The Pleiades V6 preamplifier is being conceived

The Pleiades V6 will possibly be the most revealing and lowest noise microphone electron tube preamplifier on the planet.

It will have 2 channels for stereo or binaural and it will be powered by just one 3.7V lithium ion battery for both tubes including anodes. The anode voltage will be close to 3.7V.  It may be said that the preamplifier is a modified H. D. Arnold amplifier for operation with very low anode voltage.

For each channel:

The electron tube to amplify the microphone signal will be the EF183 vari mu pentode connected as triode, i.e. screen grid, suppressor grid and anode connected together. Actually the screen grid does most of the job of collecting electrons as it is nearer to the cathode.

It will employ the fewest components possible for the simplest signal path, close to wire with gain.

Each channel will only have 6 components.

The signal path will be as follows:

Input transformer - coupling capacitor - EF183 electron tube - high MΩ resistor from anode to control grid - output transformer - 3.7V rechargeable battery

Description of each component:

The input transformer shall be made with Magnetec Nanocrystalinne toroidal core. This will permit the fewest possible turns for low noise. The primary inductance will be chosen to compensate for the proximity effect so that many world class dynamic microphones or not can be sung too at a typical distance of 4in with flat ear-brain frequency response and pristine quality. The step up ratio may be of the order of 1:20 for great sensitivity and very low noise.

The coupling capacitor will isolate the electron tube grid from the low resistance of the secondary winding. So the grid will be free to assume its potential from the surrounding charge conditions. The value of the capacitor will be chosen in consideration to the input impedance of the tube which may be of the order of 100K, see tube description.

The high resistor from anode (plate) to grid will take care of the neutralization of the negative charge on grid induced from surrounding electrons and cathode emission traffic electrons (boiling electrons ;). It will make possible the free travel of electrons to anode with just 3.7 volts and will be named Rgh in honor of Hliana for bringing to light the knowledge of the importance of the grid bring positively biased to make electrons free.

The EF183 electron tube triode connected will exhibit an input impedance of the order of 100KΩ depending on the value of the high Megohm Rgh resistor chosen for optimum behaviour. The lower than usual input impedance may prove usuful in damping any reasonance effect of the input transformer. The cathode will be connected to negative ground, no cathode resistor needed this further avoiding the need of a bypass electrolytic capacitor.

The output transformer will be made of a larger Magnetec, Nanocrystalinne toroidal core. The primary will be connected directly to the anode as is done on the Western Ekectric 47 condenser capsule amplifier. This will avoid thermal resistance noise of any anode resistor and no voltage drop. So the anode will be very near to 3.7 volts as the other side of the primary will be connected to the positive 3.7V. 

The heater will also be connected directly to the 3.7 volt battery. The cathode will be underheated operating as is done on the WE 47 and the Neumann U47 at a temperature of the order of 700oC. Aklowledgement to Oliver Archut of Tab Funkenwerk for publishing his measurements of cathode temperatures on his WE 47 article. The low temperature will further increase the sensitivity of the electron tube and further reduce noise. An explanation may be that at such low signals very few electrons are needed to carry the information to anode. If the tube is heated at specified 6.3V the electron trafic around the cathode and near grid will be tremendous and unessasary. It has also been experimentally measured by a 10MΩ Zin voltmeter that it causes the grid to be biased negatively by induction, or in other words the cathode is positive due to the missing electrons that have escaped (see older euroelectron posts).

Inputs and outputs as described above will be low impedance and balanced. So the Pleiades V6 can be connected to any microphone be it ribbon, dynamic, or condenser. The output of the Pleiades V6 will feed the input of any microphone preamplifier in the same manner as a U47 microphone does with its internal preamplifier connected to any microphone input.

A fuse may be needed in series will the battery. A resistor may be experimentally chosen in series with the heater circuit for optimum cathode temperature for maximum sensitivity.

Input and output connectors will be Neutrik XLR. Everything including the 7cm length li-ion battery will fit inside a small aluminum die cast box. The preamplifier may be automatically turned on when 1 or 2 of the EF183 electron tubes are inserted and if just one channel is needed only one tube can be pluged in for half power saving.

The Perfect Musical Temperament?

