TOPIC:

I'm getting a consistent error message in measurement that reads:

REC2IMP_IMP_START_IDX_IS_NEGATIVE

System:
DDRC24, UMIK-1 mike
Linkwitz Orion loudspeaker system on channels 1/2, 50 hz high pass filter
3 subs spaced around the room, connected together as mono over wireless link on channels 3/4, 50 hz low pass filter

I ran through the measurement drill to completion with just one sub. Got the room measurement I expected and a correction curve. All was good. Then I added the other 2 subs and went to do a new measurement of the room and now consistently get an error message like the one above.

I"ve tried tweaking the input gain and output levels, but still get the same result.

Suggestions?

The link below is to a screen shot of the error I'm seeing.

russbutton.com/Russ/audio/tmp/Cal_tool_error.JPG

I wonder if the wireless link is introducing a lot of delay that is upsetting DLCT. At any rate the first thing I would do is raise the measurement level. It look from the plot that signal-to-noise is quite poor. I'd suggest raising the SPL and then tweaking the input gain if needed. You may find that reducing the sub level will be helpful. If that still throws the error then try using a cable instead of the wireless link and see if that makes a difference.

I have no idea if there's any significant delay in the wireless link. It wouldn't be of any use if there was.

Unfortunately given where things are in the room, it's not possible to use wired connections, otherwise I would have to begin with. The subs are scattered around the room following the notions of Geddes.

But I will take your advice on working with the SPL and input gain.

It's just that it's an odd error (I've never seen it anyway). If it is a bug in the Dirac software they will need to know what causes it - hence my suggestion to try a wired connection. But see how you go with the other stuff, post some screenshots when you get there

Does Dirac have a debug switch or logs one can access? That's what I do when we have server problems at work.

Sorry I don't know.

@ Russbutton

Some great advise from John already!

As mentioned in the tech support ticket you started separately, this error is most likely thrown because of the way 3 subs are being driven, at different places (and not timealigned). In the end , it's just confusing the process of doing a proper measurement.
Try what we already suggested, i.e. use separate DDRC_24 output to control time alignment to each sub (see www.minidsp.com/applications/auto-eq-wit...measuring-time-delay), THEN start running your Dirac Live sweep.

DevTeam