audio processing

how do i distinguish between a recorded signal and a real live signal?

dspdspo wrote:
> how do i distinguish between a recorded signal and a real live signal?
> 
Open your eyes?

Some people claim that the can distinguish recordings of symphonies on 
very high end systems and the real thing.  On cheap systems it can be a 
bit more obvious.

Stan Pawlukiewicz wrote:
> dspdspo wrote:
> > how do i distinguish between a recorded signal and a real live signal?
> >
> Open your eyes?
>
> Some people claim that the can distinguish recordings of symphonies on
> very high end systems and the real thing.

Damn! I wonder how they do that? :-)

Andor wrote:
> Stan Pawlukiewicz wrote:
> > dspdspo wrote:
> > > how do i distinguish between a recorded signal and a real live signal?
> > >
> > Open your eyes?
> >
> > Some people claim that the can distinguish recordings of symphonies on
> > very high end systems and the real thing.
>
> Damn! I wonder how they do that? :-)

Yell FIRE!! and listen for the response?

Rune

dspdspo wrote:
> how do i distinguish between a recorded signal and a real live signal?

I don't know about you, but here's what I do: look to see if the 
amplifier input comes from a microphone or from a recording player. When 
the signal comes from a radio, you need other clues. The bandwidth of FM 
radio isn't as good as what can be recorded, so it will be the 
bottleneck no matter what the sound source. Live performances are almost 
always before an audience, and deviations from the music as intended 
(sour or missed notes, late entrances, etc.) can't be edited out. So 
audience noise and flubs are a good sign of a live performance, but not 
an assurance.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

We did this for Speaker Verification to defeat recorded
"spoofing".  A recorded signal goes through two
environments.  The 1st recording site, the mic, the
recording medium, the playback medium, the loudspeaker, and
finally the playback environment.  A live signal only goes
through one, the mouth and the live environment.  Lots of
differences to key on.  Check Motorola's patents and papers
for CipherVox.

-- 
Chip Wood

"Stan Pawlukiewicz" <spam@spam.mitre.org> wrote in message
news:dpjb8g$8r1$1@newslocal.mitre.org...
> dspdspo wrote:
> > how do i distinguish between a recorded signal and a
real live signal?

Chip Wood wrote:
> We did this for Speaker Verification to defeat recorded
> "spoofing".  A recorded signal goes through two
> environments.  The 1st recording site, the mic, the
> recording medium, the playback medium, the loudspeaker, and
> finally the playback environment.  A live signal only goes
> through one, the mouth and the live environment.  Lots of
> differences to key on.  Check Motorola's patents and papers
> for CipherVox.
>
> --
> Chip Wood

So the application is to beat the James Bond trick of playing some
taped conversation for the bad guys' bug to pick up, while he is out
doing the job?

Then the problem makes sense. I was thinking more along the
lines of finding out if you listen to a CD or a live band. 

Rune

Stan Pawlukiewicz wrote:

> dspdspo wrote:
> 
>> how do i distinguish between a recorded signal and a real live signal?
>>
> Open your eyes?

Just keeping the ears clean.

> 
> Some people claim that the can distinguish recordings of symphonies on 
> very high end systems and the real thing.  On cheap systems it can be a 
> bit more obvious.

On Thu, 05 Jan 2006 09:42:24 -0500, Stan Pawlukiewicz
<spam@spam.mitre.org> wrote:

>dspdspo wrote:
>> how do i distinguish between a recorded signal and a real live signal?
>> 
>Open your eyes?
>

Hi Stan,

  that was my first thought also.

If you hear music and it's coming from speakers 
or headphones, then the signal is "recorded".
If you hear music and see a live band playing in 
another part of the room, then the signal 
is a "real live signal".

[-Rick-]

RL [Sat, 07 Jan 2006 13:08:21 GMT]:
 >If you hear music and it's coming from speakers 
 >or headphones, then the signal is "recorded".

Most concerts I've been to have music coming
from speakers.  Other than the Milli Vanilli
one, I'd think they were all live.

-- 
 40th Floor - Software  @  http://40th.com/
 iPlay : the ultimate audio player for mobiles
 parametric eq, xfeed, reverb; all on a mobile