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Use your iPhone as a wireless IEM receiver

#3
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.
 
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#4
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.
 
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#5
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
Robb Fesig said:
Total latency: 8ms - 13ms
Click to expand...
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).
 
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#7

walterw said:
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).
Click to expand...

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.
 
#9
s0c9 said:
But aren't we talking IEM, not wireless FROM the bass/guitar? Tho' I agree, the latency should be in the same ballpark.. :)
Click to expand...
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?
 
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#12
walterw said:
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?
Click to expand...

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
 
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#14
Robb Fesig said:
PC encoding latency: max 3ms (probably lower)
Wireless transmission latency: 3-8ms
Phone decoding latency: 2ms
Click to expand...

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.
 
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#15
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
 

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