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Electret Condenser Mic Question

S

Spin

Jan 1, 1970
0
I have a headset electret condenser mic that has a low frequency response.
Other than changing the element is there a means of getting a higher
frequency response?
 
A

Arfa Daily

Jan 1, 1970
0
Spin said:
I have a headset electret condenser mic that has a low frequency response.
Other than changing the element is there a means of getting a higher
frequency response?

Are you saying that the frequency response is poor, as in it is unable to
respond to high frequencies such as speech sibilants ? If so, that is very
unusual, as in general, the frequency response of an electret mic is very
good - certainly more than adequate for speech, and in most cases, good
enough for pretty much anything short of professional recording. A quick
look at the specifications of a few shows them to be good to at least 16kHz.
Has the response always been poor ? Are you sure that the problem is not
something much more fundamental, such as the small hole where sound gets
into the mic, being stuffed up with fluff or other clag ? Or are you maybe
feeding it into an input with entirely the wrong sensitivity / impedance ?
Does the insert get it's supply from an internal battery, or should it be
fed with a phantom supply from the equipment that it's plugged into ? If so,
is the equipment providing such a supply ? Not quite the easy question that
you were supposing perhaps ... ??

Arfa
 
S

Spin

Jan 1, 1970
0
The electret element in question is 400 ohms imp & it was plugged into the
input of a 600 ohm imp computer sound card. Recording my speech i noticed
that it lacked "highs". I then replaced the above with a 2k ohm imp element
& there was a vast improvement. The improvement consisted of a higher freq
response & a dramatic increase in output (volume). What baffles me is, i
thought that by matching the mic & sound card with similar impedance that i
would get better efficiency? It appears that my computer sound card (600
ohm input ) works better with a 2k ohm mic than a 400 ohm mic! By the way
the sound card provided the power for both mics. Any comments concerning the
above would be appreciated.
 
D

Dave Plowman (News)

Jan 1, 1970
0
The electret element in question is 400 ohms imp & it was plugged into
the input of a 600 ohm imp computer sound card. Recording my speech i
noticed that it lacked "highs". I then replaced the above with a 2k ohm
imp element & there was a vast improvement. The improvement consisted
of a higher freq response & a dramatic increase in output (volume).
What baffles me is, i thought that by matching the mic & sound card
with similar impedance that i would get better efficiency? It appears
that my computer sound card (600 ohm input ) works better with a 2k
ohm mic than a 400 ohm mic! By the way the sound card provided the
power for both mics. Any comments concerning the above would be
appreciated.

A nominal 600 ohm input won't be 600 ohms but somewhat higher. At one
time, about 1.2k was the norm for a nominal 600 ohm mic. Which are usually
about 300 ohms. ;-) A higher input impedance shouldn't effect frequency
response but might make the noise figures worse. However, too low an input
impedance will result in a bass loss. Which might sound like a treble gain.
 
A

Arfa Daily

Jan 1, 1970
0
Dave Plowman (News) said:
A nominal 600 ohm input won't be 600 ohms but somewhat higher. At one
time, about 1.2k was the norm for a nominal 600 ohm mic. Which are usually
about 300 ohms. ;-) A higher input impedance shouldn't effect frequency
response but might make the noise figures worse. However, too low an input
impedance will result in a bass loss. Which might sound like a treble
gain.

--
I agree with what Dave says, and would bow to his superior knowledge of
studio audio anyway. Even given the levels of impedance mismatch that you
think you have, and the somewhat worse ones that Dave says you likely *do*
have, it still doesn't seem to me to be a sufficiently badly matched system
to have a such an (apparently) large difference between the two mics. It
might in the end just be "one of those things" that has no rhyme or reason
to it. The sound card might simply just not like the original mic.

Arfa
 
R

rebel

Jan 1, 1970
0
The electret element in question is 400 ohms imp & it was plugged into the
input of a 600 ohm imp computer sound card. Recording my speech i noticed
that it lacked "highs". I then replaced the above with a 2k ohm imp element
& there was a vast improvement. The improvement consisted of a higher freq
response & a dramatic increase in output (volume). What baffles me is, i
thought that by matching the mic & sound card with similar impedance that i
would get better efficiency? It appears that my computer sound card (600
ohm input ) works better with a 2k ohm mic than a 400 ohm mic! By the way
the sound card provided the power for both mics. Any comments concerning the
above would be appreciated.

Just to clear the air, can you confirm that the 2k mic was an electret and not a
dynamic? From my experience (commercial communications, not studio) the results
you are getting would be explained by the 2k being a dynamic and the electret
NOT being powered. BTW, I haven't seen a PC sound card that does power a mic.
 
J

Jeroni Paul

Jan 1, 1970
0
rebel said:
Just to clear the air, can you confirm that the 2k mic was an electret and not a
dynamic? From my experience (commercial communications, not studio) the results
you are getting would be explained by the 2k being a dynamic and the electret
NOT being powered. BTW, I haven't seen a PC sound card that does power a mic.

Most PC sound cards mic jack are stereo type and provice supply
through the center tap.
 
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