Hi All, maybe my English isn't better than my knowledge of Microsoft Volume Control. But I was only interested in knowing why: why two equations apparently related to the same concept are different. I'm sorry. I'm a student and like other students sometimes i make questions. Like other students sometimes I make wrong questions. Like other students sometimes I make questions to wrong people. That is. Now I know that with power of my floating points no bits will never be lost. maybe we will lose some “half”… but who cares (we italians have invented the shrug style, but evidently there is a bit of italian style in every man)
Thank you Daniel, Fons and Jorn, I appreciated your answers. Thank you Richard. Best Regards On 17/mar/2012, at 17:00, sursound-requ...@music.vt.edu wrote: > Message: 1 > Date: Fri, 16 Mar 2012 13:37:48 -0400 > From: Daniel Courville <courville.dan...@uqam.ca> > Subject: Re: [Sursound] question about simple equation > To: Sursound <sursound@music.vt.edu> > Message-ID: <cb88efc0.7679%courville.dan...@uqam.ca> > Content-Type: text/plain; charset="ISO-8859-1" > > Le 12-03-15 20:01, Giuseppe Silvi a ?crit: > >> I think the W component of ST450 comes out scaled by sqrt2. > > It's -3 dB, revsqrt(2), on the W at the output of the ST450. So, yes, > boosting the W by 3 dB, sqrt(2), at the input of your processor makes > sense. Anyway, it's the way I do it. > >> // M = (sqrt2 * W) + X; // several clipping problem >> M = .5 * ((sqrt2 * W) + X); // without clipping >> S = Y > > Remember that, globally, you're combining three channels into two > channels, so yes, your output can get over 1, which is a problem at the > DAC, but not internally in Max. > > - Daniel > > > Message: 3 > Date: Sat, 17 Mar 2012 05:24:39 -0000 > From: Richard Lee <rica...@justnet.com.au> > Subject: Re: [Sursound] question about simple equation > To: 'Surround Sound discussion group' <sursound@music.vt.edu> > Message-ID: <01CD040D.AA671260@edgexp> > Content-Type: text/plain; charset="us-ascii" > >> cardioid = 1/2 ( sqrt2 W + X ) > >> but for Mid-Side decoding from B-Format, where M is the same cardioid >> component, I often find this equation: > >> M = sqrt2 W + X > > This is an instance of a patented Microsoft software invention called a > Volume Control. There are also ancient hardware implementations of this > useful device which can be used to avoid clipping by those versed in the art. > > > Also to generate clipping where this is a desired effect. It is sometimes > called a Gain Control. Both positive & negative gain is possible. > >> writing the equation inside max6 I had several clipping problems with the > decoding of a Soundfield ST450 signal, that has four matched line under > single knob. > > The ST450 uses such a hardware implementation I designed circa 1980 for the > Mk4 Soundfield. Experiment to find the best settings for you. > > It is possible to have several instances (both hardware & software) of these > devices to optimise the dynamic range and clipping performance of a complex > signal processing chain at various points. > >> I record the b-format in a single quadro file. > > If you do all recording and processing in 64b Floating Point, you may be able > to avoid infringing Microsoft patents on the Volume Control. > > > > > Message: 5 > Date: Fri, 16 Mar 2012 21:53:15 +0000 > From: Fons Adriaensen <f...@linuxaudio.org> > Subject: Re: [Sursound] question about simple equation > To: sursound@music.vt.edu > Message-ID: <20120316215315.ga23...@linuxaudio.org> > Content-Type: text/plain; charset=us-ascii > > On Sat, Mar 17, 2012 at 05:24:39AM -0000, Richard Lee wrote: > >> This is an instance of a patented Microsoft software invention called a >> Volume Control. There are also ancient hardware implementations of this >> useful device which can be used to avoid clipping by those versed in the >> art. >> >> Also to generate clipping where this is a desired effect. It is sometimes >> called a Gain Control. Both positive & negative gain is possible. > > Richard, you're being cruel... > > Ciao, > > -- > FA > > Vor uns liegt ein weites Tal, die Sonne scheint - ein Glitzerstrahl. > > > > ------------------------------ > > _______________________________________________ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound > > > End of Sursound Digest, Vol 44, Issue 13 > **************************************** _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
