Re: In celing mics.

["psghome2002" <psghome@xxxxxxx>]

When I was looking into this I found some interesting info on the
Shure SCM 810 intelligent mixer which I believe allows you to devote
one channel to background sound (maybe music/TV source playing in
the room?) and be able to cancel that out for better processing of
the voice.

http://www.shure.com/mixers/installed/scm/default.asp?V=MIXINST

Any thoughts on doing this?

--- In ukha_d@y..., "David Buckley" <db@e...> wrote:
> Soft and hard knee eh?
>
> Compression is a technique whereby you reduce the incoming range
of sound.
> The knobs on your compressor adjust the way that happens.
>
> There are essentially three groups of settings, and depending onj
your
> compressor you may have knobs for all or a few (or indeed none!)
of these
> "settings"
>
> But before piling into the knobs, a bit of background.
Compression is the
> art of reducing dynamic range.  And there are a few "styles"
(for
want of a
> better word) of doing this.  One extreme is called
"limiting".
Doing this,
> you prevent your compressed sound ever exceeding a set level.
Below this
> set level, the compressor does not change the level, but over this
setting
> (the threshold) is compresses viciously.  This style is very good
for
> preserving dynamic range (for that natural sound) whilst preventing
> distortion through overload.  This is "hard knee" in action!
>
> The other end is dynamic range reduction over much or all of the
dynamic
> range spectrum.  So if an input doubles in volume (goes up by
6db), you may
> chose to have the output go up by 3db. Or more, or less.
>
> So what knobs may you have
>
> First is threshold.  This adjusts the level below which no
compression takes
> place.  Above the threshold, the compressor does
"something".  On
> compressors without a threshold knob, the input gain has a similar
(but not
> as flexible) purpose.
>
> You will probably have a ratio control, or switch.  It will
probably be
> claibrated from 1:1, to 20:1 or higher.  This adjusts how much the
> compressor reduces the change in level of the signal.  The higher
the
> ration, the more extrreme the compression.
>
> You may have zero, one or two time controls.  These adjust the
attack and
> delay times of the compressor.  The attack ajusts how quickly the
compressor
> reacts to an increase in level, and the decay how quickly the
compression
> "releases" as the input level drops.
>
> Advanced features inlcude side chain processsing, and multiband
compression.
> Yoiu may also have expansion or gating facilities.
>
> Not having tried it, I'd suggest that gating is more crtitical than
> compression, to silence unwanted pickup of audio.  Compression
should
> probably be non-agressive, unless the voice recognition system is
very fussy
> over input levels.  Too much compression will bring all background
noise up
> to a similar level to the voice you are trying ot detect.
>
> I have an opinion that by using multiple mics and good DSP
processing, room
> pickup whilst avoiding extraneous noise should be easy.  The
videoconference
> crowd have it licked for their field, and I think similar
techniques could
> be used for voice control.  But I'm not aware of anyone doing
anything about
> it :-)
>
> ----- Original Message -----
> From: "Eamon O'Gorman" <eamonogorman@e...>
> Newsgroups: tex.com.ml.ukha_d
> Sent: 19 February 2002 18:28
> Subject: Re: [ukha_d] Re: In celing mics.
>
>
> > I've got a similar set up to the one the chap in the U.S is
talking about,
> I
> > am using the Kustom 6640, which I hope to be able to use the
page input
> for
> > whole house announcements. As to mounting the mics in the
ceiling, I dont
> > see as there is any other real choice,,,,, wall mounting is out
of the
> > question (wifey would rather rip out my spine than let me chase
the
> walls).
> >
> >     I got some tips from Mike at letsautomate, so I am going to
try these
> > and see how I get on. If there are any sound engineers out
there, can they
> > please explain to me what the hell  "Soft Knee " or
"Hard Knee"
means on a
> > liimiter/gate for a start, and then explain what the other 14
knobs annd
> > buttons do.....
> >
> > Regards,
> >
> > Eamon "Way over my head here" O'Gorman
> >
> >
> > ----- Original Message -----
> > From: "psghome2002" <psghome@h...>
> > To: <ukha_d@y...>
> > Sent: Tuesday, February 19, 2002 11:43 AM
> > Subject: [ukha_d] Re: In celing mics.
> >
> >
> > > I've not done it yet but am planning on doing the same as
you
using
> > > Shure intelligent mixer and crown mics. I did get some
advice
>from
> > > US based guy - I've copied it below. I'd be VERY interested
in
your
> > > findings, I'm a few weeks away from the whole-house retrofit
of
> > > lights,power,CAT5 etc and am still undecided whether to go
the
full
> > > monty with voice recognition.
> > >
> > > Paul.
> > >
> > > +++++++++++++++++++++++++++++++++++++++++++++++++++
> > >
> > > 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.
> > >
> > > One caution, do not put the mikes in the ceiling.  Even
> > > Crown states this is not the best place even though it
> > > would seem to be.
> > >
> > > For the house audio, I have a Kustom unit.  Would prefer
> > > to have the 6640 but it wasn't out at the time I bought
> > > mine.  Would like to upgrade sometime when I find
> > > someone that has a need for just a 4X6 instead of a 6X6
> > > unit.  The page function would be great to feed HAL into
> > > so the responses go to all areas.
> > >
> > > Has doorbell inputs that could be connected to sensors
> > > or X10 devices for notification or alarms.
> > >
> > > Hope this gives you a little help.  Check out the Feb
> > > issue of Home Automation magazine for a more complete
> > > list of equipment that I have here.  My home is the
> > > Featured home of the month.
> > >
> > >
> > >
> > > --
> > > 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
> > > > Hi Don,
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > I'm just about to start a HA project covering pretty
much
> > > everything
> > > > including Lighting, Security, Heating, Audio etc. I've
got a
few
> > > > questions I hope you don't mind answering?...
> > > >
> > > >
> > > >
> > > > I'm looking at putting in a whole-house open-air
microphone
> > > system - I
> > > > presume you use something like this?
> > > >
> > > >
> > > >
> > > > I've tried HAL2000 with some success just using a
standard
> > > microphone.
> > > > How accurate (in terms of recognition accuracy) have
you
managed
> > > to get
> > > > your system? . and how difficult was it to set up?
> > > >
> > > >
> > > >
> > > > What equipment do you use?
> > > >
> > > >
> > > >
> > > > Many thanks,
> > > >
> > > >
> > > >
> > > > Paul Gale.
> > > >
> > >
> > >
> > >
> > > --- In ukha_d@y..., "Eamon  O'Gorman"
<eamonogorman@e...>
wrote:
> > > >    I have just started playing with some mics/mixers
for
voice
> > > control via in ceiling mics. I have a feeling its going to
be
a bit
> > > of a struggle to get them working reliably, but thats the
fun
of
> > > it....
> > > >
> > > >   Anyone else tried this, or had any success/failures.
I am
using
> > > HAL2000 (which has quite good recognition over phone and
using
basic
> > > pc microphone), but these limiters and gates are looking
pretty
> > > complex. I've got the wiring right for my first mic, and get
some
> > > recognition (although not near as good as with my pc mic).
If
anyone
> > > has any tips I'd appreciate it.
> > > >
> > > > Thanks,
> > > > Eamon
> > >
> > >
> > >
> > > For more information: http://www.automatedhome.co.uk
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> > >
> > >
> >
> >
> >
> >
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