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A first view on organ pipe modelling

Posted: Thu Jul 02, 2009 9:28 pm
by schmise7777
Hello folks,

Joseph and Christian (the latter is a colleague of mine at the IKA http://www.rub.de/ika), started a discussion on simulating pipe organ signals in conjunction with appropriate room acoustics to achieve flexible physical organ models. Here are some thoughts about that issue:

There are several possible ways to generate pipe organ sounds artificially without the use of samples. A widespread approach is Digital Waveguide Synthesis (the inventor of DWG, J.O. Smith of the CCRMA offers an E-Book on his institute's web site http://ccrma.stanford.edu/~jos/ which contains all necessary information). This technique is a time-domain simulation method which enables astoundingly realistic generation of instruments with linear resonators and nonlinear oscillators (such as strings, pianos, horns, flutes, drums and -of course- organ pipes). Some years ago, we used DWGs to analyse the characteristics of free- and beating-reed organ pipes. I know that there are several flute models implying DWGs that sound really nice. However, flue organ pipe modelling may be even more efficient by simply adding up the partials in frequency domain, because the harmonic structure of organ pipe sounds is rather simple. The same holds for the temporal structure, after the attack transient time is over, the sound is practically static (except for "Schwebung", of course). However, I think this shows the most critical aspects, when a special organ pipe is to be modelled: 1) the attack phase has to be reproduced very carefully, as it essentially determines the perceived timbre, 2) the formant balance which determines the spectral features of the sound has to be adapted to that of the given pipe. The first aspect can be simulated rather using a time domain approach, while the latter aspect is more easily controlled in frequency domain. Perhaps a hybrid model works best?!?
It may be very difficult to create a model that is able to synthesize the sound of a given pipe *exactly*. Of course, when size and length are provided, you will come close to the desired sound. However, the "special" cues that make pipes of, let's say, Silbermann and Cavaille-Coll or even of two different Silbermann instruments distinguishable, are determined by some "other specifications". Here, things become complicated. How does the metal or wooden body of the pipe influence the sound? How is the exact airflow geometry when the sound starts? And what does it influence at all? How is the chest constructed? Again: perhaps a hybrid model that combines DWGs and filtering works best.

By the way: in my opinion, noise reduction should be applied only very carefully to organ pipe sound samples, because the flow noise is (may be) an essential part of the sound (especially for narrow stops). How do you think about that?

And finally: Congratulations, jeuxdorgues.com is a great idea and a formidable project! The sound examples that are provided are very nice!

Best regards
Sebastian

Re: A first view on organ pipe modelling

Posted: Fri Jul 03, 2009 7:44 am
by c.borss
Hi Sebastian et al.,

schmise7777 wrote:Joseph and Christian (the latter is a colleague of mine at the IKA http://www.rub.de/ika), started a discussion on simulating pipe organ signals in conjunction with appropriate room acoustics to achieve flexible physical organ models.


With a good room acoustic model / reverb one can indeed obtain some really nice results. I'm using Jeux d'orgues to demonstrate my plausible auralization approach. Although it is based on a very simple room model, the result is quite enjoyable: http://www2.ika.rub.de/HybridReverb/index.html
If MyOrgan would support VST plugins or if it would be available even as VSTi, one could combine Jeux d'orgues with some really nice convolution reverbs.


Ciao,
Christian

Re: A first view on organ pipe modelling

Posted: Sat Jul 04, 2009 8:07 am
by Frett27
Hi Stephane,Christian and Joseph

for a phone call with Joseph, i'm quite interesing in the organ pipes modelling as the main maintainer of thé aprint software. http://pfreydiere.free.fr/aprint/fr-aprint.html
this project is barrel organs centric but share thé same sound background. Using this software your can listen real sampled pipe stops. Things are currently un progress for including a soundbank editor. So we havé thé opportunity to have some pipe stops recording samples to make model comparison.

Patrice

Re: A first view on organ pipe modelling

Posted: Sat Jul 04, 2009 9:30 am
by Frett27
An other practical document about the pipe sound procession / pression / flux


http://articles.ircam.fr/textes/Hirschberg95a/

Re: A first view on organ pipe modelling

Posted: Tue Jul 07, 2009 9:01 am
by kropjesla
If MyOrgan would support VST plugins or if it would be available even as VSTi, one could combine Jeux d'orgues with some really nice convolution reverbs.


Indeed there is a VST using the Jeux soundfont.

it's called orgeltje 1.0

check out the forumtopic:
viewtopic.php?f=2&t=59

Greetz Steven

Re: A first view on organ pipe modelling

Posted: Tue Jul 07, 2009 9:34 am
by Joz
Thanks for these ideas and useful links.

As mentionned by Patrice, a software that produces organ sound already
exists : Aeolus. Has someone tested ? How does it sound ?

An other thing of interest : PianoTeq seems to be one of the
best piano sound modelling (and NO samples) software.


Jo

Re: A first view on organ pipe modelling

Posted: Sat Jul 11, 2009 10:03 am
by Frett27
Joz wrote:Thanks for these ideas and useful links.

As mentionned by Patrice, a software that produces organ sound already
exists : Aeolus. Has someone tested ? How does it sound ?

An other thing of interest : PianoTeq seems to be one of the
best piano sound modelling (and NO samples) software.


Jo


here is the direct link to the new ? wiki ...

http://www.muse-sequencer.org/index.php/Aeolus

an other practical link :
http://www.geocities.jp/midi_organ_net/aeolus/

i'll have a look at the sources as soon as i have the time.

there might be a way to contact or meet the authors for having informations on how is it possible to take a real sample and convert it to its model ?
This can also be possible to have technical informations on the model used regarding to the initial post of this thread ?

Regards,
Patrice

Re: A first view on organ pipe modelling

Posted: Sat Jul 11, 2009 10:04 am
by Frett27
Joz wrote:Thanks for these ideas and useful links.

As mentionned by Patrice, a software that produces organ sound already
exists : Aeolus. Has someone tested ? How does it sound ?

An other thing of interest : PianoTeq seems to be one of the
best piano sound modelling (and NO samples) software.


Jo


there is also some results in ogg format on the main page of the project ... enjoy ;) ..


Patrice

Re: A first view on organ pipe modelling

Posted: Thu Mar 25, 2010 4:07 am
by Gui
http://www.virtualorgancompany.com/
here is a link to a software using only adaptive synthesis running as a VST plugin
Therefore, the download time is really short if you wish to download the program.
You should download the Portatief version to truly experience the program.
I am not sure how to describe it. It is focused so much on the sweet sounding aspects of the organ that it almost distances itself from the actual instrument.
The Positief v5 version has one reed, a regal, but, I personally find it quite unrealistic, nevertheless, maybe there is a use for this tonality.

Re: A first view on organ pipe modelling

Posted: Mon Sep 12, 2011 2:50 pm
by CatOrg
http://www.virtualorgancompany.com/

I dont hear where is the point. In comparison, wavs are much atractiver. the samples sounds just like a middle thing between e-organ and wav...
Then you have to pay for a one-manual VPO - who cares - and make an enquiry if you want two-mans-and-ped.
Sell to whoever has no idea of better, else, dont.
Or did I miss smthg?