On Thu, 2010-07-29 at 19:32 +0200, Ralf Mardorf wrote: > On Thu, 2010-07-29 at 10:00 -0700, Fernando Lopez-Lezcano wrote: > > On Thu, 2010-07-29 at 16:14 +0200, Ralf Mardorf wrote: > > > On Thu, 2010-07-29 at 17:01 +0200, JohnLM wrote: > > > > On 2010.07.29. 15:20, Gene Heskett wrote: > > > > > On Thursday, July 29, 2010 08:52:04 am Jörn Nettingsmeier did opine: > > > > > > > > > >> john, > > > > >> > > > > >> On 07/29/2010 02:35 PM, JohnLM wrote: > > > > >>> So from what I can understand, if I apply doppler effect, distance > > > > >>> attenuation and other pre-process filters to a mono input and then > > > > >>> push it through the panner plugin I get fairly correct > > > > >>> representation > > > > >>> of sound in 3D space. Right? > > > > >> > > > > >> depending on what you mean by "fairly correct", "representation", and > > > > >> "3D space" :-D > > > > >> > > > > >> doppler would come into play only if you change the distance of the > > > > >> sound, not when you move it on the sphere, as the distance remains > > > > >> constant. > > > > > > > > > > This use of 'doppler' I would call incorrect, because the doppler > > > > > shift is > > > > > a shift in the apparent frequency of the sound rising at it > > > > > approaches, and > > > > > decreasing as it leaves. I'm sure you have a term for what you mean, > > > > > but > > > > > doppler isn't it. That police officers radar gun measures your speed > > > > > by > > > > > listening to the echo from your vehicle, and comparing it to the > > > > > signal its > > > > > sending, which to simplify, results in a beat frequency which is > > > > > exactly > > > > > your speed if approaching or departing exactly to or from the radar > > > > > guns > > > > > position. That is why it is often called doppler radar& the weather > > > > > guys > > > > > us it also. Because they don't stand directly in front of you to > > > > > take a > > > > > reading, there is some small vector error in your favor. > > > > > > > > > >... > > > > > > > > > > That is why we call it the square law. The only way to get that back > > > > > is to > > > > > make the receptor itself 4 times bigger. But while I have observed > > > > > that > > > > > there are quite wide variations in ears, I have not seen an > > > > > individual with > > > > > expandable ears (yet) :) > > > > > > > > > >> when you hand-craft distance cues, you should not expect wonders for > > > > >> sounds originating inside your sphere of speakers. travelling through > > > > >> the center quickly can be made to work, though. > > > > > > > > I am fairly sure 'doppler' *is* what I meant. > > > > > > You notice a Doppler effect? So your speakers are far apart from each > > > other, while you are moving very fast from one speaker to the other? > > > Nothing else is called the Doppler effect. > > > There might be a sound similar or equal to a Doppler effect, but of > > > course using this term is bad. > > > > You don't understand. > > > > The previous posters are talking about _simulating_ moving sound > > sources. So you, the listener, stay in place, and the composer or sound > > artist is crafting cues for you that will simulate the movement of > > sources around you. If those sources move towards or away from you (ie: > > have a radial component of the velocity vector) then you should simulate > > the doppler effect they would have if they were real objects. It is a > > very powerful cue. > > > > So, yes, it is doppler and no, use of the term is not bad or incorrect. > > > > -- Fernando > > > > PS: for example, read: > > https://ccrma.stanford.edu/courses/220a-fall-2001/chowning.pdf > > http://www.dxarts.washington.edu/courses/567/08WIN/chowning.pdf > > > > > > Sorry, you could be right, if you aren't talking about 'realworld' > recordings, but about movements by virtual sources. > > E.g. the 'virtual ambulance' is driving very fast ... not a recording, > but a virtual setup. > > Interesting :). > > Ralf
PS to the German speaking people (perhaps understandable on English too): Imagine that you don't record the "TatüTata" of the police car, but you have got a sampled sound of this noise and you wish to move it by using a pan pot. We would miss the Doppler effect :D. _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
