Mike “Dr Bonkers” Santasiero is the author of this article. Please see the About Us page https://www.drbonkerssoundlab.com/about/ and Portfolio https://www.drbonkerssoundlab.com/portfolio/  page for more details on this author. Click on the grey tabs with words in each page to expand the sections for more info.

Before I entered into the business of creating bass or guitar cab impulse response (IR) files for others to use, I spent a lot of time and money purchasing dynamite packs from many of my esteemed colleagues in the business as well as trying out many people’s cool free impulse response (IR) files of certain guitar or bass cabinets captured with certain speakers.

Here is the methodology I used to get workable sounds for my projects and playing enjoyment relatively quickly, without going down the rabbit hole of spending countless hours and days agonizing over which bass or guitar cabinet impulse response (IR) file sounds better in a particular pack:

  • If you are a Fractal Audio Systems® Axe-FX II™, II XL+™, or AX-8™ user, I highly recommend trying out all 8 scenes of each preset I offer in the Interesting Amp Pairings folders in Combo and Fractal Audio Systems® versions of the files.
    • At the very least you may find an amp and cab combination along with drive or FX that you may find inspiring for your playing pleasure or a project.
  • If you are a WAV file user with other hardware or software, or using others’ Fractal Audio™ presets is not something you like to do, then start auditioning the cab impulse response (IR) mixes files I provide using an amp simulation that is a “go to” choice for you with all the tone controls or EQ flat (so that you can really hear the effect the IR has on your tone with your guitar, pickups, strings, and playing style)..
    • Use the HypeReal™ mixes first as they should be the most lively with the most dimension like a real cab.
    • Second, if the HypeReal™ mixes, don’t inspire you, go to the Choice Mixes folder and audition cab impulse response (IR) mixes that were closest to what you liked from the other folder.
      • All Choice and HypeReal™ WAV IR mixes use 500ms single mic files as their source.
        • If you have software or hardware that uses a shorter length IR file, have no fear as the software included with your IR loader usually truncates them automatically to the IR length file you need 99% of the time.
  • If the ready made mixes are not your thing, find the ones you like the best and explore single mic IR files for those mics.
    • I usually give you list of Single Mic choices as well that I thought work best to my ears, but you may feel differently.

When do I use 200ms versus 500ms versions of single mic guitar or bass cabinet impulse response (IR) files?

According to those who know the math, you should get the same audible results with both length cabinet impulse response (IR)  files. However some claim the 500ms version has a tighter bass response and more accurate treble response. So file length is a decision you will need to make with your own ears using your own monitoring situation.


Which sample rate and bit depth combination of bass or guitar cabinet impulse response (IR) files should I use with my hardware or software modeler/IR loader?

Please read your manual for hardware or software modeler/IR loader and make the appropriate choice. If you are using an IR loader plug-in to re-amp in a digital audio workstation (DAW), please use the same sample rate for your cabinet impulse response (IR) files as the rest of your session tracks are recorded using, in order to avoid any digital audio glitches or slower computer performance.


Which mic position is the “best” to use when selecting guitar or bass cabinet impulse response (IR) files?

General observations of recording engineers with certain speakers are:

  • Cap position – has the most mid-range and treble content.
  • Cone position – usually has a gentle roll off slope of -2 dB or -3dB of the mid-range and treble content versus Cap position.
  • Edge position – usually has a gentle roll off slope of an additional -1 or -2dB of the mid-range and treble content versus Cone position, but at the same time treble harmonics seem to be extended.

Certain speakers do not behave according to these generalizations, so you will have to experiment to find what works best for you in your particular playing situation.


Is a Shure® SM57™ or Sennheiser® MD-421™ really the “best” mic to use to capture a bass or guitar cabinet impulse response (IR) file?

Performing with the amp modeler you are using, your instrument, pickups, strings, and playing style, along with the other instrumentation you may be playing alongside in a band or recording mix, either of those microphone brands may work well or they may not work for you at all. There’s a reason I usually offer between 12 and 17 mics per cab per speaker in 3 mic positions as a practical offering, so you can find the best sound for your playing in your unique situation.

Don’t go by what others tell you on the internet. You are a musician, so use your ears and listen critically. I give the widest variety of tonal options on the market for a reason, so that you can invest in my cab packs with confidence that you will have exceptional if not workable sounds from my guitar or bass cabinet impulse response (IR) files.


If I am a Fractal Audio Systems® Axe-FX II™, II XL+™, or AX-8™ user, why should I buy the Combo pack rather than either the WAV only or Fractal Audio™ only guitar or bass cabinet impulse response (IR) file packs?

If you want to be able to mix single mic files and have future-proof collection of guitar or bass cabinet impulse response (IR) file packs, then investing in just the Fractal Audio® only packs I offer will not let you do those things. If you want guidance regarding which Fractal Audio® amp models are cool to use with a particular cab or you want ideas for different effects blocks settings, & signal chaining, then you will be missing all of that great content if you invest in only the WAV cab packs. I would love to be able to support other modelers in the way that I support the Fractal Audio® platform. If you invest with me now, eventually in the future I will be able to support other modelers as well with similar combo packs.


Happy playing,

Mike “Dr Bonkers” Santasiero

Use of Fractal Audio Systems®, AX-8™, Axe-FXII™, and II XL+™ are owned by Fractal Audio Systems® and mentioned on this site under the terms of fair use. Shure®, SM57™, Sennheiser®, and MD-421™ are owned by their respective corporate entities and mentioned on this site under the terms of fair use. The trade name of HypeReal™ in the context of Cabinet Impulse Response Packs as well as the actual files for sale on this website are the intellectual property of Dr Bonkers Soundlab LLC® and may only be used under the terms of the EULA.