Dropouts streaming music from NAS (USB 2.0 HDD via AirPort Extreme)

Discussion in 'Digital Audio' started by ToTo Man, Apr 18, 2012.

  1. ToTo Man macrumors regular

    Joined:
    Oct 22, 2008
    #1
    I’ve just recently got an AirPort Extreme (5th Gen) to boost wifi coverage in my house by replacing the AirPort Express I had.

    Since the Extreme allows hookup of an external USB HDD, I decided to centralise storage of my music, so the WD 500GB MyPassport HDD is now no longer connected directly to my laptop, but is now instead connected to the Extreme.

    I’ve had this setup in place now for a few days now, and the first couple of days of streaming music to my laptop were trouble-free, but recently I have experienced occasional unexpected dropouts.

    When I look at the Activity Monitor while streaming audio to the laptop, most of the time the green data throughput graph is fairly stable and fluctuates precisely between the 2 values 168kB/s and 201kB/s, which is what you would expect when streaming an uncompressed 1411kbps AIFF file. However when an audio dropout occurs the throughput drops significantly, e.g. from anywhere between 34kB/s to as low as 0kBs, and then spikes sharply e.g. to 436kB/s, and consequently the green data throughput graph becomes very volatile for a few moments before stabilising again.

    I am by no means a networking expert and so I am looking for advice on why this is occurring and how I can resolve this problem? The following info may be of use:

    1. The HDD is connected directly to the Extreme and not via a hub.
    2. The HDD is a portable USB 2.0 HDD and so draws all of its power from the Extreme.
    3. The HDD has a tendency to ‘sleep’ if inactive for a few minutes, but as long as you access it via the Finder to wake it up before launching iTunes, this isn’t a problem.
    4. The HDD contains only the audio files, I have kept the iTunes library xtl, xml, and Artwork locally on the laptop.
    5. The audio files are in full uncompressed AIFF format (i.e. 1411kbps).
    6. The Extreme is only 12ft away from the laptop and the laptop shows full signal strength, which rules out issues with weak signals.
    7. I can successfully copy AIFF files to and from the HDD connected to the Extreme at a peak throughput rate of around 9MB/s, so the HDD/Extreme do have the ability to operate at throughputs much higher than the sustained 200kB/s required for streaming uncompressed AIFF.
    8. I can successfully stream high res 24/96 4806kbps AIFF audio and achieve a throughput of ~600kB/s with no more incidences of dropouts than streaming standard 16/44 1411kbps AIFF audio.
    9. The problem occurs regardless of whether I stream music to the laptop and listen locally on the laptop via headphones or send it on to my main hifi via an AirPort Express, which eliminates the Express as the problem.

    The only other thing I can think of is interference from other household appliances, e.g. microwave ovens and cordless phones, but these all operate on the 2.4GHz band so should not be interfering with the 5GHz Extreme???

    Any help would be greatly appreciated :confused:.
     
  2. EvilC5 macrumors 6502a

    Joined:
    Sep 22, 2010
    Location:
    Hanover MD
    #2
    I had issues streaming blu-ray ripped MKV's via the usb on my extreme, the answer I got was the processor in the extreme isnt fast enough to accomplish this on such large files.

    true or not, im unsure, but the same file and same harddrive hooked to my mini, wired to my extreme allowed me to stream wirelessly to my ipad/ATV
     

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