Preparing a Pleiadss LR filter for MD211

It is getting too scientific.


A Siemens Epcos ferrite powder core of similar size as the Magnetec nanoperm 073 was picked up. And an enameled wire of 0.2mm was chosen by chance or first glance.


According to previous experiments a 40mH inductance is aimed for. And then a series resistor of 140Ω will be connected (or 2 of around 70Ω on each side). Then the total will be connected to pins 2 and 3 of a Neutrik XLR female to male adapter. The objective is to compensate not for the proximity effect (omnis do not exhibit the proximity) but for other effects, Fletcher Munson curves, voice effort curves so that the result does not sound bass heavy to the listener's brain [Lowe, Morgan]. The bass heaviness is very easy to verify by singing at not a loud voice and monitoring with reference headphones. The Sennheiser MD211 N is understandably one of the best microphones on the planet and will be used in these experiments connected to the Pleiades V6 electron tube battery powered head amp. See previous posts. The MD211 has possibly complete absence of s problems.


Before winding the 0.2mm wire to a wooden a few inch long thin wooden stick (this helps to wind all the length of wire to the ring core) it was realized that the stick was already wound with a very thin wire from a previous winding experiment. It was too thin to be seen. It can be a very good wire for introducing the required resistance.


But due to haste the 0.2mm was wound on a different wooded stick and the core was already under way. So perhaps the too thin wire will be wound at some other time.


Filling all the space at one layer (100 turns) gave 20mH. Too low perhaps for this experiment but who knows?


Fortunately in the same core drawer was found the same type of core wound with 0.16mm red colored enameled wire. It turned out that it's inductance is 40mH! So again when we rush it takes more time.


So all is set. Or Rather was already set. The 20mH may be used at a different experiment. Τιποτα δεν παει χαμένο.


Neutrik modules will be used to assemble the XLR barrel Pleides LR filter.


Bibliography:


Flat frequency response from producer's brain to listener's brain, Sound Picture Recording and Reproducing Characteristics - D. P. Lowe, K. F. Morgan - JSMPE