Using Ir's to raise the bar

What are Impulse Responses and how are Marshall using them to take your guitar sound from ‘meh’ to ‘yeah!’?

Posted: 4 September 2019

Since the 60’s Marshall has been synonymous with great guitar tone, and a large part of that is down to the legendary Celestion speakers. From the iconic G12 greenbacks through to the Seventy80s, the Vintage series and beyond, Marshall and Celestion have become the ultimate power couple. Like Bonnie and Clyde or bacon and eggs, they’ve become inseparable and formed an iconic partnership that has stood the test of time.

Which is why when Celestion dove headfirst into the bold new world of Impulse Responses Marshall were only too happy to become their partner in crime and make use of their new IR range. We’ve spent almost 60 years creating some of the greatest guitar sounds in the world, and now there’s a way to accurately capture that and share those sounds with players around the world? Well that sounds exactly like our cup of tea.

Find out below exactly what an IR is and why Marshall has used them to record samples of each of our amps. If you can’t wait to hear them, head over to our amp pages now.

What is an Impulse Response?

Put simply an Impulse Response (IR) is a sound measurement that digitally captures the qualities of a guitar amp speaker, microphone and room. Hyper realistic and incredibly accurate, a top-notch IR is sonically indistinguishable from the real thing. Think of a cabinet simulation that has been taken to the next level and you’re about there.

Take an IR that captures a 1960AX recorded in Abbey Road Studios with a Shure SM57 placed a foot away. If you go anywhere else - be it on any stage, in your living room or even in the studio - and play with the same guitar and head, then you can accurately replicate that sound as if it had been recorded at Abbey Road, recorded through that signal chain.

Why are Marshall using IR's?

Be it at home, in the studio or on the stage, our amps turn up everywhere. But whilst the quality of our equipment is always top notch, there are many factors that can lead to differences in the final sound.  Key variations are usually the venue and microphone positioning when you’re recording, but even the temperature and air pressure can lead to changes in the overall sound. This means when we record backstage at a festival, in a professional studio or at Marshall HQ we often end up with differing tones even if the amplifier is the same.

The videos below were each recorded without the use of IR's. See for yourself the difference the location can have on recordings...

Gary Holt - Slayer
In the Cabin at Download 2019
Lewie Allen - Sam Smith
In the studio
Studio Vintage Demo
At Marshall HQ
Gaetan Judd
In a venue

So how could we create an accurate representation of each amplifier to showcase how good they really sound? Well up step the IRs, which allowed us to record each amp in a controlled environment where the only variable would be the guitar and the amp model itself. Using IRs we could now record the sound of the amps in a high-quality studio space, with premium microphones that were guaranteed to be in the exact same positions for each take. This means that on marshall.com you can hear each of our amplifiers in the same surroundings, so you can judge their sound for yourself.