Aguilar: What the heck are IRS and why do bassists love them so much?

Have you ever been to a party or family gathering and everyone there seemed to be talking about some shared experience, like a movie, TV series or book that you were unfamiliar with? Not wanting to admit that you had no idea what they were so excitedly talking about you laughed when everyone laughed, sighed when everyone sighed and kept looking at your watch to see when you could sneak out at a socially acceptable moment.

A similar thing happened to me years ago when I was hanging with a group of bass players, and they were all talking about this thing called “IRs”. Even though I had been playing professionally for over three decades at the time I had no idea what they were talking about, and my fragile ego would not allow me to ask them what IRs were. After I said “goodnight” and headed home I hurriedly started researching this technology that was new to me, and I am so glad I did!

Even though IR’s have become a common part of today’s musical dialog you might be unaware of what they exactly are and how they can help you better express yourself as a bass player. So let me save you from the social embarrassment I suffered and share with you what I have learned.

IR is short for Impulse Response, which I am fully aware doesn’t clear things up, so let me go a little deeper. Technically, an IR is a file that captures the sound of a cabinet, including details like where a microphone is placed in front of the cabinet and even what microphone is used. Think of a cabinet impulse response (IR) as a "sonic fingerprint" of a speaker cabinet. It's like taking a photo that captures the unique way a bass cabinet affects sound, much like how different rooms have their own echo when you clap your hands in them. This "snapshot" lets you apply that cabinets sound to your signal, so you can make your bass sound as if it’s being played through that particular cabinet, no matter where you actually are. This means that bassists who have access to IR technology can hear what their basses sound like going through virtual cabinets, which opens an exciting new world of sonic options.

You can find IRs included in a variety of hardware devices like amplifiers, computer interfaces and foot pedals, as well as software programs primarily design for use in DAWs. In fact, there is a good chance you have heard IRs used on your favorite bands’ albums and did not even know it!

So how can this technology help you? Well, if you play at churches or venues that are going “ampless” you can now use IRs to give your bass the sound of a virtual bass rig, whether it is for the audience to hear or your in-ear monitors. Another valuable use of IRs is for studio recording, particularly for home studios where space is hard to come by. Imagine being able to choose between a variety of bass cabinets for the track you are recording without having to move furniture or even having to leave your comfy chair!

I must admit that it took this “old dog bassist” a minute to understand IRs and fully appreciate how they can enhance my musical experiences. They are definitely not a fad and I will be using them more and more on stage, in the studio and in my home. Will they replace my actual bass cabs? Not on your life! But I have always felt that the best carpenters have the most tools, and that is just what IR technology is – a tool.

Story by Dale Titus

Dale has been a professional bassist for 40 years and during that time was an instructor/counselor at the Bass Institute of Technology, a freelance writer for Bass Player magazine as well as the Editor of Bass Frontiers magazine. He also released The Ultimate Beginner Series for Bass videos and book for Alfred Publishing, as well as the Everything Bass YouTube channel.