What is a Pleiades microphone filter?

In many cases the signal from even a very high quality microphone is completely different from what the producer or listener has in mind. If a wrong for the purpose of a high quality recording (not sounding correct to the listener's brain) is fed to the signal chain (mic preamplifier etc) it may be too late to correct effectively without loosing quality. The reason for a microphone not sounding correct without a filter may be: Proximity bass boost effect, human voice recorded at low intensity but reproduced at high intensity, voice effort effect (when we sing sofly we create a broadband acoustic output, when we sing loudly we create a mid centered norrower band acoustic output. Great microphones such as RCA 77DX, Shure SM7 have the switchable bass reduction filter inside them so as to help the microphone preamplifier get the best possible signal or near to it. The Pleiades filter is just this, the inductor filter of say a 77DX, or SM7 etc being external put inside an XLR female to male barrel adaptor so almost any microphone can be used. The inductor is connected as on the classic microphones across the output of the microphone. For great high frequency detail the gentle slope high pass L,R (inducor in series with resitor) can be cascaded. So for example the signal path can be: microphone - Pleiades low cut filter - Pleiades gentle high pass filter - mic pre. Recently it was studied that the SM7 uses an inductor of 240mH. Recent Pleiades experiments showed that an SM58 at 16in can sound amazing with a 175mH to 175mH 1:1 transformer just after the mic and before the preamplifier. A high pass filter may not be needed as the capsule of the SM7, SM57, SM58 has an inherent high frequency peak. A Pleiades filter are usually put inside Neutrik XLR modules to create a nice looking XLR barrel adaptor that is small, light, beautiful with a color painted cetre for indentification of turnover frequency. The inductor is wound on a toroidal core so there is absolutely no noise, or noise picked up electromagnetically etc. Anyone can make a Pleiades filter, it is public domain as any other euroelectron or Pleiades idea that does not infringe a 3rd party.