Two pieces of physics that haven't heretofore been mentioned:
1) Propeller noise is fairly directional. For more on this, see
http://www.google.com/search?q=propeller+noise+directivity
This means that when a Real World aircraft flies past, you will
hear a more rapid build-up and more rapid fal
John Denker wrote:
> There is a huge element of arbitrariness and artificiality in the
> whole exercise, because few gamers are going to turn up there
>
...
> Again, fiddling with the gain is tantamount to fiddling with
> the reference distance
...
> None of this "reference distance" stuff has a
On jeudi 22 janvier 2009, Melchior FRANZ wrote:
> * gerard robin -- Thursday 22 January 2009:
> > On jeudi 22 janvier 2009, Melchior FRANZ wrote:
> > > The law is the same, but the distances aren't. Lower frequency
> > > travels farther.
> >
> > Not fully right. Only right when high frequencies ar
On 01/22/2009 04:20 PM, James Sleeman wrote:
> Hi John, great answer, thanks..
:-)
>> We see that at the reference distance (r0), the signal is not
>> attenuated at all. That's the defining property of the reference
>>
> So the reference distance is actually the distance from the microphone
Hi John, great answer, thanks..
John Denker wrote:
>
> We see that at the reference distance (r0), the signal is not
> attenuated at all. That's the defining property of the reference
>
So the reference distance is actually the distance from the microphone
to the sound emitting device when
* gerard robin -- Thursday 22 January 2009:
> On jeudi 22 janvier 2009, Melchior FRANZ wrote:
> > The law is the same, but the distances aren't. Lower frequency
> > travels farther.
>
> Not fully right. Only right when high frequencies are stopped
> by objects.
Yes, and there are enough partic
On jeudi 22 janvier 2009, Melchior FRANZ wrote:
> * John Denker -- Thursday 22 January 2009:
> > On 01/22/2009 06:05 AM, Melchior FRANZ wrote:
> > > But it depends on the frequency pattern, no? So we'd need to
> > > analyze the spectrum ... time to use libfftw3.
> >
> > No, the 1/r^2 attenuation is
> > I believe that the correct behaviour is as follows:
> >
> > Decrementing 126.00 results in 126.97
> > Incrementing 126.97results in 126.00
>
> Are you sure? I believe the curren behaviour is correct but not for sure
> ;-) I check it out within the next few days and drop a line here (probably
* Vivian Meazza -- Thursday 22 January 2009:
> I don't think aircraft designers should be asked to specify
> the reference distance either,
Sure, some automatism would be nice. I might even drop my
hand-crafted values if that works well. It would be nice
to have a modulation factor property that m
On 01/22/2009 02:20 PM, Vivian Meazza wrote:
> Looks good to me. Thanks for the explanation.
:-)
> I suppose we don't allow for
> humidity and pressure?
In the 1/r^2 attenuation regime, none of that matters.
Again, the exponential dissipation regime would be another
story.
> I get the imp
* John Denker -- Thursday 22 January 2009:
> On 01/22/2009 06:05 AM, Melchior FRANZ wrote:
> > But it depends on the frequency pattern, no? So we'd need to
> > analyze the spectrum ... time to use libfftw3.
>
> No, the 1/r^2 attenuation is independent of frequency. No FFT
> required.
The law is
John Denker wrote
>
> >>> Just to clarify on the reference-dist, is it that this value is a
> >>> diminishing effect, that is for reference-dist of 1 after distance 1
> >>> the volume is half original, after distance 2 the volume is 1/4
> >>> original (half of a half), distance 3 it's an 1/8th (h
* Vivian Meazza -- Thursday 22 January 2009:
> Melchior FRANZ
> I don't see any particular merit is setting the value in preferences.xml,
> but it would be nice if the default values worked as designed, no matter
> where they are set.
It's always nice to have default values changeable, rather than
On 01/22/2009 05:47 AM, Maik Justus wrote:
>>> Just to clarify on the reference-dist, is it that this value is a
>>> diminishing effect, that is for reference-dist of 1 after distance 1
>>> the volume is half original, after distance 2 the volume is 1/4
>>> original (half of a half), distance 3
Melchior FRANZ
> Subject: Re: [Flightgear-devel] doppler volume
>
> * Maik Justus -- Thursday 22 January 2009:
> > Vivian Meazza schrieb am 22.01.2009 11:17:
> > > I would think that the attenuation of sound in air is
> > > amenable to mathematical calculation.
>
> > Yes it is.
>
> But it depen
On Thu, 22 Jan 2009 12:43:22 +0100, Melchior wrote in message
<200901221243.23...@rk-nord.at>:
> * Jon S. Berndt -- Thursday 22 January 2009:
> > > Bingo737
>
> > Boing 314?
>
> That wouldn't work. It's too similar, as probably any court
> will find.
>
>
>
> > Actually, David Slocombe had
On Thu, 22 Jan 2009 09:42:30 +0100, Erik wrote in message
<49783176.9020...@ehofman.com>:
>
>
> Jon S. Berndt wrote:
> > Arnt, they are completely within their rights to add that
> stipulation. You
> > can bet all of the other manufacturers will have the same
> > stipulations.
