Originally Posted by ehlarson
Please find attached my first attempt with ARC. Suggestions much appreciated.
Speakers are Revel Performas across the fronts, sub is a SVS BP12/Plus-2, and surrounds are M&K SS-150's.
I'm rather puzzled as to what could be causing the dip at 15KHz.
It looks like you've got a pretty significant room cancellation dip around 70Hz. Among other things that is causing ARC to treat LF/RF as less than "full range" despite their significant extension into the bass. Some bass traps on the walls/corners might be called for so you can utilize a bit more of the range your fronts are capable of. It also appears to have knocked down the higher frequencies in you sub. ARC has corrected for all of this, but if you deal with the underlying room issue, ARC can likely come up with an even cleaner solution for you.
NOTE: Alternative explanations here would be that you forgot to turn off the crossover built into your sub (or crank it up to the highest frequency setting to get it out of the way as much as possible), or that your front speakers are "combo" speakers with attached, satellite subwoofers and the crossover between the main portion of the speaker and its attached sub is not set correctly.
The high frequency problem at 15KHz is pretty typical of a speaker pointing issue. High frequencies are directional and many speakers have surprising dispersal patterns -- often worse in the vertical direction.
So before you do your next Measurement pass, revisit your speaker pointing. If the speakers are not mounted at seated ear height, pay particular attention to their vertical pointing. The LF/RF speakers should be "toed-in" a bit, but not swung around all the way to point to the center seating position. A rule of thumb I've found useful is to swing them only 1/3 of the way from perpendicular towards the center seating position.
Also recheck your mic placement. You don't want the mic close to a reflective surface like a seat back. Lift the mic tip a few inches to clear the seat back or move the mic a foot closer to the screen to get it away from a seat back.
Loss of treble can also be due to speaker grill cloth and grill mounting hardware. If you have any sort of custom grill cover, check that the mounting hardware is not in front of the tweeter.
Now you are down 10dB at 15KHz, so if you raise ARC's Max EQ Frequency target value up into the 15-20KHz range ARC will be able to apply almost 6dB of correction against that. The combo of a little better speaker pointing and telling ARC it is OK to apply correction up there may do the trick for you. Check the post a few posts up about how to experiment with Max EQ Frequency target. Since ARC is doing a significant amount of bass correction in your room, you may not be able to push it up to 20KHz without losing quality in the lower frequency portions of the solution. So play around with different values looking for a nice compromise.
If you add bass traps and clean up some of the bass issues that way, ARC will have less to do down there and so you may able to push it up higher at the high frequency end.