Exactly! a dynamic high frequency expander. The video above does not demonstrate the dynamic HF aspects of this processor, because he is only using steady state amplitude for the input signal. Here is a copy of my post from the thread I linked to above:
The
BBE Sonic Maximizer uses a state-variable filter to divide the input signal into three bands (bass, mids and highs). It then remixes the bass signal (with its own level control) with the mids signal (no level control) and the highs "process" signal. The highs "process" signal has a level control along with a voltage controlled amplifier (VCA) that automatically adjusts the high levels.
BBE has JRC manufacturing most of the above circuitry on an IC, the NJM2153.
From the NJM2153 data sheet:
*************************************************
The NJM2153 is a sound enhancement audio processor for
professional audio equipments. It regenerates high definitive and
nearly real sound.
The internal VCA (voltage controlled amplifier) suppresses the
boost gain in high band to reduce noise when faint signals are
inputted.
The NJM2153 is suitable for mixer and effecter for musical
instruments, and high-end audio equipment requiring low distortion
and wide dynamic range.
**************************************************
The VCA on the high frequency band looks at the full-band input signal level and "turns-up" the high-band "process" signal level for stronger input signals and "turns-down" the level for weaker input signals. Acting more like a dynamic high frequency expander. If you look at the video again you will see the high frequencies flutter a bit as the signal generator sweeps the range. So there is a bit more going on than what he is demonstrating in his video. If he adjusted the generator levels you would have seen how the circuit was designed to operate.
I think that some people with a hissy signal chain may benefit from this processor, because it cuts HF levels for low amplitude signals. I had a guitar player in one of my bands that used it just for this purpose. It is a dynamic signal processor and does more than a simple EQ. If he demonstrated the dynamic functions of this processor it would have been an informative video... otherwise it is a misleading demonstration because he is entirely missing the scope of what this unit is designed to do.
-Frank