LOL, Jak is far too kind, but I will help where I can.
Your question is REALLY, REALLY BIG, Tobias, so I will start with the sub-question you asked, about the “cab packs.”
Cabs, also called “IRs,” are impulse response algorithms that make up a virtual speaker cabinet. They work with amp modelers. In this case, the Fractal Audio AxeFX units.
An amp modeler is just a computer program. Some, like the AxeFX, Line6 Helix, and Kemper profiler, use their own hardware to run the modeling software. They come in standalone or rack-mount units like regular amplifiers (or built into foot pedals), even though they aren’t. Some others are entirely software based, and you run them on your computer, like Bias FX and Eleven Rack. They run entirely inside a Windows or Mac computer and are typically useful only for home practice or recording.
Anyway, with amp modeling, you need – MODELS!
I’ll speak to the AxeFX mostly, because that’s what I have. The folks at Fractal take real amps, study them, take them apart, etc, and they create virtual electronic “models” of all the parts, so they can build virtual amps. In this way, they can put amazing and sometimes even historical one-off amplifiers into their tool so anyone can use them (if you have the money!!). You can also do things like take that shiny EVH 5150 and swap out the 6L6 tubes for 12AX7s just to see how it sounds (if you want to get into the whats and whys of tubes later, we can touch on it some).
So, for reference, in my AxeFx, I have a number of tones in my main preset bank that cover a lot of ground – there’s a model of the vintage Tom Scholz (Boston) Rockman portable amp that, with compression makes for a super sparkly clean tone. Next to that, I have a Vox AC-30 for a slightly crunchy clean tone. For real crunch, I’ve got a Freidman, then get into a 5150 MkIII Blue for my METAL chuggy tone. Back to the Friedman with a notch filter and overdrive and reverb for my lead tone, and several others. It’s no longer about trying to find one amp that does everything – you HAVE one amp that almost LITERALLY does everything.
On top of that, you can plug it into your computer and record those tones, perfect, every time. No double-checking mic placement or freaking out about finding the “sweet spot” you had in the studio that one time three years ago that SOUNDED SO FUCKING KILLER.
It’s right there.
Anyway, part of that amp model, end to end, is the speaker cabinet. The heaviest amp in the world doesn’t mean shit if there’s no stack of 4×12 speaker cabinets to fill the stage, right? So, the way that’s handled in a modeler is they mic up the cabinets just like they would for recording, and then use computers to measure all the wave forms it records, and how it moves the air around the microphone. Doing this for a while builds what’s called an impulse response model. It’s this IR that becomes a “cab,” short for speaker cabinet. At the end of your amp model, is the cab – it’s the final aspect of your sound.
From there, you can run it straight into headphones or audio software, or if you’re in a live-sound situation, you can run it out to a PA speaker or an FRFR cabinet (Full Range, Flat Response). An FRFR is designed to be like a recording studio speaker – putting out exactly what goes into it, which is exactly the opposite of what a guitar cabinet does. A guitar speaker is DESIGNED to add tonal flavor and even to break up (distort) as part of giving you that overall mega-crunchy sound.
So Syn’s IRs, or cabs, are the virtual models of his real-world speaker cabinets, and a little bit above, he actually answered my questions and spoke to some of what he’s used each of them for. I found that I really dug his model of the Hellwin 4×12 cabinet he uses, with only the Royer R121 ribbon microphone (different microphones add different color to a tone, as well!)
I’m thinking I may need to take a page from Jak and do a live video where we walk through an AxeFX and tone-building and shaping… My frail ego can’t handle scheduling a live video where two people show up – is there demand for this? Would people be interested in something like that?