Hey,
I have a couple of questions with regards to phase and doing XO simulations with REW measurements.
Using a calibrated USB mic and the "acoustic timing reference" option turned on in REW - will I be able to accurately use the phase data in the exported FRD file?
If not, then I reckon I can at least use it to measure the time delay between each driver? Like so: Driver time alignment
I have a couple of questions with regards to phase and doing XO simulations with REW measurements.
Using a calibrated USB mic and the "acoustic timing reference" option turned on in REW - will I be able to accurately use the phase data in the exported FRD file?
If not, then I reckon I can at least use it to measure the time delay between each driver? Like so: Driver time alignment
^You can use acoustic timing reference to lock timing with USB mic and REW. Distance from reference radiator to microphone must stay constant within few millimeters so reference radiator should be installed to mic boom or distance from reference to mic should be adjusted every time when mic is relocated for measurement of the next driver/radiator.
Single (axial) time difference value between drivers does not work to high off-axis angles so every method using other than electrical (two input channels with loopback or synchronized in and out) or acoustical timing reference simply does not work or is ridiculously slow to use.
Simplest solution is to avoid buying USB mics or trash them and using more flexible system, generic sound card with two input channels and phantom power.
Single (axial) time difference value between drivers does not work to high off-axis angles so every method using other than electrical (two input channels with loopback or synchronized in and out) or acoustical timing reference simply does not work or is ridiculously slow to use.
Simplest solution is to avoid buying USB mics or trash them and using more flexible system, generic sound card with two input channels and phantom power.
Thanks for the reply. So if I understand you correctly, I can in fact use the phase data measured with acoustic timing reference (up to maybe 45deg?) as long as distance to radiator is carefully maintained? (with the latter being a given anyways)
I would suggest not trying to find the time difference between drivers. Just measure the phase and make sure you have set the timing between measurements.
To any angle in 3D space as long as distance (and angle) between microphone and acoustic reference radiator stays constant within few millimeters.
Of course distance between mic and rotation center of driver under test should be constant (within few mm) while measuring off-axis angles and different drivers. That is the most challenging also with electrical reference with loopback from out to in.