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Topic: Pitch bend technical questions

  1. #1

    Pitch bend technical questions

    I have a problem that I wanted to discuss with someone at Garritan. I know that the stuff I'm doing is outside the spec, so I can't really expect support, but I thought I'd ask anyway.

    I've been trying to use GPO for non-standard tuning work. This involves sending MIDI data from Finale to a relay program, and then to GPO Studio. Each channel is "monophonic" and each note-on is preceded by a single pitch-bend message. These pitch-bends are generated internally by the relay program, based on a tuning table. This kind of relay work is fairly standard in the microtonal community.

    The system works OK for some tunings but not for others. And particularly, there seems to be most trouble with the strings, especially with a lot of notes to the octave. I've found that the winds and brass seem to generate pretty accurate, crisp pitch-bends, fairly instantly. The strings, however seem to have a lot more "slop" in them.

    The strings seem to take some time before they reach the desired pitch. That might be OK sometimes, but not usually in this kind of work in which there is only a single pitch-bend messages per note-on.

    Let me give an example. In a tuning where you have D, E-flat and D-sharp differentiated, and you are moving between them with some rapidity, You need to jump between (for example) MIDI note 62 with pitch-bend X and the same MIDI note with pitch-bend Y, or to a nearby note with a different pitch-bend value. The strings seem to slip and slide quite a bit, audibly.

    If you're in legato mode, and you try to go between such notes with these single pitch-bend messages, sometimes there's a really long, audible adjustment, and sometimes it never seems to reach the desired pitch at all. It's particularly troublesome with the strings.

    My question is whether the built-in Kontakt player is handling pitch-bend messages differently in the strings? Is there some parameter that is set differently for the strings, as opposed to the winds? If so, is there anything that could be set to make this adjustment happen more quickly? Is there some automatic "portamento" happening? If so, can it be corrected or turned off?

    I can supply some examples contrasting the pitch-bends in winds & strings.

    1. http://rm-and-jo.laughingsquid.org/t...PB-Compare.mp3
    2. http://rm-and-jo.laughingsquid.org/t...re-Strings.mp3

    Example 1 is a small orchestra with instruments playing a legato scale in pairs, for comparison. Note how the strings differ from the winds & brass. Example 2 focuses on the strings, singly, using the main "KS" patches. I have verified that I haven't set any portamento myself, and in the Kontakt player, portamento is set to the default 0.

  2. #2

    Re: Pitch bend technical questions

    This sounds to me like the legth contol is set too high. Also check the portamento. Maybe put in a portamento value of 0 at the beggining of the track?
    OK, on second listen it sounds more like it's a legth issue. In the Kontakt player try reducing the legth control to 10% and take out the reverb to make the listening a little easier.

    There are some interesting sounds here (first example). Can you list the instruments (or instrument combonations) in order in which they appear? Of course, these interesting sounds could be a product of me listening on REALLY bad speakers.


  3. #3

    Re: Pitch bend technical questions

    Thanks for the reply... The sounds in the first track are simple doublings of woodwinds & brass:
    flute + oboe
    oboe + clarinet
    bass clarinet + bassoon
    french horn + trumpet
    trombone + tuba

    Portamento is set to 0. Length is the "standard" 64 and hasn't been changed. Without the pitchbends, the legato is fine. Introduction of the pitch-bends causes the audible problems. (The problem with simply changing the length to 10% is that sounds more un-natural in a legato setting. And doesn't reduce the gliding.)

  4. #4

    Re: Pitch bend technical questions

    Hmm, so it's not the legth?
    When I use GPO studio as opposed to the GPO VSTi or DXi there is a slight delay between my notation program sending out the MIDI and me hearing the sound. Maybe this delay also has an effect on MIDI timing and the pitchbends are coming just after the 'note on' events?

    Just throwing out ideas here. I am by no means an expert in this area.


    PS: I'm curious about the trumpet/f. horn combo. Are there any octaves? What's the mod setting? On these speakers it sounds like a pipe organ reed stop to me. So does the trombone/tuba combo. This is cool.

  5. #5

    Re: Pitch bend technical questions

    > Maybe this delay also has an effect on MIDI timing and the
    > pitchbends are coming just after the 'note on' events?

    Thanks, but... I've been over that and many other issues with the guy who implements the relay program, and it's not a MIDI timing issue. It's something deeper, and I'm hoping for a reply from someone at Garritan...

    Anyway, I'm glad you're enjoying the sounds...

  6. #6

    Re: Pitch bend technical questions


    If you'll post midi files of the above recordings I'll examine them when I get time later this week. Maybe I can spot something unusual happening during a "special case" application like this.


  7. #7

    Re: Pitch bend technical questions

    Hi Tom, thanks so much for your offer... I may have found the source of the problem, and I have a potential fix, and a couple of other questions that raises... In another thread, someone mentioned the new GPO-HP tutorial with Finale 2006c. The tutorial says on page 26 discussion of gliss and pitch-bend range, if you turn off "delay if possible" then pitch-bends to start glisses take effect immediately. Setting that to "off" seems to rather well fix the problem I've been encountering. Rather weird, but it does. So that's helpful... The arpeggios in the above examples sound OK. However, this interacts with another parameter: "Activate GPO Support".

    "Activate GPO" can be set to "always" or "auto-detect" or "off". If it's set to "always on" then the scale examples still sound weird in some spots even with the delay set to "off". But if "Activate GPO" is set to "auto-detect" then the scales sound OK in the strings! So now my question is how the "auto-detect" parameter affects GPO, especially the strings, and *how* it is detecting anything. (In the case of ordinary musical passages, the effect of "on" versus "auto" isn't apparent, but in the scale passages, the effect is very obvious.)

    I'm not sure what the auto-detect is looking at, and *why* it affects the output in these scale passages. (If you're still willing to follow up with MIDI examples, I can post MIDI output with the parameters turned on & off, so you can look at the difference; as well as posting MP3 files of the sound differences.)

    In any case, it seems that the "delay" parameter may fix the bulk of the problem, but now I would like to know how to set the "Activate GPO Support" feature, and actually what it does to the MIDI output, and why it has the effect it does!

    And if you've been reading this far, here's a musical example of the kind of thing I'm trying to achieve, with GPO tuned to 15 equal tones per octave.


    Before the the above-applied fix, there used to be a lot of slipping and sliding into pitches while it's now pretty clean, but I'm not sure what I may be missing (or not) depending on that "Activate GPO Support" parameter...


  8. #8

    Re: Pitch bend technical questions

    Quote Originally Posted by RickMcGowan
    but I'm not sure what I may be missing (or not) depending on that "Activate GPO Support" parameter...
    Glad you seem to have gotten things working - even if questions remain. Don't think I can help you there because I don't have any specific info on what changes in Finale when "Activate GPO Support" is used. I would suggest using the settings that work best for your music and see if you can find any detailed info on the Finale site - or email them.

    I liked your example a lot. I used to listen to a lot of microtonal music - I especially loved the Ives quarter tone piano pieces. When you get things going be sure to post some of your work.


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