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Thread: Unable to achieve a low latency with Focusrite Scarlett 2i2

  1. #21

    Re: Unable to achieve a low latency with Focusrite Scarlett 2i2

    Quote Originally Posted by Sylos View Post

    It's still a mystery to me why you are having these problems. It might be worth trying a different audio distro from a Live CD to see if that suffers the same problem. If not then it might give an indication of what is causing the issue.

    Cheers
    Just some suggestion of audio distros: http://tangostudio.tuxfamily.org/en/tangostudio , http://www.bandshed.net/AVLinux.html , http://puredyne.org/about.html , http://puppylinux.org/wikka/PuppyStudio . In my experience those distros are very performant, we could use them in order to obtain hints as Sylos said.

  2. #22
    Join Date
    Jan 2013
    Beans
    12

    Re: Unable to achieve a low latency with Focusrite Scarlett 2i2

    Thank you both,

    I've tried out AV Linux, which is giving much the same results in an 'out of the box' state. I am going to take a break from trying to get it working correctly on the laptop, and then maybe go back and try some of the tips that appeared earlier on in this thread on AV Linux.

    Off Topic: I posted earlier as an aside, that I had Ubuntu Studio working perfectly on my Acer Revo 'nettop'. I have since found that this is not the case - it will only work when running off USB. No signal appears in Ardour when Ubuntu Studio is actually installed on this machine! I am lost for words. I've checked the obvious JACK settings etc, to make sure I've got the correct device is selected and the device is definitely receiving audio (verified this with its hardware monitoring feature). I haven't even begun to try and troubleshoot this (and am unlikely to!).

    CrocoDuck / Slyos: you are both a credit to the community, and I really appreciate your patience. I am going to spend some time recording on my Acer Revo, running 'Studio from USB for the time being, before reinvigorating myself and having another go at getting it working properly (on any device!).

    Thanks again.

  3. #23
    Join Date
    Nov 2012
    Beans
    3

    Re: Unable to achieve a low latency with Focusrite Scarlett 2i2

    Hi all.

    I have just solved (from a user perspective) similar problems on a ASUS A53E with i5 and 4G RAM running Ubuntu Studio 12.10.

    Focusrite USB Saffire 6 and Intel HDA onboard.

    I just got rid of them by changing to the generic kernel:

    Linux snowpea-studio 3.5.0-23-generic #35-Ubuntu SMP Thu Jan 24 13:15:40 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux


    Testing below done with this setup under Gladish and Jack, shut down and restarted between runs. All tests with all four cores in performance mode:

    mike@snowpea-studio:~$ more /proc/cpuinfo | grep MHz
    cpu MHz : 2501.000
    cpu MHz : 2501.000
    cpu MHz : 2501.000
    cpu MHz : 2501.000



    The symptoms were:

    Jack Buffer 1024, periods 2, duplex

    No problems

    Jack buffer 512, periods 2, duplex

    2-4 XRUNS in 6 minutes

    Jack buffer 256, periods 2, duplex

    4-8 XRUNS in 6 minutes



    After changing the kernel from low-latency to generic:

    Jack buffer 256, periods 2, duplex - using the Onboard chipset

    0 XRUNS in 6 minutes
    3 XRUNS in 25 minutes

    Jack buffer 256, periods 2, duplex - using the USB Saffire 6

    0 XRUNS in 6 minutes
    0 XRUNS in 25 minutes

    Interested to hear if that resolves the original poster's problems.


