Impulse responses– the term seems to be everywhere these days! Are you a guitarist? Do you record from your home studio or like to tinker with guitar amp sims and plugins? If you’ve spent a little time researching online, there’s a good chance you’ve come across impulse responses (or IRs, for short). In this beginner’s IR guide, we’ll break down what guitar impulse responses are, how to utilize them in your recording process, the differences between impulse responses and amp sims, where you can find the best guitar impulse responses (free and paid), and where you can download IR loaders.
What are impulse responses (IRs)?
Technically, an impulse response is the captured output measurement of a response to an input signal (or impulse) over time… Makes sense, right? In simple terms, just think of IRs as samples of an acoustic space that you can immediately recall and use in recording and live settings. They can be used in a variety of ways including calibrating headphones or capturing reverbs of specific acoustic spaces but in terms of guitar, this typically refers to the cabinet, mic and mic placement, and room.
Note: Mic preamps, cables, power amps, subtle reflections, and a bunch of other variables that can affect the sound when capturing guitar cab impulse responses. But for the sake of simplicity, let’s think about them in terms of cabinets, speakers, mics, and rooms.
If you’ve ever had to mic up up your cabinet to record, you know there are plenty of things that come into play (outside of your actual guitar and effects) that can affect the sound that gets recorded. For example, a recording of a Marshall cabinet in an acoustic-treated room with an SM57 placed directly on the grill is going to sound completely different than a recording of a Fender Twin in an open studio with a Shure SM7B placed a foot away.
Guitar cabinet impulse responses are snapshots of these combinations of cabinet (and speaker), mic and mic placement, and room. This means that in a live setting or recording, you can recall these exact settings to get your preferred tone by simply using an impulse response! This also means that we have access to a multitude of cab/speaker/mic/room configurations without actually having to own a ton of gear or without having to painfully set up physical combinations of gear to find that perfect tone. We can simply swap out configurations on the fly by using IRs.
Impulse responses vs. cab sims
While both impulse responses and cab sims can be used (sometimes together) to create versatile tones, they are not the same thing. As we previously stated, impulse responses are actual snapshots of the acoustic environment while cab sims are a type of emulation created digitally with software. For graphic designers, you could think of guitar impulse responses as bitmap (or a snapshot) while cab sims as vector (or a digital recreation). You have more options for tweaking with cab sims but IRs tend to sound better and are a more accurate recreation of an acoustic environment. However, it’s important to note that the quality of the IR greatly impacts the tone (i.e., using a badly captured IR will result in a bad tone). Check the video below for a short demonstration of a cab sim vs. an impulse response.
How do you use an impulse response?
Impulse responses are stored as .wav files. You can create your own impulse responses, find free ones online, or buy them from companies or artists. These files can be loaded via an IR loader plugin (discussed later on).
Best free guitar impulse responses
The easiest (and cheapest!) way to get started with impulse responses is to start with some of the free options. You can find some high-quality free IRs but there are also a ton of not-so-great ones (you get what you pay for). To get started, I recommend checking out some IRs from the following libraries:
- Free Celestion Impulse Responses
- Allure IR pack by Line 6 (requires email signup)
- God’s Cab by Wilkinson Audio
- Kalthallen Cabs
- Free Redwirez IR Library (requires email signup)
- faIR Modern Rock (requires email signup)
- SNB Impulse Response Files
- Albrecht Productions
ALSO: Dial in your tone by pairing impulse responses with a guitar amp simulator!
Best paid guitar impulse responses
While free impulse responses can sound great, you’re more likely to find higher quality IRs with the premium, paid options. The following are some tried and tested premium impulse response libraries:
- Ugritone (Use code “MAKEMUSIC” at checkout to get 20% off!)
- Lancaster Audio
- Eminence Digital
- Tone Junkie Store
- Audio Assault Cab Sims
- Premium IRs by Constantine Studios
Looking for the most brutal, high-gain impulse responses? Check out our list of the best impulse responses for metal!
Celestion Impulse Responses
Celestion has a long history in the world of rock music. They’ve been creating high-quality cabinet speakers since the ’60s so it’s no surprise that they offer some of the best impulse responses available today. Their speakers have been the standard used (and often compared to) in a variety of cabinets for many decades.
Celestionplus.com was launched in 2017 with the goal of offering its well-known guitar cabinet speakers in the digital form of impulse responses. Today, you can find high-quality digital versions of many of their physical speakers including the Vintage 30, G12M, G10 Greenback, and many more.
