Hi
I wondered about variability between tests when using REW.
I was seeing considerable differences between my curves particularly at the bottom end of the frequency range. I wondered what I could do to improve repeatability.
So just out of interest I kept repeating sets of 9 REW sweeps without changing anything.
Here is my IB calibrated to 75dB on the Galaxy 140 with 75dB target level in REW: Headroom average 25dB. REW warnings of low readings on each test.
Only 5-20Hz shown. Galaxy meter at listening position at ear height.
Below 10Hz the curves seem almost random with slight variations above.
Here I recalibrated to
80dB on the meter but
without changing REW's 75dB target setting: Headroom average now 12.5dB.
Here I recalibrated the meter to 85dB leaving target level at 75dB. Headroom average now 9.2dB.
It seems if you want improved repeatability it pays to give REW enough signal to work with.