A good conductor and orchestra does this automatically when they intonate by ear and instruments used have or are made to have nice "harmonics" (the 2nd overtone for example is slightly greater than x2 the frequency of the fundamental by the right amount required by the ear-brain).


How about keyboard instruments?


We can take to our advantage that a correct octave to ear brain system is slightly more than x2 in frequency. This will allow correctly "stretched" octaves (as a good tuner tunes by eliminating beats) which will accommodate slightly "expanded" 5ths and the circle of fifths will close ie Pythagoras's comma will be gone.


In similar words. Instead of trying solving the Pythagoras comma problem we can start with a closed fifth circle (in fact expanded one so that the lowest note will sound in tune to the highest note of the same type to our ear brain). Then built everything around it including specifying and trying by experiment every single note's overtones, for the whole range of the keyboard. Technology makes this now readily possible.


So instead of trying to hit the "target" with the arrow we can throw it where we like (pleases our ear) and then draw a nice target circle around it paraphrasing Brian Eno's words in his interviews.


So how.


We can create notes with slightly more than 2x, 3x overtones, such that they sound correct and pleasing to our ear - brain system.


Then creating a temperament by according (tuning) all notes (everything octaves, 3rds if that can be possible etc) to these notes and their overtones.


It has been tried on the DX7ii and Korg Triton (Pleiades temperament) with very nice results. More work is needed as the DX7ii using algorithm 32 can specify a general overtone structure for all notes but not for every single note. Nevertheless this ahead of its time synthsizer can then be programmed for the frequency of every single note (all note scale). Using contemporary additive synths such as Camelion it should be possible to specify every single note harmonic structure. And perhaps nature which already helps us will help us more and notes and overtones will coincide when we try to tune every single note with the true harmonics of pleading sounding notes.


References:



Discussions with piano tuner Albert Ketenjian


Pleiades tuning for DX7ii and Korg Triton


Various scientific papers found  on earlier euroelectron posts such as Octave Strech by Ernst Terharldt.


The perfect fifths tempered scale, a proposal or already a practice? - Klaus Gillessen.

Pleiades Color Microphone in line EQ filter with Neutrik XLR Modules

Pleiades in line passive microphone EQ, Filter.


The color on the Neutrik modules indicates the optimum mic to source distance for flat frequency response. (Directional microphones exhibit an increasingly large increase in bass the closer the microphone is to the source of sound).


Inside the Neutrik modules is an inductor connected to pins 2 and 3 (live, return) ie in parallel to the microphone signal. The number of turns (difference in external XLR adaptor color) in the internally housed toroidal core adjusts the turnover frequency with a slope of 6 dB per octave to equalize the
proximity effect and restore a flat frequency response for any source to microphone distance.


The 6dB per octave slope is produced by the output impedance of the microphone (usually 200 ohms) and the shunt inductance of the Pleiades EQ filter.


Most microphones may need a Pleiades filter, even omnidirectional ones.


The spectrum of our voice when we sing changes dramatically with how softly or loudly we sing. This is called the voice effort effect. Voice when soft was a tremendous increase in bass and high frequencies.


Additionally the frequency responce curve of our ear brain changes dramatically with sound intensity level.  When something has a high intensity the sensitivity of our ear-brain increases dramatically in the low and high frequencies. These curves are called Fletcger Munson or equal loudness curves.


A screaming baby in danger miles away in a dessert emits a very high midrange only content and the ear-brain of a person miles away has greatest sensitivity in that region at such a low intensity level of the far away sound. So the baby can be heard and rescued.


When the level is different between the acoustical level of a singer recording and the intended end result in reproduction, as is almost always in pop music, we need to EQ.


The Pleiades filters further act as the simplest (almost straight wire) shelving filters when we deviate from the optimum chosen distance. When closer we have a bass shelving filter. When further we have a high frequency shelving filter.


All these effects together with playing with Pleiades EQs and different microphone distance may allow as to have flat frequency responce not from mic to loudspeaker but from the vocal chords of the singer to the brain of the listener.


Reference: Sound picture recording and reproducing characteristics - D. P. Loye and K. F. Morgan - J.S.M.P.E (Journal of Society of Motion a Pictures Engineers, presented at the 1939 Spring Meeting in Hollywood, Calif; received April 17, 1939)

Sennheiser MD21 HL and Pleiades filters

This fabulous microphone was connected with various Pleiades filters.


(Later addition: see also Pleiades R,L filters of much gentler or variable bass cut or high pass slope).


The most natural singing male voice (compensating for the voice effort effect and other bass increasing effects) was with a Pleiades filter of 85mH parallel inductance. The microphone was used at a distance of 1-2in from mouth and a tilt off axis of 45 degrees to reduce the pressure doubling effect.


This inductor was made by winding 200 turns on the black grey Siemens Epcos ferrite core and fitted inside a male to female XLR adapter.


Excellent sound, amazing and loud was also obtained with Pleiades V5.


Setup:


MD21 HL (low) - Pleiades 85mH - Pleiades V4 - realistic disco mixer - HD 580


or


MD21 HL (low) - Pleiades V5 - realistic disco mixer - HD 580     (more input transformer primary inductance may be needed for this omnidirectional microphone as on the V5 it is 47mH)


The Sennheiser MD21 HL is one of the greatest microphones on the planet

In HTML JavaScript statements are commands to the browser

From www.w3schools.com


This is an amazing site where one can learn how to program in (HTML, JavaScript etc).


Αυτός ειναι ένας φανταστικός ιστότοπος όπου μπορεί κανείς να μάθει να προγραμματίζει σε HTML, JavaScript κτλ.

When you are not in a hurry you can do anything - Οταν δεν βιάζεσαι μπορείς να καταφέρεις τα παντα

Towards the end of the film Sally.

Using a microphone held by hand

There are many instances where it sounds much better. Suspending a mic may be an option too if it has freedom to subtly move. Actually there are many degrees of freedom.


If the mic is very still the sound sounds still.
For example micing the speaker of a synthesizer or organ with a stationary stand.


The speaker is stationary, the mic is dead still, which is very unnatural as a real listener subtly moves even if the deviation is a few millimeters . This gives a low frequency Doppler Leslie effect to a real listener which makes the sound alive and it is very easy to verify by experiment. Holding a mic by hand should give more of this effect as a hand cannot be dead still and the hand-mic mass is lower making acceleration easier.

"Stretched" octaves (correct to ear-brain), do they obey an slowly rising exponential law?

It would be nice to investigate experimentally.


A difficulty is that the pitch of a sinewave depends also on intensity or is it a clue?


References on how the ear brain perceives sound can be found in earlier euroelectron posts

Embedding sound creation in HTML

It would be nice and there are some excellent sites for teaching it if one googles with keywords: "HTML code for playing a 440Hz sinewave". Or "Creating sound waves with JavaScript". A very interesting site is http://js.do/blog/sound-waves-with-javascript/.
This allows to edit and hear directly. Amazing laser sounds etc.

It would be nice to adjust those sine waves so that true to ear brain octaves as heard and not exact multiples of 2 which sound flat or sending correctly adjusted midi signals.

It would be nice to create regenerative music (Brian Eno) this way.

Proposed color code for Plaiades microphone equalizers

Pleiades proximity compensating microphone passive equalizers for flat frequency responce from 20Hz to 20KHz at any distance from 4 ft to 0in

                       Red     Orange.   Yellow   Yel/green    Green   Blue    Violet   

Distance of     4ft         2ft          1ft            6in         3in      1/2in      0in

mc for flat 

20Hz-20KHz 

Pleiades 

turnover       25Hz    50Hz     100Hz     200Hz      400Hz       800Hz   1.6KHz

Frequency 

Parallel

Inductor     1.28H   640mH.   320mH     160mH    80mH       40mH     20mH

Inductance

Each EQ is a variable low or high shelving filter by decreasing or increasing the optimum mic to source distance respectively.

Each EQ is implemented inside a Neutrik module female to male XLR 3 part adapter for ease of balanced connection to microphone.

The module in the middle of the Neutrik XLR adapter houses the inductor and is painted externally in the color code as above. The code representing the visual electromagnetic frequency spectrum makes easy the quick  choice of a Pleiadws filter without reading numbers.

The coil inductor is connected in parallel to the microphone signal ie in pins 2 and 3 of the Neutrik XLR adapter (live, return). It may be a made by winding an insulated thin wire several turns on a toroidal core, Magnetec Nanocrystalinne or ferrite etc.

Pleiades filters can be connected in cascade and nature gave the useful property of being able to add turnover frequencies.

