PC TV Card Problem. Output \ Input Levels Reducing?

I have an electronics problem with my AIW 128 32MB TV tuner AGP Card
connected to my set top box (cable TV) outputs.

I think the audio output from the TV card to the sound card (line-in)
is far too high (peak voltage?) and causes audio to be slightly
clipped and muffled (even with the set-top box audio set down to
minimum.)

This is more of a problem with coax \ TV than s-vid (direct audio).
Also the sound decoded from the coax signal tends to rise and drop (a
result of overdrive \ normalising going on in the card??)

Other people have reported similar problems (even with more modern
cards) as these cards were generally not designed to hang off the back
of a set-top box which I suspect is a boosted signal adding to the
problem...


For audio would there be any problem with simply putting a resistor in
series with the common for the loopback cable (from TV card audio out
to sound card audio in)? I might just try a pot but what sort of
resistance should I aim for? 100ohms or more? Would I need anything
like a capacitor? (Voltages are likely to be between .1v to 5v
maximum??)


For video would it be feasible to reduce the input signal (to the TV
card) from the VHF coax TV coming from the set-top box. How would I do
this? Could I again place a resistor inline with the coax or does this
require a different method. (I realise the video signal will be
weakend to.)

I'm not too hot on complex electronics so easy methods would be more
helpful.

What I am concerned with is not introducing too much noise.

Any ideas?

cheers

Pete