## Re: [Audacity-users] [Audacity-nyquist] newbie question - db-to-linear (fwd)

 Re: [Audacity-users] [Audacity-nyquist] newbie question - db-to-linear (fwd) From: David R. Sky - 2008-11-19 23:22:57 ```---------- Forwarded message ---------- Date: Wed, 19 Nov 2008 22:00:26 +0100 From: Mikael Reply-To: Discussion of developing Nyquist plug-ins for Audacity To: Discussion of developing Nyquist plug-ins for Audacity Subject: Re: [Audacity-nyquist] [Audacity-users] newbie question - db-to-linear Hi again! It's exact, by definition. I could give references to standards and so on, but perhaps this is not the right forum for that. Here is a link: http://en.wikipedia.org/wiki/Decibel Regards, Mikael On Wed, Nov 19, 2008 at 9:40 PM, David R. Sky wrote: > Thanks Micael, > > I recall having read some years ago that that equation is "only" an > approximation - is this true and, if so, what's the "exact" equation and > why isn't it defunned that way in Nyquist? > > Thanks - David > > -- > David R. Sky > http://www.shellworld.net/~davidsky/ > > > On Wed, 19 Nov 2008, Mikael wrote: > >> -6 dB should not be exactly 0.5, but: >> >> -6 dB -> 10^(-6/20) = 0.50118723... >> >> Regards, >> Mikael >> >> On Wed, Nov 19, 2008 at 8:28 PM, David R. Sky wrote: >>> Thanks for posting the results Gale. I don't know why (db-to-linear -6) >>> isn't _exactly_ 0.5, so I'm cross-posting to the Audacity Nyquist list. >>> (The code in question was entered into the Audacity effects | Nyquist >>> prompt.) >>> >>> David >>> >>> On Wed, 19 Nov 2008, gale@... wrote: >>> >>>> On Tue, 18 Nov 2008 11:35:22 -0800 (PST) >>>> "David R. Sky" wrote: >>> >>>>> (format nil "0db = ~a; -6db = ~a" >>>>> (db-to-linear 0) (db-to-linear -6)) >>>>> >>>>> You might get an error message displayed, along with values displayed >>>>> which Nyquist understands 0db and -6db to be in linear terms. >>>> >>>> It reads 0 dB as "1" and - 6 dB as "0.501187". >>>> >>>> >>>> Gale >>>> >>>> >>>> >>>> ------------------------------------------------------------------------- >>>> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge >>>> Build the coolest Linux based applications with Moblin SDK & win great prizes >>>> Grand prize is a trip for two to an Open Source event anywhere in the world >>>> http://moblin-contest.org/redirect.php?banner_id=100&url=/ >>>> >>> >>> ------------------------------------------------------------------------- >>> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge >>> Build the coolest Linux based applications with Moblin SDK & win great prizes >>> Grand prize is a trip for two to an Open Source event anywhere in the world >>> http://moblin-contest.org/redirect.php?banner_id=100&url=/ >>> _______________________________________________ >>> Audacity-nyquist mailing list >>> Audacity-nyquist@... >>> https://lists.sourceforge.net/lists/listinfo/audacity-nyquist >>> >> >> ------------------------------------------------------------------------- >> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge >> Build the coolest Linux based applications with Moblin SDK & win great prizes >> Grand prize is a trip for two to an Open Source event anywhere in the world >> http://moblin-contest.org/redirect.php?banner_id=100&url=/ >> _______________________________________________ >> Audacity-nyquist mailing list >> Audacity-nyquist@... >> https://lists.sourceforge.net/lists/listinfo/audacity-nyquist >> >> > > ------------------------------------------------------------------------- > This SF.Net email is sponsored by the Moblin Your Move Developer's challenge > Build the coolest Linux based applications with Moblin SDK & win great prizes > Grand prize is a trip for two to an Open Source event anywhere in the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > Audacity-nyquist mailing list > Audacity-nyquist@... > https://lists.sourceforge.net/lists/listinfo/audacity-nyquist > ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Audacity-nyquist mailing list Audacity-nyquist@... https://lists.sourceforge.net/lists/listinfo/audacity-nyquist ```

