the complete channel strip, and are known for their painstaking accuracy.
I’d definitely experiment with the Axe-FX 3’s preamp functionality for a live preset, to help add some studio production-like polish to the tone. But for what I’m doing, it’s not for me.
Discussing The Room Functionality
This is another feature that isn’t well documented atm. As I understand it, the basic idea is to add some natural character to the IR by emulating how much of the sound of the room a real mic could have picked up. Room reflections, basically.
Why do this?
Professional recording studios are sought after, in part, for how their ‘live’ rooms sound. This wouldn’t be the case if the sound of the room didn’t matter … if it didn’t get captured as part of the recording process. The Room functionality in the Axe-FX 3 kinda emulates that, without trying to emulate specific, famous ‘live’ rooms.
(If you want that, Universal Audio has several plugins for exactly that.)
In the Axe-FX 3 we get two rooms, labeled ‘Room’ and ‘Hall’. We can tweak things like the size of the room, the EQ of the reflections, and a couple of mix parameters.
This is another feature that I’ve already been using for a long time (again, probably copied from Leon Todd). I’ve got it dialled in very subtly (mix at 6.1%, room size of Room), mostly because I think I can hear it having an effect on the post-cab delay and reverb if I dial in a lot of it.
I’m going to stick with that for now … but I’ll probably experiment more with it later on in this series. Maybe.
Summarising The Decisions
Just so that it’s easier for me to refer back to later on …
- I’m using the Axe-FX 3 for all speaker cab emulation.
- I’m going with the new DynaCab IRs over the traditional impulse responses.
- I’m going to pan all the IRs straight down the middle.
- I am going to continue to apply a low cut to the IRs at around 80 Hz.
- I am not going to apply a high cut to the IRs at all.
- I am going to continue to apply a bit of the ‘Air’ functionality in the Cab block …
- … but I’m also going (try to!) make it easy to switch over to a 5 db shelving boost at 5 kHz.
- I am not going to use the Preamp feature in the Cab block.
- I am going to continue to apply a bit of the ‘Room’ functionality in the Cab block (but more experimentation is needed to find the settings for me).
Did I miss anything?
Final Thoughts
When I started this blog post, I thought it’d take maybe a couple of hours to work through the features and make decisions. An evening, at most.
It’s taken me a week. I think that’s testament to just how powerful the Axe-FX 3 has become.
I’m just looking at one block out of 43 (at the time of writing) in this blog post. Just one block! And I haven’t actually covered its main functionality – impulse responses. All I’ve done is looked at the way the Cab block can be tweaked to suit – the features that may be (sometimes? entirely?) missing from other impulse response players and plugins. That still took me a week.
It would have taken even longer if I’d recorded audio demos for everything I’ve discussed here.
Anyway … with these decisions made, I can start dialling in each amp and cab that I want available for my pedal platform preset. Naturally, I’m going to start with the platform that matters most to me: something for tweed-tone pedals.