>
> That said
On Thu, 22 Jan 2009 09:37:39 +0100, Erik wrote in message
<49783053.7020...@ehofman.com>:
>
> Arnt Karlsen wrote:
>
> > ..no F-g way, they add a restriction beyond the GPL,
> > toss out all Boeing models and replace them all with
> > similar Airbus, Tupolev, Antonov, Shin-Meiwa, Harbin,
> > Do
On Wed, 21 Jan 2009 20:26:02 -0600, Jon wrote in message
<003901c97c38$c8d5fe10$5a81fa...@net>:
> > > However, if a situation
> > > arises in which the aircraft models are to be sold for a profit,
> > > please contact us to discuss implementation of a Trademark License
> > > Agreement for the sal
* Maik Justus -- Thursday 22 January 2009:
> Vivian Meazza schrieb am 22.01.2009 11:17:
> > I would think that the attenuation of sound in air is
> > amenable to mathematical calculation.
> Yes it is.
But it depends on the frequency pattern, no? So we'd need to
analyze the spectrum ... time to u
Hi Vivian,
Vivian Meazza schrieb am 22.01.2009 11:17:
> I would think that the attenuation of sound in air is amenable to
> mathematical calculation.
Yes it is. (at lest if your distance to the sound source is large
compared to the size of the source).
> Surely we shouldn't be guessing at some ar
* Jon S. Berndt -- Thursday 22 January 2009:
> > Bingo737
> Boing 314?
That wouldn't work. It's too similar, as probably any court
will find.
> Actually, David Slocombe had a good suggestion earlier. I'll
> formulate a letter to the Software Freedom Law Center and ask
> them for guidance.
Hi,
Maik Justus schrieb am 22.01.2009 13:45:
> Hello,
> James Sleeman schrieb am 22.01.2009 01:14:
>> Hi Maik,
>> ...
>> Just to clarify on the reference-dist, is it that this value is a
>> diminishing effect, that is for reference-dist of 1 after distance 1
>> the volume is half original, after
Hello,
James Sleeman schrieb am 22.01.2009 01:14:
> Hi Maik,
> ...
> Just to clarify on the reference-dist, is it that this value is a
> diminishing effect, that is for reference-dist of 1 after distance 1 the
> volume is half original, after distance 2 the volume is 1/4 original
> (half of a ha
> Or, as has been suggested before, do actually remove all occurrences
> of the name Boeing and use a substitute:
>
> Bingo737
>
> m.
Boing 314?
:-)
Actually, David Slocombe had a good suggestion earlier. I'll formulate a
letter to the Software Freedom Law Center and ask them for guidance.
* Tim Moore -- Thursday 22 January 2009:
> * Don't say the aircraft are GPL'ed. "Models are under any random license;
> seller beware." Yuck.
> * Rip out the non-GPLed models.
> * Create GPL'ed and "other" aircraft repositories.
Or, as has been suggested before, do actually remove all occurrences
On Thursday, 22. January 2009, Tim Moore wrote:
> We can't say that "all the models in the repository are covered by the GPL"
> and have models in there that are not. This is a terrible trap for anyone
> wanting to use FlightGear in any professional setting.
Please do not confuse the software lic
Jon S. Berndt wrote:
>
> I hope you agree with me that Boeing was very reasonable. I do hope we can
> be equally reasonable and fair, and comply with the GPL at the same time.
> This will require some creativity and thought.
>
I won't argue the fairness of their position, but it's simply not comp
James Sleeman wrote
>
> Hi Maik,
>
> Maik Justus wrote:
> > the effect you are discussing is not the Doppler effect, but just the
> >
> Yes, I know it's not a function of the Doppler itself, but I was
> thinking more along the lines of the volume drop off, if it were better,
> might help the con
On Thursday, 22. January 2009, Jon S. Berndt wrote:
> Since it appears as though JSBSim will use the product identifiers
> (e.g..Boeing 737) in a descriptive manner, and no profit will be derived
> from said usage, then we have no objection to inclusion of the product
> identifiers on the software
On 01/13/2009 12:43 PM, Torsten Dreyer quoted flying.toaster as follows:
>> The issue is that JSBSIM gets the external atmospheric model
>> (/environment/params/control-fdm-atmosphere set to true in flightgear). I
>> assume that imposes flight gear own atmosphere model to the FDM and THIS
>> mode
Jon S. Berndt wrote:
> Arnt, they are completely within their rights to add that
stipulation. You
> can bet all of the other manufacturers will have the same stipulations.
That said, the section is just a reminder to anyone who wants to
make a profit by selling a 'Boeing 747' simulator or s
Arnt Karlsen wrote:
> ..no F-g way, they add a restriction beyond the GPL,
> toss out all Boeing models and replace them all with
> similar Airbus, Tupolev, Antonov, Shin-Meiwa, Harbin,
> Dornier, Short etc models. And do it LOUDLY. ;o)
Not true in my opinion, the GPL can't explicitly allow th
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