If only two mics... ?

[ubxf]

Recorded with SCHOEPS MSTC 64 U

 

[k brown]

Charlin also mentioned (with photo) in this paper on history of binaural (first PDF below, page 772).

A current and frequent user of the Jeckilin is ex-Decca engineer, Simon Eadon. Shown are a couple of his sessions.

Many years later, Jecklin inceased the dimensions and spacing for less 'mono-ish' sound at low frequencies (see JecklinDisk PDF).

Jecklin (and baffled, head-spaced omni techniques in general) works best on smaller enembles and/or those without a lot of LF content (small to medium size choirs, and chamber groups). For full orchestra they are best combined with widely spaced omni 'outriggers', or 'flanks'.
________

It's worth mentioning that Alan Blumlein described the technique of head-spaced baffled omnis in the '30s! (long before Jecklin or Charlin). Best known for the technique of figure-8s coincident at 90 degrees, he was also the first to describe baffled omnis.

 

[Barry Hufker]

"Follow the link Barry : I found everything doin' so (brevet, article, schematic)"

D'oh! Sorry I missed that. Thanks Philip!

 

[Emmathom]

Hi guys
A bit off topic but not really if you consider that searching for "only two mics" leads to keep on searching and try things...

So in this spirit I bought 2 PUI5024 electret capsules and just set them up according to the "Simple P48" project : one 150KΩ resistor and a good quality capacitor (I used a Panasonic FC 4,7uF@50v) for use with phantom power and the result is really amazing ! at first audio test (with the capsule not yet installed in the XLR connector so just hanging at the end of a one foot audio shielded cable > just for a first quick audio test to check if I have sound... and I do !)

This weekend I will do some more audio tests to compare with my Line Audio Omni1 pair (voiceover & acoustic guitar something like 5 feet away > ambiant recording) and will post them here asap (in a blind test of course )

Thanx to @ricardo who guided me to this project that I didn't know and provided me the good infos & links

To be continued...

 

[kags]

[EDIT: Already posted in #262 above as Stephan Paul article]
An interesting academic journal article that covers several devices, including the tete Charlin:

 

[k brown]

An interesting academic journal article that covers several devices, including the tete Charlin:

Already linked to in post #262 ^

 

[jean-luc brion]

Hi guys
A bit off topic but not really if you consider that searching for "only two mics" leads to keep on searching and try things...

So in this spirit I bought 2 PUI5024 electret capsules and just set them up according to the "Simple P48" project : one 150KΩ resistor and a good quality capacitor (I used a Panasonic FC 4,7uF@50v) for use with phantom power and the result is really amazing ! at first audio test (with the capsule not yet installed in the XLR connector so just hanging at the end of a one foot audio shielded cable > just for a first quick audio test to check if I have sound... and I do !)

This weekend I will do some more audio tests to compare with my Line Audio Omni1 pair (voiceover & acoustic guitar something like 5 feet away > ambiant recording) and will post them here asap (in a blind test of course )

Thanx to @ricardo who guided me to this project that I didn't know and provided me the good infos & links

To be continued...

hi Emmathom
i also made several aom5024, in pip as in p48 ... it works pretty well.
I use it in a minimalist system,
in pip on a tascam dr05 the microphones placed on the ground (pzm)
spaced 50 to 60 cm
as it is very sensitive, the preamps of the first price recorders are less used, so their defects too (well it seems to me)
they only take 110db but I have never heard any problems. at the same time I have only recorded small acoustic groups.
it makes a very discreet and very light system (no stand, no cable)
I also tried the simple p48 RCA assembly (René Charge Amp) which allows to absorb more and is less sensitive
I put 68k and 4.7uF25V
and to isolate the capsule from the ground I used Teflon tape (the one from plumbers)

 

