Saturday, May 19, 2018

Variable Pleiades Microphone Wave Filter with 2 degrees of Freedom


Could it be a box with 2 rotary controls? Or 4 including a variable slope CR high cut wave filter by selecting different values of shut C in series with a variable R.

Let's describe the low cut section. The high cut section can be implemented by analogy.


For the low cut section there can be 2 controls. One for the inductance L and one for the resistance R.


The schematic is L in series with R and the resultant connected across the mic's output or voice coil.


Many inductors can be connected to a rotary switch. So with one hand the turnover frequency is adjusted while the other hand rotating the variable resistor adjusts for slope while trying to obtain the desired acoustic result.


Or switching in inductors corresponding to 100Hz, 200Hz, 400Hz in all permissible binary combinations, 8 for example using 3 inductors giving 0Hz to 700Hz in steps of 100Hz.


Or having an XLR female socket and inserting Pleiades barrel inductor filters on top of each other.


Pleiades inductor wave filters have the property that if one XLR adapter is x Hz and the other is y Hz, the resultant of connecting one barrel after the other (ie inductors in parallel), is a frequency turnover of (x+y) Hz. See older euroelectro posts on binary combinations.


See also close posts including one on connecting a fixed LR Pleiades wave filter to the Sennheiser MD211 output before connecting to the Pleiades V6 head amplifier (electron tube, battery powered).



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