Mapman, let's take the BrickWall surge suppressor/line filter that I use as an example. Its specs that are relevant to noise filtering, which are certainly measurable as well as probably being analytically predictable to a reasonable approximation, are as follows:
But can they, or any other manufacturer of such products, predict with any confidence what sonic benefits and/or side-effects will result when a product having those kinds of specifications is used in an arbitrarily chosen system powered by AC having arbitrary and unknown characteristics? The answers to those rhetorical questions seem clear. The bottom line, IMO, being as you stated in your last sentence :-)
Best regards,
-- Al
EMI/RFI Filter Response (bi-directional, wave tracking): With 50 ohm Rg load: 3db at 5kHz; 26dB at 100kHz; 38dB at 300kHz.As with most designs, presumably those characteristics were chosen based on what the designers considered to be a preferable set of tradeoffs between the likelihood of audible benefit; the likelihood of undesirable side-effects; development cost; manufacturing cost; parts availability; physical characteristics; target selling price; marketability; profitability; utilization of available human, equipment, and intellectual property resources; etc., etc.
Let-Through Slew Rate: 5,000 volt/µs disturbance reduced to 28v/µs within AC power wave envelope, and less than 10v/µs outside the power wave envelope.
But can they, or any other manufacturer of such products, predict with any confidence what sonic benefits and/or side-effects will result when a product having those kinds of specifications is used in an arbitrarily chosen system powered by AC having arbitrary and unknown characteristics? The answers to those rhetorical questions seem clear. The bottom line, IMO, being as you stated in your last sentence :-)
Best regards,
-- Al