Rdio has been infamously cagey about what kind of quality they are delivering. They say that their iPhone app uses a higher bitrate stream when on WIFI, compared to 3G, and they claim that the web and Adobe AIr application have “CD Quality” streams. For comparison, Chris Breen suggests that many of the competitors offer between 128kB/s to 320 kB/s (320 kB/s LAME encoded MP3s are generally considered “transparent”, that is, indistinguishable from CD quality sound). NOTE: Chris Breen’s article says that Rdio uses 320kB/s streams, but my results (below) differ substantially. 

Generally speaking, I think Rdio streams are acceptable. I’ve got something of a tin ear, and a decent but by no means audiophile setup (T-amp with Mission 700 Leading Edge speakers, streamed through Apple Airport Express), and I don’t feel like I’m missing much. Yet, in the interest of science, I conducted a quick real world bitrate test. Using Wild Nothing’s Gemini album, on my Rogers 25mB/s cable connection, over WIFI (B/G class) I monitored my network traffic using Codebox Software’s BitMeter OS application. 

Here’s the results (I’ll continue to monitor the stream, and if it looks like these are unusual results I will post an update):

The bitstream spikes and then drops way down, pretty consistently, and averages just under 40kB/s!