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Topic: Big bug regarding sustain/legato - much research

  1. #1

    Big bug regarding sustain/legato - much research

    I had some time ago experienced some problems with the solo horn sounds, getting clicks in certain passages. I began to assemble example files so I could demo the problem, and in the process, I think I\'ve discovered a long-standing bug that is likely related to the old \"clicking flute on the right channel\" problem.

    All of these example bugs are repeatable with any of the wind instruments in solo mode. I have used the french horn, because it is the most obvious.

    First, listen to French Horn Solo I in THIS MP3 (Converted from gpo_click.wav). Here I am using SUSTAIN MODE = NO SUSTAIN / MIDI SWITCH. The musical passage is four notes, with a sustain (control 64=128) coming after note one, and a sustain-off (control 64=0) coming after note three. The passage is played once centered, once panned left, and once panned right. When centered, there is a nasty click on the right channel. Here is a look at the waveform showing the first three notes panned to center:

    There several things of note here. First, the click, which appears to be the beginning of a new note that is abruptly shut off. That\'s the click that has been driving me crazy. Next, you can see that legato is still leaving gaps between the notes, most notably between notes 2 and three, where there is about 0.09 seconds gap. That\'s a very audible space between two notes.

    Now listen to the mp3 again... notice anything about the last passage panned right? There is overlap between the notes. It's actually playing polyphonically, even though I have Kontakt player set to play only one note for this voice (default for solo horn). To confirm this, I next created THIS EXAMPLE using the sustain pedal for legato, with long overlapping notes. What you are listening to is a solo horn in a single voice playing five notes simultaneously!! Note the distortion caused by clipping; the player is overloaded by the five voices. When panned left, this example works correctly (almost). Here is a comparison:

    Panned 100% Left - Legato (with bad gap between notes 1 & 2)
    Panned 100% Right - Polyphonic and badly clipped
    Panned 98% Right - Overlapping notes

    These are the exact same passages, with just different panning. The last example is interesting in that the notes are overlapping just a bit. You can hear some minor polyphony. The problem seems greatly exaggerated as you near 100% panned right.

    There is a bug in the way Kontakt player is handling legato mode for GPO. It seems to handle the left and right channels quite differently. The left channel sometimes plays legato, but sometimes leaves gaps (making trills in winds impossible). The right channel plays solo instruments polyphonically in this mode. When centered, the two different implementations fight against each other, and sometimes leave unwanted clicks and other artifacts.

    Sample Sonar Files

    My Configuration
    Kontakt 1.02.008 (Library 1.0)
    Sonar 3 PE 3.1.1
    WDM & ASIO drivers (both tested)
    VST/DXI (both tested)
    Dell Dimension 4550
    Pentium 4 2.53GHz, 1GB RAM
    Windows XP
    Delta 66 - latest driver

  2. #2

    Re: Big bug regarding sustain/legato - much research

    Hmm. Sounds like something very similar I\'ve experienced with the solo strings. I wasn\'t too sure what was causing it though. I was thinking it might have been the mod wheel that was causing digital peaks to occur when at higher dynamic levels, but the pops happen even when I have the volume and gain attenuated to much lower levels.

  3. #3
    Join Date
    Oct 2000
    Orcas Island

    Re: Big bug regarding sustain/legato - much research


    I appreciate your taking the time to do this investigative work. Very thorough. I could use someone like you on the beta team.

    We will pass your results on to Native Instruments. It may in fact be a Native Instruments Player bug, but it also may be a configuration issue, or a soundcard issue, or a host of other factors.

    Before we say for certain that it is a Native Instrument\'s bug, it would be helpful to test this on different machines and soundcards. Perhaps others here can also test this. I recall Tom running across a similar problem with one particular soundcard, but the probelm disappeared when he used a different card. Tom is on vacation and I\'ll ask him to test and respond when he returns.

    The cause of the problem is ascertainable and if it is in the Player, then it can be corrected in the next update. If not, we\'ll do our best to find out what it is and find a solution.

    Gary Garritan

  4. #4

    Re: Big bug regarding sustain/legato - much research

    Wow, Jamie, an impressive and very thorough piece of work. (totally OT: Interesting, the waveforms reminded me of my Master\'s degree research at MIT, where I was exploding molten tin by dropping it into pure water, measuring the waveform, and trying to develop a theory to explain it.)