For example:

If the use of an AKG D112 is required to record vocals or any source from approximately 20Hz to 20KHz, (this depends on mic and source of course) at less than 3in a green and yellow Pleiades EQ can be connected in cascade giving a compensation turnover of 400Hz + 100Hz = 500Hz

Connecting many microphones in parallel

At your own risk.


One could connect 2 or more microphones in parallel and sing to them. This means literally pin 1 with pin 1, pin 2 with pin 2 etc.


This would create an effective large diaphragm but with the transient response of a small one and sensitivity of a large.


So the combined microphone could be further away and still capture the same percentage of the spherical waveform.


The voltage would theoretically be the some but current double (for 2 mics) , ie impedance half so less noise.


The array would further increase directionality if reciprocity with array speakers apply.


In fact the idea is very similar to many small speakers driving air one next to the other, one aiding the radiation impedance of the other, increasing efficiency. Also there is increased bass, less excursion distortion, and directionality.

Paso M8 microphone, circuit and Pleiades filters

Very interesting small diaphragm cardioid dynamic microphone.


Sounds bright and there is some hiss. It is so much proximity compensated than one can sing at 0in with natural sound


Opening it carefully by removing the sticker the circuit was as follows. One side of the capsule is connected to Tuchel out. The other side is connected to Tuchel out through a 100nF ceramic capacitor. This explains the very high frequency cutoff. When the switch goes from music to voice a 2.2KΩ resistor is connected in parallel with Tuchel out, further increasing HF cutoff.


The capacitor was bypassed to hear the capsule and it has a very full sound.


A Pleiades bass cut filter was made with Magnetec 060 core. 45 turns of Teflon insulated wire wrap wire gave 75mH inductance. The 2.2K resistor was left in place so at the V position there would be this inductor in parallel with 2.2K. Would this resistor reduce too bright HF? Everything was flitted inside,  and the mic closed.


The sound was very interesting, the optimum distance for 75mH//2.2K was about 4in.


With an external 52mH Pleiades XLR adaptor filter it was approximately 2-3in and there was more voice signal as the small capsule received a greater percentage of the spherical voice wave.


With 25mH one could sing at 0in to the mic with natural and loud sound. There was some air  noise  problem.


From all the combinations perhaps the 4in 75mH//2K2 is the best or 3in with less added parallel inductance ,more experiments are needed.


In general an inductance of 80mH seems to compensate for 4in distance for many microphones.


And microphones seem to capture a natural sound at about 4in although one can hear an untreated room at >1in and signal is somewhat less strong. More experiments are needed with a very low noise amplifier such as Pleiades V5 EF183 battery electron tube only preamplifier.


Setup:


Paso M8 - Sony TC-D5 pro- Sennheiser HD580

Pleiades filters reveal...

the good things about amazing microphones.


Everything that was masked in the mud of exaggerated proximity mid bass predominance.

Pressure ie omnidirectional microphones off axis

A bit or more off axis reduces the high frequency boost effect due to pressure doubling .


So we have a variable and very useful high cut filter without electronics.

Sennheiser MD21 HL (or HN) to Pleiades K117 to iPad

What an amazing mic.


Straight to a Sony TC-D5 Pro II a Pleiades filter of 100 to 200Hz was better for singing to reduce the voice effort effect of bass increase.


To iPad it went straight through the Pleiades K117 JFET preamplifier fitted inside the mini Tuchel connector to iPad's headphone mics input. The iPad 1/8 socket powered the Pleiades K117 as it normally does for electret condenser mics.


Sound was great.


Away from 0 degrees say at 45 degrees from the axis of the gave a nice high cut filter to compensate for the pressure doubling effect of High frequency exaggeration.


So almost portable. A top quality mic, a cable, and iPad mini or iPhone? Oops headphones too!


Signal path:


Sennheiser MD21 Hi Z (impedance) transformer stepped up output - Pleiades K117 (to get the most of the hi impedance as is done on condenser mics - iPad - GarageBand - HD580

3D effect with AKG D130 and Electro-Voice 635A

A stereo recording with them at about ears distance is very nice.


But placing them in a way that they touch our ears and then record gives the brain of a headphone listener many more clues.


Setup:


635A on L
                     - Sony TC-D5 Pro II - HD 580
D130 on R.  

