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Harmonic Shaping Filters

Sampling pipe organs and turning them into something you can play in Hauptwerk.

Harmonic Shaping Filters

Postby tf11972 » Thu Jun 29, 2017 11:05 am

Hello all,
in development of our sampleset, we have one problem with a 32'-rank (Untersatz). A few notes of the recorded lower octave sounded so bad that we decided to replace them by adjacent notes. The result was a slightly rumbling noise when playing them in Hauptwerk (in a DAW they sound clean, I have implemented a highpass-filter in advance).

Today I disabled the Harmonic Shaping Filters and suddenly the Untersatz sounds pretty good. But disabling the Filters affects the whole organ (I don't hear a difference in sound however).

Looking at the CODM I found these entries in the noise ranks (they are only there):

<HarmonicShaping_PipeMIDINoteNum036_3rdAndUpperHarmLvlAdjDb>0</HarmonicShaping_PipeMIDINoteNum036_3rdAndUpperHarmLvlAdjDb>
<HarmonicShaping_PipeMIDINoteNum096_3rdAndUpperHarmLvlAdjDb>0</HarmonicShaping_PipeMIDINoteNum096_3rdAndUpperHarmLvlAdjDb>
<HarmonicShaping_PipeMIDINoteNum036_WindModelModDepthAdjDb>0</HarmonicShaping_PipeMIDINoteNum036_WindModelModDepthAdjDb>
<HarmonicShaping_PipeMIDINoteNum096_WindModelModDepthAdjDb>0</HarmonicShaping_PipeMIDINoteNum096_WindModelModDepthAdjDb>
<HarmonicShaping_PipeMIDINoteNum036_TremulantModDepthAdjDb>0</HarmonicShaping_PipeMIDINoteNum036_TremulantModDepthAdjDb>
<HarmonicShaping_PipeMIDINoteNum096_TremulantModDepthAdjDb>0</HarmonicShaping_PipeMIDINoteNum096_TremulantModDepthAdjDb>

When I copied them into the Untersatz-Rank, the rumbling noise was gone, but the rank sounded completely different than before. The manual says: "The filter behaves roughly like a high or low-pass filter, with the gain for frequencies above the third harmonic being as nearly as possible the same as for the third harmonic."

What is the best approach to resolve this issue?
1. Disable the Harmonic Shaping Filters for the whole organ (wind model is enabled) or
2. Copy the entries into the CODM of the Untersatz and risk a completely different sounding stop (or what are the best values to avoid sound differencies).

I hope you understand what I mean. Thanks in advance.
Best regards
Thomas

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Re: Harmonic Shaping Filters

Postby mdyde » Thu Jun 29, 2017 11:52 am

Hello Thomas,

Have you discussed it with Chris Schmitz, who I understand is working with you on the organ definition development for the sample set ( viewtopic.php?f=2&t=16125 )?

tf11972 wrote:Looking at the CODM I found these entries in the noise ranks (they are only there):

<HarmonicShaping_PipeMIDINoteNum036_3rdAndUpperHarmLvlAdjDb>0</HarmonicShaping_PipeMIDINoteNum036_3rdAndUpperHarmLvlAdjDb>
<HarmonicShaping_PipeMIDINoteNum096_3rdAndUpperHarmLvlAdjDb>0</HarmonicShaping_PipeMIDINoteNum096_3rdAndUpperHarmLvlAdjDb>
<HarmonicShaping_PipeMIDINoteNum036_WindModelModDepthAdjDb>0</HarmonicShaping_PipeMIDINoteNum036_WindModelModDepthAdjDb>
<HarmonicShaping_PipeMIDINoteNum096_WindModelModDepthAdjDb>0</HarmonicShaping_PipeMIDINoteNum096_WindModelModDepthAdjDb>
<HarmonicShaping_PipeMIDINoteNum036_TremulantModDepthAdjDb>0</HarmonicShaping_PipeMIDINoteNum036_TremulantModDepthAdjDb>
<HarmonicShaping_PipeMIDINoteNum096_TremulantModDepthAdjDb>0</HarmonicShaping_PipeMIDINoteNum096_TremulantModDepthAdjDb>

When I copied them into the Untersatz-Rank, the rumbling noise was gone, but the rank sounded completely different than before.


If those values were previously zero, and if you then replaced them with values that were zero and the sound changed, then I think you must previously have made some voicing changes which Chris had imported into the compiled ODF, which would have been overwritten if you compiled your CODM ODF again, and/or you had had some relevant user voicing adjustments affecting them and you chose the option to reset the voicing when loading the organ via the Design Tools menu. Either would result in the relevant voicing being changed, explaining the difference in sound.

Those CODM ODF values combine with whatever user voicing settings you have (and with any previous user voicing settings that Chris had imported into the compiled ODF for you). Changing those values from zero to zero won't affect anything in itself (but overwriting a compiled ODF that contains voicing, and/or resetting non-default user voicing, certainly would). Hence please discuss that with Chris, if you haven't done so already.

tf11972 wrote:in development of our sampleset, we have one problem with a 32'-rank (Untersatz). A few notes of the recorded lower octave sounded so bad that we decided to replace them by adjacent notes. The result was a slightly rumbling noise when playing them in Hauptwerk (in a DAW they sound clean, I have implemented a highpass-filter in advance).


For highest quality results you would need to re-pitch the relevant bad samples in an audio editor from their nearest good neighbours, using a high-quality (=>slow) re-pitching algorithm, and then detect and store the new pitches in the new samples, then re-compile the CODM organ so that Hauptwerk will pick up the new samples.

tf11972 wrote:Today I disabled the Harmonic Shaping Filters and suddenly the Untersatz sounds pretty good. But disabling the Filters affects the whole organ (I don't hear a difference in sound however).


