wrote:
I got a Sony ECM CR120 microphone to replace an ECM T145 and it sounds
a little better, recording to minidisc. These are both OmniDirectional
Electret Condenser Microphone. I have some questions about the
specifications on the Sony website.

1) ECM-CR120 has impedance of 5.5ohms whereas the T145 has impedance
of 2.8 ohms. What does this mean in simple language?

You sure those aren't kilo-ohms? Check the FAQ for a good description
of impedance.... you can think of impedance as the ratio of output voltage
to current. High-Z devices want to source a lot of voltage, low-Z devices
want to source a lot of current.

2) CR120 has Sensitivity of -46dB whereas T145 has sensitivity -42dB,
each of these +/- 4dB. Is the difference significant? These are
tieclip microphones, how are these figures computed and do they merely
indicate sensitivity to quiet sounds, or audio quality from the mic?

They merely list the _average_ sound level required to get a given voltage
out of the microphone. Since the unit-to-unit variations on cheap electret
capsules is probably greater than 4 dB, a 4 dB difference between models is
probably not very significant.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

omni wrote ...
How can one mic be 2.8kohms and the other be 5.5kohms,
yet they both go into the same minidisc recorder?

There is nothing particularly unusual about those impedances.
Since no "impedance matching" is necessary or implemented, the
source impedance doesn't really make any significant difference.

Is the High-Z device the CR120 more sensitive / better quality
because it is High-Z, or is that attribute irrelevant?

I wouldn't consider calling anything below 10K "Hi-Z".
They are both considered relatively "low-Z" IMHO.
Impedance is independent of sensitivity, quality, etc.

Where is this group's FAQ, please?

http://www.faqs.org/faqs/AudioFAQ/pro-audio-faq/ and
http://www.recaudiopro.net/ (Google is your friend)

Cheap electret capsules?

Electret capsules frequently cost $1

This mic cost an arm and a leg.

The name "Sony" on the label cost several times more than
the capsule cost. I'd be extremely surprised if Sony spent
more than $5 for the capsule(s)

It produces quite good audio quality. Are all omnidirectional
tieclip type mics 'electret condenser' or are there other better
types?

"quite good audio quality" is a relative term. Over in the
news:rec.arts.movies.production.sound newsgroup, they frequently
discuss electret "tieclip type" mics that cost upwards of $1000

Would the various types of microphone be in the FAQ? T-Y.

I believe I recall seeing discussion of various kinds (dynamic,
condenser, etc.) and polarizations (omni, cardioid, etc.) of
microphones. If not there certainly there are microphone FAQs
and other good sources of tutorial information.

Question about Sony ECM CR120 microphone

Group: rec.audio.pro Date: Fri, Dec 31, 2004, 6:28pm (EST-3) From:
(Richard=A0Crowley)
omni wrote ...

It produces quite good audio quality. Are all omnidirectional tieclip
type mics 'electret condenser' or are there other better types?
"quite good audio quality" is a relative term.

Over in the news:rec.arts.movies.production.sound newsgroup, they
frequently discuss electret "tieclip type" mics that cost upwards of
$1000

$1000 is pushing it a bit. Top of the line lavs for production sound run
around $300-$400. These lavs are usually connected to wireless systems
that run well over $2k.

Eric

wrote:
On 29 Dec 2004 14:50:36 -0500, (Scott Dorsey) wrote:

wrote:
I got a Sony ECM CR120 microphone to replace an ECM T145 and it sounds
a little better, recording to minidisc. These are both OmniDirectional
Electret Condenser Microphone. I have some questions about the
specifications on the Sony website.

1) ECM-CR120 has impedance of 5.5ohms whereas the T145 has impedance
of 2.8 ohms. What does this mean in simple language?

You sure those aren't kilo-ohms? Check the FAQ for a good description
of impedance.... you can think of impedance as the ratio of output voltage
to current. High-Z devices want to source a lot of voltage, low-Z devices
want to source a lot of current.

Yes, it appears to be kilo-ohms. On the Sonystyle.com site it says
ohms, but other sites say kOhms.

That tells you something about how much you can trust the Sony marketing
department, doesn't it?

How can one mic be 2.8kohms and the other be 5.5kohms, yet they both
go into the same minidisc recorder? Is the High-Z device the CR120
more sensitive / better quality because it is High-Z, or is that
attribute irrelevant?

No, those are both pretty high-Z. They're in the ballpark, and they are
both going into a microphone input that is much higher Z than the source.
When everything is electronic (ie. no dynamic mikes whose characteristics
change with loading), you'll basically see low-Z outputs into high-Z inputs
these days. Matching is pretty much irrelevant.

Where is this group's FAQ, please?

It is posted noexpire so it should be the first message on your server.

2) CR120 has Sensitivity of -46dB whereas T145 has sensitivity -42dB,
each of these +/- 4dB. Is the difference significant? These are
tieclip microphones, how are these figures computed and do they merely
indicate sensitivity to quiet sounds, or audio quality from the mic?

They merely list the _average_ sound level required to get a given voltage
out of the microphone. Since the unit-to-unit variations on cheap electret
capsules is probably greater than 4 dB, a 4 dB difference between models is
probably not very significant.

Cheap electret capsules? This mic cost an arm and a leg. It produces
quite good audio quality. Are all omnidirectional tieclip type mics
'electret condenser' or are there other better types? Would the
various types of microphone be in the FAQ? T-Y.

Electret condensers are basically the only easy way to make very small
microphones. These use Sony capsules that cost perhaps three or four
dollars each to make. They have really no electronics in them because
they just have a single FET that is powered by the differential "plug in
power" supplied by the recorder. So the total manufacturing cost is
probably under ten bucks, which means I'd expect it to sell for around
a hundred dollars with typical markup. Welcome to the wonderful world of
cheap consumer electronics.

If you want to look at some decent mikes in that range, check out the
Countryman lavaliers, and the little DPA 4060. Be prepared first for
some sticker shock, secondly for the fact that most of these mikes are
going to require some decent current for good dynamic range and will
tend to be sold with phantom power and balanced output electronics.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."