Recent content by trobbins

One possible alternative path to derive separate signals is to use an existing dual tone signal from REW, and then split the signal into two paths, each path with a notch at one/other of the IMD tones. Recombining the two paths and making a loopback RTA may indicate how well that baseline...

Jan, perhaps not important for your testing scenario, but be aware that the single tone generator in REW can have its harmonic levels manually adjusted (using the Adjust harmonic levels tickbox). In a typical loopback scenario around a soundcard, adjusting the harmonics can realise an RTA...

Wrt free-field, the Cirrus calibrator manual comments: Adjust the Sound Level Meter to the correct level where applicable. There are several factors to be considered when correcting the value generated by the calibrator. These are: 1. A correction for the type of microphone capsule. 2. A...

Same style/layout as my Cirrus CR511E calibrator. It's manual makes the comments: The frequency is 1000 Hz, therefore the frequency weighting of the instrument has no influence on the accuracy of the calibration. The CR:511E Acoustic Calibrator meets the requirements of IEC 942, it corresponds...

Do you have a cheapo sound level meter that can be set to C-weighting, and whilst playing a steady tone then move the meter away from your listening head position and note the change with distance in a few directions. That could provide some insight as to room modes and what to expect from a...

Are you using log scale for impedance ?

Perhaps use the burst period setting to define the 6.5 cycles your want. I've used the burst mode before and it works fine when appropriately set up afaik.

Does a DCR measurement of your speaker (using a meter that say measured your 99.32 ohm ref) match the REW measurement at say 10Hz (circa 3.5 ohm) ?

Perhaps check some of the threads at diyaudio.

A lot of parameters have significantly more resolution than seems appropriate. Some measured parameters likely have a significant accuracy tolerance, depending on how the measurement was taken, and with what means, and whether the measurement was done at an appropriate location (eg. the voice...

Thanks for checking - much appreciated. I'm still a bit flummoxed. I updated to beta 66. Rebooted soundcard. Repeated calibrations (I get 100.5 ohm for O/C, which help indicates is as expected; I get 30mohm for S/C; I get 10R for reference as expected, and phase responses out to 96kHz all...

Hi John, I am running V5.40 Beta 42, and was just doing some impedance sweeps and noticed an approx 4.4x inaccuracy for C and L calculated levels (both L and C are ~4.4x lower in value) for a variety of my metrology standards. It's been nearly three years since I last used REW's impedance tool...

Removed.

Perhaps limit upper frequency to 10kHz in sweep. For a simple loopback using those out/in ports, do you get flat line responses?

Change Y axis to Log scale.