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  1. #1
    Newbie Objectionist wgscott's Avatar
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    Streaming with 2.4GHz vs. 5GHz

    I may have just discovered the obvious, but if I set my (music only) bedroom ATV2 to use the 2.4GHz rather than 5GHz signal from my distally-located Airport Extreme, it works vastly better. No dropouts in an hour of listening. Apparently the lower-frequency signal is more robust at long distances.
    Living Room: 2012 i7 Mac mini --> Halide Bridge-->Peachtree Nova --> Class D Audio 254 X 2 --> B&W CM7R + Rel R218
    (iTunes | Audirvana | BitPerfect | Decibel ) & Dirac
    iTunes on remote computer controls Audirvana on server

    Home Office: 2007 iMac --> Vanatoo powered speakers (iTunes | Audirvana | BitPerfect | Decibel )

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    Señor, señor, let's disconnect these cables
    Overturn these tables
    This place don't make sense to me no more.

  2. #2
    A lower frequency signal definitely is more robust at overcoming obstructions such as distance or certain materials, draw a parallel with how well low frequency audio can be heard through walls and whole buildings sometimes or how red light is much better visible at long distances (e.g. sunsets). The technical explanation behind this phenomenon is of course the fact that lower frequency electromagnetic waves have a longer wavelength. But you have to keep in mind that the frequency spectrum around 2.4 GHz is well saturated by a lot of devices nowadays, which is why surprisingly often the 5 GHz band might be a much better choice. But it is universally true that it's a good idea for anyone using any kind of wireless technology to check what channels are used in ones surroundings and to optimize for best reception. Another thing that is true is that dual band antennas (say 2.4/5 GHz antennas used in some laptops) are always a compromise, single band antennas usually work much better at the prescribed frequency. In one of my ALIX boards I have a single band 2.4 GHz antenna installed, and I had to make sure that the board always connects to the 2.4 GHz access point of my AirPort Extreme (which, as most routers, has two separate antennas, one for each frequency band). Letting the board choose randomly by itself would sometimes lead to it connecting to the wrong access point resulting in a very weak signal.

    So remember kids, always make sure you check the wireless frequency pollution of your surroundings!

    A nice tool for Mac OS X would be iStumbler for example. When your AirPort is enabled it shows you all the access points near by and which channel they use.
    Listening Room: ALIX.2D2 (Voyage MPD) --> Arcam rDAC --> Marantz PM-15S2 --> Quadral Wotan Mk V
    Drinking Room: ALIX.2D2 --> M2Tech hiFace 2 --> Cambridge Audio Azur 740C --> Rotel RC-06/RB-06 --> B&W XT4
    Home head-fi: Grado SR80i, Sennheiser HD 650
    On the go head-fi: Sennheiser IE 8

  3. #3
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    I'm using Kismet to check the wireless situation frequently.

    Good to remember that things which don't show up there but still interfere at 2.4 GHz band are Bluetooth and such.

    I always prefer using access points with good external antennas.
    Signalyst - http://www.signalyst.com
    Developer of HQPlayer

  4. #4
    Newbie Objectionist wgscott's Avatar
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    In 10.8, there is a new utility called Wifi Diagnostics. You can get to it easily by option-clicking on the wifi menu bar icon.

    (I'm doing this from a computer near to my Airport Extreme, not the problematic area.)

    screen-shot-2012-09-27-5.57.05-pm.png

    screen-shot-2012-09-27-5.57.20-pm.png
    Living Room: 2012 i7 Mac mini --> Halide Bridge-->Peachtree Nova --> Class D Audio 254 X 2 --> B&W CM7R + Rel R218
    (iTunes | Audirvana | BitPerfect | Decibel ) & Dirac
    iTunes on remote computer controls Audirvana on server

    Home Office: 2007 iMac --> Vanatoo powered speakers (iTunes | Audirvana | BitPerfect | Decibel )

    ------------------------------------------------------------------------------------------------------------------------------------

    Señor, señor, let's disconnect these cables
    Overturn these tables
    This place don't make sense to me no more.

