Open air Mics (was RE: RE: LAN E-mail w/Outlook)

["Doug Woolridge" <doug_woolridge@xxxxxxx>]

I've put the open air microphone idea on hold due to budgetary constraints.
There was a good thread here on UKHA_D not long ago on this topic (Sorry, I
can't remember the thread).

Here's a quote from one of the posts that I happened to save:
<SNIP>
>Well whole room voice recognition still has a way to
>go.  There is just too much background noise to make it
>100%.  Using the local phones work much better since it
>reduces the outside noise such as radios, others
>talking, etc.

>I am single so that is not as much a problem for me.

>I have 4 Crown PZM-11 mikes mounted in the major rooms
>feeding into a Shure 410 mixer/gate.  Does a pretty good
>job but there are times where I have to turn down the
>radio/TV to get understood.  Quieter rooms such as the
>bedrooms or bathrooms work much better.

>If I don't want to turn down the volume due to guests, I
>just pick up a phone, dial # and talk to HAL.
<SNIP>
>--
>Don    K9SOA/4  EM77EX

>www.k9soa.net

>Home of "JEANNIE" The House That
>Listens

>My voice controlled, automated
>home that was featured on HGTV's
>Dream Builder show on home
>automation

>Featured Home of the Month
>Feb 2002 issue
>Home Automation magazine
</SNIP>

Key points I got out of the thread:
1)  Do NOT put the microphones in the ceiling
2)  A proper mixer for the microphones is expensive (
http://www.iautomate.com/mics.htm
 SCM-410 @ $800)
3)  Decent wall mount microphones are about $70 a piece (PZM-11 at the same
URL)
4)  Dynamic microphones won't work for voice recognition across the room.
Condensor microphones are needed which require some power source.  Phantom
power
seems to be the best, but also is the most costly.

See http://www.shure.com/support/technotes/default.htm
for some great technical
information on microphones.

The ideal system just isn't in my budget, so I plan to play around with
voice
recognition at the computer microphone for now.  Not really useful, but
should
be educational.


I'm not sure you'd want to use my speaker system.  I did it as cheaply as
possible because I wasn't too concerned with audio quality.

I had some car speakers laying around as well as some electrical mains wire
(12
gage) from re-wiring my house.  I cut holes in the ceiling and mounted the
car
speakers.  Some ceiling speaker covers from Radio Shack completed the
upstairs
installation.  The living room speakers are car speakers bought at Radio
Shack
(on sale) and mounted in the ceiling as well.  The system is amplified
using an
automobile stereo amplifier powered by an old PC power supply.

Total Cost:
-----------
Upstairs Speakers           $FREE  (more or less)
Speaker Covers (4)          $30
Wire (12 gage, 4 conducter) $FREE  (couldn't get rid of it)
Living Room Speakers        $15
Amplifier                   $20
Old PC Power Supply         $FREE  (from retired 486-33)
Local Volume Controls (2)   $60
=======
$125 plus a bunch of work

I wired the 2 sets of 4-ohm speakers in parallel, which means my 4-ohm
amplifier
is driving a 2-ohm load.  I'm considering adding a couple of autoformers to
bring the impediance back up to 4-ohms total.  I can't wire the speakers in
series (which would give 8-ohms) because I would not be able to have volume
control in both of the "zones".

The speakers can always be upgraded (with a trip through the attic
fiberglass
insulation) when more funds are available.

I wouldn't recommend this setup for any audiophiles out there.  The plan is
for
Homeseer voice synthesis and maybe some MP3's as background
"noise".  I have a
surround system in the living room for serious music listening.


Why do my short posts seem to turn into long dissertations??

Doug Woolridge


Original Message:
>   Date: Fri, 1 Mar 2002 14:01:10 -0000
>   From: "Nikola Kasic" <nikola@xxxxxxx>
>Subject: RE: RE: LAN E-mail w/Outlook
>
>Keep us posted.
>I'm interested in voice recognition as well.
>What kind of microphones you plan to use, and what kind of speakers?
How
>much they need to be apart?
>Nik



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