Impulse responses (IRs) are revolutionizing guitar tone recording for both home studio musicians and professional engineers. But how do they compare to the sound and feel of a real guitar cabinet? In this guide, you’ll:
- Understand how cabinets and IRs shape guitar sound
- Compare recording workflows with real amps and IRs
- Hear A/B listening examples
- Get practical tips and best-use cases
How Guitar Cabinets Shape Tone
The cabinet, microphone, and room are as crucial as your amp for achieving a professional guitar tone. Classic cabs like the Marshall 1960A with Celestion G12-T75 speakers, famous from albums by Nirvana and AC/DC, add signature midrange punch and “air.” The speaker’s frequency response, cabinet resonance, mic choice (like the Shure SM57), and room reflections all shape what you hear in a mix.
What Is an Impulse Response?
An Impulse Response (IR) is an audio “snapshot” of a cabinet-microphone-room chain. Specialized software uses convolution to apply that cabinet’s unique sound profile to your DI guitar. In seconds, you can access hundreds of cabinet and mic combinations—ranging from tight modern tones to vintage warmth.
IRs capture not only EQ curves but also phase, resonance, and even room ambiance, making them essential for guitar cabinet simulation and amp modeling.
Real Cabinet Recording: Workflow and Pros & Cons
Recording a real cabinet usually means plugging your amp into a physical cab and miking it. You might use dynamic mics (like SM57s) or blend with ribbons for extra guitar tone shaping. The amp pushes air, and every detail—from mic placement to the room—impacts tone.
Advantages:
- Maximum realism and three-dimensional feel
- Physical interaction (amp “pushing air” influences playing dynamics)
- Creative mic and room choices
Drawbacks:
- High volume & needs a treated space
- Expensive gear and time-consuming setups
- More difficult to recall exact sounds later
Recording with Impulse Responses: Workflow and Pros & Cons
Load an IR into your DAW or hardware IR loader, route your guitar amp’s line out (or an amp sim), and instantly apply any cabinet, mic, or room you want. This is the go-to strategy for home studio guitar recording and silent practice.
Advantages:
- Silent operation (record at midnight, no complaints)
- Massive flexibility (hundreds of cabs/mics at your fingertips)
- Consistent and recallable for fast production
Drawbacks:
- Some say IRs lack the “amp-in-the-room” feel
- Can be overwhelming to choose; not every IR pack matches every style
A/B Listening: Can You Spot the Real Cabinet?
In the player below are four clips: one is a real mic’d Marshall 1960A, the others are impulse responses captured via different techniques (“sine sweep,” “MLS,” proprietary, etc.).
What to listen for: low-end punch, high-end smoothness, liveliness, and natural “air.”
Ready for the answer? Watch the detailed walkthrough below for all IR recording details and the correct answer!
IR Capture Techniques & Pro Recording Tips
- Capture methods: IRs are made using sine sweeps, maximum length sequences (MLS), or proprietary methods like S.P.A.R.C. Each has subtle effects on frequency detail and capture accuracy.
- Microphone strategies: The “Fredman Technique” (two SM57s at 55°) gives a modern aggressive sound; combining dynamic and ribbon mics adds depth. Always check phase alignment for punchy low end.
- Room impact: Anechoic/small rooms minimize coloration; big rooms add ambiance baked into the IR.
- Pro tip: Record a DI track along with your amp. You can always re-amp through real cabs or reload with new IRs.
When to Choose IRs vs. Cabinets?
- Home studios: IRs offer silent, flexible recording—ideal for apartments or late-night sessions.
- Pro studios: Real cabs excel for organic, three-dimensional tracking—but always grab a DI for future IR use.
- Touring/live: An IR loader (like Kemper, Helix) ensures consistency show to show without stage volume headaches.
Bonus Tips & Top Resources
- Test free IR packs (“Celestion Free IRs,” “God’s Cab,” etc.), and try both dynamic and ribbon IRs for best results.
- Use high-quality amp sims with your favorite IRs to dial in polished, mix-ready tones for any musical genre.
- Experiment with blending real cabs and IRs for truly unique tones.
FAQ: Impulse Responses and Guitar Recording
- What is an impulse response for guitar?
- An IR is a digital file that reproduces the sound of a specific cabinet/mic/room chain using convolution. Load it in your DAW with an amp simulator or real amp to get authentic speaker tones instantly.
- Are IRs better than amp sims?
- IRs emulate just the cabinet/mic/room. Use with amp sims for maximum realism, or re-amp real amp DIs.
- Can IRs replace real cabinets in live shows?
- Many touring acts use IRs live for stage consistency and silent monitoring. Both real cabs and IRs have their place, depending on the gig and sound goals.
Try It Yourself: Free IR Download
Practice with the same impulse responses and compare them to your own cab recordings. Share your results and join the community of modern guitarists exploring the boundaries of guitar amp recording.