Freesound Forums

Very probably a no, but still worth asking.
What is the legality of making our own impulse response of hardware? Such as reverbs or amp simulators especially those which may be using convolution / impulse responses to make their effect?

To clarify, by re-sampling I don't mean playing someone else's IR and recording the IR's audio directly. I mean re-building one by sending our own audio impulse be it a burst, click, or sinesweep to make our own IR.

I presume it's very similar case to romplers, however this is a bit less straight forward, where different IR techniques could be used, probably affecting the result along the way, it's also not a direct copy of sound, after all the effect unit is by default silent. We're getting back an alteration of our own sound we're emitting.

I don't know if it is or isn't copyrighted, but I think it ought to be. If one is buying/renting expensive amps and mics or reverb equipment to just be copied by re-doing the easy affordable process to have a intended same result, it's obviously unfair and stealing.
Anyone doing that would probably be happier just getting their hands on the original IR which would be copyrighted.

But I could be wrong. It also sounds weird to copyright a timbre or reverb (not the hardware or the logic to make it, but effect itself).
What do you think? Cheers!

Hi! That's an interesting question. I hadn't really thought about it. So I won't say for sure. I know that, for example, the ALTIVERB convolutional reverb has an IR of various equipment. I don't see much point in it, but... If it exists, it probably means that someone needs it. I make impulses of a living environment.

It is not possible to use a normal musical recording (such as a choir performance) as a true impulse response, because a proper IR requires either a sine sweep or a sharp impulse like a clap. However, it is possible to create an interesting “pseudo-IR” by isolating the natural reverb tail from the recording, trimming and normalizing it, and then loading it into a convolution reverb. This won’t produce an accurate room IR, but it can result in unique and creative reverb textures.

It is not possible to use a normal musical recording (such as a choir performance)

I don't mean to capture a sample of a reverbed sound from a musical source and try to make a IR out of it.
I mean making an IR by sine sweep or impulse though a device that produces reverb (or tonal change like an amp simulator). Specifically one which might already be using loaded impulse responses to create it's FX.

An example would be.
I make a "acoustic" IR of a room.
I load that "acoustic" IR in a convolution reverb plugin.
I playback an impulse though that convolution reverb plugin using my "acoustic" IR.
I record the reverb response of that digital impulse. I have a new "digital" IR emulating the reverb of my VST (which itself emulates the acoustic reverb of a room)

Another would be,
I meet a friend on stage, he recorded a sine sweep of his guitar amp using his ribbon microphone. And de-convolutes it to make a IR. Maybe even does some edits in DAW (mixes it with another IR, or adds a splash of reverb). He loads it into a Boss IR-2 so he can conveniently transport his tone on tour.
I think it's a freaking awesome tone, so with his permission I plug in my player and recorder to the pedal, record a sine-sweep, de-convolute it at home, and load it into my daw with a STL Tones NadIR (Amp sim VST). I believe my IR would be close enough to the IR he made/loaded into the pedal.
(Didn't test this in practice, maybe I'm missing something)

I think those two scenarios are in theory possible.
Now replace my own IR with a setting I like in ALTIVERB convolution reverb VST.
And my friend giving his permission with a stock amp-sim on the Boss IR-2.
While I wouldn't have the original IRs, and would be recording the processing of gear/software, I believe this would be problematic on a copyright basis.

Similar examples, but more ethical and probably allowed, would be making a IR though a reverb pedal I like. Or the tone of an amp via sine-sweep though its DI out. Same ideas, making IR's of their effect, but their process isn't by using an IR.

If you record a very expensive hardware unit for your own use - completely OK.
If you want to share it - include an honest note / disclaimer, for example:

“This impulse response captures the sound of my hardware unit.
It is not affiliated with or endorsed by the manufacturer.”

Yep!
I think recording hardware units is fine. I'm not even sure mentioning the unit itself would be required (though preferable).
However I'm not sure if the hardware unit uses IR's to do its effect. There would be way less variables there than a tweakable analog unit or digital one. If a hardware or software uses an IR, wouldn't making a IR out of it come very close to its original IR and be somewhat protected?

I'm interested in this topic from a different angle. I'm trying to create an impulse response of the unique reverberation of an Estonian church, but I currently can't easily return there to record a proper sweep. What I do have are some choir recordings made on my phone, and I’m hoping I can extract a pseudo-IR from them. It won’t be 100% accurate, but it might produce an interesting result. I’m quite excited to see how it turns out. I don’t intend to share the IR publicly, it would be only for my personal use. The pseudo-IR would be made from those mobile phone choir recordings.

Sadiquecat wrote:
What is the legality of making our own impulse response of ... amp simulators ...

The EULA usually has terms prohibiting "reverse engineering".
So not a copyright thing, but going against the terms of the contract.

Who's EULA?
That might solve it for most VST's or softwares. Though when buying hardware I doubt there would be any.
Where may I read more about this?

https://www.cisa.gov/sites/default/files/publications/EULA.pdf

Thanks !

EULAs restrict how you can use the software. EULAs often include clauses that
limit the number of computers you can load the software on. They sometimes also
prohibit reverse engineering for the purpose of creating compatible software. In some
cases they prohibit software testing and even publishing the results of this testing.

This would still be software/EULA dependent.
If we take this public awareness of EULA's as an example : prohibiting reverse engineering for the purpose of creating compatible software. I think this would apply for the code of how a IR is applied/used or similar features/macros, (then wouldn't that be the role of a patent?) I'm not sure this would apply for none code but material such as an IR. I guess it would be reverse engineering though. And the disclosure "In some
cases they prohibit software testing and even publishing the results of this testing." would perhaps encapsulate a IR as testing of the software's reverb / amp sim capacity.

So yeah I guess softwares could be protected from remaking IRs (maybe even making IRs) due to their EULA's.

I still wonder for Hardware?