TOPIC:

Hi. I’ve just read somewhere that all Dirac miniDSPs have to measure using the 90 degree mic txt pointing to the ceiling... is this correct?

Even for simple stereo, using the DDRC24?

People say the strangest things... do you have a link?

paul7777x wrote:

Hi. I’ve just read somewhere that all Dirac miniDSPs have to measure using the 90 degree mic txt pointing to the ceiling... is this correct?

Even for simple stereo, using the DDRC24?

Dirac Live Direct RCS user guide
Direct the microphone upward, pointing to the ceiling, to get the most
omnidirectional recording of the room response, or towards the speakers depending
on the particular microphone and its calibration file (if any). Please follow the
instructions from your supplier

Support MiniDSP FAQ
The UMIK-1 comes with two unique calibration files:
- 0deg: Point the microphone towards the sound source being measured. This calibration is so called on-axis calibration file.
- 90deg: Point the microphone towards the ceiling. This calibration file is only to be used for surround sound measurement (i.e. audio coming from multiple directions). For Dirac Live applications (e.g. DDRC-88A, nanoAVR DL), you should always use the 90deg file.

Kev

Also from the Umik FAQ (highlights are mine)

"Which calibration file should I use and where to point the UMIK-1?
We provide two calibration files to be used depending on your application.

- For stereo system (e.g. 2ch dirac live, single speaker measurement), use the 0deg file and point the UMIK-1 at the speakers
- For multichannel system (E.g. 5.1/7.1) or a surround application where multiple speakers are spreadout around the room, use the 90deg file and point the UMIK-1 at the ceiling."

So, if using the DDRC-24, use the 0 deg and point at speakers. That's what I do.

Dirac also mentioned using the 90deg. orientation to get the best representation of the room interactions even when testing 2 channel stereo.
Kev

Thanks for your help gents.

I have tried both ways and the 0 degree orientation does appear to be the most accurate in that there is more micro detail easily discernible.

But I thought it best to check, just in case.

Cheers, Paul.

Thanks, good info. What were you trying to accomplish? Speaker EQ or Room EQ? I am trying to adjust for the deficiencies of my room so I want Dirac to "hear" the room.
Kev

Personally, I'm somewhat doubtful that there's benefit in trying to second guess what Dirac's algorithm is doing. Like the UMIK-1 page says, the 90 degree file is auto-generated, whereas the 0 deg file is measured, so I'd use the 0 deg unless it's not feasible (as is the case for surround sound). But, there's nothing to stop you from trying it both ways.

This is a response I received from Dirac support.

By pointing the microphone upwards you will get the same coloration on the sound coming from the backward/side/front wall as the direct wave from the speaker. This is important in the filter deign process so we don't do any wrong decisions. If you point the microphone to the speakers instead, the coloration of the room will differ from the direct wave, this could result in filters which are overcompensated in certain frequencies. For our room correction system I would always recommend to point the microphone upwards.

UMIK-1 instructions from MiniDSP.

For Dirac Live applications (e.g. DDRC-88A, nanoAVR DL), you should always use the 90deg file.


Best Regards,

Frans

Hi Frans.
Thank you for your reply.

Were Dirac referring to stereo sound as well as surround sound do you know?

I’ll do the measurements both ways tomorrow I think. Then set them up so I can swap between them.

Regards, Paul.

john.reekie wrote:

Personally, I'm somewhat doubtful that there's benefit in trying to second guess what Dirac's algorithm is doing. Like the UMIK-1 page says, the 90 degree file is auto-generated, whereas the 0 deg file is measured, so I'd use the 0 deg unless it's not feasible (as is the case for surround sound). But, there's nothing to stop you from trying it both ways.

Who is "second guessing what Dirac algorithm is doing"? Dirac & MiniDSP both recommend using the 90 deg orientation when using a Dirac application. Why do you suggest otherwise? Are you suggesting that the UMIK-1 90 deg calibration file is not accurate?
Kev

Hi, I am measuring a pair of active speakers in room.

paul7777x wrote:

Hi Frans.
Thank you for your reply.

Were Dirac referring to stereo sound as well as surround sound do you know?

I’ll do the measurements both ways tomorrow I think. Then set them up so I can swap between them.

Regards, Paul.

Hi Paul,
BTW Frans is with Dirac, who I quoted.
Yes, Dirac was answering my question regarding testing the room response for 2 channel stereo setup. Dirac Live RCS is room correction software so they recommend the 90 deg orientation so the mic hears how your room is contributing to what you hear. MiniDSP says the same. I think an important distinction is whether you are trying to EQ your speaker response in isolation or trying to compensate for how your room is effecting what you hear in the listening position regardless of it being 2 channel or surround sound. The distinction between 2 channel & multi channel is selected when setting up the Derac Live software.
Kev

Hi Kev.

Thanks very much for clearing that up.

It is the room response that I’m dealing with.

Thanks again. Very kind of you sir.

Regards, Paul