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MiniDSP DDRC-24 DIRAC umik-1 placement help

Lawyrup843

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Gentlemen, when running Dirac should my mic be pointed at the speakers or straight up in the air? Also should I be using the 90deg calibration file? Currently I point my mic towards the speakers for all positions and I am using the 90deg cal file. It sounds great after running Dirac but got to thinking about wether or not I’m doing it right, if there are any words of advice when doing this please advise.Thanks
 

RayDunzl

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Gentlemen, when running Dirac should my mic be pointed at the speakers or straight up in the air?

I thought Dirac wanted measurements from multiple positions. My trial did. I didn't keep it. (rereading now, I guess you did that)

I point my UMIK-1 (stereo system) toward the phantom center, from where my ears would be centered.

The 90 degree file adjusts the calculated (calibrated) frequency response (a little) of the mic for when you point it at the ceiling.


It sounds great after running Dirac

Maybe you're done.
 
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Χ Ξ Σ

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I searched for the answer to that when I first started using Dirac. I don't recall whether there was any official documentation on this subject, but after reading several discussions, I have been since pointing the mic to the ceiling and using the 90deg cal file. Dirac does three consecutive L-R-L sweeps and doesn't give me any time to reposition the mic to the next speaker, so I don't really understand why I should point the mic 0dge at any speakers, let alone between speakers. I understand the argument of positioning the mic parallelled with the floor/desk to capture more reflections, but that means all speakers are off-axis to the mic, and I would have to compensate for that when adjusting the target.

The speakers I own have anechoic and Spinorama data available, so I can compare Dirac's sweep result with them. At least for my setup, pointing to the ceiling at 90deg yielded a flat high-frequency response that is similar to that from the anechoic or Spinorama data, and Dirac will suggest a target that overlaps with the sweep results pretty well. If you can find anechoic or Spinorama data for your speakers, you can compare them to your Dirac sweep using different mic positions and then decide which one is for you.
 

dominikz

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Although I'm not sure what Dirac Live recommendation is, I find that in general vertical mic orientation (i.e. pointing to ceiling) + 90° calibration file give the most precise results for in-room measurements, as it provides the best mix of direct and reflected sound spectrum.

To illustrate, here's how the typical measurement mic FR looks:
1627042879000.png

Notice how the on-axis FR is pretty flat, but HF response goes down as you move off-axis.
So:
  • If you use the 90° calibration curve and point the microphone vertically to the ceiling, all sounds (direct or reflected) coming to the microphone from any direction in the horizontal plane will be registered with the correct spectrum by the microphone! Ceiling and floor reflections will contain some HF deviations, but this is a smaller part of the total captured sound so the balance should be correct.
  • If you use the 0° calibration curve and point the microphone horizontally between the speakers, only the sound coming directly to the front of the microphone will be registered with the correct spectrum by the microphone! Any horizontal or vertical reflections will be captured with some HF roll-off, resulting in HF loss in the total measured in-room response.
 

dominikz

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Although I'm not sure what Dirac Live recommendation is
Seems that using a vertical microphone position (towards ceiling) + 90° calibration is also a recommendation from Dirac:
• Point the microphone toward the ceiling (90°) when measuring to ensure that the microphone's coloration is similar for both the wall reflections and the direct wave from the speaker. A 90° microphone calibration file is needed in this case.
Source: Dirac Live manual
 

abdo123

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I do 90 degrees because i read somewhere that this is what you should use for Dirac.

eitherway I don’t correct above ~4KHz so it shouldn’t matter
 

thewas

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If you use the 0° calibration curve and point the microphone horizontally between the speakers, only the sound coming directly to the front of the microphone will be registered with the correct spectrum by the microphone! Any horizontal or vertical reflections will be captured with some HF roll-off, resulting in HF loss in the total measured in-room response.
On the other side for usual stereo setups the angle error is 30° and as you showed in your above plot even 45° the deviation is less than 1dB till 10 kHz.
 
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Lawyrup843

Lawyrup843

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Although I'm not sure what Dirac Live recommendation is, I find that in general vertical mic orientation (i.e. pointing to ceiling) + 90° calibration file give the most precise results for in-room measurements, as it provides the best mix of direct and reflected sound spectrum.

To illustrate, here's how the typical measurement mic FR looks:
View attachment 143107
Notice how the on-axis FR is pretty flat, but HF response goes down as you move off-axis.
So:
  • If you use the 90° calibration curve and point the microphone vertically to the ceiling, all sounds (direct or reflected) coming to the microphone from any direction in the horizontal plane will be registered with the correct spectrum by the microphone! Ceiling and floor reflections will contain some HF deviations, but this is a smaller part of the total captured sound so the balance should be correct.
  • If you use the 0° calibration curve and point the microphone horizontally between the speakers, only the sound coming directly to the front of the microphone will be registered with the correct spectrum by the microphone! Any horizontal or vertical reflections will be captured with some HF roll-off, resulting in HF loss in the total measured in-room response.
Thanks for the breakdown!
 

Tukkae

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Just as a bit of a curveball: what about measurements that involve Atmos in-ceiling speakers?
I run a receiver with Dirac and I position the mic vertically as per instructions (I'm assuming the receiver uses a 90 degree cal file for the ground level speakers) but does that mean that during the measurement process Dirac will switch to a 0 degree cal file when my in-ceiling speakers start to get measured?
 
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