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Discussion Starter · #1 · (Edited)
Hello all!

I'm new to REW and am having a bit of a problem.

Setup: mic stand, calibrated behringer 8000 and USB Dual Pre sound card.

I have some concerns with the results of my sweeps:

http://i.imgur.com/nUXYx.jpg

In the 3rd sweep - I clapped and screamed while the test tone played. This noise did not register in the resulting graph (although I did get an error message stating that clipping was detected).

I tweaked the AV's treble and bass and there was also no change in the graph. I'm getting bass below 10hz. My speakers are only rated upper 30's as I have no sub.

http://i.imgur.com/6wF3S.jpg

I'm concerned that my results here are not accurate. What can I do to confirm the findings?
 

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I clapped and screamed while the test tone played. This noise did not register in the resulting graph (although I did get an error message stating that clipping was detected).
The log sweep is quite good at rejecting content that is not related to the signal.

I tweaked the AV's treble and bass and there was also no change in the graph.
Are you sure those controls are applied for the input you were using? How much did you change them? The graph image has a huge vertical range, which makes large variations look small, see Please read - Posting a graph for advice on setting the range.

Finally - I'm getting bass below 10hz. My speakers are only rated upper 30's as I have no sub.
At what level? the noise floor will span the full frequency range, and corrections (mic cal and soundcard cal) boost the response to counter the roll-off of the mic/soundcard, in regions where noise dominates the response that boosts the noise.

I'm concerned that my results here are not accurate. What can I do to confirm the findings?
You could try other measurement software, such as ARTA, or attach one of your measurements for us to look at.
 

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Discussion Starter · #3 ·
Thanks John!

The log sweep is quite good at rejecting content that is not related to the signal.
Are you sure those controls are applied for the input you were using? How much did you change them? The graph image has a huge vertical range, which makes large variations look small, see Please read - Posting a graph for advice on setting the range.

Good to know about rejecting content. The range is currently set to 15-22, and 45-105 which isn't far off from the link you posted. What would you recommend to help see the differences here?

At what level? the noise floor will span the full frequency range, and corrections (mic cal and soundcard cal) boost the response to counter the roll-off of the mic/soundcard, in regions where noise dominates the response that boosts the noise.
Considering that I have no sub, I expected to see a huge rolloff somewhere around my speakers lower limits (35hz). So the readings look correct?

You could try other measurement software, such as ARTA, or attach one of your measurements for us to look at.
I will give it a try. I'm trying to rule out any hardware issues (new mic, sound card, etc). Thank you!
 
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