I talked earlier about soundcard measurements, and here is some news: Pioneer Hill Software
updated SpectraPLUS 5 so that it can now use ASIO.
ASIO (Audio Stream Input-Output) replaces Windows' own MME (MultiMedia Extensions) or DirectSound. As far as I understand, the beauty of ASIO is that it bypasses Windows Mixer and thus doesn't bring any issues associated with sample rate conversion or level adjustment.
The ASIO drivers that came with my E-MU 0204 crash every time (on Windows 7 and WIndows 8). Thankfully, there is ASIO4ALL
, which works well for me.
First picture shows two spectra taken with SpectraPLUS: red is the E-MU 0204 output fed directly into E-MU's input; and blue is the output of the E-MU fed into Pete Millett's interface, output of the interface fed to the input of the interface, and then back to the sound card. THD+N is 0.000781% is the first case and 0.001272% in the second.
Next two screenshots are THD+N vs frequency...