[PD] physical modelling/general pd

Jack jack at rybn.org
Sat Aug 9 19:13:08 CEST 2008 

I'm not an expert in sound. You have to ask to other people on the  
list for this problem.
I only use Pd with simple sound synthesis in my wind chime example.
Have a look to Andy's website, it could help :
http://www.obiwannabe.co.uk/
This one seems nice for you :
http://www.obiwannabe.co.uk/sounds/effect-elastic-collisions.mp3
I can help with GEM and PMPD.
++

Jack


Le 9 août 08 à 14:46, Julian Brooks a écrit :

> Hey Jack,
>
> That's cool with me.  Out of curiosity, what did you use for the sound
> generation of your chimes, samples or code - csound/pd/a.n.other?
>
> Jb
>
> -----Original Message-----
> From: Jack [mailto:jack at rybn.org]
> Sent: 09 August 2008 13:16
> To: Julian Brooks
> Cc: pd-list
> Subject: Re: [PD] physical modelling/general pd
>
>
> Le 8 août 08 à 14:46, Julian Brooks a écrit :
>
>> Hi Jack,
>>
>> Well I was surprised that someone else hadn't tried it already, to be
>> honest.
>>
>> Congratulations, respect, and thanks for showing me that it is indeed
>> possible.
>>
>> If you don't mind I would like to be able to email you with
>> problems that I
>> think you can help/give advise for.
> I think the better way is to post on the Pd list because i'm not
> always available to answer (lot of work sometimes) and a lot of
> people are good users of this programming language. The list exists
> for this sort of problem ;)
> You have a lot of time to realize your patch, i think after 12 months
> you will have a good patch for your wind chime. All you need is to
> know PD/GEM/PMPD. I will be happy to help you and to answer to you on
> the list like a lot of other people.
> ++
>
> Jack
>
>
>>
>> Best wishes,
>>
>> Jb
>>
>> -----Original Message-----
>> From: pd-list-bounces at iem.at [mailto:pd-list-bounces at iem.at] On
>> Behalf Of
>> Jack
>> Sent: 08 August 2008 12:38
>> To: cyrille henry
>> Cc: pd-list at iem.at; Mark Sexton
>> Subject: Re: [PD] physical modelling/general pd
>>
>> Hello Julian,
>> I have done a wind chime there is 2-3 years ago with PD/GEM/PMPD. I
>> used PHP to get on the web the value of direction and force of wind
>> in differents cities in Europe.
>> Here a link for a video without sound (i remove it from the export) :
>> http://djrayban2.free.fr/Movie/windChime.mov
>> ++
>>
>> Jack
>>
>> Le 8 août 08 à 12:16, cyrille henry a écrit :
>>
>>> hello,
>>>
>>>
>>> Mark Sexton a écrit :
>>>> Hi Julian
>>>> Building a physical model of a wind chime might be easier than you
>>>> think, if
>>>> you use modal or banded waveguide approaches to physical modelling
>>>> rather
>>>> than the brute force approach of pmpd.
>>>
>>> pmpd aim to model the movement, not the sound.
>>> the hamer and the tube of a simple wind chime could be modeled with
>>> about 10 masses.
>>> To create a physical model of the sound is very different.
>>> but you need both to model the wind chime.
>>>
>>> Cyrille
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>>
>>>> If you think of the wind chimes should as stiff bars, banded
>>>> waveguides
>>>> would be ideal and are much more computationally efficient to
>>>> implement than
>>>> brute force approaches: a resonant filter and delay per mode you
>>>> want to
>>>> synthesis.  I'd recommend perhaps starting with a simple modal
>>>> implementation using filters and build up from there. This paper
>>>> gives a
>>>> good introduction:
>>>> http://www.cs.ubc.ca/~kvdoel/publications/modalpaper.pdf
>>>>
>>>>
>>>> If you're not familiar with modal synthesis and banded waveguides
>>>> there's
>>>> plenty of information online and Perry Cook's book gives a good
>>>> overview of
>>>> a range of approaches to modelling.
>>>> http://www.cs.princeton.edu/~prc/AKPetersBook.htm
>>>>
>>>> Some starting hints if you want to go down this route:
>>>>
>>>> 1. Create an impulse: a buffer of noise or single sample impulse
>>>> 2. Feed this into perhaps 5 band pass IIR filters with a very
>>>> narrow Q,
>>>> these will provide your resonant modes for each chime.
>>>> 3. The frequencies of these filters will probably be non-integer
