Under The Hood - Kemper Profiler Main Manual

PROFILING an Amp 305

Under the Hood

In case you enjoy reading about technical details, below is a description of what the PROFILER is doing during the
PROFILING process:
During the first phase, you will hear white noise with a rising amplitude. The PROFILER is now collecting data about
the frequency response of the reference amp. The frequency response will change dramatically as the gain
increases. This is how the PROFILER learns about the circuitry of the reference amp and the frequency response of
the guitar cabinet. Also, the characteristic impedance curve of the speaker, including its feedback to the power amp,
is detected in fine detail.
In the next phase, slowly pulsating white noise is sent to the reference amp. The volume of the white noise is set to a
level at which the reference amp starts to distort. This is how the PROFILER learns about the dynamic distortion
curve of the tubes in the reference amplifier. Using this information, the PROFILER can recreate that curve with the
highest possible accuracy. This is also true for transistor-based, as well as digitally modeled, distortions.
In the third step, the PROFILER sends a complex tonal texture that follows a mathematically based set of rules to
the reference amp. This texture creates unique interference patterns that allow the PROFILER to take a "fingerprint"
of the DNA of the reference amp's sound. The distortions of the speaker, along with the partial pattern of the
loudspeaker diaphragm (also known as "cone breakup" are excited by this tonal mixture. They complete the
characteristic interference pattern that the PROFILER will reproduce faithfully, once the measurements have been
taken.