WarOfAttrition
Well-Known Member
Can someone please explain what these are? 
What is an impulse response?
- Thread starter WarOfAttrition
- Start date
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An impulse usually consist of the text "impulse response" being put into the google search bar in your upper right corner of your browser. I usually like to type this in and click search. After that I will usually read the wiki and instantly my guitar tones sound djent.
Go To Bed Jessica
Well-Known Member
Read all about it and a new "profiler" which uses that technology here:
Profiler | Kemper Profiling Amplifier | Guitar Amplification Redefined
Interesting stuff, that seems to be taking a different approach to the usual modelling route.
Just to clarify (as it seems they don't really use the term "impulse response" on that page) - a source (in this case, the Kemper amp itself) is connected to an amplifier and a microphone set up in front of the amp. The source sends a test signal to the amp, which is captured by the mic. The comparison between the original signal and what is picked up by the microphone allows the profiling software to produce an Impulse Response, which tells it exactly how the ampifier reacted to the various sounds in the test pattern. This IR can then be loaded as a profile, giving you a virtual version of the amp you recorded. You can also introduce pedals or whatever else into the signal chain as long as they are used in an Always On fashion. The speaker cabinet itself is obviously part of the profile, as is the microphone used to record it.
Admittedly this isn't something I have been following closely, but I wasn't aware of any other devices around which do this.
To the poster who suggested that you should create an impulse response of your amp before selling it - what software/hardware would you being using to do this?
Profiler | Kemper Profiling Amplifier | Guitar Amplification Redefined
Interesting stuff, that seems to be taking a different approach to the usual modelling route.
Just to clarify (as it seems they don't really use the term "impulse response" on that page) - a source (in this case, the Kemper amp itself) is connected to an amplifier and a microphone set up in front of the amp. The source sends a test signal to the amp, which is captured by the mic. The comparison between the original signal and what is picked up by the microphone allows the profiling software to produce an Impulse Response, which tells it exactly how the ampifier reacted to the various sounds in the test pattern. This IR can then be loaded as a profile, giving you a virtual version of the amp you recorded. You can also introduce pedals or whatever else into the signal chain as long as they are used in an Always On fashion. The speaker cabinet itself is obviously part of the profile, as is the microphone used to record it.
Admittedly this isn't something I have been following closely, but I wasn't aware of any other devices around which do this.
To the poster who suggested that you should create an impulse response of your amp before selling it - what software/hardware would you being using to do this?
Last edited:
Stealthdjentstic
Banned
Basically a virtual cab.
WarOfAttrition
Well-Known Member
Thanks! By the way ST3MOCON I am not going for a djent tone at all, I am just wanting to know what an IR is because I was looking up the DAR FBM 
DrJustice
New Member
Ok - out of lurker mode...
An impulse response (IR for short) is the response that something gives if you subject it to a single 'infinitely' narrow pulse (very narrow in practice, say a BANG!). E.g., if you explode a balloon in a concert hall, the sound that the hall gives as a response is your IR. For a concert hall it's quite obvious what the IR consist of then - it's the echoes and reverb from that single impulse. To capture the IR you simply record the sound of the response. Likewise, if you send an impulse through a speaker the speaker will emit an IR that reveals it frequency and phase characteristics. The Axe-Fx uses IRs for speaker cabinet emulation.
A captured IR (actually a sound sample) can then be used to transform another sound (by a method called convolution) so that it takes on the characteristics of the IR. If you convolve your guitar sound with the IR from the concert hall, you get a reverb that is the exact same that you'd get in that hall. You may have heard about 'Convolution reverbs' - they're in vogue now.
The Kemper Profiling Amp does not use impulse responses for the amp profiling.
Taking an impulse response only works for linear systems - that is, not with anything that distorts, compresses or otherwise plays havoc with the dynamics of the signal. That is why the Kemper needs to use other methods for profiling. It uses test tones in combinations and sweeps to reveal intermodulation distortion products (and some more 'secret sauce'!) that can capture the characteristics of an overdriven (non-linear) amp.
DJ
--
An impulse response (IR for short) is the response that something gives if you subject it to a single 'infinitely' narrow pulse (very narrow in practice, say a BANG!). E.g., if you explode a balloon in a concert hall, the sound that the hall gives as a response is your IR. For a concert hall it's quite obvious what the IR consist of then - it's the echoes and reverb from that single impulse. To capture the IR you simply record the sound of the response. Likewise, if you send an impulse through a speaker the speaker will emit an IR that reveals it frequency and phase characteristics. The Axe-Fx uses IRs for speaker cabinet emulation.
A captured IR (actually a sound sample) can then be used to transform another sound (by a method called convolution) so that it takes on the characteristics of the IR. If you convolve your guitar sound with the IR from the concert hall, you get a reverb that is the exact same that you'd get in that hall. You may have heard about 'Convolution reverbs' - they're in vogue now.
The Kemper Profiling Amp does not use impulse responses for the amp profiling.
Taking an impulse response only works for linear systems - that is, not with anything that distorts, compresses or otherwise plays havoc with the dynamics of the signal. That is why the Kemper needs to use other methods for profiling. It uses test tones in combinations and sweeps to reveal intermodulation distortion products (and some more 'secret sauce'!) that can capture the characteristics of an overdriven (non-linear) amp.
DJ
--
Go To Bed Jessica
Well-Known Member
Cheers DrJustice - good reply.
Everyone, listen to this guy!
Everyone, listen to this guy!
