View attachment REW 128 256 512 1M.mdatCan you post the measurement file?
I just tried the high pass option and then a lower level measurement (-16db instead of -6db) with no change in results.Do you have anything else you could use as an input for a measurement, an SPL meter maybe? Might even be worth trying a built-in mic just to see if the results are more consistent at different sweep lengths. Could also try a low sweep level in case there is some clipping happening somewhere, and try selecting the "High Pass" input option in REW in case there is some DC offset in the input path.
I thought markus said he doesn't have a USB mic? if so that is the main difference so far; 2 USB mic users have a problem, 2 analogue mic users do not.We havent been able to determine what is different in setup from those that are having the problem from those that are not, so far
IN your post at AVS, you said "Dayton EMM-6 mic via a usb preamp/audio device (RME Fireface 800), no loopback, IRs do not vary with length".I thought markus said he doesn't have a USB mic? if so that is the main difference so far; 2 USB mic users have a problem, 2 analogue mic users do not.
I meant I go USB to the preamp but the mic is analog. Anyway John's reply knocks that theory out anyway.IN your post at AVS, you said "Dayton EMM-6 mic via a usb preamp/audio device (RME Fireface 800), no loopback, IRs do not vary with length".
I took that to mean you were using a USB mic since you mentioned a USB preamp. If that is not the case, then your correlation might have some bearing on this, yes.
Changing the buffer size makes no difference.My measurements were with a UMIK-1.
Jim, see if reducing the buffer size settings on the REW soundcard prefs to 32k input and output makes any difference. Also take a look at the Scope plot for the Captured trace after each measurement to see if there are any obvious differences in those - the plot only has data for the last measurement made, so you need to capture the graph after each measurement.