When I posted that I hadn't yet listened to it on headphones. After
listening on headphones, listening on headphones and flipping the
phase on one side, and now having read your description of the setup,
I don't think you did anything particularly wrong. Flipping the phase
didn't make a noticeable difference in the front back imaging to me.
If it is wired as you have said then you did not wire anything out of
phase. That's good news.
If you have the omni capsules facing 180 degrees from each other and
there is no baffle on the back side like a SASS, or anything else that
would make one side of your rig a "front side", then your rig doesn't
really differentiate front and back. In theory omnis are supposed to
be omni, but in reality omnis are more directional at high frequencies
so you could point them forward and get more front/back information.
I would agree with what others have said, that the sense of the sound
happening behind you is a function of the way headphones work.
Imagine yourself having recorded the sound with your back to the
action. It wouldn't have made any difference to the mics. :-)
-Richard
--- In "Steve Pelikan" <>
wrote:
>
>
>
> The setup for the recording was basically the same as one of Curt
> Olson's experiments --- Shure 183's (omnis) attached to opposite sides
> of parallel 1 x 3 boards.
> (I wired the 2 microphones into a single t-r-s miniplug with the red
> wires going to the tip and ring and every thing else going to the
> ground. So I guess the connections could be bad, but I don't see what
> could be crossed.)
>
> If there were no boards and the mics were perfectly omni's at all
> frequencies there would be no front/back information since
> interchanging the microphones, switching channels, and rotating the
> setup 180 degress would all produce exactly the same effect. So it
> seems to me.
>
> Departures from symmetric polar pattern at even some frequencies would
> mean that there might be front/back information in the recording and I
> could believe that sticking the suckers on boards would increase this
> even more, though I haven't convinced myself that this is the case.
>
> Am I correct that it is also impossible to make a front/back
> assignment to a stationary souce that is located on the mid-plane?
>
> If the mp3 compression is messing things up, should I post a .wav file?
>
> Thanks,
>
> Steve P
>
>
>
>
> In "Richard Humphries" <mdsfx@>
> wrote:
> >
> > --- In "Steve Pelikan" <pelikan@>
> > wrote:
> > >
> > > Friends: I'd appreciate any ideas you can give me about a matter
that
> > > (I hope) will improve my understanding of stereo.
> > >
> > > In the mp3 clip http://homepages.uc.edu/~pelikas/goose.mp3
> > > you'll hear a Canada Goose flying from right to left. To me, when I
> > > listen to the recording with headphones, it sounds like the goose is
> > > flying behind me (rather than in front of me --- where it might be
> > > seen, for example).
> > >
> > > Am I nuts in this perception? or arbitrary? Can anyone
agree/disagree
> > > with the effect?
> > >
> > > When I reverse the channels (switch the headphones around left for
> > > right) it STILL sounds like the goose passes behind me. So it seems
> > > that switching left for right is a "flip" in a vertical mirror
rather
> > > than a "rotation".
> > >
> > > What kind of information conveys/creates the "front/back" effect?
> > >
> > > Finally, or to be less theoretical: When the recording was made, the
> > > goose flew in front of me. What could I have done wrong?
> > >
> > > Thanks ever so much for any hints to reduce by confusion....
> > >
> > > Steve P
> > >
> >
> >
> > The recording has slightly more anti-phase information in it than in
> > phase. Is it possible that you have a wire crossed in your recording
> > setup?
> >
> > -Richard
> >
>
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