Distortion thru SPDIF and USB out , if 48khz

    Hi,


    Ive just got a focusrite pro 14 and connected it to my TI via SPDIF, the AI is set to be the clock sync @48khz, and the TI is set to Auto (i.e. should be slave) - so far so good, but I get distortion ( almost a high pitch ringing)
    If I try the analog outs, no problem - no distortion.


    As this the focusrite was new, I thought Id take the focusrite out the equation,
    so disconnected it, and instead connected to the TI via VC over USB, and set my app to use 48khz - same distortion.
    if i set it to 44khz, the distortion was gone (which is why ive not noticed before, as i usually run at 44k)


    Ive tried a few patches (and its in the factory patches e.g. E-Grand)


    any ideas, do others use 48khz?


    Thanks
    Mark


    TI Keyboard mk1, 5.0.3

    ok, ignore this... it seems to be somehow something to do with when the TI is connected to the my Mac via USB, its is reverting to 44k, but the audio interface is saying 48k
    im guessing this may be sorted out by telling my mac to use the audio interface, hopefully that will push it to 48k


    still a bit unsure why im getting the glitching when i tell my app/soundcard on mac to do 48k

    Doh, finally got everything connected and the problem remains!



    Mac -> Virus Control -> USB -> Virus TI
    Virus TI -> SPDIF (out)-> Saffire Focusrite pro 14


    Saffire is set to Internal Clock 48khz
    TI set to Audio Clock 48khz
    Mac and DAW set to use Saffire at 48khz



    Other VSTs played from Mac to Saffire - Fine
    Other apps can play thru at 48 to saffire - Fine



    Virus TI - played via Virus Control - SPDIF (out1) - distorted


    Virus TI - with no DAW, still plugged into USB - distorted




    Unplug USB, Virus TI is fine


    Or
    ----
    keep USB plugged in - switch to 44 Khz - all is fine.




    As far as I can see, it seems like it doesn't like to be connected via the USB and SPDIF as well,
    is it for some reason getting a clock from USB and SPDIF that differ?




    Also, unrelated if i plug SPDIF IN, then I get 'Illegal clock rate" - any ideas?



    thoughts, I cannot find a solution... Id like to have the USB left plugged in for VC, and also the SPDIF for an FX loop.
    (id also prefer to have TI as slave not as master for clock, just in case it happens not to be turned on when Im using other synths etc)

    will do, thanks


    btw, just one question...


    If I go to Audio Device (Mac) , I can see the Acces Virus TI 2in/2out - and I cat see this is saying 44.1khz, the drop down has 48Khz, but doesn't let me change to it.
    (i.e. I select it, but it goes back to 44.1khz) .. is this normal?


    (on virus , it says clock is 'synced to host')

    well support have asked me if without SPDIF, can I select 48khz in Ableton - Ive replied, No ... but not got a reply yet...



    So it appears, that the issues is simple when I have the USB connected I cannot select 48khz , i.e. nothing to do with the soundcard/spdif.
    (the issue then occurs with spdif because the usb has forced it to 44.1 so creates a mismatch)


    Has anyone got the Virus TI connected with USB running at 48khz?
    (im on mac 10.8, TI 5.0.3)


    EDIT.. just seen this unanswered post, which seems the same
    Virus TI as usb Soundcard, ProTools session at 48khz

    ok, having spent more precious time on this, ive finally sorted it out myself !


    I plugged in my macbook and found i was able to select 48khz in the audio settings for the TI when plugged into USB.


    So went back to my iMac, decided to try plugging the TI into a USB hub - bingo, suddenly I can now select 48khz in the audio settings, and then immediately works with my audio interface at 48khz with no distortion.


    ( i only thought of the hub, after reading about it at http://www.usb-audio.com, this I found, when I checked virus usb driver and found it was Ploytec GMBh that writes the USB driver for access)


    my assumption that USB was forcing it down to 44.1khz, and so being out of sync with the audio interface was correct.


    Access - why are there no error messages?
    I checked in the (system) console and theres nothing... I've a device is requested to do something, and it cannot - it should log a messages, with a reason code - so we have something to go on.

    pardon???


    Im not implying fault or trying to lay blame... im trying to provide some useful feedback to help future users....
    so I don't think we need to be defensive.


    Virus TI Manual, p 16 - About USB connection - First line in Bold - "Dont use a hub" , last line in paragraph - we ... decided not to support use of hubs at all.
    Setup Guide p4, "In general we recommend you avoid using a USB hub..."


    Your users will go by what the manual says first, regardless of what can be found 'elsewhere)


    Next you statement regarding high speed hubs seem like it might be inaccurate, USB 1.1 is much slower than 2.0, so speed/bandwidth is not the issue par se.
    the issue is using mutliple 1.1 devices on a hub that only has a single TT, ( as is discussed on tomshardware)
    http://www.tomshardware.com/reviews/usb-technology,677.html
    unfortunately, its almost impossible to find out if your hub has a multi tt or single tt - so best answer is to ensure you only plug one 1.1 device IF you don't know.


    >changing the SR has nothing really to do with the hub though.
    i beg to differ about SR not being affected by USB, it is ... as i clearly showed here, and have also shown in
    USB 3.0 issues on recent iMacs? (not able to select 48khz)
    it appears there is a USB 3.0 to USB 1.1 issue...


    I don't know you drivers code, so I cannot say why, but in practice it does... as I speculated, perhaps it requests more bandwidth for higher SR... but thats speculation,
    I can only give you the facts about behaviour.
    I dont expect Access to just 'believe' me, what I expect is for Access to test the TI on a late 2012+ mac and see if you can replicate the SR issue,



    why should you care? because my iMac is new, and so as your users replace there macs with new models, they are going to start facing the same issues.
    Therefore, it would he helpful to clarify if this is a general issue, which will make your support job much easier.



    i repeat, the only reason im making these posts is to help others, and Id hope also Access could make use of the extra information.
    I understand there is alot of 'myth' about whats going on around USB and the TI, but I hoped my posts show that id researched and tested this before making claims.
    (also please bare in mind Im a software dev of 25 years experience of high speed, low level drivers/applications)

    I realize I may not add any value to your issue here however I cannot help but notice that you have stated that saffire is internal 48khz and virus is set to 48khz... you have not specified who is syn'ing to who.
    my understanding is that the receiving end should sync to the transmitter...so if the virus has its clock at 48kHz and the saffire has its clock at 48kHz and is not sync'd to the incoming clock then I personally would expect distortion, or even no audio.


    so..either have the saffire sync to external clock (the virus), or if you really want the saffire to be the clock master, additionally connect spdif saffire>virus also.. then the virus should extract the clk.


    on a totally different note, and while acknowledging you should be able to setup a 48kHz system, I would say 'why bother"?.. the norm is more for 44.1kHz ..but that's just my 2c :)


    Thanks, there is no issue really now. It was the USB as above.


    Saffire is set to internal , ti is set to auto ie Safire is master and ti is slave.
    ( spdif always connected)
    So when USB is not connected, Ti syncs to Safire over spdif
    When you connect via USB, ti syncs to host (mac) which is in turn sync to Safire


    All working very nicely :)