# ETC help



## Cali (Feb 24, 2011)

I am looking for some clarification in these 2 graphs.

For the center channel, do I do anything about the spike at 22ms or just ignore?

For the front at approx 10.5ms...is that a reflection to be treated?


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## bpape (Sep 14, 2006)

Need to show the graph with the initial impulse at approximately 0 also to see what's up.


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## Cali (Feb 24, 2011)

I think this is what you want....
I guess I should be looking at everything within 20ms of the INITIAL huh?
Not just 20ms..


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## bpape (Sep 14, 2006)

Those should be addressed. Anything stronger than -20db and in the firt 20ms should be addressed.


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## Cali (Feb 24, 2011)

Thanks for confirming. 

Is the area in red to be included ?
I asked because for the life of me- I could not find where that was coming from. I even surrounded the speaker with panels and I still saw it.

Also is more better? or enough to be effective is enough?

Example, for one speaker I measured at every seat- I see the points pretty much match up to what the 'mirror trick' shows. Placing 2" ecose panel ON the wall attenuates reflection and brings it well south of the 20db down mark.

If I can cover said reflection point with say 2x2 piece of 1" panel VS full 2" panel, is there a benefit or is it just a waste?


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## bpape (Sep 14, 2006)

Did you check floor and ceiling too? Also remember not all reflections are mids and highs. Those could be lower frequency reflections.


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## Cali (Feb 24, 2011)

bpape said:


> Did you check floor and ceiling too? Also remember not all reflections are mids and highs. Those could be lower frequency reflections.


Yes I have found those points already. good point on the LF reflection. I will try to look into how ot identify that wit REW


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