Impulse Responses: Are They More Important Than Amp Sims?

Impulse Responses: Are They More Important Than Amp Sims?

Hey there! Jens again. Today, I want to discuss the importance of amps vs. speakers & microphones when looking to achieve great metal guitar tones. Let’s discover how choosing the right impulse responses can get you there in a matter of seconds.


Jens Bogren Rhythm IR Pack

Focusing On The Wrong Things?

When talking about guitar tone, a lot of people seem to be totally obsessed with amps. They’ll rant about how “X version of the Dual Rectifier is SO MUCH BETTER than the Y version”. In reality though, we’re only talking about a few % of difference. 

Don’t get me wrong. Amps matter. A lot. However, most high-quality amplifiers (and amp-sims) will sound good even at their default “all knobs at noon” setting. I mean, that’s essentially “the sound of the amp” that the manufacturer intended anyway, right?

PS. Check out my “Crushing Rhythm Tone” blog for example, where I use Brainworx’ awesome Diezel VH4 amp sim at practically “flat” settings (alongside my Bogren Digital “Rhythm” impulse response pack) to dial in a killer rhythm tone on a Sepultura track.

Diezel VH4

So, all this being the case, why do people seem to struggle so much with achieving tight, aggressive, clear rhythm tones in the studio, even when using great amplifiers or amp sims?

Well, usually, it’s not the sound of the amp which is the problem: it’s how you go about capturing it.

The Last (And Most Important) Link in The Chain

Based on my experience, 80-85% of the tone comes from the choices you make after the amp. Namely, a combination of the cabinet, speaker, microphone, and positioning.

The classic “Dual Rectifier into a Mesa 4x12 with an SM57” setup is regarded as a time-tested, “perfect” combination for metal. However, it’s not about just throwing the microphone in front of the speakers and magically capturing a legendary tone...

Long story short, it doesn’t matter how great your amp is. If you’re not capturing it right, it won’t sound right. This is where the problem with a lot of the impulse response packs you’ll find on the internet emerges:

Hold On... Impulse Responses? What Are Those?

Just in case you’re unaware of the concept: An impulse response, also known as an IR, is a digital capture of a recording chain in the form of a tiny .wav file.

While I’m not going to bore you with all the details of impulse response creation in this blog, the bottom line is: You can use IRs in conjunction with an IR loader to accurately recall the complex EQ curve of a specific signal chain within your DAW (In our particular case, a speaker cabinet, microphone, preamp and any other cables, hardware and gear being used in the loop).

Vikings IR Q-Clone
The frequency curve for the “Vikings” IR from my “Rhythm” pack, visualised in a spectrum analyser.

But Not All Impulse Responses Are Created Equal...

The problem is, an amateur engineer new to the world of audio might come across a random IR named something like “GREAT-IR-MESA-57”, and just assume it’s the result of a great speaker, in a great cab, being captured with a great microphone, using great mic placement technique, placed in a great sounding room, going into a great preamp.

They might blindly trust that whoever made this IR knew exactly what they were doing, load it into their software, and proceed to spend hours trying to dial in a good tone on the amp, all the while wondering why regardless of the settings they use, it always sounds terrible.

The truth is, if you think about all of the variables involved in capturing a high-quality speaker chain, it’s actually much more likely that the IR is the furthest thing from “great”, even to the point that it’s totally ruining the potential of them ever dialing in a decent tone.

On the other side of the coin, even if the IR is technically “great”, it may only be great for the particular tonal context in which it was created. The bottom line is, there’s no such thing as a “one size fits all” speaker and microphone setup that’ll work well for every single riff!

Top Album Recording Chains, Bottled For Top-Quality Tone

The goal with my Bogren Digital IR packs was to take all of the guessing and randomness which usually goes hand in hand with having hundreds of similar, totally “raw” impulses to choose from, and instead give the user access to a handpicked selection of exact, start-to-finish “mix-ready” recording chains I’ve used with bands like Sepultura, Arch Enemy, Amorphis, Opeth, BTBAM, and more.

The difference here is that we’re not just capturing a raw microphone that we placed on the speaker in an average, “default” position that may or may not work. We’re capturing actual, specific, “finished” album-tone setups, with all of the additional “after the fact” wizardry (preamps, EQ, mic blends, etc.) baked-in from the get-go, even to the point that no additional processing is required whatsoever.

And again, based on the fact that an “SM57 on a Mesa” IR could range anywhere from sounding absolutely perfect to absolutely hideous for your particular song, we decided to skip the usual naming conventions in favour of a lighter approach:

Libra IR Loader
“Greasy Beard” and “Fart Me Up” from the Bogren Digital “Rhythm” pack in the “Libra” IR Loader by Ignite Audio



Professional? Maybe not... But this way, you won't choose impulses based purely on the gear used, but rather on how they actually sound when paired with your specific tone and song.

Simply load up your amp sim of choice and load up the pack using a high-quality IR loader. Next, skip through the options available until you find something you like. Finally, tweak the amp settings slightly to where things are sounding best. Done!

Summary: Go Forth And Conquer!

There's lots of amazing guitar recording technology available nowadays. However, it's still difficult to know where to start when dialling in a heavy sounding rock or metal tone.


While there’s definite value in learning to set up the actual gear for yourself, these things take time and experience. In the meantime, why not make sure you’re still able to get professional results fast?


Check out our “RHYTHM” and “LEAD + CLEAN” IR packs, and hopefully the results will speak for themselves.

Cheers, and happy chugging!