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shotgun & array microphones for speech recognition

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February 3, 2005 9:42:24 AM

Archived from groups: rec.audio.pro (More info?)

Has anyone here experimented with professional shotgun microphones for
speech recognition? I'm considering buying this microphone:
Audio-Technica AT835B Short Shotgun Condenser Microphone
(http://www.fullcompass.com/Products/pages/SKU--23740/)

I believe I can achieve far better results with this mic in a noisy
room. I actually plan to use this mic for my home jukebox system (and
later in a car system.) The current mics I'm using do work pretty
well though. In a car the crown pzm-10 and pzm-11 mic's work pretty
well even while on the freeway with a moderate amount of road noise.
With the crown mic's I can control my jukebox from 20 feet away with
high accuracy in a quiet room. My headset microphone (parrot talkpro)
works even better with lots of road noise and the stereo turned up.

I'm also considering buying this microphone - Acoustic Magic
(http://www.acousticmagic.com/products/)

Does anyone know which mic might be better in a noisy environment,
e.g. human speech, tv, ect. The user's mouth will be from 1-2 feet
away from the microphone.

Thanks,
Jeff
IntelligentJukebox (dot) com
Anonymous
February 3, 2005 12:33:46 PM

Archived from groups: rec.audio.pro (More info?)

Jeff <jeff__==remove--_@theintelligenthome.com> wrote:
>Has anyone here experimented with professional shotgun microphones for
>speech recognition? I'm considering buying this microphone:
>Audio-Technica AT835B Short Shotgun Condenser Microphone
>(http://www.fullcompass.com/Products/pages/SKU--23740/)
>
>I believe I can achieve far better results with this mic in a noisy
>room. I actually plan to use this mic for my home jukebox system (and
>later in a car system.) The current mics I'm using do work pretty
>well though. In a car the crown pzm-10 and pzm-11 mic's work pretty
>well even while on the freeway with a moderate amount of road noise.
>With the crown mic's I can control my jukebox from 20 feet away with
>high accuracy in a quiet room. My headset microphone (parrot talkpro)
>works even better with lots of road noise and the stereo turned up.

It won't do what you think it will do. It will not do anything to deal
with the acoustical problems and near-field noise.

>I'm also considering buying this microphone - Acoustic Magic
>(http://www.acousticmagic.com/products/)

This isn't much of an array, actually. I can't imagine something this
small is going to be actually effective even for voice work. It might
be interesting to try, though.

>Does anyone know which mic might be better in a noisy environment,
>e.g. human speech, tv, ect. The user's mouth will be from 1-2 feet
>away from the microphone.

There's your problem. Get the microphone closer to the source. Try
a headworn mike, and if that isn't enough, try the Coles lip mike.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
February 4, 2005 11:36:27 AM

Archived from groups: rec.audio.pro (More info?)

On 3 Feb 2005 09:33:46 -0500, kludge@panix.com (Scott Dorsey) wrote:

>Jeff <jeff__==remove--_@theintelligenthome.com> wrote:
>>Has anyone here experimented with professional shotgun microphones for
>>speech recognition? I'm considering buying this microphone:
>>Audio-Technica AT835B Short Shotgun Condenser Microphone
>>(http://www.fullcompass.com/Products/pages/SKU--23740/)
>>
>>I believe I can achieve far better results with this mic in a noisy
>>room. I actually plan to use this mic for my home jukebox system (and
>>later in a car system.) The current mics I'm using do work pretty
>>well though. In a car the crown pzm-10 and pzm-11 mic's work pretty
>>well even while on the freeway with a moderate amount of road noise.
>>With the crown mic's I can control my jukebox from 20 feet away with
>>high accuracy in a quiet room. My headset microphone (parrot talkpro)
>>works even better with lots of road noise and the stereo turned up.
>
>It won't do what you think it will do.


> It will not do anything to deal
>with the acoustical problems and near-field noise.

