Coaxial Audio Filter

Hi,

I have a quastion to ask. It requires a bit of explanation so listen
up!

I have a very, very old television at home (I estimate it was purchased
around 1985). Due to its age, it lacks any facility for changing the
tone of the audio (i.e bass, middle treble). The tone of the audio has
a lot of bass in it. Basically (no pun intended), I want to get a
higher frequency tone (i.e more treble) and reduce the bass. I suspect
I might need some kind of filter. Preferably , I would not like to have
to open the television. I imagine some kind of filter unit could be
placed between the cable (coaxial) and the RF on the televison. The
television has no SCART.

Please Help!!!!

 

[DBLEXPOSURE]

<mjdoyle@tcd.ie> wrote in message
news:1126012829.839103.224880@f14g2000cwb.googlegroups.com...

Hi,

I have a quastion to ask. It requires a bit of explanation so listen
up!

I have a very, very old television at home (I estimate it was purchased
around 1985). Due to its age, it lacks any facility for changing the
tone of the audio (i.e bass, middle treble). The tone of the audio has
a lot of bass in it. Basically (no pun intended), I want to get a
higher frequency tone (i.e more treble) and reduce the bass. I suspect
I might need some kind of filter. Preferably , I would not like to have
to open the television. I imagine some kind of filter unit could be
placed between the cable (coaxial) and the RF on the televison. The
television has no SCART.

Please Help!!!!

Can't be done via the coax. you would need to put a low end blocking filter
or a high pass filter on the speaker or speakers themselves.

I suppose you could find a tuner box or a VCR that allows you to adjust the
tone and then outputs your TV on chnl 3 or 4...

 

[Bob Masta]

On Tue, 6 Sep 2005 17:06:15 -0500, "DBLEXPOSURE"
<celstuff@hotmail.com> wrote:

mjdoyle@tcd.ie> wrote in message
news:1126012829.839103.224880@f14g2000cwb.googlegroups.com...
Hi,

I have a quastion to ask. It requires a bit of explanation so listen
up!

I have a very, very old television at home (I estimate it was purchased
around 1985). Due to its age, it lacks any facility for changing the
tone of the audio (i.e bass, middle treble). The tone of the audio has
a lot of bass in it. Basically (no pun intended), I want to get a
higher frequency tone (i.e more treble) and reduce the bass. I suspect
I might need some kind of filter. Preferably , I would not like to have
to open the television. I imagine some kind of filter unit could be
placed between the cable (coaxial) and the RF on the televison. The
television has no SCART.

Please Help!!!!


Can't be done via the coax. you would need to put a low end blocking filter
or a high pass filter on the speaker or speakers themselves.

Filtering at the low impedances of the speakers will be a problem...
he'd need to be hand-winding big inductors, etc. If he's
opening the case anyway, he should put his filter just
ahead of the volume control, which should be easy to find.
Or he might even find the shunt cap around there that
is causing the present low-pass response.

Otherwise, he would essentially have to cut the bass while passing
the treble, then boost the overall volume to compensate.
That would give increased hiss... and my guess is that
the reason the TV was built this way in the first place
was to make the hiss less noticeable.

May not be worth a lot of trouble....

Best regards,


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Home of DaqGen, the FREEWARE signal generator

 

[Jasen Betts]

In article <1126012829.839103.224880@f14g2000cwb.googlegroups.com>, mjdoyle@tcd.ie wrote:

Hi,

I have a quastion to ask. It requires a bit of explanation so listen
up!

I have a very, very old television at home (I estimate it was purchased
around 1985). Due to its age, it lacks any facility for changing the
tone of the audio (i.e bass, middle treble). The tone of the audio has
a lot of bass in it. Basically (no pun intended), I want to get a
higher frequency tone (i.e more treble) and reduce the bass. I suspect
I might need some kind of filter. Preferably , I would not like to have
to open the television. I imagine some kind of filter unit could be
placed between the cable (coaxial) and the RF on the televison. The
television has no SCART.

Please Help!!!!

Get a TV serviceperson to fit headphone or audio-out sockets
and attach a mixer and amplifier there.


doing it the way you want requires demodulation and re-modulating the FM
audio signals that are coming up the antenna lead for whichever channel you
have selected... the only practical way I can see to do that would be to
inperpose a tuner (eg a VCR - possibly one with a broken playback mechanism)
and then feeding the audio out signal from that into a mixer and then
feeding it into a modulator (another broken VCR) and even then you have to
select channels with the tuner (first broken VCR) rather than use the tuner
that's built into the TV and you'll lose picture quality in the
demodulation/remodulation process...


Bye.
Jasen