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Squeezebox Touch: jitter thru wi-fi?

I'm looking into a SB Touch to go with a non-dedicated PC, and to feed my preamp (so initially, I'll use the Touch's DAC).

Eventually I plan to buy an external DAC, and I'm interested in the asynch USB DACs, which are supposed to avoid jitter through that interface. There's a Touch tweak going around to turn the USB input into an output, so that would be a preferred way to connect to said DAC.

Now how about mistimmings in the data transfer (jitter) through my wi-fi from PC to Touch? Is that an issue?

Thanks!
lewinskih01
audioengr
3,282 posts
 
Jitter is only an issue with the clock and S/PDIF output of the Touch, not the WiFi transfer. Only dropouts can occur with the WiFi interface. These are not jitter. Dropouts are rare and depend on the usage of your ethernet network.

Steve N.
Empirical Audio
mapman's avatar
mapman
22,566 posts
 
Audioengr reminded me that a Wifi network is shared and used by all active devices connected to it. it is only dedicated to streaming audio from server to player if nobody else is using it for tasks that consume bandwidth (web browsing, file downloads, etc.). So concurrent usage for things other than streaming audio can cause delays/dropouts.

For example, I have two Roku players on two systems that conenct via wireless G to the same music server computer. Often if I play both at the same time with lossless CD .wav files, the dropouts/delays will occur regularly and become an annoyance. Less of a problem as I mentioned earlier for lossy or lower resolution files, like MP3.
kijanki's avatar
kijanki
4,432 posts
 
The worse case for two channel spdif is 24bit at 192kHz.
24 bit data is transferred in 32bit packets (8 bit preamble).

32bit x 2channels x 192kHz = 12.3Mbps

802.11g runs at up to 54Mbps while 802.11n more than doubles it.
mapman's avatar
mapman
22,566 posts
 
Kijanki,

54Mbps is what wireless g can do optimally based on the spec I think, right?

Weak/sub optimal signals reduces that bandwidth.

Also I've found not all g routers are the same. Actual bandwidth at a particular range seems to vary from router to router. There may be many reasons for this

Processors and programming can vary.

Differences in the performance of the radio transmitter /receiver technology may be another factor. Antenna's used are one factor. I suspect there are others also.
almarg's avatar
Ag insider logo xs@2x
almarg
9,670 posts
 
802.11g runs at up to 54Mbps
Not in the real world. 15 mbps would be a reasonable expectation for a fairly optimal setup, and I'm sure that less than 10 is not uncommon.

I don't have a feel yet for typical 802.11n performance, but given that the theoretical maximums that were advertised for a, b, and g were all essentially fictional, I'd be surprised if the same didn't apply there.

Best regards,
-- Al
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