Mic Capsule Polarization Question

When polarizing a condenser capsule how much does the actual voltage matter? For example, if I wanted to create a CARDIOID pattern could the CEK12 (Peluso's CK12) be polarized with just +48V instead of the +80V shown on Jakob's G7 page?

Thank You,
Tamas

[quote author="tk@halmi"]When polarizing a condenser capsule how much does the actual voltage matter? For example, if I wanted to create a CARDIOID pattern could the CEK12 (Peluso's CK12) be polarized with just +48V instead of the +80V shown on Jakob's G7 page?
Thank You,
Tamas[/quote]
Sensitivity of the mic in constant charge connection is
directly proportional to polarization voltage.
If you use 40 V instead of 80 V, it is equivalent to 6 dB pad.
(and some problems in HF via negative reactancy, rather theoretical..)
There is MAXIMAL voltage on the capsule, It is parameter
of producer. Above it microphone membrane can glue to backplate,
or you can destroy microphone.
Normally microphone operates at maximal voltage, because of
maximal sensitivity.

xvlk

Thanks!

What xvlk said.

Lower polarization means lower output level. From 80V to 48V will be noticable, but still usable.

Higher polarization increases output BUT at some point the diaphragm is sucked into the backplate, which is bad.

And when a designer has control of all factors (voltage, spacing, tension), the polarization voltage is just a little less than the suck-in voltage, and the output level in a quiet studio is just high enough to overcome buffer noise. So you never want to increase voltage, and probably don't want to reduce it very much (80V to 48V is OK).

As you approach suck-in voltage, the diaphragm stiffness is partly canceled by polarization voltage force. As xvlk says, "negative reactancy, rather theoretical..". Most mass-produced mikes don't use a polarization voltage so close to suck-in voltage that the stiffness really changes.

:shock:

So, for the G7 or other mics, an HT at 120v or 160v make a real difference ?
no ?

and what is "close-to" the suckin-voltage ???
1v ? 10v ?

:?

I think suckin-voltage would be different for different models of capsules. In the case of the CEK12 it would be some value more than 80 potential difference between the center and the diaphragm.

:green:

I want to see the suckin-voltage on the spec sheet for capsules.

but would the spec be :
greater than xx volts (>80V )
or
not less than xx volts ( not< 80V )
... what is the sign for not-less than ??

when the center & the diaphragm are sticked
we can hear a very strange noise ?? no ??

i have test the G7 with a CEK367 & a CEK12
when i make a small breeze on the CEK12 behind
the anti-pop, it's ok
but behind the CEK367, the small breeze is transformed
in a apocalyptik alive noise. :grin:

if i have understand, the optimal polarization voltage of the CEK367
is lower than that of the CEK12 ??

can that explain, the more precise high-end of the CEK367 ??
because 80v is too close to his suck-in voltage than that of the CEK12 ??


(ooo god my english sorry)

The noise chould be from dirt smoke etc between the gold spot and the edge of the capsule causeing leakage of the capsule charge. I use an optic brush to "dust off" clean a capsule before I use distilled water or anything else.


The best thing for you to do is to try different capsule voltages IMO this is a fine tuning to get the best out of a capsule.

I am not going to give any voltages you need to try it yourself plus maybe what I hear is what I want to hear.

As a general rule the higher the voltage the better the signal to noise ratio.

dirt smoke ? the capsule is brand new ??
i can't clean the capsule, the capsule is perfectly clean :?

what is IMO ?

thanks :green:

[quote author="Jazzy_Pidjay"]what is IMO ? [/quote]

in my opinion

IMNSHO

not so humble

and so on.....

:green:

now i understand a lot of thread !!

thanks

Lowering polarization voltage will somewhat change tonal balance, as well. From my experience, different capsules respond to it differently. Try it and see what you get.

Suck in voltage will also vary from edge terminated (lower) to center terminated (higher) due to the extra support from the center type. But I dont think you gain in sensitivity.
Steve

I am confused :?
All time we are talking about 40-80V polarisation on caopsule but we have
a couple volts on capsule after high ohm resistor.
Duka

Duka,

If you measure with a standard voltmeter it will pull the voltage to nearly zero but the voltage drop across 1Gohm to the capsule under normal operating conditions will be very small.
Steve

Ok !

So it's exactly the opposite of what
i have observed with the peluso's capsules.

Perhaps it's du to another problem.

but the strange noise (vinyl scratching...) is not really a problem
because i can cause it when i want,
but i have no problem during my recording.

:thumb:

PS : If we can't measure voltage at the capsule ??
how to adjust it ? :? :roll:

You measure the voltage going to the high value resistor (1G or similar) and ignore the voltage drop across it to the capsule. Thats to say it's the rail voltage that counts, forget trying to measure the voltage that reaches the capsule.
Steve

thanks !! :grin: