Audible 'clicking' on output

  • Ive got another small issue, with SPDIF, causing an very quiet regular clicking sounds (about twice a second), audible at high frequencies


    Setup:
    Audio Interface: Focusrite Saffire Pro 14, connected via SPDIF to TI, 48khz clock rate, AI is Master for clock
    TI Keyboard v1 : Audio : Auto, Status , sync to SPDIF OS 5.0.3


    Not connected via USB etc.


    Generally its fine, except for this small clicking sound, which is barely audible.


    Reproduce:
    Select INIT patch, OSC balance to OSC 1 , Filter 1 to HP
    now play a high pitch note: say C7 ... turn the resonance up say to 127, and you can 'tune' in the cutoff to hear the clicking (around 80)


    if you play a different note, you can tune it using the cutoff/resonance - so its definitely there in the audio path on the TI , i.e. not an artifact of the Audio interface, other wise it would not be affected by cutoff.


    Ive checked the following:
    a) its present on shape/waves
    b) its not LFO related (tried changing rate etc)


    Its also definitely the external SPDIF that causes it...
    I did the following tests:
    a) Changed to a 'analog out' e.g. OUT 2 L+R - goes away (i was in seq mode, so could easily switch without altering anything else)
    b) Change the audio interface, so that it was Slave to the TI - clicking goes away (even though Im still using OUT 1 over SPDIF)



    so definitely appears to be when using TI sync to external SPDIF source, and using SPDIF OUT.


    Id really like to keep my TI as a slave to audio interface for clock for a variety of reasons, but obviously would prefer not to have this audio issues..


    Can anyone else reproduce this?

  • I have an Access Virus TI2 and I have the same problem. I'm using it through USB, which SHOULD work fine.


    I know this because when I play back midi lines through 1, 3, 5, 7, 9, etc it works perfectly but when I play the EXACT SAME midi line with the EXACT SAME preset on channel 2, 4, 6, 8, etc, I hear glitches and pops every 2 seconds or so. I’ve already tried resolving it by reinstalling the latest OS but the problem remained!


    I actually exported a song yesterday in which you can clearly hear the clicking/popping. it's definitely more audible in the first 10 second, where the sound is lowpassed.


    like you say, the sound is OK but there are clicks every second or so.


    also, the dynamics sound a bit awkward because the virus is dropping voices every 5 seconds or so!! SUPER annoying!


    this Virus is only 6 months old! I never even moved or dropped the unit! and it's already breaking down! ridiculous!!! :cursing:


    [soundcloud][/soundcloud]

  • Marc, do you think I have a hardware problem or skittb123 or both?


    I can see skittb123 might be as its on odd midi channels, so might be one dsp.


    I can't see how mine can be - as its only present when its clocked via external SPDIF and not using internal, and not using analog outs.
    ( i don't think it does it via USB either, but not tested as this would be very different - due to clocking be from host not SPDIF, so i suspect it would not happen on USB)

    Im willing to raise a support ticket if you wish though.


    Is it possible for you or someone else in Access to try to reproduce my scenario, I think Ive given enough details to reproduce,
    but will supply more if required.

  • Cool
    Are you or anyone else in Access able to see if you can reproduce my SPDIF click issue?
    If you need more details, then just let me know.


    Is anyone using SPDIF out there? have you tried syncing to an external clock?

  • Yes in is connected via spdif as well.


    I've tried disconnecting the in and makes no difference


    Also like others have stated in the past it's a bit flakey on the input side,
    Occasionally get 'clock problem on input'


    Interestingly if you don't have the spdif in plugged in,
    It still stays it's synced to spdif. So id assumed spdif was bi directional.


    I did mention this to access support,
    But never got any reply :(

  • Ok, so Ive now figured out that the TI cannot be used properly as an SPDIF slave.
    Its down to some fundamental issue, probably related to the 'clock input at spdif input' issue, which has been raised here before but never gets a response by Access.


    Ive got two brand new cables, they both sync perfectly fine why TI is used as master (and audio is fine) - so the cable is not the issue.


    I can workaround the issue by putting the TI to Internal, and always using it as the MASTER, and then making the audio interface the SLAVE.
    the drawback of this, is if I don't have the TI turned on, then I have to change the audio interface over to MASTER. (which is why I wanted it to be the master, as the AI is always on)


    I'll raise the clock input issue with Access as a support ticket and see if they are willing to test it.

  • if you loop in the virus with an external master clock (saphire out -> virus -> saphire in) you need to make sure that there is an SR converter or something else that decouples at the input of the saphire. the last time i've checked looping with a Pro Tools HD 192 i/o and that worked fine once i enable the SR conversion at the inputs.
    hth, marc

  • Thanks for the reply but I dont understand...


    I thought sample conversion was only done where you change the time base, e.g. going from 44.1 to 48 khz, whereas in this case we are staying with the same 48khz clock rate.


    my understanding on the way this should work is the virus is sync'd to the external clock from the saphire on the TI input, it uses that clock pulse to send on the output, in practice of course the output will probably be 1 sample behind (for processing time) but importantly it is in sync with the clock.


    basically we are not changing a time base here, all we are doing in syncing our sample to a single clock source.


    as I mentioned, if you flip this around it works.
    i.e. if the saphire is sync'd to the virus internal, then it will expect input (so ti output) to be on that clock pulse, and will output signals (so to ti input) on that same clock pulse. This the TI seems to be happy with.


    using a sample rate converter, sounds like its trying to deal with 2 clocks not in sync, but that should not be the case ....
    or am i missing something?

  • basically we are not changing a time base here, all we are doing in syncing our sample to a single clock source.


    it's an old trick i've learned when connecting e.g. a lexicon pcm90 to my protools HD rig. the problem is not so much the sampling rate but the offset in the clock produced by piping the data through the DSP. in an ideal world, you have a word clock which syncs the components and AES/EBU or S/PDIF which transports the samples. but that's not the case here (and in most non-video cases these days) and therefore you need to re-sync the clock.
    i hope this trick works for you as well, i did help me but it certainly depends on the components involved as well.
    hth, marc

  • Thanks for the reply but I dont understand...


    I thought sample conversion was only done where you change the time base, e.g. going from 44.1 to 48 khz, whereas in this case we are staying with the same 48khz clock rate.


    using a sample rate converter, sounds like its trying to deal with 2 clocks not in sync, but that should not be the case ....
    or am i missing something?


    iirc (and its been a while) sample rate conversion would both reclock and resync the incoming data stream to that for the target device. in this case it would be a sample rate conversion of 1:1 to overcome sync error.

  • thats what I was trying to say in the last paragraph...


    resampling, is a fix for resync'ing clocks - but they should not need resyncing...


    when you produce output, you have to produce output at a given clock signal, so this clock signal should be the one that is sync'd to the spdif input - there are not 2 clock signals that are out of step, so i do not see the issue.



    Ok, so I did another test....
    I disconnected the SPDIF output all together and left SPDIF input connected (with intention of taking digital input, and then using analogue output) - and I still get the same clock problem on spdif input...


    so even if my above statements are not correct (and it would be good to know why), then why this error? .... there is now only 1 clock to sync to ... the SPDIF input.

  • Ive had this problem also and found out that there are two issues that causes this. It may not be the same for you but.


    1. On the filter i needed to adjust the attack time.
    2. Make sure your virus gets enough bandwidth on the USB port. I bought a external USB hub where i keep my external hdd´s and other stuff which solved a lot of clicking for me. Hopefully the future viruses will be able to run thru thunderbolt or USB 3.0 or something faster.
    3. Also since you cannot use the max amount of buffer size you computer needs to work harder. So when the computer cannot compensate the latency it can create snapple, crackle and pops. Read more about it here http://support.apple.com/kb/HT1314


    So there is a lot of factors that i personally think shouldn't need to be there but they are. ^^

  • Hello Marc, hello technobear,


    my Virus TI2 Keyboard also creates those clicks when connected via S/PDIF in+out as clock slave. I can also confirm the clicks are gone when using the Virus as clock master and the audio interface as slave.


    I have contacted Access support, and they were being helpful, although their answer did not make me entirely happy:
    "the reason why you get clicks is that your fireface assumes that the clock timing of the audio stream it receives is identical to it's internal clock but that's not necessarily the case. the components used in the virus slightly shift the timing and that results in what you discover. there is no easy workaround for what you try to do. you could buy an audio interface which is prepared to receive asynchronous data or you could slave you interface to the TI while recording the output."


    "audio interface which is prepared to receive asynchronous data“ -> ie. an audio interface that has a sample rate converter.
    My audio interface (a TC Electronic Studio Konnekt) does not have a sample rate converter so I am left with the solution to use the TI as master.


    But why does the Virus shift the timing? I imagine no matter how long it takes the DSPs to compute audio data, the input clock should always be obeyed by the output stream. DSP takes time, this is understood, but at worst this means it can fill the output buffers only a bit later.


    Interestingly, I have a Lexicon MX400 (multi-fx rack unit) which has S/PDIF in+out, and it syncs perfectly as slave to the audio interface. So the clock problem is not a conceptual issue — it happens only with the Virus.

  • what support says it exactly what it boils down to. an SPDIF signal needs to be synced, one or the other way. this is true for the vast majority of digital devices i've come across over the years. by the way: it is not the Virus creating clicks, the signal which comes out of the Virus doesn't contain clicks. The artifacts happen because you digital components are not in sync.