bleed / audible clicks

  • i've already sent tehn an email about this, but curious if anyone is having similar problems or can suggest a solution...

    i'm experiencing two kinds of bleed with my aleph, both the audio and cv inputs bleed into the audio outs to some degree.

    with cv this is noticeable when i send analog pulse/clocks signals to they aleph: i can occasionally hear tiny pops in the output signal. it's really starting to drive me crazy, b/c i can't quite reproduce it in exactly the same way every time i test it. sometimes it is very present, sometime less so; it also seems dependent on the bees patch, which is weird

    i also experience bleed from the audio in to the audio out and headphone out, this is pretty subtle and a lot worse from the headphone jack, but it's hard to get total silence w/o closing off the input

  • further testing: I'm wrong about the cv bleed. I can reproduce the problem with an internal metro. seems to happen intermittently when the delay value is randomly changed, and it gets worse if I increase the fade parameters (what do those do?)

  • the cv out clicks sounds like the DSP is dropping frames meaning it couldn't compute everything required in the given sample. this will generally occur when changing a number of dsp parameters at once. i don't know the lines code well enough to say exactly the impact of the fade param but if it's doing some kind of linear crossfade it might be more dsp intensive while it slides between two play positions.

    not sure what to say here, apart from there's potential for optimization in the code which ezra's spoken about for a while, but not sure how high that is on his priority list.

    regarding the audio bleed, this has to do with the way the audio section has a floating ground. the result is that you'll get best rejection of bleed when the controls are set to their max values. i think the 2 output volume controls can also cause bleed interaction as well. so try setting the unused one to maximum or minimum and that might improve things. it seems counter-intuitive, but i think setting the unused knob to maximum will actually provide better bleed cancellation...

    hope that helps?!

  • that makes sense. thank you. i'll run some tests and report back

  • the weird thing is I'm hearing it now all over the 'default' scenes like space, and I swear space didn't sound like this last week

  • is this specifically the cv-out clicks, or the audio bleed?

  • the clicks. which i think may just be dsp related and not cv related since I can hear them w/ space now and I'm not using cv.

    re audio bleed: I have best results turning the headphone gain to max and having the audio input gains set very low. unused gain pots seem happier at 0 rather than at max

    i'll do more extensive tests tomorrow

  • oh for sure, keep the input gains low unless you're using them. i've always found the outputs to be on the quiet side so i almost always have the main output maxed.

    the clicks could definitely be related to the DSP but also could be due to the crossfader not being finished before space asks it to move the read head again... perhaps this is the reason why decreasing the fade parameter works. it's slowly crossfading between two read positions to allow smooth transitions but if it receives another input before it's done it might be jumping while halfway (though i'm sure i've seen code to avoid this in the lines source).

  • right, so after extensive testing. the problem has nothing to do with cv, but is linked to changes in delay values. even w/ say just an encoder mapped to delayN there will be a tiny click for each step of the encoder.

    the problem is especially noticeable when using small delay values and feedback, which i like to do

    so far:

    best solution: very careful gain staging

    bummer: hard to use lines with quiet/sparse sounds unless you stick w/ a delay time

    upside: i discovered how to make some mental no-input lines music

  • rad!

    i wanna hear more of this upside...

  • you know what... there's definitely sill an audio bleed problem that is also contributing. i can have the headphones at 0 and the input very low, play some mellow drones from my ipod into the aleph and hear a crackly ghost version through in my cans.

    i think an even more subtle crackling version of the input is bleeding into the outputs... maybe?

    would it help if i made some recordings?

  • @gli haha imagine clicky digital merzbow w/ a little bit of rhythm

  • can anyone w/ an aleph confirm the bleed i'm hearing... @gli?

  • here are some sound examples:

    clicks are iPod into space, nothing else

    for the bleed: the audio is recorded from output 1, output gain pot at 0, sweeping the input gain

  • added a no input recording just for @gli : just space, twiddling all parameters

  • lol

    i will try to replicate the click/bleed scenarios but off memory, now that i've heard them, i'm almost certain i've heard the clicks before

    i rather like them cause they add a bit of texture to the drones i frequently work with [but i can see why they would be bothersome...especially if the source material is acoustic]

  • noticing the same clicking with waves and the this scene. especially when changing the wm10 parameter, but also linked to the metro period

    it's kind of like vinyl crackle

  • well just had a session using lines w/ lots of feedback and delay changes and was very happy w/ the sound results. gain staging is really key: especially balancing the internal filter levels, wet and dry levels, delay to dac levels, AND the physical pots (phew)

    anyway, thanks for humouring my frustrations. glad to know nothing is broken :)

  • @analogue01 : i had to re-download and reinstall 0.6.0 again.
    about 'this' scene : now i don't hear crackles but the metro is slowing down while playing with wm10 encoder. (at some point, when reinstalling, i've heard crackles and the metro was not slowing down while moving the wm10 encoder).
    also : i like this no-input space sound :)

  • @beo: interesting. I ended up reinstalling everything as well.... it definitely seemed to help... will need to pay attention to the metros