Please improve resolution on distortion sweeps

[keantoken]

REW doesn't have enough resolution to measure the distortion of my motherboard soundcard at 80% volume, even using the 4M sweep. I cannot use multiple sweeps as they interfere when summed presumably due to clock drift. I can clearly see harmonics in the RTA which reports them correctly. I can accept much longer sweeps if that is necessary.

Furthermore, REW displays 16 bits in the lower left, are sweep measurements done at 16bit resolution?

 

[John Mulcahy]

That's a limitation of log sweep measurements, to capture low distortion levels use stepped sine in the RTA.

On Windows Java offers 16-bit data, use ASIO drivers (or an ASIO wrapper like ASIO4All or FlexASIO) to get 24-bit data.