    If you want to privately email me with any additional information needed - for example your exact midi file - I can run this same set of experiments on my Mac and see what I get. Or on my gigastudio PC, for that matter. It seems we should readily be able to isolate the problem as a Kontakt player, or a soundcard issue, if enough of us check this out. (trond@bellsouth.net)


  5. #5

    Re: Big bug regarding sustain/legato - much research

    I too have had similar clicks, but they were only in one of the flutes, if alot of notes were played staccato, clicks would appear, and harp glissando\'s were unuseable. When I increased the latency on my RME Hammerfall HDSP9652 soundcard that is in the PC, it all went away. I did notice that all the clicks were in the right channel though. I am using GPO as a stand alone, piping the sounds from the PC into the Mac G4 running Digital Performer. I too recorded the audio before I knew what the problem was, and could very easily see the click when I zoomed into the audio track. Just wanted to share my experience with these clicks.

  6. #6

    Re: Big bug regarding sustain/legato - much research


    It seems we run pretty much identical rigs - I\'ve got the same soundcard in my PC, and sequence in DP on a G4 dual gig Quicksilver ( OS 10.3.3 ).

    Interesting that you noticed the buffer size (latency) affected the clicking problem.
    Jamie, have you trialed latency as a factor?

    It also occurs to me to try the same experiment in the GPO Kontakt player, and then also in the full Kontakt (which I have). Wonder if they behave the same way?


  7. #7

    Re: Big bug regarding sustain/legato - much research

    Hi Trond, maybe we can help each other out when we have trouble. I am still using OS9 and DP 3.11 because of too much cost involved in upgrading plugins. How many simultaneous sounds can you load in the \"full\" version of Kontakt? In other words, how many sounds can you load at once, and still have each of them separately assigned to stereo pairs of the RME ADAT outputs?

    Very interested, but more importantly, at least I don\'t feel like I\'m the only one using DP and a stand alone version of GPO [img]/ubbthreads/images/graemlins/smile.gif[/img] Thanks Trond!

  8. #8

    Re: Big bug regarding sustain/legato - much resear

    Latency is not an issue. I have run up to 70 instruments simultaneously without a problem on this machine. This test scenario is with one instance, one instrument, and with a very large buffer size. The click always appears at the same place, and the polyphony issue remains.

    For those of you who wish to repeat the experiment but do not have sonar to load those files, it\'s very easy. Use solo horn 1, set the sustain pedal to legato mode, and pan the horn hard right. Don\'t pan the whole GPO instance, but rather the instrument.

    Next, hold down the sustain pedal, and play several notes in succession, holding down each one as you go.

    It would be nice to get other people\'s results, along with their setups.

  9. #9

    Re: Big bug regarding sustain/legato - much resear

    Hmm... I also get this polyphony thing. (SB Audigy 2, P42.4GHz, Win XP, Gig of RAM)

    I have noticed right channel clicks and crackels on the solo horns myself in my music.

    On my setup, the clicks are intermittent (But the polyphony is not), as this MP3 shows:

    I did several sets of C-E-G-C with the pan in different places. I only got pops once, at center.

    Very interesting bug. Hopefully it can be fixed soon.

  10. #10

    Re: Big bug regarding sustain/legato - much resear


    I downloaded your Sonar files and ran the experiments as suggested. First, here is my setup:

    Sound Blaster Audigy2 Platinum Pro
    AMD Athlon Barton 3000+
    1.2 GB PC3200 DDR400 Kingston
    2x 120mb Maxtor HD
    Sonar Producer Edition 3.1
    Windows XP Pro

    I did not run the test using the VST version, since I only use GPO DXi. I did not encounter anything like you mentioned. I never got a click during playback, and the 5 note demonstration played all the notes separately. The only thing that happened was an overlapping of notes when the instrument was panned far right. Look at the pic below:

    Each track is the SAME Sonar file with different pan settings. As you can see, the more right you go, the more the Kontakt player disobeys the 1 voice maximum. This is very strange, but the overlapping voices do not occur until you reach approximately 92% Right. Otherwise, it\'s fine.

    I ran the experiment with both French Horn Solo instruments, and got the same results. When panned right, overlapping notes seem to continue to play until their note-offs regardless of the max voice setting for that instrument.

    I hope this helped!

    - Junk

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