On 27/09/12 12:05, Romain Beauxis wrote: > 2012/9/27 Richard Lamont <[email protected]>: >> [snip] If I take audio in and out via >> jack, using a very simple script ... >> >> stream = mksafe(input.jack()) >> output.jack(stream) >> >> ... the output is 2.5 dB quieter than the input (corresponding to a >> linear level ratio of 0.75). Why? > > I do not think there is any reason for that. How can we reproduce your > level testing? Also, are you able to try without jack like > output.file(sine(), ...) to see if that may come from the jack > bindings?
I'm generating sine wave test tones using jaaa, with the output level set to -18 dBFS (this being the EBU Rec. R.68 Alignment Level). I'm measuring the output using jnoisemeter. If I connect them directly via jack then jnoisemeter indicates -18 dB as expected. If I insert liquidsoap into the chain as above it indicates - 20.5 dB. FWIW I also use the jmeters Peak Programme Meter (with the option -g 6 to get the sensitivity per R.68, i.e. '4' on the scale at - 18 dBFS). This also shows the 2.5 dB discrepancy. Not sure about output.file(sine(),...) - I'll have a think. -- Richard Lamont <[email protected]> ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://ad.doubleclick.net/clk;258768047;13503038;j? http://info.appdynamics.com/FreeJavaPerformanceDownload.html _______________________________________________ Savonet-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/savonet-users
