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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Audio Measurement and Testing => Topic started by: Ivan Beaver on July 22, 2013, 08:32:55 pm

Title: Smaart 7 question
Post by: Ivan Beaver on July 22, 2013, 08:32:55 pm
I have just had my computer rebuilt and reinstalled Smaart 7.

Today all sorts of "weird" things were happening when trying to use my multimic setup.  I had 7 mics going into it via a MOTU 8 pre and firewire (ASIO).

It used to work just fine-but when I turn on more than 5 mics-the freq response changes quite a bit on 2 of the mics.  Sometimes below 2K it drops down and other times it rises up.  But with 5 mics it is fine.

Has anybody experienced this?

I will call Rational tomorrow (as I figured it out late today) and see if they have any ideas.

I think it might be a video display issue.

In the past-when I tried to use the autolocate on all the channels the display would freeeze up and jump around-but this time I can use all the autolocate and the display looks fine-just the frq is off quite a bit-to the tune of 15dB or so.

Thanks for any ideas

Title: Re: Smaart 7 question
Post by: Adam Black on July 23, 2013, 10:41:11 am
Hey Ivan,

Best bet is to give us a call. But I'll respond with my current line of thinking in case you aren't able to do so.

Plotting, i.e. rendering speed, is the weakest link on most systems. Though with high loads this typically results in plotting lag or the plots being less responsive. The rendering and math engines run in different threads and are loosely coupled, thus have limited affect on each other. If the CPU load is high, then graphics can exhibit some lag in some environments. But graphics lag should have little to no affect on the math engines. Worst case if the load is high enough, an overall performance hit could be encountered, but that shouldn't impact the accuracy of the math involved; but merely slow it down.

A +/-15dB variance is massive. I find it interesting that it's only below 2k. How wide is the variance? We talking ripple or multi octave bump? Is there a pattern to the variance? I ask because I'm thinking crosstalk or some other driver anomaly. I'd like to attempt the same test using a different device, if possible. That should assist in discerning if the device or driver is the cause.

That's the best I can do with the information at hand. I'll post more if anything else comes to mind.

-A
Title: Re: Smaart 7 question
Post by: Ivan Beaver on July 23, 2013, 11:25:55 pm
Hey Ivan,

Best bet is to give us a call. But I'll respond with my current line of thinking in case you aren't able to do so.

Plotting, i.e. rendering speed, is the weakest link on most systems. Though with high loads this typically results in plotting lag or the plots being less responsive. The rendering and math engines run in different threads and are loosely coupled, thus have limited affect on each other. If the CPU load is high, then graphics can exhibit some lag in some environments. But graphics lag should have little to no affect on the math engines. Worst case if the load is high enough, an overall performance hit could be encountered, but that shouldn't impact the accuracy of the math involved; but merely slow it down.

A +/-15dB variance is massive. I find it interesting that it's only below 2k. How wide is the variance? We talking ripple or multi octave bump? Is there a pattern to the variance? I ask because I'm thinking crosstalk or some other driver anomaly. I'd like to attempt the same test using a different device, if possible. That should assist in discerning if the device or driver is the cause.

That's the best I can do with the information at hand. I'll post more if anything else comes to mind.

-A
It was basically like a "hinge" at 2Khz. so no ripples but the whole thing tilted up or down.  It never appeared to be "slow" or Jittery.

I will check into this soon to see what the issue might be.

I did delete my configuration and rebuilt it-but it did not make a difference.  I also switched my computer power to "high performance", but it seems worse today than yesterday-I could only use a couple of mics-while yesterday I could look at 6 with no problem

We ended up using a different approach (TEF) for the actual alignment because at some mic positions the local noise was 80-90dB.  So we needed much higher noise immunity.
Title: Re: Smaart 7 question
Post by: Rasmus Rosenberg on July 24, 2013, 04:29:56 pm
It was basically like a "hinge" at 2Khz. so no ripples but the whole thing tilted up or down.  It never appeared to be "slow" or Jittery.

I will check into this soon to see what the issue might be.

I did delete my configuration and rebuilt it-but it did not make a difference.  I also switched my computer power to "high performance", but it seems worse today than yesterday-I could only use a couple of mics-while yesterday I could look at 6 with no problem

We ended up using a different approach (TEF) for the actual alignment because at some mic positions the local noise was 80-90dB.  So we needed much higher noise immunity.

Hey Ivan,
On what inputs did it happen? How is your cue mix setup?
mvh
Rasmus 
Title: Re: Smaart 7 question
Post by: Ivan Beaver on July 25, 2013, 08:01:31 am
Hey Ivan,
On what inputs did it happen? How is your cue mix setup?
mvh
Rasmus
It would happen on any and all of them-I could not find a "pattern".

I am looping back the mainout of the 8 pre to channel 8 input as my reference