[AG-TECH] Rigging up a Temporary AG Node

[John Hodrien]

On Thu, 10 Feb 2005, Osland, CD (Chris) wrote:

> The choice between option a and the rest depends on the requirement, not on
> the implementation!

Indeed, but the requirements will have to fit with what's reasonably possible,
and as such are somewhat flexible.

> Even in option b (lapel mic) the person with the mic needs to be able to
> hear the far end; if this is via a loudspeaker, that means the mic will hear
> it too and you will have echo problems.

But potentially at a slightly more manageable level, since the input gain (for
want of a better way to put it) would be less on a mic an inch from someone's
mouth.  Am I dreaming in thinking that software echo cancelling could be
workable?  I've used an ISDN video conferencing rig before that solely used
software echo cancelling and it was... just about alright.

> Option d: don't even think of using switches - put all mics through a mixer
> with linear faders and LABEL THE FADERS!  While the person on the mixer has
> to stay awake, it's not an impossible task - I regularly do it for meetings
> where 20 people share 10 gooseneck mics and extra people are on mics on
> stands.  However ...

This does however require the posession of a mixer.

> Whenever you change the 'acoustics' of your room (person walking round with
> lapel mic, muting mics, flying faders up and down) you are in danger of
> disturbing echo canceller balance.  In principle, if you don't have an echo
> canceller and everyone else does, you can get away with it by muting the
> incoming audio while anyone at your end is speaking, and muting your
> outgoing audio when no-one is, but this adds considerably to the mixer
> operator's workload.  Also the operator has a difficult decision to make if
> someone remote replies to you before your end has finished speaking!

Indeed.  Impossible workload on the mixer operator was a fear I had.

> One consideration is how much your site's participation may disrupt the
> remote meeting; only experience will answer that!

I believe the only purpose of the meeting is to act as a demo.

> We also have a 150-200 seater auditorium from which we do meetings - mainly
> video conferences so far, but the principles are the same.  We find that
> handheld radiomics are the only successful solution to getting questions
> from the floor to remote sites.  Ceiling mics, rifle mics and mics in aisles
> on stands have all been tried and all work worse and/or are more confusing
> than handheld radiomics.

We are in possession of a couple of hand held radio mics I believe.  More than
anything it was the ways of dealing with echo cancellation that I was fearing,
specifically because this is a one-off with no identifiable budget.

jh

-- 
"Madame, si c'est possible, c'est fait, impossible?  Cela se fera."
                                               -- Charles Alexandre de Calonnne