Re: Switching audio via an Ocelot and SECU's

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"John W" <Don't_Spam_Me@xxxxxxx> wrote in message
news:66mdnUjmAdtIJUPeRVn-gg@xxxxxxxxxxxxxxx
> Since you are using amplified speakers, the SECU16 relays will easily
handle
> the line level (i.e. unamplified) audio that you need to feed the
speakers.
> The 38W you refer to is the output of the amplifier in the speakers.
Input
> to the speakers is a relatively low voltage (line level) like that put out
> by the sound card in your PC.

Yes - but my concern is still that the low voltage line level inputs will be
subjected to hum if run through unshielded wire.  I've seen people tackle
this with baluns, mini coax and other forms of ground loop isolation and
still have hum issues.  I'd hate to wire it up and find out that there's
some sort of unresolvable hum issue.

> I use PC-style amplified speakers for my whole house audio and have no
> problems with buzz or hum even though some of them have 50 feet of cable
> connecting them.  I use regular telephone cable (twisted pairs) for
cabling
> and buy it in boxes of 1000 feet for under $30.  I use the same cable for
my
> PIR's and other SECU inputs as well.

It could be that you're just lucky not to have any hum issues.
Unfortunately, I've already discovered I couldn't run one set of amplified
speakers through 3 position RCA stereo switchbox without outrageous hum.  I
was trying to switch inputs from a small TV, a PC and a portable MP3 player
into a set of amplified speakers and as soon as the RCA cable from the PC
was plugged in, there was an outrageous hum problem.

I'm anticipating a number of devices feeding into the SECU audio switcher
with the output going to at least 3 sets of amplified speakers.  My gut
tells me at least one of those combinations is going to hum if wired through
twisted pair.  But I can simulate it pretty easily with uninstalled CAT-5
pieces I have lying around before I go through the trouble of pulling cable.
I just think the electrons in Canada behavior themselves better in audio
systems.  :-)

> So far, I have not tried switching audio sources with SECU relays but I
may
> do that to switch from my SpeakEasy to my PC sound card so I can play
MP3's > from my PC on the same speakers.

That's where I think you might run into hum and crosstalk issues.  Of
course, I live within a few hundred meters of a big cell tower, so that
might explain why hum is a bigger problem for me.

--
Bobby G.