In addition to the many IRs that they offer, Celestion Plus also has created a cab simulator plugin called SpeakerMix Pro that uses their impressive Dynamic Speaker Response (DSR) technology. DSRs are the latest evolution in impulse responses and are more customizable and flexible than standard IRs. Not only does SpeakerMix Pro offer the extended functionality of DSRs, but it also gives you more options to tweak traditional IRs, which is why it’s listed as our top paid IR loader! Read our review of the software to learn more about SpeakerMix Pro.
Whether you want to dive into their DSR technology or are just looking for high-quality impulse responses, Celestion Plus is sure to have what you’re looking for and will not disappoint. Check out their full catalog of impulse responses which can be purchased in collections or single IR downloads.
Ugritone Impulse Responses
Ugritone offers some top-notch impulse responses. Their unique approach to capturing IRs involves capturing the sound from an entire 3D space instead of the standard one or two-mic positions. This approach has led to some of the best-sounding impulse responses available online today, especially if you’re looking for some heavy metal tones.
Ugritone also has an IR loader plugin called the TRVE Cab Loader which allows you to load IRs in up to eight different slots. This means you can mix and match these slots to create a much fuller tone with lots of room for tweaking and customizing.
In addition to impulse responses, Ugritone also offers a variety of other plugins for all your music production needs. Check out their impressive lineup of Heavy Metal Drum Samples (includes the Ugritone Drums plugin with every download), their Midi Packs, or their reverb plugin called Verbcore!
Want 20% off impulse responses? Use code “MAKEMUSIC” at checkout on Ugritone.com to get 20% off!
How to use impulse responses in your DAW with an IR loader
Assuming you have already have a recording interface and DAW, guitar impulse responses can be used during recording via an IR Loader. You can record a direct input of your guitar and then use an IR loader like any other plugin to swap between various IRs to get the sound you’re looking for.
Best free IR loaders
- NadIR by Ignite Amps
- Pulse by Lancaster Audio
- FenrIR Impulse Loader by Aurora DSP
- Boogex by Voxengo
- IR Loader by ChopTones
Best paid IR loaders
- SpeakerMix Pro by Celestion (Read our SpeakerMix Pro review!)
- TRVE CAB IR Loader by Ugritone
- IR Loader Impulse Response Tool By Nembrini Audio
- Ignite: Libra by STLTones
- faIRmageddon by Forward Audio
- aIR Impulse Rack by Audio Assault
Note: Some AMP simulators like Amplitube feature their own IR Loaders. You can disable their cabinet simulator and instead load your own custom guitar impulse responses. The general consensus online is that this is a much better alternative to Amplitube’s built-in cab sims (although this is debatable). You can also disable Amplitube’s cabinets and IR loader altogether, and instead load IRS using a separate IR loader plugin from the lists above– I’ve had to do this in the past due to issues with Amplitube crashing when trying to load my custom impulse responses.
Save time and money with guitar cab impulse responses
If you made it this far, then you’ve learned the basics and should have no trouble testing and trying out different guitar impulse responses on your own. Impulse responses are a quick, cheap, and fast way to experiment with a variety of tones during your recording process. There are also options to use impulse responses in a live setting but that’s a topic for another day (and an entirely separate blog post!). Sign up for a newsletter and be the first to know when our latest blog post drops!
Impulse Response FAQs
What is the best impulse response loader?
There are plenty of free and paid impulse response loaders to choose from. Pulse is a great free IR loader to start with! However, check out our full list of free and paid IR loaders for more options.
How are impulse responses used in a DAW?
Impulse responses can be loaded in a DAW with an impulse response loader plugin. Check out our list of IR loaders to find the perfect one for your DAW.
What is an impulse response pack?
Premium Impulse responses are commonly sold in packs. An IR pack will typically contain related impulse responses that are genre-specific or artist-specific to the type of pack. For example, Lancaster Audio offers multiple genre-specific packs ranging from Pop to Rock packs to artist and producer-specific packs.
Check our list of best paid impulse responses to browse a variety of IR packs.
Are the Celestion impulse responses good?
Celestion impulse responses are among some of the best IRs to date. They’re highly versatile with plenty of options and are reasonably priced. You can get individual IRs for as low as $11.99 and IR collections ranging from $19.99 – $37.99. You can even own the complete collection of all IRs released for $499.99 to really dial in your guitar tone.