Where is the Cinema Engineering EQ 4031-B schematic?

So far it could not be found but information was for the Motwon graphic EQ, Altec graphic EQ, Langevin EQ 151'A which i do not undestand yet.

Still don't know

At your risk. But here is some light. It was decided to try Cinema Engineering EQ 4031-B. If memory is correct it can be seen on a documentary of Motown in the recording studio? Anyway, a Shure SM58 was connected directly to it. Then the output of the EQ directly to the Sony TC-D5M mic preamp in mono mode. Male singer to mic distance was the usual 24in, mic axis 30 degrees above head, towards nose. Surprisingly it worked although there is attenuation in the EQ. Of cource there was some hiss as the Sony recording level control had to be cranked up to maximum sensitivity. At EQ setting out, or both bass and treble controls to 0 the vocal sound was the usual muddy bass due to room acoustics, equal loudness curves, voice effort curves etc. As soon as the bass attenuate control reached -12db (at 100Hz?, bearing in mind that according to Audio Cyclopedia-Tremain, frequency response, attenuation starts at around 1KHz). (Monitoring was in real time trough Sennheiser HD-580 reference headphones while singing.) At -12dB the male voice quality was crispy clear and amazing, reminding of any greatly produced song. Say for exaple Could this be Magic - Manilow. Then a Pleiades one stage K117 JFET mic booster preamplifier was connected just after the mic, before the EQ, using a Canford input transformer and a Neutrik red jack with transformer inside as output transformer. There was no hiss as the cinema Eng EQ was more appropriately driven. Amazing sound again at -12dB low attenuation. The sound really sparkled when boosting also 2 to 4dB at 10kHz on both previous setupss. Then everything was disconnected and the SM57 was tried feeding directly the Sony TC-D5PRO. Again muddy, unclear, prominant mi8d bass, giving the impresion that someone is singing indide a very small space. Then a Pleiades (175mH:175mH) inline bass correcting transformer was insirted between mic and pre. Bass was much better but the mid bass still muddy. Then insited of this transformer a Pleiades (130Ohms,20mH) high pass filter was connected between the mic and pre. Now the vocal sound was much better with definition in mid and high frequencies but still not as good as using the Cinema Eng EQ in the bass register. When cascading both inline filters still the sound was not as good and worse in the mid. So winner is Cinema Eng EQ 4031-B, second best Pleiades (130Ohm,20mH) bass correcting high pass filter. At this point it was realised that the Pleiades (130Ohm,20mH) is a shelving filter of a different frequency than the Cinema Eng. Could a Cinema Eng equivqlent EQ or filter, possibly same schematic too be built inside an XLR to XLR adaptor? WHere is the Cinema Eng schematic?

Not trusting what we see as mic used on studio on a videoclip seems a good idea

At your risk. See for example Where do Broken Hearts go - Whitney Houston video showing a condencer microphone, and compare the Whitney: Inside the Album with Producer Narada Michael Walden video, Narada holding in his hands what looks like A Shure SM7 dynamic (moving coil microphone): https://www.youtube.com/watch?v=uUHKIK4f5AY

A Brief History of Early Motion Sound Recording and Reproducing Practices - John K. Hilliard - Journal of the Audio Engineering Society, Volume 3, Number 4, 1985 April

Very nice paper discribing also the bass, mid bass, mid? heaviness effects created in listener's brain when a microphones is just connected to a preamplifioer with no EQ correction for the Fletcher Munson equal loudness curves, voice effort curves, recording space boominess due to standing waves etc.

Variable Mid frequency correction box or Pleiades vocal microph9one correction box

At your risk. A variable passive filter to correct for bass, mid heaviness due to proximity effect, Fletcher Munson equal loudness curvs, voice effort curves, low frequency small room standing waves etc. It is the usual Pleiades filter but the inductor is a multitap inductor, currently 12 position. Then in series is a 1K military quality potentiometer. Then in series there is provision for 3 swichable capacitors, say 10nF, 100nF, 1uF. capacitors are for creating a Shure SM7 type notch or band reject filter for removing a high frequency peak, or even for attenuating the fundamental of a singing voice. So all L,R,C are in series and the total connected across the microphone output. The toroidal core used is the Magnetec nanocrystaline M-059-03F6. Starting with 2 turns then multiplying by 1.42 to find yhe next number of turns for next tap. 1.42 times 1.42 makes roughly 2 so frequency cutoff is advancing in octaves. So 2 turns 0.6mH, 3 turns 1mH, 6 turns 2.4mH, 8 turns 4.3mH, 11 turns 8mH, 16 turns 17mH, 23 turns 35mH, 33 turns 73mH, 46 turns 141mH, 66 turns 290mH, 94v turns 600mH. Everything with be attempted to be fitted inside an orange color Hammond guitar pedal size aluminum box. Ie the 2 Neutrik male and female XLRs, the inductor under a 12 position 1 pole rotary switch, the 1K potemtiometer, the 4 position 1 pole switch and the 3 or 4 capacitors. Gray-silver colored knobs. Maybe a provision for disconecting the filter by a switch or an unconnected inductor rotary switch terminal for EQ in or out. Further reading for the bass, mid heaviness effects in the listener's brain mentioned in sentence 2: A Brief History of Early Motion Sound Recording and Reproducing Practices - John K. Hilliard - Journal of the Audio Engineering Society, Volume 3, Number 4, 1985 April

Pleiades DK91 9V, 1.2V battery electron tube (electronic valve) microphone booster (pre preamplifier) updates

At your risk. Considering containing everything in an Hammond orange, size of double guitar pedal, aluminium box. Ie the Bulgin 9V and AA 1.2V battery holders, the 2 Neutrik chassis XLRs, 2 octal bases for the input and output transformer, 1 miniature base for the DK91 pentagrid electron tube used in triode mode. (anode is g2 internaly connected to g4). These grids are close to the cathode filament making smooth operation of the electron tube with just Vb=9V. In fact miraculusly anode current is about 30 micramperes when grid is at space potrential, ie unconnected DC wise, only ac signal ie music deriving it through a coupling capacitor. If said control grid is connected to a 8.2 Megohm resistor and other side of resistor is connected to negative terminal of 1.2V filament cathode battery, Ia=90 microamperes, and if at positive terminal, Ia=120 microamperes. So grid 2, grid 4, (and possibly other grids too) is the anode to collect the dancing to the music signal loving electrons. Considering at some later stage making a gift to producer Nerada who was giving all those loving gifts, like talking teddybears to Whitney.

Narada interview, How to get 57 number ones? (discusion on Clive Davis great input towards the end)

https://www.youtube.com/watch?v=Pg1rVxlLXxc