    Cheers


    Mike Thomas

    mike@snowpea-studio:~$ cat /proc/interrupts
    CPU0 CPU1 CPU2 CPU3
    0: 44 0 0 0 IO-APIC-edge timer
    1: 5516 0 0 0 IO-APIC-edge i8042
    8: 1 0 0 0 IO-APIC-edge rtc0
    9: 3578 0 0 0 IO-APIC-fasteoi acpi
    12: 675001 0 0 0 IO-APIC-edge i8042
    16: 175 0 0 0 IO-APIC-fasteoi ehci_hcd:usb1
    17: 313 57530 0 0 IO-APIC-fasteoi ath9k
    23: 79 9800568 0 0 IO-APIC-fasteoi ehci_hcd:usb2
    40: 0 0 0 0 PCI-MSI-edge PCIe PME
    41: 0 0 0 0 PCI-MSI-edge PCIe PME
    42: 0 0 0 0 PCI-MSI-edge PCIe PME
    43: 0 0 0 0 PCI-MSI-edge PCIe PME
    44: 32224 0 0 0 PCI-MSI-edge ahci
    45: 0 0 0 0 PCI-MSI-edge xhci_hcd
    46: 0 0 0 0 PCI-MSI-edge xhci_hcd
    47: 0 0 0 0 PCI-MSI-edge xhci_hcd
    48: 0 0 0 0 PCI-MSI-edge xhci_hcd
    49: 0 0 0 0 PCI-MSI-edge xhci_hcd
    50: 14 0 0 0 PCI-MSI-edge mei
    51: 9457 0 0 0 PCI-MSI-edge i915
    52: 845748 0 0 0 PCI-MSI-edge snd_hda_intel
    53: 0 0 0 0 PCI-MSI-edge eth0
    NMI: 435 453 221 205 Non-maskable interrupts
    LOC: 769821 649630 260064 293655 Local timer interrupts
    SPU: 0 0 0 0 Spurious interrupts
    PMI: 435 453 221 205 Performance monitoring interrupts
    IWI: 0 0 0 0 IRQ work interrupts
    RTR: 3 0 0 0 APIC ICR read retries
    RES: 340574 203109 154808 297031 Rescheduling interrupts
    CAL: 240 448 496 473 Function call interrupts
    TLB: 3593 2808 2823 2004 TLB shootdowns
    TRM: 0 0 0 0 Thermal event interrupts
    THR: 0 0 0 0 Threshold APIC interrupts
    MCE: 0 0 0 0 Machine check exceptions
    MCP: 20 20 20 20 Machine check polls
    ERR: 0
    MIS: 0


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    Will Not Detach
    Manifestation Tolerant
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    bDescriptorSubtype 2 (INPUT_TERMINAL)
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    Bus 002 Device 003: ID 046d:c52b Logitech, Inc. Unifying Receiver
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    bInterval 2

  4. #24
    Join Date
    Jan 2013
    Beans
    12

    Re: Unable to achieve a low latency with Focusrite Scarlett 2i2

    Hi,

    Thanks for the suggestion regarding using the generic kernel. I installed this and reboot, before trying to record again in Ardour.

    I found that I was getting Xruns at ~30sec intervals after the change, which is actually worse than before.

    I think the next step for me is to try and interpret the JACK logs to find the source of the faults, however that's easier said that done

    Thanks again,


    ehdee

  5. #25
    Join Date
    Jun 2013
    Beans
    1

    Re: Unable to achieve a low latency with Focusrite Scarlett 2i2

    I had exactly the same problem with the Scarlett 2i2 on a Core i3 with 4 GB RAM.

    As soon as I changed from 48 000 Hz to 44 100 Hz in Qjackcontrol the xruns disappeared nearly completely.

    Have you tried that?

  6. #26

    Re: Unable to achieve a low latency with Focusrite Scarlett 2i2

    Maybe you have tried it a lot of times, but here what I just thought: try to bump period/buffers to 3. It should be the ideal perdiod/buffer setting for USB devices. I see that your soundcard supports a lot of sample rates: 44.1 KHz, 48 KHz, 88.2 KHz, 96 KHz . Have a try starting from something like this:

    Code:
    /usr/bin/jackd -v -P89 -p128 -t5000 -dalsa -r48000 -p64 -n3 -D -Chw:CODEC,0 -Phw:CODEC,0
    for the jack configuration. Of course, select your Scarlett for -Chw e -Phw. Knowing the hardware and the drivers in use by the system helped me in the past to solve audio issues (the last with x-runny performances on Archbang using my UCA202, with the help of cool people from Archbang forums). Can you repost the output of

    Code:
    lspci -vnn
    ?
    Check my linux audio experiments at https://soundcloud.com/crocoduck

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