Enclosure Parameters

[chr.schmitz]

Why are the <rank> parameters ...FiltParamWhenOpen... required and how should they be determined? When the pipe is recorded with swell box open, why should I modulate the frequency response of the open swell box further?

Chris

[mdyde]

Hello Chris,

The CODM Rank.Encl_... are all required if and only if the rank is enclosed.

In that case, the Encl_FiltParamWhenOpen... parameters are necessary to avoid a discontinuity in the sound/effect as the swell box approaches the fully open position, and to define the limits towards which the filter frequencies should tend. The filter attenuations at fully open are always considered to be zero, but the '... when open ...' frequencies still need to be specified so that that the filter frequencies can tend towards the specified values (projected linearly between the '... when closed ...' values) as the swell box approaches the open position.

The 'Hauptwerk's swell box model' section in the CODM user's guide (pages 16-17 in the current v4.2.1 version) covers how the filter values are calculated for intermediate positions (i.e. by linear projection) and has very broad suggestions for how to approach setting the parameters.

[chr.schmitz]

Martin,

thank you very much for this helpful explanations. I read the mentioned section of the CODM manual several times. But I did not fully understand everything. And still...

I also looked into the ExampleCustomOrgan6-StAnnes-WithAllFrills CODM. Hard to believe that the parameters have to be so variable between different ranks. We will follow your recommendation and try to find some "start values" with reference recordings for the lowest and highest pipe of a stop.

Thanks again!

Best, Chris

[mdyde]

Thanks, Chris.

I also looked into the ExampleCustomOrgan6-StAnnes-WithAllFrills CODM. Hard to believe that the parameters have to be so variable between different ranks.

It isn't that they 'have to' be different as such -- there's no right or wrong way to set them. I mainly made them different to help impart additional complexity to the effect of the box closing when multiple stops are drawn, whilst still aiming to maintain the broad character of the effect on each rank, compared to reference recordings.

[chr.schmitz]

One additional question regarding enclosures: is it possible to set the default of an expression pedal to "closed"? The default seems to be "fully open". And I can't see a parameter to change that.

Thanks in advance for every advice!

Best,
Chris

[mdyde]

Hello Chris,

Not in the CODM, I'm afraid. It always defaults them to open initially, but the user can then change the default anyway if he/she wishes via the user settings for the enclosure pedal.

[chr.schmitz]

Wow! This was a quick response! Thank you very much!

[engrssc]

Not exactly relevant, but most real pipe organs (that I'm familiar with) default to opening the shades when the blower is shut down in order to minimize temperature differential. If there is a more factual explanation, feel free to respond

Rgds,
Ed

[chr.schmitz]

Ed,

you are right! It was just for cosmetic reasons The console looks nicer with the swell pedals in closed position.

Best,
Chris

[engrssc]

The console looks nicer with the swell pedals in closed position.

Something like the accelerator pedal in my car

Rgds,
Ed