My guess is that you have some voicing set that is emphasizing some unwanted frequencies in the samples (e.g. having turned up their brightness via the voicing screen, either now or via previously-ODF-imported voicing) for those virtual pipes.

Have re-pitched the pipes in an audio editor and recompiled the CODM ODF (as above), you would probably want to revisit the voicing for those pipes.

There definitely shouldn't be a need to disable the harmonic-shaping filters (which can add a great deal of realism to the organ if used properly).
Best regards,
Martin.

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Re: Harmonic Shaping Filters

Postby chr.schmitz » Thu Jun 29, 2017 12:50 pm

Hello Martin,

we discussed this issue already. But I could not get a helpful answer, even after I read the CODM manual several times.

It did not take care of the harmonic_shaping at all. I even omitted these entries in the rank node. I suppose that the ODF compiler sets them to a default value. Is this default value 0?

I currently "adjust" the parameters AmpLvl_LevelAdjustDecibels and HarmonicShaping_ThirdAndUpperHarmonicsLevelAdjustDecibels in the final ODF only if they were changed within HW with the voicing tool. This was (until now) not the case for the Untersatz 32.

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Re: Harmonic Shaping Filters

Postby mdyde » Thu Jun 29, 2017 2:10 pm

Hello Chris,

chr.schmitz wrote:It did not take care of the harmonic_shaping at all. I even omitted these entries in the rank node. I suppose that the ODF compiler sets them to a default value. Is this default value 0?


Yes -- all of those Rank.HarmonicShaping_...AdjDb attributes default to zero if they aren't specified anyway. Hence just specifying the values as zero (vs. not specifying them at all) can't make a difference to the sound in itself.

chr.schmitz wrote:I currently "adjust" the parameters AmpLvl_LevelAdjustDecibels and HarmonicShaping_ThirdAndUpperHarmonicsLevelAdjustDecibels in the final ODF only if they were changed within HW with the voicing tool. This was (until now) not the case for the Untersatz 32.


If they were left at their defaults of zero on the voicing screen (and in any imported ODF voicing), and if the CODM ODF's Rank.HarmonicShaping_...AdjDb attributes were all zero (or not specified), then the harmonic shaping filters wouldn't be doing anything significant anyway, except as a result of the wind model and any tremulants (I assume you wouldn't have any tremulants affecting a 32' rank). You could try temporarily disabling the wind model, to try to determine whether that was relevant.

However, as long as the neighbouring samples are good, and re-pitched to a high quality in an audio editor etc. (as discussed) then the effects of any (or no) harmonic shaping filter adjustments should be almost identical upon the re-pitched pipes as upon the neighbours from which they were re-pitched.
Best regards,
Martin.

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Re: Harmonic Shaping Filters

Postby chr.schmitz » Thu Jun 29, 2017 3:25 pm

Martin,

thanks a lot! With this additional information we will experiment a little bit.

Chris
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Re: Harmonic Shaping Filters

Postby mdyde » Fri Jun 30, 2017 4:15 am

Thanks, Chris.
Best regards,
Martin.

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Re: Harmonic Shaping Filters

Postby chr.schmitz » Fri Jun 30, 2017 5:18 am

Hello Martin,

For highest quality results you would need to re-pitch the relevant bad samples in an audio editor from their nearest good neighbours, using a high-quality (=>slow) re-pitching algorithm, and then detect and store the new pitches in the new samples, then re-compile the CODM organ so that Hauptwerk will pick up the new samples.


Do you have any software recommendation? I was not able to find anything in the forum or in the manuals.

Thanks in advance!

Best regards,
Chris
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Re: Harmonic Shaping Filters

Postby mdyde » Fri Jun 30, 2017 5:46 am

Hello Chris,

It's been a very long time since I created a sample set myself (15-ish years!), but at that time I used Sound Forge. Adobe Audition and Steinberg WaveLab are other major current professional-quality sample editors, all which I would expect to have high-quality re-pitching algorithms. The freeware Audacity might well too.
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Martin.

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Re: Harmonic Shaping Filters

Postby chr.schmitz » Fri Jun 30, 2017 6:13 am

Hello Martin,

thanks for these recommendations!

We are currently using Adobe Audition and Audacity for different tasks. All of them have their own limitations. The "Swiss knife" for HW audio postproduction obviously does not yet exist.

All the best,
Chris
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Re: Harmonic Shaping Filters

Postby chr.schmitz » Thu Jul 13, 2017 8:07 am

Hello Martin,

Yes -- all of those Rank.HarmonicShaping_...AdjDb attributes default to zero if they aren't specified anyway. Hence just specifying the values as zero (vs. not specifying them at all) can't make a difference to the sound in itself.


Is it possible to deactivate harmonic shaping for an individual rank setting the Rank.HarmonicShaping_...AdjDb attributes to -99999.9 (the smallest value allowed), while keeping harmonic shaping for the other ranks activated?

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Chris
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Re: Harmonic Shaping Filters

Postby mdyde » Thu Jul 13, 2017 8:25 am

Hello Chris,

Yes -- you could certainly do that if you wished. They can't be entirely disabled on a per-rank basis, but turning their effects down in that way would be very, very, very nearly the same thing (in that their effects should then be inaudible and almost certainly unmeasurable).
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Re: Harmonic Shaping Filters

Postby chr.schmitz » Thu Jul 13, 2017 8:28 am

Martin,

thanks for the lightning fast response! I really appreciate your invaluable support!

Chris
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Re: Harmonic Shaping Filters

Postby mdyde » Thu Jul 13, 2017 10:10 am

Thanks, Chris. You're very welcome.
Best regards,
Martin.

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