Bass correction filter is a better term to low cut filter for microphones. BCF, ΦΔΒ (φιλτρο διορθωσης βασης), φδβ

At your risk. This term was found in the book Microphones by BBC producer Alec Nisbet. In fact the proximity effect of directional microphones does not only emphasize bass but mid bass and mid frequencies too. This can be clearly seen on the Neumann Microphone manual by Bore, Peus. So it could even be caleed a bass, mid correction filter instead of a high pass filter. In fact the Pleiades gentle slope (130ohm,20mH) inline filter does this. It starts at a mid frequency dictated by an inductance of 20mH and gently deemphasizes as frequency is decreased, slope depending on the value of resistance R, for example 130 ohms. L is in series with R (in fact 2 R/2 on each side for balanced symmetry) and the total is connected across the output of the microphone ie in parallel. Yesterday Shure SM58 was recorded for a trial vocal. At 24in distance from head, above head say 30 degrees. Without any filter (due also too equal loudness curves, voice effort curves) sound appeared bass and mid heavy to listener's brain. (Monitoring is with celestion Ditton 150 driven by one transistor Pleiades 2N3053 power amplifier). Adding an inline Pleiades 175mH:175mH transformer decreased bass but mid still appearted emphasized. Adding one after the other the Pleiades (130ohm,20mH) removed mid heaviness but sound was lacking in body. Then leaving just the (130omh,20mH) bass, mid correction filter gave the best result. High frequencies would now come through in a sparkling way like Whitney Houston's 1st album on female and male voice which sounds fantastic, Is it recorded with Shure Sm7? Male voice on this experiment was singing one of the male voices on this album, recording to Sony TC-D5M which has a frequency respone up to 16KHz on type Ii cassette. Anyway, Shure SM59 sounds so far best with both filters cascaded. very nice treble definition, giving a smooth airy airy edge. But according to yesterday's experiments recording with the BeyerDynamic M260.80, at 24in, with both Pleiades filters gave the best result. Amazing detail smooth and sparkling edge to voice. Ribbon mics deserve this as the moving part is of so low mass, the ribbon itself which generates the EMF 9electromotive force), the voice voltage signal itself. From an extra thin conductive aluminum ribbon suspended inside a permenant magnetic field. As it vibrates by singing voice, electrons on it start vibrating too. As electrons now have velocity at every instant in time, each electron creates a magnetic field around it. Which varies at evey instant in time. This magnetic field interacts with the permenent magnetic field and each electron has a force and is pushed along the ribbon. This force varies at every instant in time. It is as if each electron is now dancing along with the acoustic music signal from the singer's voice. Electrons dancing up and down at the edges of the ribbon are the electric signal output which is sent to the voltage step up (impedance matching) transformer inside the mic. There must also be a damping effect on the electrons due to Lenz's law, so the so light electrons follow the singer's voice pretty accurately! Further reading: Feynmann Lectures in Physics Vol.2