How does the brightness control work?

I am curious as to how the brightness control works. It seems to be more than a low pass/high pass filter, but I can’t figure out what it could be doing.

[mdyde]

Hello John,

The per-pipe 'brightness' filter (whose level is determined by the voicing user's voicing adjustments, added to those from the CODM organ definition for each pipe) applies what is effectively a 'shelf filter', raising or lowering the level of the third-harmonic and all higher harmonics relative to the fundamental.

Its frequency response will look like that of the swell box filter (an example of which can be seen on page 12 of the v5.0.1 CODM user's guide), with its lower peak/trough at the pipe's fundamental frequency, and its higher trough/peak at the third harmonic.

Hello John,

The per-pipe 'brightness' filter (whose level is determined by the voicing user's voicing adjustments, added to those from the CODM organ definition for each pipe) applies what is effectively a 'shelf filter', raising or lowering the level of the third-harmonic and all higher harmonics relative to the fundamental.

Its frequency response will look like that of the swell box filter (an example of which can be seen on page 12 of the v5.0.1 CODM user's guide), with its lower peak/trough at the pipe's fundamental frequency, and its higher trough/peak at the third harmonic.

Ok, so do I have to provide the pitch of the pipe so that it can determine what the 3rd harmonic is?

[mdyde]

Hello John,

You don't need to specify any pipe pitch settings for the harmonic-shaping filters additionally, but when using the CODM you must always make sure that the pitches of pipes and samples are specified correctly anyway (via the Rank_... table), as covered in the CODM's format documentation for that table, and also briefly in the user guide (see pages 6, 10 and 15). Hauptwerk needs to know what the pitches of the pipes and samples are, otherwise user temperament/tuning adjustments wouldn't work properly (as well as the harmonic-shaping filters), for example.