RE: Re: placing speakers and microphones

["Nikola Kasic" <nikola@xxxxxxx>]

The mics I have in mind are Crown PZM-11 like here:
http://www.letsautomate.com/multiroom.cfm?CFID=125173
<http://www.letsautomate.com/multiroom.cfm?CFID=125173&CFTOKEN=68939494>
&CFTOKEN=68939494

Let's Automate says that it's ceiling mounted microphone, but Crown
doesn't recommend mounting them on the ceiling, but on the walls
instead.

I just wonder if there is anyone on the group with experience in this
area. What I plan to do is e.g. announce "telephone call from Joe
Bloggs" over speakers, and then issue command "forward to
voicemail"
through the mic.
I wouldn't want mic and VR software to pick up "telephone
call...",
although it might be unavoidable.
Unfortunatelly, I don't have money to buy all the mics, gates, mixer
etc. at once and especially those expensive equalizers.
I have to cut holes and place speakers first and leave enough mic cable
to reach future mic positions.
There are some people on the group who played with microphones and VR
with mixed results.
I would like to hear from them what are their experience. I have a
feeling that if speaker is on the same wall as PZM11 it will not
interfere a lot, because of the way PZM works. It picks up the sound
that bounces from the plate mic is placed on. If sound goes along the
wall it should not be bounced to the mic, so it should not interfere,
only the one that's reflected from the oposite wall should come to the
mic, but that one would be attenuated. Especially if there are curtains
on the other side.
But that's only my theory, with some hole in it, probably.

Cheers,
Nik


-----Original Message-----
From: David Buckley [mailto:db@xxxxxxx]
Sent: 20 May 2003 23:22
To: ukha_d@xxxxxxx
Subject: [ukha_d] Re: placing speakers and microphones




What you need to do is to try and aim the sound coming out of the
speakers to be going away from the microphones, which is the first
step in trying to keep the speaker audio out of the mics.

next step is careful equalisation.

There are electronics techniques one can use to try and reduce
speaker sound interfering with mics, like hybrids, but its all a bit
tough in a random space.  DSPs do it for room audio conferencing
systems, but they are not in the least cheap, have a look at Rane
stuff for an example.

Good luck; you are in a difficult area.


--- In ukha_d@xxxxxxx, "Nikola Kasic" <nikola@k...> wrote:
> I finished most of the wiring and I plan to put speaker and
microphone
> into each room. I will put speakers first (for PA) and mics later
(they
> are more expensive).
>
> I need to know where should I place them relative one to another.
The
> cables are pulled together and they come to the same point on the
wall.
>
> Should I position them as apart as possible, or it doesn't matter.
Mics
> are supposed to be for voice commands, so I would not like speakers
to
> saturate them.
>
> They will be both on the same wall.
>
> What if I use the same plasterboard partition wall for installing
> speakers in two rooms, should they be separated, or can be one next
to
> other, each facing separate room?
>
> Any comments are wellcome.
>
> Cheers,
>
> Nik
>
>
>
> [Non-text portions of this message have been removed]