DIY inline low cut?

Archived from groups: rec.audio.pro (More info?)

J.A.A. <hyeena@fi.sci> wrote:
>I have miniature microphone that I use directly with MD recorder.
>Now next step is to make 9V powersupply for better performance.
>What I also need is (on/off switch preferrable) 80Hz / 160Hz hi-pass filter
>that removes unwanted
>rumble.
>
>Mic specs are here:
>
>Type : Condenser Microphone
>Directivity : Omnidirectional
>Frequency range : On Axis 20 - 20,000 Hz
>Maximum sound pressure : 145 dBspl peak f> 250 Hz
>S/N -69 dB typical
>Total harmonic distortion : 130 dBspl peak below 0,4% THD
>Open circuit sensitivity: 10 mV/PA
>Operating temperature range : -20°C to 44°C ( -4°F to 111°F )

If you put a capacitor in series with the line, it will remove low end
at 6 dB/octave. The value required for a given corner frequency
depends on the input impedance of the recorder and not on the mike.
--scott

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

Archived from groups: rec.audio.pro (More info?)

ment MZ-R91 and I need to roll bass -6dB @ somewhere 160/180Hz


"J.A.A." <hyeena@fi.sci> wrote in message
news:yaupe.3561$nm1.2712@reader1.news.jippii.net...
> Its sony MZ-R1 that has 0.35-1.38 mV input voltages. dont know anything
> else.
>
> jukka
>
> "Scott Dorsey" <kludge@panix.com> wrote in message
> news85kvv$ruj$1@panix2.panix.com...
> > J.A.A. <hyeena@fi.sci> wrote:
> > >I have miniature microphone that I use directly with MD recorder.
> > >Now next step is to make 9V powersupply for better performance.
> > >What I also need is (on/off switch preferrable) 80Hz / 160Hz hi-pass
> filter
> > >that removes unwanted
> > >rumble.
> > >
> > >Mic specs are here:
> > >
> > >Type : Condenser Microphone
> > >Directivity : Omnidirectional
> > >Frequency range : On Axis 20 - 20,000 Hz
> > >Maximum sound pressure : 145 dBspl peak f> 250 Hz
> > >S/N -69 dB typical
> > >Total harmonic distortion : 130 dBspl peak below 0,4% THD
> > >Open circuit sensitivity: 10 mV/PA
> > >Operating temperature range : -20°C to 44°C ( -4°F to 111°F )
> >
> > If you put a capacitor in series with the line, it will remove low end
> > at 6 dB/octave. The value required for a given corner frequency
> > depends on the input impedance of the recorder and not on the mike.
> > --scott
> >
> > --
> > "C'est un Nagra. C'est suisse, et tres, tres precis."
>
>

Archived from groups: rec.audio.pro (More info?)

In article <yaupe.3561$nm1.2712@reader1.news.jippii.net> hyeena@fi.sci writes:

> Its sony MZ-R1 that has 0.35-1.38 mV input voltages. dont know anything
> else.

Then you'll just have to find out by experimenting, won't you? This is
the way that DIY projects get developed.

> "Scott Dorsey" <kludge@panix.com> wrote in message
> news85kvv$ruj$1@panix2.panix.com...
> > If you put a capacitor in series with the line, it will remove low end
> > at 6 dB/octave. The value required for a given corner frequency
> > depends on the input impedance of the recorder and not on the mike.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

Archived from groups: rec.audio.pro (More info?)

0.22 uF and 5000 Ohms comes to about 145 Hz -3 dB


Xc = 1/(2*pi*F*C)

where Xc = the reactance of the cap (5000 Ohms in your example)
F= frequency in Hz
C= capaciatnace in Farads

when the Xc = your R then the signal will be attenuated by 3 dB.

And technically the R is the sum of the input Z of the recorder and the
output Z of the mic. The output Z of the mic is probably much less
compared to 5000 Ohms so it can be ignored in this case



Mark

Archived from groups: rec.audio.pro (More info?)

J.A.A. wrote:
> well I was told that its 5,000 ohm mic impedance for the Sony MZ-R91.
> Can someone show me table or specify needed capacitor.

R=5k C=1uF f=31.8Hz
R=5k C=470nF f=67.7Hz
R=5k C=330nF f=96.5Hz
R=5k C=220nF f=145Hz

I have a little command line programme for working these things out, but
the formula is:

f = 1 / (2 * pi * R * C)

Anahata