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glitches in slice modulation

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  • glitches in slice modulation

    issue 1: working mainly with sliced drumloops at the moment, and if slice placement is precise or otherwise anywhere with lots of sound, I often get a milliseconds-long pop of the previous assignment at the beginning of the next slice. sometimes the slice assignment also does not change, but the slice of the previous step repeats. also, a pitch CV change sent on the same step as the trigger from the ER-101 sometimes takes effect, sometimes not. if the trigger/gate to the cell is delayed slightly, a few milliseconds, the erratic behavior seems to go away for the most part.

    tried also with the social entropy engine, and seemed to encounter the same erratic behaviors, but mostly sequencing with the ER-101. i asked folks at MW, and one wiggler stated he has had no problems with varigate and eloquencer.

    issue 2: when modulating the volume parameter with an intellijel dual ADSR, on the fast transients there is a slight zipper noise. some kind of A>D aliasing that's happening or something else?

    also sent a pm to you guys at 1010 even suggesting a solution to issue 1, but also wanted to hear if other users have encountered similar problems!

    edit: feel free to move this to support subforum
    Last edited by leterell; 03-28-2018, 07:16 AM. Reason: font size, failing to post in appropriate subforum, added minor gripe

  • #2
    I have the same issue when sequencing slices with an Ornament & Crime. I noticed the the problem is a lot less when setting the slice selection to V/Oct instead of just CV.

    The zipper sounds I also noticed with kicks, but that is just normal VCA-like behaviour: try modulating a deep 808 kick volume with a normal analog VCA and you will have similar zipper noises. For that reason, I have the WMD digital VCA that has a mode where it only changes the amplitude at zero-crossing. Maybe that’s something that can be implemented in the BitBox too Aaron?

    Correction of the above about zipper sounds:
    I redid the experiment and the above description is not correct. When applying an all analog VCA with fast envelope to a clean and deep 30Hz sine wave, you get some distortion in the sound (generated because the envelope speed is quite high relative to the sine frequency), but it does not at all sound like the zipper sounds you get when you do the same on the bitbox. The distortion in the analog example above can be almost but not fully removed by use a zero-crossing-detection VCA.
    Last edited by yrn1; 03-28-2018, 09:39 AM.


    • #3
      Based on some research, this problem comes from the CV value not reaching the final value before the trigger happens. I have seen sequencers like the Arturia BeatStep Pro have a 5ms lag between gate and pitch reaching the final value. This issue points out the weakness of using CV for slice selection. Bitbox starts playing the wrong slice then quickly switches the desired one once the value reaches the intended value. The firmware has a small window where it will accept an incoming CV change following the trigger.

      Here are a few alternatives:
      1) Use MIDI. With this control scheme the note number controls the slice. So, the start command and slice selection are in the same message.
      2) Use some other scheme to determine the CV for slice selection so that the value is stable ahead of the trigger.
      3) Use some external gear to delay triggers (what you are already doing)
      4) Take your source WAV file into a wave editor and delay the whole thing by 5-10ms. This will add a fixed delay and depending on the material it will give you the desired response. (You will hear a tiny bit of the previous slice. If this is silence, you are OK.) You will need to edit the file in place, as selecting a new file on Bitbox will delete the existing slices.

      I look forward to hearing any other possible options.


      • #4
        thanks for the suggestions, yrn1, Aaron!

        now, i did further explorations yesterday, and found the problem only worse with the social entropy engine-sequencer. yesterday, in both cases, ER-101 and engine, the slice selection was absolutely unusable without a delay of several milliseconds (how many exactly i do not know, did not record the CV output of the synthrotek ADSR providing the gate-delaying)... the problem seems to fluctuate somewhat, and somehow settle after a minute or two of modulation. i do not know if this is possible but it seemed that way.

        the logical next step for me is to record and examine the gates and CV's the two machines produce, and see by how much the CV changes are delayed relative to the gates. maybe the problem is also escalated by using 3 separate modulators for a single cell as i have been doing the last days, resulting in more stress of the CPU? at all possible, Aaron?

        as to solution 1, yes, this is possible with engine. however, i am very excited about being able to sequence sliced drum samples and other material specifically with the ER-101 which i am fond of and familiar with. it allows for an open mind going in to the sequencing, not providing a set 1-16 step context. converting CV > MIDI is not an option in this case. this also means solution 2 is out of the question. separate trigger- and CV-sequencing is exactly what i do not want to do.

        as to 3, yes, i will continue to take this route. i will see if V/oct modulation is more effective. the problem with that thus far has been that not all slices seem to be able to be addressed in this mode, but further exploration is necessary on my part.

        as to 4, in my case this would mean manual slicing, and approximating some ms before the onset of sound. this is pretty damn difficult at the moment since a time scale is not displayed along with the audio file, and as you pointed out, slices are lost when selecting a new file. thinking about this option futher now i do not know how it is at all practically applicable to my scenario, I'm sorry to say.

        i understand the motivation to keep the UI lean, and i can see this might be a part of the design filosofy on your side. i would, however, especially since this is an inherent problem acknowledged by you guys also, Aaron, wish for an additional option to delay the onset of slice playback relative to receipt of trigger/gate. i understand completely that this is unlikely to happend based on the wish of a single user, though =)

        thanks again!


        • #5
          I like your last suggestion to build in a trigger delay option. The ornament and crime also has it built in and I find myself using it quite a lot.


          • #6
            Originally posted by yrn1 View Post
            I like your last suggestion to build in a trigger delay option. The ornament and crime also has it built in and I find myself using it quite a lot.
            O&C is pretty special then in that respect. or at least my sequencers-of-choice do not offer this option.

            we'll see!


            • #7
              hello Aaron,
              what is update rate of the CV-inputs for this particular case (slice selection) please?
              would be good to know, I noticed for example that my Metropolis outputs CV's with a minimum rise time of 1ms...


              • #8
                Originally posted by yrn1 View Post
                I like your last suggestion to build in a trigger delay option. The ornament and crime also has it built in and I find myself using it quite a lot.
                Yeah just like the one in Braids


                • #9
                  Thanks for the discussion. I don't have the timing numbers handy. I can tell you the shorter the window of uncertainly on the CV value, the better the results will be.

                  We will keep this request in mind. I have added it to our long request list.


                  • #10
                    So to update the info on the ER-101, according to the manufacturer the lag is 0.2ms, and on my unit this is also the case.


                    • #11
                      So are we saying that the ER101 is not the best sequencer for the bitbox given the issues raised here?