French term (edited): circuit bouchon

In radio-frequency systems (oscillators, tuned amplifiers, filters, etc.) a circuit bouchon is basically an inductor (L) and a capacitor (C) connected in parallel, which offers high impedance at a certain frequency determined by the values of L and C – and therefore ‘blocks’ the flow of current.
The standard English term is “tank circuit” – where ‘tank’ alludes to the idea that the circuit ‘stores energy’. What’s really happening is the energy flows to and fro between the L and C, like water sloshing from side to side in a tank, until the movement subsides owing to the energy lost (in the form of heat) in the internal resistance of the components (similar to how baffles in a water tank reduce the movement of the water).
It is often impractical to build a tank circuit for use at low audio frequencies, owing to the physical dimensions of the components needed. However, the ST is describing a “device for transforming characteristics of an audio signal” by means of “computer processing the audio signals before sending to loudspeakers”. IOW, the system is doing a software simulation of the functions of a variety of audio hardware components. And a circuit bouchon that cannot reasonably be built in hardware for audio frequencies can be simulated (emulated) by software where the only ‘size’ limit is that of the numbers that can be represented by the processor.



--------------------------------------------------
Note added at 6 hrs (2022-06-24 13:53:44 GMT)
--------------------------------------------------

@Asker: There are other more 'scientific' terms for this ('parallel L-C resonator', for example), but 'tank circuit' is readily understood by folk who design or build such things - and in terms of jargon usage is in the same league as the French circuit bouchon.