Franco Del Principe wrote:

Dear members of RAHE,



snip

Why is a singer's voice not always in the center and why is
it sometimes moving?

Sometimes it is the recording.

There was a cut on a Dorian Sampler of a duet, male/female with
a quartet backing... the voices seemed to move oddly.

I know the recording engineer, and mastering engineer. So I asked.
The recording was made with stereo microphones. The singer moved
as she sang. You can hear it. :- )

So, it depends upon the recording. MOST pop recordings are made with
MONO (single) microphones for vocals and the mix is a "pan potted"
affair where mono signals are moved left/right electronically. The
"stereo" is synthetic. So the sound of the singer or anything else done
this way will be stable and not move at all.

snip


What if an exactly centered voice moves during the playback
within one and the same song? It is not much, but clearly
perceivable, about 1-2 feet left or right, forward or
backward, sometimes even up or down.

Up/down is almost certainly a phase shift related phenomenon where
you are possibly getting reflections off the ceiling at certain frequencies
that cause a shift in the apparent location of a given part of the mix - it
tends to happen with respect to frequency, and is likely to be an artifact
of the polar response of the speakers and your room interacting with that.
(this includes nasty edge refractions)

Up/down is *not* information that is inherent in the recording, nor is it something
that two speakers *can* do under normal circumstances, since there is
nothing above or below physically to generate a sound, and there is
no "data" in the recording that corresponds to this position. Normally,
speakers can produce left/right - front/back. Not up/down.



I encountered some explanations in the audio press like
- pre-amp, amp, CD player are badly designed
- the speakers are flawed
- the recording is flawed
- the singer is moving in front of the microphone
- modulating interference between direct and reflected sound
in my listening room

Most likely one of the the latter three... the speakers or electronics
are unlikley to cause the singer's position to move.

The *only* chance that the speakers are causing a *left/right* movement
is if the left and right speakers have enough variation in the frequency
response so that the relative amplitudes at any give frequency between
the left and right speaker are different. Almost like having two completely
different speakers for your left and right... but if you have recordings where
the image is rock solid, then you can completely forget about this possibility
AND the possibility that there is some problem in the signal chain (which
is *extremely* low probability).

_-_-bear





snip



Cheers,
Franco