Recent content by trobbins

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.

Ta - so a P18 pot core - and yes very common 40 years ago 👍. Signal voltage shouldn't then be a concern wrt the core material. The measured inductance may have a large tolerance between samples if the coreset is ungapped. Do you only have ungapped coresets, or some gapped sets? Are you using...

Hi Klaus, it looks like you may be measuring iron or ferrite cored inductors? If so then their inductance may be significantly affected applied signal voltage level, which may then need to be part of the measurement reporting. Does your application also pass dc through the inductor?

-3dB at 1.4Hz for a loopback is a good start for using the low frequency capability of REW. My EMU 0404 has a DAC/headphone output with -3dB at 1.5Hz (up to 94kHz), but the ADC/input amp coupling is far more limiting with -3dB at 2.8Hz at 44.1/48kHz sampling, rising to 5Hz at 192kHz sampling...

Maybe not related, but the soundcard may have a significant low frequency response roll-off in magnitude and phase, both for signal output and input (which may be different due to internal electronic filters, and the selection of sampling rate on ADC and DAC control). Typical compensation to...

You need to describe the signal loop you want to use. Eg. New mic to a PA amp mic input. A PA amp output (somewhere along the signal chain in the PA amp, and at a suitable level that can be input to your PC's soundcard input. Use a separate amp to drive a speaker using your PC and soundcard...

Hi John, I'm getting sporadic exceptions with RTA, with latest beta as well as latest formal release. Dump and diagnostic files attached. I can't identify a change with my EMU0404 USB soundcard or PC that may have been a cause, and the soundcard signal connections are isolated and not mains...

Can you describe what you think you need to do, and what you have done so far with your mic and interface?