Sampling a Real Amp with a Modeling Amp Question

[Steve Haynie]

How long does it take someone to sample an amplifier like an old Marshall with a Kemper or other modeling amp?  

[Dutchman]

From what I've witnessed you plug the real amp into the Kemper push some buttons turn some knobs and it makes noises like R2D2 with the shits and then it's all over. It just profiled your amp. Less than an hours time from start to finish.

[tbonesullivan]

Does it just do a profile at a specific level of gain, or is it able to profile that too somehow? I've always been kinda mystified by the process, just like how they create speaker cabinet impulse responses, and add in all these options for microphone type, microphone location, and so forth.

[JGale]

Methinks they are modeling the dynamic response of the various components of the signal chain as they react to reproduce a specific input, a known baseline they can subtract from the full signal to get just the changes in the overall response pattern due to the components contribution.

Coming up with a base sound profile to apply these variations to should be easy: just look what Tech21NYC has been able to accomplish in the analog realm.

Not that I know squat aboot this.

[JGale]

But if you think about it in the digital realm, you only have two numbers to be concerned with,

t or rather delta-t since the time interval is constant so this number is constant and never needs calculating, just synchronization for accuracy.

y the value of the height of the waveform occurring at time t, and a number with a considerable amount of decimal places to the right. It’s the influence of any algorithm on the calculation of those decimal places that results in the “sound” you receive after decoding to analog.

Again, YMMV.

 

 

 

#disomegoodshitmon

[JGale]

Also, if you listen to an IR signal, they can be rendered into WAV format, they are very, very short and brutal, soooo, they must be applied to the calculation at every step (?). Very weird technology.
 

More study is indicated.

[burningyen]

Michael Britt offers some of the best Kemper profiles that I've used. In this vid he shows his process, which involves about 1 minute of the Kemper sending test signals into the amp and about 45 seconds of him playing random stuff to help refine the profile. Most of the time is spent dialing in the amp and setting up the mics and other outboard gear: