Sennheiser MD441 U3 to Pleiades (130Ω,40mH) filter

Unbelievable sound at 6-12in.


Smaller distance a Pleiades 333mH was connected in cascade for proximity compensation.


For even smaller distance, close to 2in another 333mH was connected in cascade.


Especially at the larger distance there was some hiss. It should be less if the Pleiades V6 head amp is included before the Sony mic input.


Signal path, setup:


Male singing voice at 2-12in - Sennheiser MD441 U3 - Pleiades (130Ω,40mH) - (Pleiades L, see text) - Phase inverting XLR adaptor used for correct phase through headphones - Sony TC-D5 Pro - Sennheiser HD580


Amazing sound on vocals. In the background the Pleiades 2N3053 - PHILIPS AD5046N could be heard playing music as the mic was pointed to the relevant room with great fidelity.


Another test was the MD441 U3 driving only 2 cascaded Pleiades 333mH filters. The sound was unacceptable. (The problem that was mentioned in previous posts). It was nasal and mid heavy in a bad sense. When the Pleiades 130Ω, 40mH is added by being cascaded everything falls in place.


So we may say that we have a Pleiades R,L for Fletcher Munson and voice effort curves and Pleiades L for compensating the proximity effect.


A good thing may be that since the low Z input of the Pleiades V6 is made of a primary transformer winding of 140mH proximity is already compensated for small distances. The 130Ω,40mH needs only be connected in parallel (by a switch). See next post.