Guitar pedals

IR loaders and cab sims: how to take your favorite pedals direct to FOH or interface

You’ve built a pedalboard you really like, but: * some venues won’t let you run a **loud amp**; * at home you can’t record at gig volume; * you’d love to go **...

You’ve built a pedalboard you really like, but:

some venues won’t let you run a loud amp;
at home you can’t record at gig volume;
you’d love to go straight to FOH or to your interface without losing your sound.

This is where IR loaders and cab sims come in: they let you use your pedals as usual, but instead of hitting a miked cab they feed a realistic cab + mic simulation straight to the mixer or audio interface.

In this guide we’ll look at:

what IRs and cab sims actually do;
how to connect your pedals, preamp and IR loader in real‑world chains;
differences between live (FOH) and home recording use;
basic settings to avoid harsh, fizzy or muddy tones;
common mistakes to avoid when going direct.

To explore real‑world options on Muviber:

1. What IRs and cab sims really do

1.1 IR (Impulse Response)

An IR is a digital "snapshot" of:

a speaker cabinet;
a microphone (model + position);
sometimes a bit of the room.

The IR loader is the device (pedal or rack) that loads and applies those IRs to your signal.

Result: your guitar goes through a very realistic cab + mic simulation, as if you had actually miked an amp.

1.2 Cab sims

Cab sims are cabinet simulations (analog or digital), often fixed or with a few variants. They can be:

built into a preamp pedal;
inside a modeler / multi‑FX;
part of a DI box with "speaker sim".

They don’t always use IRs, but they still perform the core job: filter extreme frequencies and shape the response like a miked cab.

In general:

IR loader = more flexible, you can change IRs, mics, blends;
simple cab sim = easier and quicker to use, fewer options.

2. Typical signal chains: from pedalboard to FOH / interface

2.1 Pedals → preamp → IR loader → mixer/interface

Classic "silent stage" or home recording chain:

pedals (tuner, drives, mods, delay, reverb);
preamp / amp‑in‑a‑box pedal;
IR loader / cab sim;
balanced out (XLR) to FOH or line out to your interface.

Without a proper preamp in the chain, many drive/distortion pedals sound thin and fizzy into an IR loader. The amp‑in‑a‑box stage gives you the feel and response of a real amp front end.

2.2 Using a real amp’s send / line out + IR

If you want to keep your amp but still go direct:

take the FX loop send or a dedicated line out;
feed a load box with IRs or an IR loader afterwards;
go straight to the mixer.

If you tap the signal after the power amp (speaker out), you must use a proper load box matched to the amp’s impedance. Never connect a speaker output directly into a line‑level IR box.

2.3 Modelers / multi‑FX with cab sims

Many modern multi‑FX already contain:

amp models;
cab sims or IR loading;
balanced outputs.

In that case the chain is simple:

multi‑FX with cab sim enabled → mixer/interface.

Just make sure you know when cab sim is on or off so you don’t end up stacking sims.

3. Live vs studio: what changes when you go direct

3.1 Live / FOH

Going direct gives you:

consistent sound night after night (no mic placement lottery);
lower stage volume (especially with IEMs or FRFR wedges);
faster soundchecks.

Things to keep in mind:

FOH often runs in mono – decide whether to send mono, or stereo only when it truly makes sense;
use balanced XLR outs (or a DI) to avoid hum and noise;
send a clean line‑level signal, not too hot.

3.2 Home recording / studio

With IRs and cab sims you can:

record silently at night;
swap IRs after recording (with plugins or some units);
track a clean DI plus a cab‑sim track.

Typical chain:

guitar → pedalboard → preamp → IR loader → line input on interface;
optional split pre‑IR to capture a raw DI for future re‑amping.

4. Core settings: avoiding fizz and mud

4.1 High‑pass and low‑pass filters

Most good IRs already have a realistic curve, but if you have extra controls:

high‑pass guitar around 60–80 Hz to tame rumble;
low‑pass between 6–8 kHz as a starting point to reduce harsh top‑end fizz.

For bass, the numbers change (lower HPF, higher LPF); ideally use bass‑specific IRs or cab sims.

4.2 Levels and gain staging

don’t clip your IR loader input;
don’t send FOH a red‑lining signal;
with heavy drives, adjust output level of the pedals, not just gain.

4.3 Choosing IRs

start with 1–2 go‑to IRs (4x12 for high gain, 2x12/1x12 for clean/crunch);
don’t keep scrolling IRs for every riff – think in terms of mix context;
organise your IRs into folders by role/genre (clean, crunch, lead, ambient, etc.).

5. Common mistakes when going direct

Double cab sim: internal amp sim + external IR, or a cab‑sim out feeding another cab sim → dark, boxy, undefined tone.
Using guitar IRs for bass without control → muddy, low‑end heavy mixes.
Sending FOH a too‑wet, over‑compressed signal with no room for adjustment.
Wrong level type (instrument into line input or the opposite) causing noise or clipping.
Expecting IRs to be magic fixes: if the source (playing, tuning, basic tone) is weak, no IR will save it.

6. Choosing IR loaders and cab sims for your setup

Questions to ask:

Do you play mostly live or mostly in the studio?
Do you already own a modeler, or are you 100% on analog pedals?
Do you need a balanced XLR out?
Do you want to load your own IRs, or are built‑in sims enough?

Examples:

if you run a big analog board and no modeler: a dedicated preamp + IR loader with XLR is often ideal;
if you already use a modern multi‑FX: enabling its internal cab sim and going balanced may be all you need;
if you play lots of sessions with changing backlines: a small self‑contained direct rig (preamp + IR loader in a bag) is a life saver.

You can compare options by searching:

7. Quick checklist for going direct to FOH or interface

[ ] Is the chain clear? (pedals → preamp → cab/IR → mixer/interface)
[ ] Have you checked there’s only one cab sim active?
[ ] Correct output type: balanced XLR or proper line out (DI if needed).
[ ] Levels set with headroom, no clipping.
[ ] You have a safe, clean/crunch preset ready as a fallback.
[ ] If you run stereo, FOH knows exactly what they’re getting.

FAQ – IR loaders and cab sims

Can I run an IR loader with just drive pedals, no preamp?

You can, but the result is often thin and harsh. Putting a preamp or amp‑in‑a‑box before the IR loader usually gives you a fuller, more amp‑like response.

Do I need separate IRs for live and studio?

Not necessarily, but it’s common to have different presets: simpler, more defined tones for live, and more detailed, layered IR combinations for studio work.

What’s the difference between cab IRs and reverb/room IRs?

Cab IRs emulate the response of a speaker + mic. Reverb/room IRs emulate the response of a space (room, hall, plate). Same technology, different purpose.

Should I go mono or stereo?

For electric guitar, mono is usually the safest choice live (the audience isn’t all in the sweet spot). Stereo can work great for ambient, worship or special shows where FOH and the venue can actually support it.

Can I use the same IRs for guitar and bass?

Better not. Bass needs IRs or cab sims designed for low frequencies. Alternatively you can use a good DI for bass and add amp/cab simulation later in the DAW.