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Use your iPhone as a wireless IEM receiver

Discussion in 'Live Sound [BG]' started by Robb Fesig, May 17, 2018.


  1. Robb Fesig

    Robb Fesig

    Mar 14, 2015
    Pennsylvania
    Hi guys.

    Came across this link today: https://audiofusionsystems.com/
    Software running on a PC broadcasting wifi to iPhones for IEM receivers.
    This comes up fairly often here, and we all agree (like heck we all agree!) that Bluetooth is too latent for this use. Looks like its $200 to try it.
     
  2. DonaldR

    DonaldR

    Mar 26, 2012
    Been dreaming for years to use my iPhone as my IEM receiver, but I will never rely on a PC for it.
    I'm using software plugins for headphone practice and with all software/os patches it's a pain.
     
    Robb Fesig likes this.
  3. Ulf_Hansson

    Ulf_Hansson

    Apr 15, 2014
    There is not a lot technology detail on their site, so I wonder how they pull this off. I spoke a lot to a friend (who is a software engineer, doing music apps) about this idea several years ago. As you can imagine, it started out with investigating if Bluetooth could be used for this, but we quickly decided that latency would be far too long. So obviously wifi came up as an alternative, but if I remember correctly the professional protocols available was only for wired ethernet and I think iOS prevented use of any proprietary protocols.
    I'll ask him to have a look at what Audiofusion does.
     
    Robb Fesig likes this.
  4. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    alpha-music.com
    so it's gonna run on 5GHz wi-fi, which i guess makes some kind of sense.

    the obvious issue is still latency, and i suspect that it's not really solved yet. i note the ad copy testimonials are all from musicians marveling for the first time at the advantage of in-ears in general vs any kind of comparison between this setup and a real IEM system.
     
    Robb Fesig likes this.
  5. Robb Fesig

    Robb Fesig

    Mar 14, 2015
    Pennsylvania
    In theory, if the stream decoder can do its job fast enough, and the wireless latency doesn't get too bad, I don't see why this wouldn't work. It possibly uses something like Icecast as a server to stream the audio, which on a PC/Mac isn't taxing at all. Phones are used all the time to decode audio streams, so I don't see that as a problem either.

    PC encoding latency: max 3ms (probably lower)
    Wireless transmission latency: 3-8ms
    Phone decoding latency: 2ms
    Total latency: 8ms - 13ms

    Should work okay. With that said, I certainly wouldn't just buy it without a trial version for PC.
     
  6. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    alpha-music.com
    if that's the best case then it's probably not viable. above 10ms latency is enough to create phasing weirdness between your bone conducted internal head voice and the sound of your voice in the ears.

    add that to the typical couple-ms latency of a digital board and you've got issues.

    by comparison a good 2.4GHz digital guitar wireless is in the 4ms range and a really good one is squeezing that down to less than 1.5ms (line 6 relay G70-75).
     
    s0c9, Robb Fesig and Ethereal Thorn like this.
  7. Robb Fesig

    Robb Fesig

    Mar 14, 2015
    Pennsylvania



    I'm guessing at the numbers based on other experiences I've had with Icecast, WiFi, and Spotify. Perhaps their algorithm is more efficient. In any event, I wouldn't buy it without trying it from a demo.
     
  8. s0c9

    s0c9 Supporting Member

    Jan 9, 2014
    Ft.Worth/Dallas
    1964 Audio artist, Fractal Audio Beta Tester
    But aren't we talking IEM, not wireless FROM the bass/guitar? Tho' I agree, the latency should be in the same ballpark.. :)
     
    DirkP likes this.
  9. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    alpha-music.com
    yeah, which as i understand it is the problem; a latency that's OK for an instrument wireless might be a no-go for an IEM system. otherwise where are all the $400 line 6 or shure 2.4GHz digital "bar band IEM" systems? why isn't that a thing?
     
    s0c9 likes this.
  10. s0c9

    s0c9 Supporting Member

    Jan 9, 2014
    Ft.Worth/Dallas
    1964 Audio artist, Fractal Audio Beta Tester
    I had to laugh at the "audio fusion systems" web site page..

    "Audiofusion™ is being used by multiple bands, venues and churches and is now available for pre-order."

    SERIOUSLY ???? o_Oo_O
    Anyone see anything WRONG with that statement ???
     
    WayneP and Robb Fesig like this.
  11. DonaldR

    DonaldR

    Mar 26, 2012
    I laughed also as it's just stupid marketing and doesn't make sense. Maybe "being used by multiple bands, venues and churches" is now the new buzzword for beta testers...
     
    Robb Fesig likes this.
  12. Robb Fesig

    Robb Fesig

    Mar 14, 2015
    Pennsylvania


    Warning: I may be making this up (I can't always trust my brain)

    Wireless guitar/mic:
    Transmitter: 1 channel, relatively narrow audio spectrum
    Receiver: Diversity wireless antennas with enough room to pick up tangential signals
    Receiver: Pre-amp chips and their power supplies can be larger

    Wireless IEM:
    Transmitter: 2 channels, wider audio spectrum
    Receiver: special requirements for diversity connections on a small device
    Receiver: headphone amp driven by battery power requires more expensive/smaller voltage regulation and amplifier chip
     
    walterw likes this.
  13. Im curious to how the latency will be and what external hardware you will need to run this
     
    Robb Fesig likes this.
  14. Ulf_Hansson

    Ulf_Hansson

    Apr 15, 2014
    According to my friend, who knows a little something about programming for iPhone and 'droids, low latency for iOS usually is in the ballpark of 5 ms. For Android usually much, much worse (though some Samsung phones apparently has some proprietary patches).

    I guess I could just shoot Audiofusion a question, referring to this thread, and let them sort it out.
     
    Robb Fesig likes this.
  15. Robb Fesig

    Robb Fesig

    Mar 14, 2015
    Pennsylvania
    From the paper "The Effects of Latency on Live Sound Monitoring" by the Audio Engineering Society:

    "Sensitivity to latency is more strongly dependent on instrument rather than the individual subject."

    "The differences in latency perception from instrument to instrument prevent the ability to define absolute thresholds for the quality of live sound monitoring given a specific amount of latency."

    "How much latency can be present in a signal path before a musician will perceive an actual delay in the signal? This is highly dependent on instrument type. If we ignore the inconsistent saxophone data, latency values greater than 16ms for wedges and greater than 6.5ms for IEM would likely produce some audible delay for some instruments."

    Link to paper here: The Effects of Latency on Live Sound Monitoring
     
  16. Robb Fesig

    Robb Fesig

    Mar 14, 2015
    Pennsylvania
    So, if 6.5ms is noticeable for a vocalist on IEMs, then the 8ms to 13ms guess that I made earlier would mean this can't possibly work in the real world.

    It would seem Audiofusion's product is a non-starter based on current computer/iPhone processing power and wireless encrypting/decrypting processing.
     
    s0c9 likes this.
  17. Its usually 10 ms on vocals before you start having to much issue honestly with istruments you can go abit higher 13ms should still be fine on guitar or bass for most imho
     

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