 Re: [Audacity-users] [Audacity-nyquist] newbie question - db-to-linear (fwd) From: David R. Sky - 2008-11-19 23:22:57 ```---------- Forwarded message ---------- Date: Wed, 19 Nov 2008 22:00:26 +0100 From: Mikael Reply-To: Discussion of developing Nyquist plug-ins for Audacity To: Discussion of developing Nyquist plug-ins for Audacity Subject: Re: [Audacity-nyquist] [Audacity-users] newbie question - db-to-linear Hi again! It's exact, by definition. I could give references to standards and so on, but perhaps this is not the right forum for that. Here is a link: http://en.wikipedia.org/wiki/Decibel Regards, Mikael On Wed, Nov 19, 2008 at 9:40 PM, David R. Sky wrote: > Thanks Micael, > > I recall having read some years ago that that equation is "only" an > approximation - is this true and, if so, what's the "exact" equation and > why isn't it defunned that way in Nyquist? > > Thanks - David > > -- > David R. Sky > http://www.shellworld.net/~davidsky/ > > > On Wed, 19 Nov 2008, Mikael wrote: > >> -6 dB should not be exactly 0.5, but: >> >> -6 dB -> 10^(-6/20) = 0.50118723... >> >> Regards, >> Mikael >> >> On Wed, Nov 19, 2008 at 8:28 PM, David R. Sky wrote: >>> Thanks for posting the results Gale. I don't know why (db-to-linear -6) >>> isn't _exactly_ 0.5, so I'm cross-posting to the Audacity Nyquist list. >>> (The code in question was entered into the Audacity effects | Nyquist >>> prompt.) >>> >>> David >>> >>> On Wed, 19 Nov 2008, gale@... wrote: >>> >>>> On Tue, 18 Nov 2008 11:35:22 -0800 (PST) >>>> "David R. Sky" wrote: >>> >>>>> (format nil "0db = ~a; -6db = ~a" >>>>> (db-to-linear 0) (db-to-linear -6)) >>>>> >>>>> You might get an error message displayed, along with values displayed >>>>> which Nyquist understands 0db and -6db to be in linear terms. >>>> >>>> It reads 0 dB as "1" and - 6 dB as "0.501187". >>>> >>>> >>>> Gale >>>> >>>> >>>> >>>> ------------------------------------------------------------------------- >>>> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge >>>> Build the coolest Linux based applications with Moblin SDK & win great prizes >>>> Grand prize is a trip for two to an Open Source event anywhere in the world >>>> http://moblin-contest.org/redirect.php?banner_id=100&url=/ >>>> >>> >>> ------------------------------------------------------------------------- >>> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge >>> Build the coolest Linux based applications with Moblin SDK & win great prizes >>> Grand prize is a trip for two to an Open Source event anywhere in the world >>> http://moblin-contest.org/redirect.php?banner_id=100&url=/ >>> _______________________________________________ >>> Audacity-nyquist mailing list >>> Audacity-nyquist@... >>> https://lists.sourceforge.net/lists/listinfo/audacity-nyquist >>> >> >> ------------------------------------------------------------------------- >> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge >> Build the coolest Linux based applications with Moblin SDK & win great prizes >> Grand prize is a trip for two to an Open Source event anywhere in the world >> http://moblin-contest.org/redirect.php?banner_id=100&url=/ >> _______________________________________________ >> Audacity-nyquist mailing list >> Audacity-nyquist@... >> https://lists.sourceforge.net/lists/listinfo/audacity-nyquist >> >> > > ------------------------------------------------------------------------- > This SF.Net email is sponsored by the Moblin Your Move Developer's challenge > Build the coolest Linux based applications with Moblin SDK & win great prizes > Grand prize is a trip for two to an Open Source event anywhere in the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > Audacity-nyquist mailing list > Audacity-nyquist@... > https://lists.sourceforge.net/lists/listinfo/audacity-nyquist > ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Audacity-nyquist mailing list Audacity-nyquist@... https://lists.sourceforge.net/lists/listinfo/audacity-nyquist ```