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#37 MG routed to VCA causes sound to be heard instead of decayin

admin
closed-wont-fix
Nick Copeland
5
2009-04-26
2009-03-22
Andrew C
No

Selecting poly28.mem and then turning the Level up in the MG and holding a note causes the sound to die and then start clipping for no reason at all..

Andrew Coughlan.

Discussion

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  • Andrew C
    Andrew C
    2009-03-22

    Oops, my bad. The problem actually is that instead of the sound decaying into nothing, when the modwheel activates/turns on the MG, you can still hear the sound being modulated.

    Example: Poly28.mem

     
  • Andrew C
    Andrew C
    2009-03-22

    • summary: MG routed to VCA on polysix causes clipping on memory poly28 --> MG routed to VCA causes sound to be heard instead of decayin
     
  • Nick Copeland
    Nick Copeland
    2009-03-22

    • assigned_to: nobody --> ncopeland
    • labels: --> Bristol Engine
    • milestone: --> admin
     
  • Nick Copeland
    Nick Copeland
    2009-03-22

    Will review the memory and see what the result is. The only known issue is that when summing the envelope and an LFO into the amplifier then since the singal is summed it does not decay smoothly, the LFO can continue to open the amplifier and may need to be gated itself.

     
  • Nick Copeland
    Nick Copeland
    2009-03-25

    Hi Andrew,

    I think this is just totally excessive gain levels, you might need to lower the overall signal level. The 'Clipping' message is something I print when the output level is normalised to be outside of the range of a 16bit sample. This is not really an error, the synth is just overdriving the output.

    Can you try to lower the output signal with the main volume and increase your soundcard mixer singal to compensate. I may consider whether I need to do this for the next release, ie, reduce the signal level produced by the Polysix?

    Regards,

    Nick

     
  • Andrew C
    Andrew C
    2009-03-25

    Apologies Nick, It wasn't actually clipping. I just thought it was! But it was in fact the MG still modulating a supposedly silent Oscillator: Like I said:

    Oops, my bad. The problem actually is that instead of the sound decaying
    into nothing, when the modwheel activates/turns on the MG, you can still
    hear the sound being modulated.

    Hence, why I changed the Summary. ;-)
    Hope this didn't confuse you.

    Andrew Coughlan.

     
  • Nick Copeland
    Nick Copeland
    2009-03-26

    Hi Andrew, I think it actually was clipping, or at least I could reproduce that and have made a couple of changes to the overall signal level to prevent this, it lowers the overall output signal just a little and reduces the MG signal to the VCA. The latter only changes by a fraction but it prevents excess output and also there was a bit of signal inversion taking place.

    I will have another look at poly28 later today.

     
  • Nick Copeland
    Nick Copeland
    2009-04-21

    Hi Andrew,

    I have lost track of this bug a little - is this still an issue? I know it is now not related to clipping however I am not sure about your report of the interaction between the ModWheel and 'decay'.

    Regards, Nick.

     
  • Andrew C
    Andrew C
    2009-04-22

    Nick,

    Well, It definatly isn't to do with clipping, But yeah, my apologies if this is a mistaken bug report...
    Like, applying the modwheel and then hitting a key, causes the patch to work fine, you can hear the slowness of the tremolo do it's thing right?

    But when the sound itself is supposed to decay into nothingness, we're still left with this artifact of the sound increasing in speed when the sound decays to nothing. I'll get an audio sample soon.

    Andrew.

     
  • Andrew C
    Andrew C
    2009-04-22

    http://moose.linux-coders.org/Bristol/trem.mp3

    In that file I play a note and let it decay to silence and then i turn on the modwheel to full, so you can hear the bug.

    I then play a note with the modwheel up full and the sound goes from a slow tremolo to a very fast one again, like as I stated above.

    I hope this helps,

    Andrew.

     
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