  5. #5
    Newbie Objectionist wgscott's Avatar
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    Funny thing is, in the bedroom where this ATV2 is located, I have several neighborhood signals on channel 1. (I would change mine, but my redeye remote doesn't seem to cope). Despite this, it is a radical improvement. I didn't think a factor of two would make that much difference. The signal needs to go through two walls and a floor. I've been contemplating putting in an ethernet hose. I am glad I tried this first.
    Living Room: 2012 i7 Mac mini --> Halide Bridge-->Peachtree Nova --> Class D Audio 254 X 2 --> B&W CM7R + Rel R218
    (iTunes | Audirvana | BitPerfect | Decibel ) & Dirac
    iTunes on remote computer controls Audirvana on server

    Home Office: 2007 iMac --> Vanatoo powered speakers (iTunes | Audirvana | BitPerfect | Decibel )

    ------------------------------------------------------------------------------------------------------------------------------------

    Señor, señor, let's disconnect these cables
    Overturn these tables
    This place don't make sense to me no more.

  6. #6
    Newbie Objectionist wgscott's Avatar
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    Here is how it looks from the bedroom:

    screen-shot-2012-09-27-6.31.02-pm.png
    Living Room: 2012 i7 Mac mini --> Halide Bridge-->Peachtree Nova --> Class D Audio 254 X 2 --> B&W CM7R + Rel R218
    (iTunes | Audirvana | BitPerfect | Decibel ) & Dirac
    iTunes on remote computer controls Audirvana on server

    Home Office: 2007 iMac --> Vanatoo powered speakers (iTunes | Audirvana | BitPerfect | Decibel )

    ------------------------------------------------------------------------------------------------------------------------------------

    Señor, señor, let's disconnect these cables
    Overturn these tables
    This place don't make sense to me no more.

  7. #7
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    With 2.4 and HD video via tha ATV3, I couldn't keep up with the buffering, and hence playback would pause as the stream was catching up. With 5, no more buffering issues and content loads much faster BUT with heavy action sequences, the 5khz resulted in excessive 'blocking' of the image. I've since moved to a combination of hardware and power line adapters, using wifi only for the iPad and iTouch. Streamed BD rips at 1080p encoded in H.264 are indistinguishable from the Disc they were burned from.

  8. #8
    Quote Originally Posted by mayhem13 View Post
    With 2.4 and HD video via tha ATV3, I couldn't keep up with the buffering, and hence playback would pause as the stream was catching up. With 5, no more buffering issues and content loads much faster BUT with heavy action sequences, the 5khz resulted in excessive 'blocking' of the image. I've since moved to a combination of hardware and power line adapters, using wifi only for the iPad and iTouch. Streamed BD rips at 1080p encoded in H.264 are indistinguishable from the Disc they were burned from.
    There is actually very little correlation between network speed and the wireless frequency used. In your case it simply seems that 2.4 GHz didn't lead to a signal as good as with 5 GHz. The blocking of the image is the server which decides to compress the video a bit more (or the compression algorithm used is sensitive to action sequences, though that would be rather stupid since even basic DivX doesn't have this issue). I also had the experience that for smooth video playback I had to use a wired connection. I'm streaming from my iMac to a Playstation 3 and as in your case I can stream 1080p video without a hitch.
    Listening Room: ALIX.2D2 (Voyage MPD) --> Arcam rDAC --> Marantz PM-15S2 --> Quadral Wotan Mk V
    Drinking Room: ALIX.2D2 --> M2Tech hiFace 2 --> Cambridge Audio Azur 740C --> Rotel RC-06/RB-06 --> B&W XT4
    Home head-fi: Grado SR80i, Sennheiser HD 650
    On the go head-fi: Sennheiser IE 8