RE: Re: placing microphones...

["Nikola Kasic" <nikola@xxxxxxx>]

Paul,

I am sitting in a sofa opposite the TV and I am faced towards TV. Where should I mount my mic? If I mount mic on a wall behind me it will be closer to me then to the TV but it will be behind my back. If I place it behind TV, I'll be faced towards mic, but TV will be closer. So, which way to go?

My original plan is neither. I planned to put it above the doors of the lounge, so it would be at on the side, almost equally distanced from me and TV (slightly closer to TV). But distance between me and mic and TV and mic will be about 4-5m, while distance between me and TV is about 3.5m.

Is that O.K?

I am reading all the theory, but I'm not smarter. All the documents are for the environment when you know where speaker is standing, so you use different kinds of mics to enhance reception from speaker and attenuate the noise. Hence kardioid etc. mics.

However, in a flat I'll be moving and for moving speakers they recommend using wireless mics which you wear, but you don't want those either. So there's no proper solution. I'll asume that I'll be in a sofa and try to adjust everything for that scenario. All the rest is in god's hands.

Where did you buy your microphones from?

 

I just ordered mic cable. It would cost me about 44 quid, because delivery is £8.

Spoke to Mark from West London Elec as you recommended.

They don't have web site yet (will in a month, he said) and their address is 9-11Acton High Road if anyone is interested.

 

You said that you did a lot of research before diving into this. What makes you think that recognition is not good because of software and not because of hardware or microphone placement?

Did you ever consider placing wireless microphones, instead of wired ones, so you can place more of them, at more appropriate places?

Regarding noise cancellation, did you consider having one mic very close to TV speaker and use that signal for cancellation. Maybe having wireless one and place it on top, or inside the TV speaker, or inside TV?

 

Nik

-----Original Message-----
From: psghome2002 [mailto:psghome@xxxxxxx]
Sent: 15 July 2002 13:21
To: ukha_d@xxxxxxxSubject: [ukha_d] Re: placing microphones...

I'm emailing several people with the same info at the moment - maybe
I should put it all down on a web page (if I ever get the time!).
See my comments below (rather long though):


> What do you use them for, at the moment?

Used for Voice Recognition - tried HAL2000 and HomeVoice. Both got
serious limitations in the way I want to use it though. I've been
talking to Dan Hoenhen (ACE) about him developing an ACE VR module
which could potentially be much more flexible than HAL or HomeVoice.

Also will use as additional voice/noise tracking as part of Comfort
alarm system - recording when alarm activated. Got a lot to do
before that though.

> Do you have one in each room, or maybe two in larger rooms like
lounge?

only one in each room (well 7 so far). Although some of my rooms are
fairly large, one mic picks up voice OK (depending on background
noise). Interesting listening to conversations - not that I'd do
that of course!

> Which cable did you use? Someone said that it's very important to
put good
> quality microphone cable. Where did you buy it?

I agree - mic cable is very different to other types of cable. I
used an Adastra Z323 cable - 2 cores with overall screen.
recommended for 'installed' sound applications. Got it from  West
London Elec - Mark - 0208 9922155. £35.25 inc VAT per 100m drum.


> And what's your longest run from mic to mixer?

About 20-30m I guess. Mic cable can run much longer distances
though. I've used it on productions in excess of 60m

> I am sorry for so many questions, but there are only few people
with
> microphones on this group, so you are very valuable source of
information.
> It seems that the most important thing is placing them.
> Where did you place yours?

On the wall at light switch height. Although the guys at Shure are
very adamant about not ceiling mounting, I did try taping a mic at
various points around the room and the difference was normally quite
small. Best to site it towards where you will speak. I suggest you
try it like this before running cable.

> At the begining, I'll have my microphone in the lounge only.
Therefore, I'll
> not use mixer yet (have to save money for it first). That's where
it will be
> mostly used for giving commands for controlling devices. My lounge
is
> 6.5mx3.8m. Sofa is opposite to the TV and that's where, usually
I'll be
> giving commands from.
> But it's not simple for me to bring microphone close to the sofa.
How did
> you place yours?
> How does it behave when TV is playing? Is it capable of
distinguishing your
> voice from TV voice, or do you have to yell?

