Subsequent EQing of speaker impulse responses?

120dBRockNRoll · Jan 2nd 2017

Hi everybody,

I have a general question (not only about the Kemper) related to speaker impulse responses: does it make sense, to EQ an exisiting speaker impulse subsequently?

The special application in this case would be to optimize an IR for a DigiTech GSP1101, which is used by our band's other guitarist. The currently used IR is almost ok, but needs some slight EQ correction (high- & low pass), that always has to be applied by an external/additional device, because the GSP1101 doesn't have a separate EQ for the cab sim output.

My idea would be, to apply an EQ to the "almost ok" IR file and then use it in the GSP1101 (or Kemper...), so we could get rid of the external EQ.

Has anybody of you tried something like this? Is it a suitable idea or complete nonsense?

Michael_dk · Jan 2nd 2017

I think it should be definitely possible. You can make impulse responses from plugins I think, so why not from a plugin chain consisting of an IR loader with your current cab, followed by an EQ rolling off a suitable amount of lows and highs?

120dBRockNRoll · Jan 2nd 2017

Thank you, Michael!

My idea was, to EQ the existing IR file directly: load it in e.g. Wavelab, set up the eq and apply it, store the IR and load it to the GSP1101.
But your suggestion definitely should work... I'll give it a try.

tylerhb · Jan 2nd 2017

as long as you make sure you are not clipping the signal this is no problem.

120dBRockNRoll · Jan 2nd 2017

Quote from tylerhb

as long as you make sure you are not clipping the signal this is no problem.

Do you mean the process described by Michael or my idea about the direct EQing?

tylerhb · Jan 2nd 2017

This would be true for each method. IRs are often normalized to max volume. Adding EQs without level adjusments can easily result in clipped IRs. And those sound REALLY nasty...

120dBRockNRoll · Jan 2nd 2017

Ok, thank you. As I just want to cut off the low and high end this should be no problem in this case.

Lokasenna · Jan 2nd 2017

I've EQed impulse responses a few time as well, works fine.

120dBRockNRoll · Jan 8th 2017

I EQed the impulse responses... before the sound was quite good, but now it's awesome!
No more external EQing needed, perfect!

I also clipped (just 1 dB) one IR intentionally: sounds really horrible!

LiamThompson · Jan 9th 2017

Yes I've had this done for myself by my brother before, he added a touch of mids around 800 and a little cut around 220 and a little bit high shelving to remove a touch of fizz.

Not sure exactly how he did it but it wasn't hard he said. I don't think he just added these cuts to the actual .wav though. I'm sure he loaded it up within Pro Tools I sent him my wave I recorded with the Kemper with the cab section disabled he then tweaked the impulse with equal till it sounded right then I think he either tone matched the .wav or something. I'll ask for you I can get hold of him quick enough.

tylerhb · Jan 9th 2017

Quote from LiamThompson

Yes I've had this done for myself by my brother before, he added a touch of mids around 800 and a little cut around 220 and a little bit high shelving to remove a touch of fizz.

Not sure exactly how he did it but it wasn't hard he said. I don't think he just added these cuts to the actual .wav though. I'm sure he loaded it up within Pro Tools I sent him my wave I recorded with the Kemper with the cab section disabled he then tweaked the impulse with equal till it sounded right then I think he either tone matched the .wav or something. I'll ask for you I can get hold of him quick enough.

If you load the IR within your DAW you will have to create another IR afterwards. Using something like Wavelab will allow you to create a EQ template and batch process a unlimited number of IRs in almost no time.

LiamThompson · Jan 9th 2017

Quote from tylerhb

If you load the IR within your DAW you will have to create another IR afterwards. Using something like Wavelab will allow you to create a EQ template and batch process a unlimited number of IRs in almost no time.

Yes that sounds like what he did.

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