A way to control bass response on the AKG D130

At your own risk.


The beautiful metal mesh can be unscrewed carefully.


The capsule detached gently from it and from the mic case.


Then attached gently to the mic case.


Then the metal mesh screwed back but half way.


Singing voice was found to be more natural at 4in at this point.


More screwing increases bass until normal mic spec when all the way tight.


This adjustable bass cut seems to nicely compensate for the voice effort effect.


When we speak softly the spectrum of our voice increases much more on bass and treble frequencies relative to mid ones.


Then if we reproduce at higher levels it sounds unnatural to out brain.


The Fletcher Munson curves make it even worse. Our voice reproduced by then sounds too bass heavy and unnatural.


In pop music in many instances we reproduce voice much louder than when it was recorded as the singer might like to sing effortlessly and the listener might like to listen relatively loud.


This little hack makes a variable bass cut without modifying this amazing microphone in any way.

How did Sennheiser HD 580 sounded as 3D VR microphones for drums

At your own risk


Results were promising.


All that is needed is to make a cable (female headphone on one side, 2 male XLR on the other).


Drummer wears headphones (microphones). The voice is very bad due to extreme proximity effect.


Drums sounded very interesting and there was certainly a sense of 3D. Cymbals were soft and not harsh. The sound was full.


It may be worth experimenting with other microphones...headphones.


Setup:


Room with Pleiades roofing felt* membrane panel absorbers and cotton - drums - HD580 as mics - Sony TC-D5 pro with issues - TDK SA-X type II cassette - Sony TC-D5 pro - HD580 for playback


*it seems better to use linoleum bass panel absorbers as they do not give an odor 

The simplest recording signal path on the planet?

Is it the following?


One omnidirectional in ear capsule in each ear one for each recording reproducing channel.


Musicians playing softly so that there is high average to peak signal and so it sounds loud without the need of compressor, peak limiter etc.


This will require low noise preamps. JFETs or electron tubes with reduced heater voltage, high resistance from anode to grid and low battery anode (plate) voltage.


On the recording device side instead of the load resistor would it be even better with a JFET? So when mic with its JFET is connected to the device the configuration becomes cascode (one JFET on top of each other).


But could it be that just a low noise load resistor is simpler and better?


If dynamic in ear capsules are used, the signal may be stepped up with a Pleiades input transformer using a Magnetec Nanocrystalinne Nanoperm core before feeding the active devices.


If instantaneous peak limiting is needed maybe the Pleiades V5 preamplifier is the simplest signal path with just 2 EF183 electron tubes and very few components, battery powered.

3D microphones and ASMR

The girls on YouTube have success in getting binaural recording known after than 70 years efforts?


Credits should go to Bell Laboratories scientists Fletcher etc when they inserted microphones to the ears of Oscar a man looking doll.


Also to Sennheiser for microphones to be worn in ears.


Also to Zuccarelli.


Excellent results can be made with in ear microphone capsules such as the Pleiades microphones.


So how about some whispering singing one singer near the left ear and the other near the right.


How about a nice pop production with all instruments recorded this way.


And somebody like Madonna singing right in front of you.


Or perhaps it could be someone else.

Orchestra conductor and 3D microphones

It would be nice to give an orchestra conductor or a pop music producer a pair of Pleiades in ear microphones.


So that the recording is produced from these.


The listener with headphones on YouTube etc would at least theoretically hear what he she heared when the recording was taking place.

Recording with loudspeakers

It would be nice to record drums, close voice, piano etc with 2 loudspeakers proximity compensated and stepped up with Pleiades transformers from 8 ohms to 200 ohms.  Very few turns <10? should be needed. A step up ratio of 5 to transform from 8Ω to 200Ω.


If Magnetec Nanocrystalinne toroidal cores are used even less turns would be needed.

A Pleiades preamp straight to an A to D converter and then to lightning connector

It would be nice to have a nice ADC to lightning with Pleiades V5 front end (electron tube and only EF183 preamplifier) or Pleiades K117 JFET.


2 such low noise preamps for stereo or binaural 3D.

3 more things needed to make iPad - Gargeband the best?

These 3 would possibly make an iPad Farageband combination the winner on the planet in portable recording.