>>>> multiples
>>>> of the fundamental, eventually you can get these by analysing an
>>>> actual wind
>>>> chime, but if you wanted to build a proof of concept now then
>>>> these are
>>>> typical modes of an aluminium bar (you can find further modal
>>>> frequency
>>>> ratios in the Csound manual):
>>>> [1, 2.756, 5.423, 8.988, 13.448, 18.680]
>>>> 4. Scale the outputs of each of the resonant filters as
>>>> appropriate, this
>>>> should be straight forward once you've done an audio analysis of
>>>> your wind
>>>> chime.
>>>>
>>>> At this point you have a simple resonating model of a wind chime.
>>>>
>>>> 5. Perhaps replace the impulse: you can remove the resonant
>>>> components of
>>>> your wind chime recording and this will leave you with the
>>>> original noise
>>>> impulse. Using this to trigger your model should help improve
>>>> realism.
>>>> 6. Create a banded waveguide version, by adding feedback delays
>>>> for each
>>>> mode. (have a read of this paper and a look at Fig. 4):
>>>> http://soundlab.cs.princeton.edu/publications/1999_icmc_bar.pdf
>>>>
>>>> There's a few further tweaks and improvements that can be done, but
>>>> something along these lines should give a good result, be fairly
>>>> easy to
>>>> implement and run more efficiently than brute force.
>>>>
>>>> Happy to chat more on or off list on the physical model side or
>>>> algorithmic
>>>> composition side, but you may find it easier than you thought once
>>>> you get
>>>> going.
>>>>
>>>>
>>>> All the best
>>>>
>>>> Mark Sexton
>>>> Senior Lecturer
>>>> MSc Computational Sound
>>>> University of Portsmouth
>>>>
>>>>> Message: 2
>>>>> Date: Thu, 7 Aug 2008 12:30:51 +0100
>>>>> From: "Julian Brooks" <julian.brooks at virgin.net>
>>>>> Subject: [PD] physical modelling/general pd - mentor/tuition  
>>>>> sought
>>>>> (money offered)
>>>>> To: <pd-list at iem.at>
>>>>> Message-ID: <000001c8f881$0d514a40$27f3dec0$@brooks at virgin.net>
>>>>> Content-Type: text/plain; charset="us-ascii"
>>>>>
>>>>> Hi all,
>>>>>
>>>>>
>>>>>
>>>>> I have a 12 month project as part of a masters degree, where I
>>>>> wish to build
>>>>> a physical model of a wind chime.  I then want to use the
>>>>> interface to play
>>>>> some of my indeterminate compositions.  I was going to attempt it
>>>>> for my
>>>>> undergraduate degree but realised that it was far too complex for
>>>>> the
>>>>> available time that I had then.
>>>>>
>>>>>
>>>>>
>>>>> I have been using pd for a few years now, list lurking, working
>>>>> through
>>>>> basic examples, building simple tools, using other peoples
>>>>> patches etc.  But
>>>>> this is too complex for me to do on my own.  At my uni there
>>>>> isn't anyone
>>>>> with better skills than me and I don't know of any local fellow
>>>>> patchers.
>>>>>
>>>>>
>>>>>
>>>>> Now as a musician, when I need to up my skills, I will look to
>>>>> find some
>>>>> lessons when I have got as far as I can on my own.
>>>>>
>>>>>
>>>>>
>>>>> So here goes...
>>>>>
>>>>>
>>>>>
>>>>> Is there anyone with an hour a week to spare who can offer some
>>>>> mentoring/tuition for what we can deem to be the 'going rate'.  I
>>>>> am more
>>>>> than happy to do this remotely/online, I'm sure there is a way we
>>>>> can work
>>>>> it out.  There would be full credit given of course.
>>>>>
>>>>>
>>>>>
>>>>> Pmpd seems like the way to go with this.  I have worked through  
>>>>> the
>>>>> examples, and, although I have my eye on what examples I would
>>>>> presume to be
>>>>> the best starting points, I'm struggling to get started.  The
>>>>> physical
>>>>> modelling is where I first need to start but there's loads of pd
>>>>> stuff I
>>>>> would like to be able to work through with someone, so this could
>>>>> be a (me
>>>>> love you)longtime regular small money earner, if anyone's
>>>>> interested.
>>>>>
>>>>>
>>>>>
>>>>> I am in Hebden Bridge, West Yorkshire, UK, by the way.  Any
>>>>> pd'ers local,
>>>>> give us a shout.
>>>>>
>>>>>
>>>>>
>>>>> Best wishes to all,
>>>>>
>>>>>
>>>>>
>>>>> Jb
>>>>>
>>>>
>>>>
>>>>
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