Gearing up for measurements with REW -various issues I might need some help with.

[antcollinet]

I've renamed the thread to make it more generic for different topics.

 

[Sokel]

Just a check, did you set the right range at the distortion settings tab?

(under the gear sign at the RTA window)

That's how you set filters given the I/O is right.

 

[Sokel]

I forgot, there' also a known glitch about bit-depth, sometimes REW changes it to 16-bit without a warning.
Changing sample rate back and forth couple of times fixes it.
It's a good idea to do it before every session.

 

[antcollinet]

Just a check, did you set the right range at the distortion settings tab?

(under the gear sign at the RTA window)

That's how you set filters given the I/O is right.

I think that is just for filtering out frequencies from the distortion calculation - it doesn't alter the plot. In any case the low pass filter was disabled.

I'm now getting a weird glitchy plot in the RTA - see attached gif-video of it.

Anyone seen anything like this before. I've had it a few times, but it seems to randomly go away then come back.

 

[Sokel]

I think that is just for filtering out frequencies from the distortion calculation - it doesn't alter the plot. In any case the low pass filter was disabled.

I'm now getting a weird glitchy plot in the RTA - see attached gif-video of it.

Anyone seen anything like this before. I've had it a few times, but it seems to randomly go away then come back.

View attachment 435703

Oh,I see what you mean now.

What's shown in the video can't be REW, it almost looks like a filter misbehaving, on the hardware side or at the Mac's side.
(Unfortunately I can't steal my wife's Mac to try it, she's working on it and I generally like staying healthy and whole )

 

[antcollinet]

Oh,I see what you mean now.

What's shown in the video can't be REW, it almost looks like a filter misbehaving, on the hardware side or at the Mac's side.
(Unfortunately I can't steal my wife's Mac to try it, she's working on it and I generally like staying healthy and whole )

Well it might have been a hardware issue. The ultralite has just failed completely. Confirmed by Motu live chat.

So no more happening until I can get hold of a replacement from the supplier (it is only 3 weeks old, so there should be no issue - except they are currently out of stock)

Thanks for looking again.

 

[Sokel]

Well it might have been a hardware issue. The ultralite has just failed completely. Confirmed by Motu live chat.

So no more happening until I can get hold of a replacement from the supplier (it is only 3 weeks old, so there should be no issue - except they are currently out of stock)

Thanks for looking again.

It's good it failed so early, I guess it will be a hustle-free replacement in order.
And it's really interesting how the loop showed the early signs of misbehavior, even with that strange filter failing.

 

[antcollinet]

It's good it failed so early, I guess it will be a hustle-free replacement in order.
And it's really interesting how the loop showed the early signs of misbehavior, even with that strange filter failing.

I'm still not certain the two issues are related - we'll see when I get a replacement.

Though I think it is the internal PSU that has gone -external wall wart is fine, but the unit is totally dead. Nothing on the display, no sign of a connection to USB and the optical out is not lit.

So it could have been an intermittent/jittery internal rail causing the filter problem which has now gone down altogether.

 

[Sokel]

I'm still not certain the two issues are related - we'll see when I get a replacement.

Though I think it is the internal PSU that has gone -external wall wart is fine, but the unit is totally dead. Nothing on the display, no sign of a connection to USB and the optical out is not lit.

So it could have been an intermittent/jittery internal rail causing the filter problem which has now gone down altogether.

Higher rates usually consume more current/recourses so PS issues can very well be a explanation.
It showed that it was trying to get higher but it couldn't, in a declining fashion.

You're probably right then.