I'm not sure if this is a problem. AFAIK the Crown pzm's don't take
care of these problems. All I need is the same quality as the Crowns,
but with a different pickup pattern - super-cardiod. Do you think the
AT835B will work as well as my Crowns?

>
>>I'm also considering buying this microphone - Acoustic Magic
>>(http://www.acousticmagic.com/products/)
>
>This isn't much of an array, actually. I can't imagine something this
>small is going to be actually effective even for voice work. It might
>be interesting to try, though.

Can you recommend any good array microphones? Price is no object.

>
>>Does anyone know which mic might be better in a noisy environment,
>>e.g. human speech, tv, ect. The user's mouth will be from 1-2 feet
>>away from the microphone.
>
>There's your problem. Get the microphone closer to the source. Try
>a headworn mike, and if that isn't enough, try the Coles lip mike.
>--scott

Headsets and lavaliers are not an option for my product. My mic must
be hands-free.

Thanks,
Jeff
Related resources
Anonymous
February 4, 2005 11:36:28 AM

Archived from groups: rec.audio.pro (More info?)

"Jeff" wrote ...
> I'm not sure if this is a problem. AFAIK the Crown pzm's
> don't take care of these problems. All I need is the same
> quality as the Crowns, but with a different pickup pattern -
> super-cardiod. Do you think the AT835B will work as
> well as my Crowns?

How are you going to aim it? You can't use anything like that
in a vehicle. Not just because of the physical length, but also
because of the physics of sound in enclosed spaces (especially
small places like vehicles).

Not clear that "that is all you need". Do you understand the physics
of sound wave propogation in an enclosed space, the consequences
of the inverse-square law, and the difficulty of extracting speech
from broadband interfrence (like music or road noise)?

You seem to be tying to do something that teams of PhDs with
big budgets haven't solved yet. Absolutely no problem with that.
But expecting to find plug-in, off-the-shelf solutions seems overly
optimistic at this stage of human understanding.

> Can you recommend any good array microphones?
> Price is no object.

Have you investigated the university research projects? I saw a
pretty impressive experiment (at MIT, I think) that used several
hundred electret capsules and several racks full of processing.

> Headsets and lavaliers are not an option for my product.
> My mic must be hands-free.

Not sure the technology is there yet. We saw voice-command
computers, etc. in science-fiction movies and TV decades ago,
but you were hearing a human-aimed shotgun just outside the
frame, (or dubbed dialog recorded with a close mic after the
shooting). It doesn't work like that in the real world. Hang
around news:rec.arts.movies.producion.sound for a while to
see what the practical issues are.

Have you listened/recorded the audio out of your mics to hear
what your voice-recognition is dealing with?
Anonymous
February 4, 2005 12:26:26 PM

Archived from groups: rec.audio.pro (More info?)

Jeff <jeff__==remove--_@theintelligenthome.com> wrote:
>On 3 Feb 2005 09:33:46 -0500, kludge@panix.com (Scott Dorsey) wrote:
>
>> It will not do anything to deal
>>with the acoustical problems and near-field noise.
>
>I'm not sure if this is a problem. AFAIK the Crown pzm's don't take
>care of these problems. All I need is the same quality as the Crowns,
>but with a different pickup pattern - super-cardiod. Do you think the
>AT835B will work as well as my Crowns?

Probably. They'll certainly work better than any interference tube
microphone.

>>>I'm also considering buying this microphone - Acoustic Magic
>>>(http://www.acousticmagic.com/products/)
>>
>>This isn't much of an array, actually. I can't imagine something this
>>small is going to be actually effective even for voice work. It might
>>be interesting to try, though.
>
>Can you recommend any good array microphones? Price is no object.

Is size an object? The problem is that an array that is actually useful
is going to have to be very large. I don't know of any that work which
are commercial products although I have seen some research demos at
conferences.

>Headsets and lavaliers are not an option for my product. My mic must
>be hands-free.

Then you're going to have problems with external noise pickup.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
!