1. A stereo microphone input. Thus will make iPad ready for 3 D recordings. The best 3D microphones on the planet can be made with 2 omni capsules placed in ear like in ear headphones?


2. Making instead of the 259Hz? low cut filter on iPad or Garageband mic recorder a full 39Hz - 16KHz bandwidth. The low cut has to be switchable.


3. Stretching octaves on GarageBand as a true to ear - brain octave is not an exact integer multiple of 2, (why should it be?). X2 is just for lesser things not the best music creating software on the planet. An a,ternate was solution would be to making it all note scale user defined (not just one octave), in cent frequency deviation for theoretical equal temperament.


An optional instrument input too?


Will it be ready to make 3D music?


"Shortcomings" can lead to creativity. For example counteract low cut by creative use of sampler, counteract u stretched octaves by creative use of pitch bender. Using a figure of eight ribbon mic record an instrument on channel L then twist the mic 90 degrees double tracking the same part on channel right. Then re record similarly another so same part in the same way from a different position in space. Or use an omni record then move the mic 14cm and redecorate the same thing. Or record with one mic in ear capsule in the left ear then re record with same capsule in the right ear.





Reference: open source references on euroelectron blogspot

Dynamic headphones ready as great 3D microphones?

(At your own risk) The microphones of the future or present? will be the headphones themselves?


Will they be ribbon (both sides open so you hear with one side and record with the other) or dynamic or condenser?


A dynamic (as ribbons too) driver unit is already a microphone. A microphone and a speaker have in common coil and magnet. When you apply a voltage to the coil it becomes and electromagnet. It therefore interacts with the permanent magnet and there is force that moves the membrane therefore movemeant of air therefore sound.


When we speak to a speaker or a mic vibrating air molecules hit the membrane it moves, the coil attached to it moves too and there's EMF ie voltage induced on the wire coil because it is surrounded by the magnetic field of the stationary percent magnet.


This is the reciprocity principle. You connect voltage to something and it moves. Then you move it, it generates voltage. This is exactly the same as the motor which can become a generator and vice versa. Like listening through a dynamic microphone by connecting it to the headphones output.


So can we use our headphones as 3D microphones?


An advantage is that the same transducer is the reproducing and recording one, earphone microphone.


This means the sound field reproduced could be as close as possible to the original? The membrane is in the same position next to our ears as when recording was taking place.


So the open back Seenheiser HD580 are ready to record?


They are 300ohms which is very convenient as most mics are 200-300ohms so with the right adapter they can be connected to 2 mini microphone preamplifiers or a stereo one.


Omni transducers can be tried too.

Pleiades 3D microphone

Your own risk.


On the Pleiades 3D microphone the capsules are carefully fitted inside our ears just like in ear headphones.


In ear microphones.


What is recorded is what somebody's ears would capture in the sound field.


Everything gives a clue, hair, skin etc as they influence the sound field and give clues to our brain.


The recording is played back by headphones. The right headphone plays what the right ear mic have recorded and similarly for left.


How the Pleiades microphone is made.


We need small mics.


We can remove the driver units of ordinary in ear headphones. We can then fit small mic capsules facing in the outside direction, solder the leads insulate thoroughly and they are ready. The headphones should be made open back.


Mics can be (preferably?) omnidirectional as they do not introduce bass exaggeration when close just like our own ears


If we use electret condenser capsules we solder insulate thoroughly and are ready to go.


We could use dynamic capsules and a candidate could be the headphone drive unit itself but placed the other way round. Its impedance is 8 ohms so it needs to be stepped up by an audio transformer and then drive a Pleiades K117 JFET preamplifier. An audio transformer relatively easy to make is the Pleiades transformer wound on Magnetec Nanocrystalinne core. 2 separate insulated windings should be used for isolation in each transformer. The impedance is stepped as the square of the turn ratio. Primary winding turns adjust how deep it goes in bass frequencies.


We must take all precautions to prevent metal parts touching our ears, isolate with audio transformers and everything needed to prevent an accident in case something goes wrong.


If done correctly the reproduction is as exceptional as possible.


We must never forget that no matter how realistic virtual reality can be the smile of a real person (physically in front) the caress of a real person the touch and smell and thoughts of a real person and the sharing of these asking nothing in return is the joy of giving for the sake of it and it may be called love.

