NEW UPDATED Room Calibration for Film and TV Post

[Arno Peeters]

In the A/85, Annex D, I read:
"Put a sound level meter at the position of the center of the head of the normal position for the operator, pointing it at the loudspeaker channel in use. "

But in this test from RealTraps it reads:
"Although omnidirectional microphones supposedly receive sound equally from all directions, when measuring rooms and loudspeakers the convention is to "aim" the microphone upward. No omni microphone has exactly the same frequency response from all directions, though microphones with tiny diaphragms and slim bodies are often more uniform than larger models. So when balancing loudspeaker volume levels on a surround system, pointing the microphone toward the ceiling favors all of the loudspeakers equally."

What's your take on this?

And another question about bass-management: is it possible to adequately mimic it's effect within PT (with routing and eq), according to it's diagram?

[Eric Seaberg]

We've got a Sencore test set for our monitors as well as the Genelec DSP system. For both setups, Genelec DSP and non-DSP, I do point the mics straight up with the diaphragm close to ear level. The level and test results are very consistent for both measuring microphones.

[SDDP]

Originally Posted by Arno Peeters

In the A/85, Annex D, I read:
"Put a sound level meter at the position of the center of the head of the normal position for the operator, pointing it at the loudspeaker channel in use. "

But in this test from RealTraps it reads:
"Although omnidirectional microphones supposedly receive sound equally from all directions, when measuring rooms and loudspeakers the convention is to "aim" the microphone upward. No omni microphone has exactly the same frequency response from all directions, though microphones with tiny diaphragms and slim bodies are often more uniform than larger models. So when balancing loudspeaker volume levels on a surround system, pointing the microphone toward the ceiling favors all of the loudspeakers equally."

What's your take on this?

If I'm not mistaken, technically on paper this sounds correct, but throw in the Psychoacoustics of our ears design, I think it be best to mimic our ear and have the mic pointed straight at the center speaker at ear level. In that way we are calibrating to how the mixer at the mixing position would hear and thus make his decisions.

[danijel]

Originally Posted by dr sound

Read the Blue Sky set up FAQ on the page
http://www.abluesky.com/asp/catalogu...asp?linkid=172

Marti, looks like the Blue Sky re-worked their web. Here is the new link:
http://abluesky.com/support/blue-sky...on-test-files/

[dr sound]

Originally Posted by danijel

Marti, looks like the Blue Sky re-worked their web. Here is the new link:
http://abluesky.com/support/blue-sky...on-test-files/

Danijel,
Thanks for the heads up. The Updated "Room Calibration..."
has the new link.

[zzstation]

I've just downloaded the BlueSky files to calibrate my room once again.
It is a small room.
My only doubt is if I point my Radio Shack to each speaker at time. Or if I always point the mic to the center while panning the pink noise to the others speaker.
Thankk,
ZZstation

[dr sound]

Originally Posted by zzstation

I've just downloaded the BlueSky files to calibrate my room once again.
It is a small room.
My only doubt is if I point my Radio Shack to each speaker at time. Or if I always point the mic to the center while panning the pink noise to the others speaker.
Thankk,
ZZstation

I just updated the link (5-31-11) .
Please go to the new Dolby link at the top and follow the link.
This will answer your question.

[jimlongo]

A question about that Dolby document. 3.4.3 Taking a First Measurement

3. Ensure that you are sitting in your normal, proper reference listening or mixing
position. Set the SPL meter to “C” weighting and “slow” response.

4. Facing the front speakers, hold the SPL meter at chest level, with the microphone
facing up at an angle of approximately 45 degrees to the center speaker. Keep the
meter at arm’s length to prevent measuring audio that may reflect from your body.
You should be able to take SPL readings as you look down at the meter.

5. Keep the SPL meter in this position. Make sure that the meter is aimed at the
center speaker as you take readings for the left and right speakers.

6. When taking the SPL readings for the left surround or right surround speakers,
keep the meter at the same angle and position as you did for the front speakers.
Turn your body 90 degrees from the center speaker towards the wall closest to the
surround speaker you are measuring. This will minimize “shadowing” or
obscuring the meter with your body.

#4 in a small room that measurement can be awfully close to the monitors. I've always put the meter on a stand and positioned it right about where my head would be. What do you think? Again in a small room armslength puts the meter closer to the front than the L-R, and is off angle to the L-R.

#6 when they say "same angle and position" I take that as meaning "relative to your body"? IOW 2 feet from center, facing the surround side.

[zzstation]

Great! Thanks, Marti!

[Charles Deenen]

btw, once again, the dolby document does not work well for small rooms. (marti, no need to comment, I know you don't agree). They only work for small rooms with wide dispersion speakers (and at least 10 foot of space between listening spot and speakers), which most small rooms from what I've seen won't be using.

The rules dramatically change once your speakers are less than 8 feet away, and are 45 degree or more spread out from listening position.

This is the guidelines that we're using at our company, and they translate well. Use at will, or ignore. It doesn't matter to me :)

http://www.cdeenen.com/Charles_Biz/T...n_Vid_Game.pdf