[Emmathom]

hi Emmathom
i also made several aom5024, in pip as in p48 ... it works pretty well.
I use it in a minimalist system,
in pip on a tascam dr05 the microphones placed on the ground (pzm)
spaced 50 to 60 cm
as it is very sensitive, the preamps of the first price recorders are less used, so their defects too (well it seems to me)
they only take 110db but I have never heard any problems. at the same time I have only recorded small acoustic groups.
it makes a very discreet and very light system (no stand, no cable)
I also tried the simple p48 RCA assembly (René Charge Amp) which allows to absorb more and is less sensitive
I put 68k and 4.7uF25V
and to isolate the capsule from the ground I used Teflon tape (the one from plumbers)

Hi @jean-luc brion thanx for your input !

I thought about RCA mod. but I'm afraid to open this tiny capsule...

According to the official paper I was about to wrap the capsule into heat-shrink then in into cooper-foil connected to cable shield, but why not with teflon adhesive tape !

What about the 150KΩ I put ? It's according to Richard Lee. I measured 40,5v across it (and 1,3v between capsule's pin)

 

[jean-luc brion]

I also made a Demi Jecklin disk that sits on the floor between the microphones, which I space about twenty centimeters apart.

 

[Emmathom]

I send you a MP if you please (to not polluate this thread)

 

[jean-luc brion]

Je me suis basé là-dessus

 

[Emmathom]

Je me suis basé là-dessus

document très intéressant ! merci

 

[jean-luc brion]

Je t'envoie un MP s'il te plait (pour ne pas polluer ce fil)

D'accord

 

[pmfalcman]

I bought 2 PUI5024 electret capsules and just set them up according to the "Simple P48" project : one 150KΩ resistor and a good quality capacitor (I used a Panasonic FC 4,7uF@50v) for use with phantom power and the result is really amazing ! at first audio test (with the capsule not yet installed in the XLR connector so just hanging at the end of a one foot audio shielded cable

That's how I mounted mine. May give you ideas

https://groups.io/g/MicBuilders/topic/aoms_5024_in_enclosures_from/99914178

https://groups.io/g/MicBuilders/topic/handy_metal_body_for_electret/103491193


Get wind protection for them if you plan to use them outside. They're insanely sensitive to wind.

 

[Emmathom]

That's how I mounted mine. May give you ideas

https://groups.io/g/MicBuilders/topic/aoms_5024_in_enclosures_from/99914178

https://groups.io/g/MicBuilders/topic/handy_metal_body_for_electret/103491193


Get wind protection for them if you plan to use them outside. They're insanely sensitive to wind.

Thank you for your experience !
what R value did you use ? for 48v powered ?
I don't intend to use it outside

 

[pmfalcman]

According to the official paper I was about to wrap the capsule into heat-shrink then in into cooper-foil connected to cable shield,

You can skip the copper foil.

What about the 150KΩ I put ?

The value seems a bit high. For better SNR aim for 5-8 V at the capsule. I started with 120 kOhm and went below 100 kOhm - I do not recall exact value at the moment. Got aroud 8V.
At slightly less than 48V output from my recorder. 47-46,5V if I remember.

 

[Emmathom]

I will put 2*180KΩ in // so 90KΩ... (I don't have 82KΩ in stock but 90KΩ will do well)
Thank you !

 

[pmfalcman]

I don't intend to use it outside

Wind protection is also useful if someone has tendency to move the mics too fast... Khem...

(Sorry, I couldn't help my myself. Just a friendly joke )
Nb.: happened to me as well - I had to put on windshields because movements caused whooosh noises.

 

[ubxf]

wind protection is also useful indoors for a/c air movement and even in studio for a door opening or closing. If mounted on a boom definitely watch out for whoosh during movement

 

[Emmathom]

Wind protection is also useful if someone has tendency to move the mics too fast... Khem...

(Sorry, I couldn't help my myself. Just a friendly joke )
Nb.: happened to me as well - I had to put on windshields because movements caused whooosh noises.

I avoid to go outside in winter...