You need to set your expectations as to what to expect from 'open
air voice recognition'. The results will range >from yourself many
times!). VR technology (at least in open air) is still limited. If
you've got a TV on (depending on volume) the results will vary a
lot. After all, how could the software distinguish between someone
talking on the TV and your voice?

I've been thinking about noise cancelling technology to help with
this - maybe feeding the output of the TV/Stereo into a circuit with
the mic signal and cancelling out the TV/Stereo frequencies. I
suspect it'd be quite difficult though as the signal transmitted
from the TV speaker will sound very different to the 'clean' line-
out signal. Any thoughts anyone?

> You have that intelligent mixer and it detects which microphones is
> receiving sound an makes it active. If TV or music is playing in
the lounge,
> will that lock the mixer to microphone in the lounge, so it will
not listen
> in other rooms?

Yes it can lock it out. The mixer has input balancing controls for
each input and an overall master control. You set these controls
depending on the ambient levels in each room so that it switches
correctly. This of course doesn't account for when someone switches
on loud TV or music in the kitchen and you're trying to talk to your
PC in the lounge. That's why I went for the Shure mixer with it's
logic control - using outputs from HV or other HA hardware, you can
manually select which mic to 'lock on' (or you could wire up a very
simple override switch - uses 5V logic). You can also detect which
mic is active - which I will use to eventually feed back PC voice to
only the room giving commands.

I went for all this as I'm interested in the technology. I think it
still has a long way to go to get to the 'Startrek Voyager' stage!

> Cheers,
> Nik
>
>
>   -----Original Message-----
>   From: psghome2002 [mailto:psghome@h...]
>   Sent: 13 July 2002 19:12
>   To: ukha_d@xxxxxxx>   Subject: [ukha_d] Re: placing microphones...
>
>
>   Round 2...
>
>   I also put in mics in most rooms for voice recognition. I did a
LOT
>   of research and eventually put in Crown PZM11 wall mics. They're
>   fairly inobtrusive and based on the US 'J Box' size format (you
can
>   use a J Box or just cut a hole in the wall and use rawl plugs for
>   the screw fixing - I did both).
>
>   The mic quality is great - it's a pressure zone mic and designed
to
>   pick up voice frequencies (has a bit of bass roll-off to cut HVAC
>   noises etc). I fed these via standard mic cable (very important
to
>   use good quality cable) which is screened (doesn't cost a great
deal
>   either) into a Shure SCM810 intelligent mixer. This mixer
supplies
>   +48V phantom power to the mics. It automatically senses which mic
>   has the loudest input and switches to that source. Also has a
logic
>   input so you can do some clever stuff linked to HomeVision etc.
>
>   Shure web site (www.shure.com)
>   Crown web site (www.crownaudio.com)
>
>   Shure has a good document on why you SHOULD NOT place mics on the
>   ceiling:
>
>   http://www.shure.com/support/technotes/app-ceiling.html
>
>   Mics will pick up all noise in the room, so depends on what you
want
>   to do with it.
>
>   I'm planning to try and create a whole-house hands-free telephone
>   system. Don't know how successful it'll be though.
>
>   I put a couple of pics on the Yahoo group Photos area - mic and
>   keypad for audio system - Under subject 'Pauls mics'
>
>   Let me know if you want more info.
>
>   Paul.
>
>
>
>   --- In ukha_d@y..., "Nikola Kasic" <nikola@k...> wrote:
>   > Along with speakers, I plan to put microphones in each room as
>   well.
>   > My main question is: what kind of cable I should put in and
what's
>   the
>   > longest run I can use before degrading signal?
>   > Also, where should I place microphones, relative to the
speakers,
>   in order
>   > to avoid feedback and echoing?
>   > If speaker is close to the microphone and music is coming out
of
>   it, will I
>   > have to yell in order to be heard by microphone?
>   > I know that there are very few people with installed
microphones
>   in this
>   > group. Can they come forward and tell me what's their
experience,
>   which
>   > cables they used and where did they place microphones.
>   > Cheers,
>   > Nik
>
>
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