Recent content by dch53

Hi. Just getting back into REW after a few months. I updated to the latest version. When I run RTA, the distortion window includes the red text "Turn off Get fundamental from generator". Can someone tell me what that's all about please? I've looked around for somewhere to turn-off "Get...

Remembered that originally I calibrated with the Juli@ card looped back to itself. Not with the soundcard interface in the loop. The soundcard interface provides range switching, a digital metre and protection. More investigation required as to why measurements with the Focusrite give such...

I did my first measurement with the Focusrite: Terrible noise result so I redid it using the Juli@ soundcard: Not flash either but it is a tube amp. A 21dB difference in the noise level. So, I did some loopback tests. Juli@ first: and Focusrite: More than 25dBFS worse Noise level...

Thanks.

Thanks John. I decided to put my Pete Millett Souncard Interface in the loop. Much better result: I've calibrated with that. 1kHz THC+N looks like this: Noise is higher than I'd expect at -75.6dBFS. The Focusrite control panel doesn't appear to have a the latency adjustment like the ESS...

Hi. After using a Juli@ soundcard to test amps and crossovers for a few years I decided I needed an external soundcard. I'm trying to create an REW calibration file. So, I've found a couple of threads on calibrating REW with this device. One had a similar problem to mine but it was never...

Thanks again John. -40dBFS gives me around 100mV out of the crossover. -20dBFS gives me around 800mV.I'll try running all the measurements at -30dBFS. The 1/48th octave smoothing does indeed do an excellent job.

Hi John, I reran all the measurements with "use loopback as timing reference" and a -40dBFS level instead of -55dBFS. The results are attached. The Bass SPL & Phase looks very good. The Lower mid looks better but I had to tweek it. The Upper mid looked good anyway but the phase shifts in the...

Thanks very much for this John. This is an amazing piece of software! 40 years since I did this sort of stuff at university and never used it since so I obviously only know enough to be dangerous. I was trying to set 10Hz as the lower limit in the SPL & Phase graph after clicking the "20 ...

Thanks very much John. Here are the 4 mdat files. Apart from the hash (which I didn't have when I did the original measurements a few months ago) I obviously have some work to do correcting the crossover points (supposed to be 35Hz, 35Hz to 125Hz, 125Hz to 14kHz and 14kHz. The slopes should...

Hi, I'm using REW V5.20 Beta 17 to test some tube crossovers. The passband responses look OK but the out-of-band SPL and phase contain lots of spurious excursions. I've attached some examples. I need to know whether they're indicative of a problem or just measurement artifacts. The last one...

Thanks John. That will be very helpful. I really need to find the cause of the glitches. I suspect the fridge.

Ahhhhhh! That's my problem! I've been running with an overlap of 0%! As soon as I changed it 50% my plots were as before. The first "average" looks like this: while subsequent averages look like this: I knew it had to be something I'd inadvertently changed. Now I can go back to...

To answer some of your questions: the interface is not assigned as the Windows default for playback The 19.8Hz response is normal. All subsequent steps starting from the next one, 24.9hz, bump up from the first sample. I listened to a test tone and there does seem to be noise superimposed...

Hi John, Yes, I am using ASIO drivers. The only setting in my Juli@ control panel is "Latency" and I currently have it set to the maximum of 2048 samples. Thing is, up to a couple of weeks ago I wasn't having this problem. I've checked all the tasks that are running and closed down as much as...