Well I gave this a try but initially I am not even getting consistent results from one run to the next. I am making 10 seconds recordings - maybe I need to go longer?
Using Transporter as source and a (don't laugh) "Turtle beach audio advantage roadie" as the ADC, I got these results: Baseline test: reference vs same thing recorded a second time: 87.5 (L), 84.1 (R) -10 db digital: 79.1, 69.5 passive: 76.3, 73.2 -20 db digital: 68.5, 66.3 passive: 90.4, 66.9 (90.4 is not a typo) -30 db digital: 71.1, 72.4 passive: 67.4, 74.6 -40 db digital: 56.3, 56.7 passive: not tested However if I repeat any of the tests I just get different numbers so I don't think any of this is meaningful. Somewhere I have a Benchmark ADC which is what I want to use for this, but I can't find it. I believe there is a major flaw in this methodology in that the signal is not being boosted back to the original level before the ADC. For that reason the reduction in SNR at the DAC is matched by an equal reduction in snr at the ADC. This would mitigate measured differences as far as whether the attenuation is done before vs after the DAC. I also think that I'm clipping the inputs at the higher levels. I have the mixer control for the input set at the minimum, but it still goes red. Will need to dig up a proper sound card... -- seanadams ------------------------------------------------------------------------ seanadams's Profile: http://forums.slimdevices.com/member.php?userid=3 View this thread: http://forums.slimdevices.com/showthread.php?t=60041 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
