Volume discrepancy between tvtime and other apps

[Tim]

On Tue, 2007-12-25 at 13:24 -0500, Vicki Stanfield wrote:
> I think it might be that this tvcard is not going to output enough
> volume. I wouldn't mind so much, but it is quite jarring when I get an
> IM or have some other thing with normal volume kick off. 

I have a MPEG decoder card that has a very low volume output, and many
stand-alone DVD players have low outputs.  Conversely most early CD
players had very high outputs (almost broadcast standard levels, though
not broadcast standard quality).

This sort of thing is not helped much by there being NO standard level
for line level signals in the domestic world.  I've come across
equipment that has ranged from about as low as 20 mV up to around 2 V,
and that's quite a range.  Each manufacturer does whatever they want,
and they're not even consistent across their own range of gear.  As far
as they're concerned, that's what the volume knob is for, and they don't
care about the problems associated with connecting two pieces of gear
together that expect different levels.

In the broadcasting world, there are standards.  And they're needed
since interconnection and simultaneous use of different gear are prime
requirements.  A "line level" signal is generally +8 dBm (older) or +4
dBu (more recently), for nominal signal levels.  That gives you easily
usable signal levels that can be used between almost any pieces of
equipment, most can accomodate either fairly easily.  Though that got
messed up with the digital age, mostly thanks to headroom issues.

As Gene said, you may have to abuse the microphone input (though I'd be
inclined to think you'd want the extra mic gain to be OFF, not on).
Perhaps the gear was designed to be run into a mic socket, or for it to
not cause any damage if it were.  There's also the possibility that the
TV card has its own output level control, and that it's currently set
quite low.

-- 
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2.6.23.1-10.fc7 i686 i386

Using FC 4, 5, 6 & 7, plus CentOS 5.  Today, it's FC7.

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