What is an Impulse Response and how to use it in the Quad Cortex?

Forgive me this noob question, but what exactly is an Impulse Response and how can I utilize it in the Quad Cortex?

I first learned about the existence of IR’s from the QC manual, and ok… by a bit of Googling I understand that an IR is a function on an incoming signal.

So what can I do with the result of that function, maybe a specific example of usage?



To give you an accurate definition from Google:
An Impulse Response (IR for short) is a way you can ‘capture’ the qualities of a guitar amp speaker, microphone, and room and recreate it almost perfectly in the studio or for live performances.

The block for QC factory amp cabs is actually several IR’s. When you move the mic placement or adjust speaker levels within the cab block(s), you are essentially switching between numerous individual various IRs. You would also utilize your own IRs on the QC if you had a favorite cabinet/speaker that isn’t available on the QC. Hope that helps!

Thanks for your explanation. But then, what is the difference between an IR and capturing/profiling? Are both the same thing?

Long story short - they’re essentially the same. IRs refer to the actual file and are not platform specific. IRs also typically refer to speakers or room captures (when used for reverb) and capture/profile is typically used to refer to an amp/preamp/signal chain capture.

An IR is a wave file of a captured/profiled speaker/room. An IR is a specific type of capture/model that is more universal and can be used across different platforms, assuming they’re the correct samplerate/length.

In this case, an IR could be a type of capture/profile, but in this world is typically used to denote a speaker while a “capture”/“profile” is generally used when referring to amps/preamps – but you can also have a capture/profile of a speaker alone too. If that speaker capture is saved as a wave file of a certain type – then it’s an IR.

Just think of IRs as a snapshot of a cab/speaker. Like the above poster said when you move the mics around you’re technically moving between tons of different IRs.

Captures are a snapshot of a signal chain. Think of capturing the amp itself or the amp + cab or pedal + amp + cab. You’ll find the amp gives the general voice of the tone but the cab eqs it just like a normal speaker. Like they said above, you should find other IRs and load them in, you can find some superior ones (just my taste). You’ll also find that if you use an amp without a cab IR it will sound like mess.

@15or20 and @Teatime48 Thank you both for your explanation and examples. For me, it clarifies the differences and similarities between the two terms. :pray: