Any tips for using these?

I grabbed some packs and I see it's common there are many variations of the same setup. When should one use longer response (500 ms for example) over short ones (100 ms)? What's the difference actually?
What about the quality? Is it OK if I just ditch everything that's not 48kHz? Why bother with higher or lower sample rates?
I came across this pack called VampIRetone, and it seemed quite popular. How did they get these IRs (seems close to the target)? Should you tweak the microphones further when using such files?

 

Last edited: May 3, 2022

What Is A Cab IR And How Do I Use It? (Cab Sim/Impulse Response)

 

So, basically ~20 ms is enough, 100 ms will give you more bass and ambience, and 500 ms is overkill?
What about the sample rate, what more do you get by using 96 kHz IRs?

 

milliseconds are not so important to me but what matters is to simulate a real cab well. Use the IRs in pairs, one with the microphone and the other with the REAR at -10db. This is to better simulate the real sound you would get from a real cabinet (the sound from behind also comes out of the cabinet and is part of what the ear hears).

 

Use the same samplerate that your DAW/interface is set to. I wouldn't say that anything over 20ms is unnecessary, but when you go over 250ms there is pretty much no difference (unless it's reverb IRs).

The different mics and mixes that you usually get with IR packs are just so that you can choose whatever setup you want yourself. Some people like to use the classical SM57+R121 setup or the 2xSM57 (aka the "Fredman technique") so they usually include these single mic files so that you can mix and match whatever you'd like. The mixed files are usually pairs of mics that the developer themselves think sound good and/or common mics to pair with each other.

 

What @Arabian_jesus said, so keep your DAW sample rate (48, 96 whatever) and I'd keep those medium length 100 ms.
The thing with very short ones is that because of the nature of the technology the very low end has low precision.

I totally making this up but say with 50ms IRs you have control only at 0.5, 1, 2 Khz
With 100ms would be 0.25, 0.5, 1 Khz, 2Khz

Again, totally made up the numbers and equivalences but that's the gist of it.

 

Thanks for all the answers and videos. Very helpful.

What about cab simulation (the stuff you see in Guitar Rig, Amplitube, etc.), should you assume it's always of higher quality than the IR sample you can find?

 

Manufacturers also buy IR's on the open market, and since they want to be better than the competition, one assumes that they only buy high quality IR's. In other words they want to sell a very good product, because only then they get enough paying customers.

I would consider high quality to be the use of very good microphones on a high quality recording device without noise.
It depends on who you buy from. There is very good quality and not so good quality.

 

I'm not sure about Guitar Rig, but Amplitube uses IRs now. Most amp sim developers uses IRs nowadays because it's just much better (more realistic) than cab sims. The thing in Amplitube where you can grab a mic and move it around to different spots at a cab is just a UI thing. A skewmorphic UI like that just makes it easier for some people to use it. You are really just blending between a bunch of different IRs when you move it around like that.

The old amp modellers like Line 6 POD and others used cab simulation because it's much less CPU intensive, but we have much more powerful CPU's now. Loading one IR in a IR loader shouldn't use more than maybe 0.1-0.3% on a mediocre/decent CPU.