Originally Posted by Danne2
First post here...
Have had my D2v for some weeks now. Overall a good experience, but ARC is not doing what it "should" as I see it, when it comes to 0-200Hz.
I have dipoles 7.1 setup, set them as Dipole in the setup menu. 2 subs, middle of front wall and middle of back wall. Might add more later, seem like I have to due to room modes.
Room is very treated, but not absorption, almost diffusion only above 400Hz, and mostly membrane and panel (like helmholtz) absorption at lower frequencies. About 15ms ISD gap in sweetspot.
Unfortunately there is a dip at 300Hz I don't have a solution for now, need to investigate that further.
Running ARC, it sets Fronts XO to 90Hz, and sub at 90Hz. But that creates a big dip in FR (25dB) between 50 to 100Hz. If I set lower Front XO to say 60Hz, this is cured. But I can not believe how ARC can set it the way it does.
I would like to have the sub XO still at 90Hz, but ARC does not let me, it sets it to 60Hz when Front XO is 60Hz. I have raised sub cutoff to 160, but that does not raise the sub XO.
So, I'm quite dissapointed about the solution ARC is giving me, it sounds like crap in the bass, and that also reflects higher up. I created the Music config like I wanted it (above) and that sound much better at lower freq.
Anyone knows why this happens, the whole idea with ARC is kind of failing for me, I could just have a minidsp XO instead as it seems now.
I use REW and UMIK from minidsp and control measure (in sweetspot) every change I do.
I always have Movie config as ARC default, and do my changes in Music to easy comparison when listening and measuring.
Here is measurements with REW, showing with ARC Movie, and my changes done in Music config.
Also Targets showing my 2 changes of Front cutoff and sub cutoff (which did not have much affect unfortunately)
As already posted above, this looks very much like a Phase error in your two subs.
ARC can't see Phase error when it is building the solution since it does not hear the Subs playing at the same time as the mains.
Since you have two subs configured, you need to adjust their Volume and Phase (using the individual controls on each Sub), before you run your ARC Measurement. That's because ARC hears the two Subs playing together, and thus any error in their Phase relative to each other will be picked up. Note that you also have to set the distance for the Subs ahead of time, since Phase is a function of distance. Since there is only one distance setting, use the average of the two Sub distances, then go check Phase for each. If you also have a Polarity adjustment on each Sub, then check Phase with both Polarity choices for each sub and pick the Polarity/Phase combo that works best. Typically a Sub in the front of the room will work best with "normal" Polarity, and a sub in the rear of the room will work best with "inverted" Polarity -- just picture the direction of cone motion for a Sub turned around 180 degrees.
Polarity inverts the signal for all frequencies. Phase operates only near the crossover frequencies. By shifting the Crossovers you may simply be evading a Phase error that still exists.
It would be very helpful if you could post ARC's own charts, not just your REW chart. In the ARC View menu you can select whether it is displaying charts for the Movie or Music solution. Do continue to post your Targets window when posting ARC charts so we always have the charts and Targets together in the same post to avoid confusion.
If Phase error is not the answer, then we need to go back to basics and make sure there isn't something simple going wrong in your configuration.
First, you have two Subs, so the extra preliminaries mentioned above need to be done. Also, in your configuration in the Anthem, make sure you have "1 Sub" specified even though you have more than 1. The Sub Volume Trim value ARC Uploads is Calculated assuming you will always have "1 Sub" set.
Next, consider wiring. We need to know that you don't have anything complicated going on in your wiring. There should be only one feed line going to each Sub, and that should come directly from a Sub output of the Anthem. There should be only one feed line to each main speaker, and that should be originating as that main speakers output from the Anthem, going through an Amp channel, and then to that speaker. If there is anything more complicated than this going on -- for example if you have more than one feed line going to a Sub or main speaker, or if you have wiring connecting BETWEEN the Sub and mains or between the mains themselves, or if you have any other bass management device in the signal path, or anything other than a traditional power amp between the Anthem and the main speakers we need to know, as that will complicate things.
So for example, if your LF/RF speakers have powered woofers, and you are also running LFE lines to them in addition to your standalone Subs then that's a real complication.
And while you are at it, be aware that the HDMI output of the Anthem also carries audio. Double check that any built in speakers in your Display really are disabled so they aren't confusing the audio setup.
Next, for each Sub, make sure its internal Crossover is either disabled or cranked up to the highest possible frequency to get it out of the way as much as possible.
At this point it would be wise to spend some time with the Quick Measure Tool in ARC and see what the raw output of each speaker (and sub) looks like to the ARC mic at the various ARC mic locations -- which, as I said in the post above, should follow the ARC mic positioning guidelines. This will give you a better handle on just what ARC is seeing. The Measured curve in the ARC charts is an unweighted average of the different mic positions for each speaker. Comparing that to what you see in Quick Measure for each mic position will give you a better understanding of what ARC is trying to correct.
FOR EXAMPLE: If you don't see that dip you are worried about, then that means the dip is not "real". I.e., it really is an artifact of, for example, Phase error. If you DO see the dip, then some positioning experiments with the Sub or main speaker(s) are in order.
Also remember that the ARC mic must point straight up at each mic position, with the tip set at seated ear height, and away from reflecting/absorbing surfaces such as seat backs or walls.
Pushing the Sub Cutoff up to 160Hz is almost certainly wrong. But at this point we really need to see the actual ARC charts associated with a Targets window to get a better handle on what's happening.