Dunno if this is relevant. The stereo imager on Logic Pro assigns frequency bands to be boosted and cut slightly in each channel (roughly describing a sine wave through the frequency spectrum) so that there'll be more of one band in the left, the same band is slightly cut in the right, thus creating the illusion of a wider stereo image. Although this is fully adjustable so I can't really tell you where to start emulating this. It's a very subtle effect, too, even at it's most severe there's very little difference. As a simple version of this you could use the hi-fi 'surround' method, simply boost the treble (from about 10kHz) in one or other chanel, in theory then that will cause more reflectivity in the room and stereo effects become 'surround' (sic) effects. It's not as good as it sounds, but it is one way to vary your stereo image.
Date: Wed, 11 Nov 2009 23:37:03 +0100 From: derek@umatic.nl To: THIS_IS_POP@web.de CC: pd-list@iem.at Subject: Re: [PD] imager
Ah you must mean this:
http://en.wikipedia.org/wiki/Stereo_imaging
Your delay idea only covers one part of the psychoacoustics of the stereo image: the difference in time when a sound reaches each ear. Psychoacoustics are a bit more complicated than that I'm afraid. You might look up HRTF (head related transfer functions) to get a better idea of the time differences involved. But there are a lot of other factors. An intro book on psychoacoustic might be a good place to start.
Maybe some of the ambisonics experts around here will chip in some other things...
best, Derek
Derek Holzer wrote:
What is an imager supposed to do? I've never heard of this effect and Google isn't too helpful on the subject.
D.
Johannes wrote:
hello people,
i like to build an imager effect in pd but have some trouble with it. what i´ve acually tryed is very simple: sending one signalchannel of an stereo pair into delaywrite~ (while the other goes directy into dac~) after 6 - 26 ms later i read out of it with delread~ and is connected to the second input of dac~.
is this the right way to build an imager?
does anybody know the theoretic background of the imager?
some other ideas how i can do an imager in pd?
-- ::: derek holzer ::: http://blog.myspace.com/macumbista ::: http://www.vimeo.com/macumbista ::: ---Oblique Strategy # 24: "Bridges -build -burn"
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