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What to do when Dirac won’t center the stereo image?

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tjcinnamon

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I ran into this myself. I redid the measurement/calibration with measured and marked mike locations and a reasonable distance between mike and wall. Cleared things right up.
I'll give that a shot. My rear wall is pretty damped which should mitigate it. 4" for OC703. I'm about 2' off the wall (no choice). 4' would put me halfway between MLP and my TV.
 

SIY

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I'll give that a shot. My rear wall is pretty damped which should mitigate it. 4" for OC703. I'm about 2' off the wall (no choice). 4' would put me halfway between MLP and my TV.
It's super important to have the mike positions symmetrical with respect to the listening position. I found that out the hard way.
 
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tjcinnamon

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So I think I know what was going on. I have some miniDSP's and that was introducing enough delay to really mess things up. My AVR limits out at 25ms. I was able to get a balanced measurement by basically bypassing the miniDSP and going directly to a single sub. It could be a limitation of my AVR? Anyways, it's resolved despite me liking that measurement I lucked into. I run MSOP after Dirac anyways to get all 6 subs aligned (in fairness, I run 4 of them like one because they are nearfield/at-my-back) it's more like 3 subs.

I've posted the MDAT REW file. I'm still very intrigued by a new AVR because I could run the Denon X4700 in Pre-out mode and I have enough amps to run all 11 channels through that. Additionally, a direct HDMI 2.1 connection would be nice.

Although, I had a Marantz before and I remember it not being as good as Dirac... I was blown away when I first heard Dirac in the NAD vs the Marantz 7012 with Audessy XT32.

Here is a link to the MDAT REW file: https://drive.google.com/file/d/1PI77Pwoq_wot1eQAFM1cP0lQV7G1lkMo/view?usp=sharing

The Key:

Dirac L/R Good are my lucky measurement from a few months ago
No dirac is... no dirac
Right "bad" dirac is one that I ran on my own that skews a touch to the left BUT it's after I first removed the MiniDSP (so I don't have a readily terrible measurement)
New Dirac L/R I ran today and actually took 3 measurements.
 

dougi

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I am having the same problem with DIRAC on a minidsp flex digital. Despite very careful mic positioning (for stereo) it always seems to calculate the delay wrong (0.6-1.0ms mostly, but once 7.0ms!). Plus reduces the gain on that channel a bit (0.8-1.0dB). It is wrong as when listening it is a bit off centre. You cant compare with turning DIRAC off either as the "input" gain and delay settings that DIRAC determined are retained. Luckily I can correct it with either output stage adjustments in the minidsp or balance adjustments in the DAC that follows it. Why can it not get it right? My DAC is not using SRC and set to lock the clock to the incoming SPDIF from the miniDSP, so unlikely a clock issue that I have caused.
 
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tjcinnamon

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Sorry youre having issues. I haven’t been able to get a good calibration better than the one I lucked into.

I’m getting a Denon X4700 with Audyssey on Thursday or Friday. I’ll report back my findings. I had Audyssey a number of years back and liked Dirac better but Audyssey has improved and I can move the target curves.
 

Bugal1998

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I am having the same problem with DIRAC on a minidsp flex digital. Despite very careful mic positioning (for stereo) it always seems to calculate the delay wrong (0.6-1.0ms mostly, but once 7.0ms!). Plus reduces the gain on that channel a bit (0.8-1.0dB). It is wrong as when listening it is a bit off centre. You cant compare with turning DIRAC off either as the "input" gain and delay settings that DIRAC determined are retained. Luckily I can correct it with either output stage adjustments in the minidsp or balance adjustments in the DAC that follows it. Why can it not get it right? My DAC is not using SRC and set to lock the clock to the incoming SPDIF from the miniDSP, so unlikely a clock issue that I have caused.
These issues are frustrating for sure. If you've followed all the suggestions in the thread, then opening a Dirac support ticket would be your best bet.

Is your measurement mic connected to a Mac or PC? If so, couldn't there still be a clock timing error between the microphone input ADC and the DAC generating the test sweep?
 

dougi

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These issues are frustrating for sure. If you've followed all the suggestions in the thread, then opening a Dirac support ticket would be your best bet.

Is your measurement mic connected to a Mac or PC? If so, couldn't there still be a clock timing error between the microphone input ADC and the DAC generating the test sweep?
Yep, a PC using a focusrite scarlet 2i2 Gen ii as adc. Running at 96khz, or so Dirac reported. DAC claims 96 as well, despite the minidsp supposedly using 48 for Dirac.
 

Bugal1998

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Yep, a PC using a focusrite scarlet 2i2 Gen ii as adc. Running at 96khz, or so Dirac reported. DAC claims 96 as well, despite the minidsp supposedly using 48 for Dirac.
If you go to Dirac tech support it would be interesting to hear what they offer as a reason for the post-calibration off-center behavior.
 

dougi

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If you go to Dirac tech support it would be interesting to hear what they offer as a reason for the post-calibration off-center behavior.
I didn't use DIRAC support, but after looking at their troubleshooting FAQ, I have resolved it. Reducing the ADC/audio interface sample rate to 44.1kHz and the buffer size to 64 samples (I think, as the interface doesn't say what the units are, but can't be ms), I got much better results. 0.02ms delay between channels with only an eyeballed mic positioning and must better corrected step responses after re-measuring with REW (which confirmed timing was now fine between the channels). I could got out and buy a UMIK1/2 but I already have a calibrated measurement mic (the Sonarworks version of the ECM8000) so didn't want to spend money where I didn't need to. Happy enough, but the RoomPerfect procedure is somewhat more foolproof (but still gets 3-6 kHz region wrong often).
 

sarumbear

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So I think I know what was going on. I have some miniDSP's and that was introducing enough delay to really mess things up. My AVR limits out at 25ms. I was able to get a balanced measurement by basically bypassing the miniDSP and going directly to a single sub. It could be a limitation of my AVR? Anyways, it's resolved despite me liking that measurement I lucked into. I run MSOP after Dirac anyways to get all 6 subs aligned (in fairness, I run 4 of them like one because they are nearfield/at-my-back) it's more like 3 subs.

I've posted the MDAT REW file. I'm still very intrigued by a new AVR because I could run the Denon X4700 in Pre-out mode and I have enough amps to run all 11 channels through that. Additionally, a direct HDMI 2.1 connection would be nice.

Although, I had a Marantz before and I remember it not being as good as Dirac... I was blown away when I first heard Dirac in the NAD vs the Marantz 7012 with Audessy XT32.

Here is a link to the MDAT REW file: https://drive.google.com/file/d/1PI77Pwoq_wot1eQAFM1cP0lQV7G1lkMo/view?usp=sharing

The Key:

Dirac L/R Good are my lucky measurement from a few months ago
No dirac is... no dirac
Right "bad" dirac is one that I ran on my own that skews a touch to the left BUT it's after I first removed the MiniDSP (so I don't have a readily terrible measurement)
New Dirac L/R I ran today and actually took 3 measurements.
You have far too many equipment to listen stereo music.
 
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tjcinnamon

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Sometimes Dirac is weird particularly if your subs have a minidsp and a large delay. The best method I’ve found is to manually adjust the timings. It’s usually 2ms at max to get them centered.

Regardless of what others say about phase or anything else, the true phantom image is way more important than the small changes that the timing impacts.
 
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