[Csnd] ambisonic rotation

Date	2013-06-08 02:37
From	hcenteno
Subject	[Csnd] ambisonic rotation
	Hello, I'm decoding first order ambisonic recordings (using a tetrahedral mic) through a cube of virtual speakers (binaural) using Csound. I'm also doing rotation on the z-axis of the ambisonic soundfield using this formula: ax = (ax * cos(kyaw)) - (ay * sin(kyaw)) ay = (ax * sin(kyaw)) + (ay * cos(kyaw)) Where kyaw is the angle in radians. I'm getting very mixed results that I'll try to summarize below (in all cases I use hrtfmove with the same parameters): 1. Using bfromdec1 for decoding, when I rotate the soundfield I get very bad results and it's hard to perceive the rotation and the overall sound localization is very blurred. When I go from 0 to 360 degrees it sounds almost like the soundfield is rotating twice since I seem to hear sounds jumping from left to right twice, but overall is hard to tell what's going on. 2. Using bfromdec1 but instead rotating the virtual speakers, I can hear the soundfield rotating and the localization works much better. 3. Using the deprecated bformdec I get the best results and I can hear the sounds pan around much more clearly. So I guess the question is, what's the difference between bformdec and bformdec1? Does anyone have an idea what's going on? Is the rotation formula the problem? Thanks! Hector -- View this message in context: http://csound.1045644.n5.nabble.com/ambisonic-rotation-tp5724316.html Sent from the Csound - General mailing list archive at Nabble.com.

Date	2013-06-08 08:16
From	peiman khosravi
Subject	Re: [Csnd] ambisonic rotation
	Hello, I have had problems with bformdec1 in the past, and they never got solved as far as I know: http://csound.1045644.n5.nabble.com/ambisonic-Csound-td3277318.html I just gave up though, as I find amplitude panning more flexible and have never heard the goodness of ambisonic that everyone goes on about. P www.peimankhosravi.co.uk \|\| Subscribe to RSS Feed To receive emails about upcoming concerts visit this page & enter your email address in the 'follow' section. On 8 June 2013 02:37, hcenteno <hcengar@gmail.com> wrote: Hello, I'm decoding first order ambisonic recordings (using a tetrahedral mic) through a cube of virtual speakers (binaural) using Csound. I'm also doing rotation on the z-axis of the ambisonic soundfield using this formula: ax = (ax * cos(kyaw)) - (ay * sin(kyaw)) ay = (ax * sin(kyaw)) + (ay * cos(kyaw)) Where kyaw is the angle in radians. I'm getting very mixed results that I'll try to summarize below (in all cases I use hrtfmove with the same parameters): 1. Using bfromdec1 for decoding, when I rotate the soundfield I get very bad results and it's hard to perceive the rotation and the overall sound localization is very blurred. When I go from 0 to 360 degrees it sounds almost like the soundfield is rotating twice since I seem to hear sounds jumping from left to right twice, but overall is hard to tell what's going on. 2. Using bfromdec1 but instead rotating the virtual speakers, I can hear the soundfield rotating and the localization works much better. 3. Using the deprecated bformdec I get the best results and I can hear the sounds pan around much more clearly. So I guess the question is, what's the difference between bformdec and bformdec1? Does anyone have an idea what's going on? Is the rotation formula the problem? Thanks! Hector -- View this message in context: http://csound.1045644.n5.nabble.com/ambisonic-rotation-tp5724316.html Sent from the Csound - General mailing list archive at Nabble.com. Send bugs reports to the Sourceforge bug tracker https://sourceforge.net/tracker/?group_id=81968&atid=564599 Discussions of bugs and features can be posted here To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe csound"

Date	2013-06-08 15:48
From	hcenteno
Subject	[Csnd] Re: ambisonic rotation
	Hello Peiman, Yes, I came across your posting and some other one mentioning problems with bformdec1. I did a quick check to the source code and it seems to be fine regarding the logic, but I don't know if there's something wrong with the coefficients. I guess Fons would be the one to ask? I'm going to do some more tests and see if I can figure out something. Hector -- View this message in context: http://csound.1045644.n5.nabble.com/ambisonic-rotation-tp5724316p5724319.html Sent from the Csound - General mailing list archive at Nabble.com.

Date	2013-06-09 17:59
From	hcenteno
Subject	[Csnd] Re: ambisonic rotation
	OK, my bad. I had a silly error when using the values from the decoder in the equations. ambdec1 works fine. I was feeding the result of the ax equation to the ay equation instead of the original ax. Hector -- View this message in context: http://csound.1045644.n5.nabble.com/ambisonic-rotation-tp5724316p5724328.html Sent from the Csound - General mailing list archive at Nabble.com.