Electrolytic capacitors in light color

Should electrolytic capacitors come in bright color?


This would minimize heat absorption from their heat radiating environment.


Same reason why we wear bright clothes in the summer for keeping their temperature low.


Reference:


Black body radiation, Conceptual Physics, Hewitt

3D microphone of iOS, iPad, iPhone etc

It would be nice to have a very small flat leightweight box that constrains 2 Pleiades K117 JFET preamplifiers ie just 2 JFETs with as few components as possible, 1 or 2 resistors. Then a top quality A to D converter.

One side connects to a lightning connector for connecting to iPad or iPhone.

The other side to 2 electret or small dynamic microphones that fit to each ear just like in ear headphones. 

These in ear headphones can make possibly the best 3D binaural recordings one could hear.

This setup utilises the shape of our head, hair, texture of our skin, as all of there process the sound wave when we normally hear for clues.

If one hears such recording through headphones everything is so realistic... Up and down, front and behind can be distinguished as well as left right. It feels as you are there or everything is here.


Would iRig be the first to make such a Pleiades 3D microphone?

Or if Apple includes a stereo mini mic input, 2 such microphone capsules (should they be omnidirectional?) can be connected directly. 

Stereo microphone for iPad

At your own risk.


The iRig seems very nice.


It would be nice to have or make the option of disconnecting the electret mics inside and connect great microphones such as MD441, RE16, MD21 etc.


Just after the mics Pleiades filters can be used for proximity compensation. So the microphones could then be used real close making an effective macro sound capture.


A Pleiades K117 low noise  JFET preamplifier could follow if needed.


This could make a minimal signal path using the iRig's A to D converter from top quality dynamic or ribbon or condenser microphones to lightning connector.


Or,


Could an A to D converter and Pleiades K117 preamplifier fit inside a mini Tuchel? One could connect a top quality dynamic mic that has the option of hi Z (impedance) such as Sennheiser MD421 or MD21.


So it would be a top quality microphone being connected directly to lightning with nothing shown sticking out.


Or 2 top quality microphones such as above connected directly to the lightning connector.


Or could Apple include a stereo mic input on iPad with a great converter?


Then it would top a top quality microphone with a Pleiades K117 preamplifier inside the microphone connector.


Neutrik XLR modules can be really useful as one can make a larger female XLR with them if needed to include a Pleiades filter with a Nanocrystalinne toroidal core inside for top quality macro capture of sound as close to the source may be needed.

The path to highest analog quality is...

that which is closest to a straight wire.


Reference: Robert Orban, Greg Ogonowski, Maintaining Audio Quality in th Broadcast Facility, 2003 edition, p.28

A stereo test recording with Pleiades filters on Sennheiser MD441 U3 and AKG D112

Bruce Swedien is extremely right. Recording just one source (instead of mono) in stereo with 2 mics makes a tremendous difference.


One can feel all the space around.


Both mics were held by hand and pointed to singing mouth at a distance of approximately 4in. Proximity effect was compensated with Pleiades filters of 82 and 87 mH. Details on how they are made in earlier euroelectron posts.


The difference is amazing without and with Pleiades filters. From muddy lows to crystal clear sound with body. On stereo the sound was a joy.


Setup:


Sennheiser MD441 U3 - Pleiades 82mH - Sony TC-D5 PRO II L channel

AKG D112 - Pleiades 87mH - Sony TC-D5 PRO II R channel

(monitoring on Sennheiser HD 580 precision, cassette was TDK SAX 60)


Both mics sounded amazing. What can one say about these miracles of engineering. And the analog recording made one press stop and rewind, "did this happen now or was it recorded on tape?"

Pleiades 87mH and 82mH filters comparison on AKG D112 and Sennheiser MD441 U3

The 87mH Pleiades (proximity EQ filter) is made with Siemens core and has higher series resistance due to higher turns needed.


The 82mH Pleiades filter is made with Magnetec core and has a lower series resistance due to thicker wire and less turns needed. This is due to the higher inductance index of the Nanocrystalinne core to the ferrite core.


The Siemens-Epcos sounded more full and the Magnetec more clear. The 82mH Magnetec may have suited better the MD441 and the 87mH Siemens- Epcos the D112.


Setup:


Mic - Pleiades filter - Sony TCD5 PRO I