On Thu, 23 Jun 2016 21:24:57 +0100, Java Jive
wrote:

On Thu, 23 Jun 2016 08:28:04 -0500, Richard Robinson
wrote:

Bob Latham said:
In article ,
Richard Robinson wrote:

Hello. I'm baffled and looking for help.

I've been trying to play audio over my home wifi :- the backend is a
raspbery pi sending audio out via USB into a DAC, the frontend is a
laptop running Debian 8, sending to a pulseaudio "SMC9514 hub digital
stereo (IEC958) on pi@raspberypi" sink (I find pulseaudio deeply obscure
and offputting, but I haven't found much else that offers the
possibility of doing this at all).

Not used a RPi, so can't help much with that at all. BTW, Jim is no
fan of pulse audio - neither am I, so I'm not grumbling - but
pulse audio or not, I suspect the WiFi is the problem, see below.

This connects, to the extent of
getting a noise out of the speakers, but the sound is useless - broken
up, stuttering, as much silence than sound - it gives the impression
that the data's just not being sent fast enough.

What transfer rate do you get if you just copy a file via WiFi from
the laptop to the RPi?

Wifi-wise, the pi is the bottleneck, with 'iwconfig wlan0' giving "Bit
Rate=54 Mb/s" (the rest of the system could go faster).

That sounds like it's telling you the theoretical maximum rate for
802.11g rather than the actual rate being achieved:
802.11b 2.4GHz 11 Mb/s
802.11g 2.4GHz 54 Mb/s
802.11n 2.4GHz 320 Mb/s

But
handwavingly, this is ~5megabytes/sec, CD-quality sound is
~10megabytes/min, so I'd have expected that to be plenty.

5MB/s is approximately equal to 54Mb/s (bytes vs bits), so, even if
you are being told the actual rate being achieved, you could easily be
maxing it out.

So what am I missing ? Is there some deep reason why this won't work, am
I doing something stupid, what's going on ?

I don't think your WiFi can be handling the throughput. You might
wish to investigate the coverage in as scientific a manner as
possible. It is generally accepted that to achieve a stable WiFi
connection, you need a signal-to-noise ratio of around -70dBm or
better. You can get smartphone/tablet apps that measure WiFi signals.
I have used an Android mobile phone app called WiFi Analyser, which I
rate as being pretty good ...
https://play.google.com/store/apps/d....wifi.analyzer
... while for i* there's this, although I have no experience of it ...
https://itunes.apple.com/gb/app/netw...562315041?mt=8
Use one of these or something similar to check out the WiFi coverage.

Anyone who lives in a city is lucky if their wifi works at all.
Typically dozens of stations are crammed onto each channel, and the
signal is not the most robust. By London standards, my house is in a
pretty good location, but I still contend with this

http://www.soundthoughts.co.uk/look/wifi.png

d

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus