Room EQ with ATMOS 9.2.4 Monitoring

[ric982]

Hi,
Setting up an ATMOS mix room. I haven't found much information about how to EQ a room with bass management and dual sub-woofers. Looking for feedback on proposed approach described below.

Planned setup:
- ProTools Studio/DAB/DAPS/DVS/MTRX Studio/9.2.4 Monitors
- Will use Bass Management in MTRX Studio on all 13 satellites.
- Room is 12x15x8 feet. Fairly well sealed. Sub and satellites are not ported.
- All Blue Sky Sat5/Sat8 monitors. Sub f0=34.5 Hz.
- Room treatment is not complete yet but should be "well treated" when done.

Satellite placement (within dolby spec):
- Satellite placement is equistant at 1.5m radius.
- Ear hight speakers at 0, +/-31, +/-46, +/-106, +/-145 degree azimuth
- Top speakers at +/-45, +/-135 azmuth, 50 degree lateral elevation

Sub placement has limitations. Two options being considered:
1) Straddling the Center. Both facing front wall.
2) Front sub right of Center, Rear sub left of center line. Both facing front wall.
REW room sumulation likes (2). Probably will experiment some once up and running.

This is what I think I'm going to do:

MTRX Studio setup.
- Bass Management enabled. 80 Hz, Linkwitz-Riley 24 dB/oct.
- Monitor output has each satellite's LP sent -3dB to each sub (normally 0dB to one sub)
- LFE sent +7 dB to each subs. (Normally 10dB to one sub).
- Satellite gains all set to 0 dB.

Process:
1) Time align satellites/subs to listening position with MTRX Studio delay.
With the satellites equidistant, this should probably amount to aligning the subs with each other and then aligning all satellites with the same delay.
2) Run some REW samples on one channel to see how sub response lines up with satellite response. Play with sub phase angles and gains to see if can flatten the LF response and minimize the deviation of the average between highpass and lowpass bands. Repeat this for whatever sub locations I'm considering. Select a sub position and sub gain and call it good.
2) Add dolby room curve into REW
2) With both sub's enabled, REW each channel (other than LFE) at several positions in vacinity of listening position. Mic pointed at each satellite's acoustic center.
3) Averge readings for each channel and generate PEQ filters for each channel. Probably limit correction to maybe +2dB max. Input PEQ parameters to MTRX Studio SPQ for each channel.
4) Retest at listening position to see how the response looks just to check.

Does this seem reasonable? Any suggestions.

[gives]

Originally Posted by ric982

Hi,
Setting up an ATMOS mix room. I haven't found much information about how to EQ a room with bass management and dual sub-woofers. Looking for feedback on proposed approach described below.

Planned setup:
- ProTools Studio/DAB/DAPS/DVS/MTRX Studio/9.2.4 Monitors
- Will use Bass Management in MTRX Studio on all 13 satellites.
- Room is 12x15x8 feet. Fairly well sealed. Sub and satellites are not ported.
- All Blue Sky Sat5/Sat8 monitors. Sub f0=34.5 Hz.
- Room treatment is not complete yet but should be "well treated" when done.

Satellite placement (within dolby spec):
- Satellite placement is equistant at 1.5m radius.
- Ear hight speakers at 0, +/-31, +/-46, +/-106, +/-145 degree azimuth
- Top speakers at +/-45, +/-135 azmuth, 50 degree lateral elevation

Sub placement has limitations. Two options being considered:
1) Straddling the Center. Both facing front wall.
2) Front sub right of Center, Rear sub left of center line. Both facing front wall.
REW room sumulation likes (2). Probably will experiment some once up and running.

This is what I think I'm going to do:

MTRX Studio setup.
- Bass Management enabled. 80 Hz, Linkwitz-Riley 24 dB/oct.
- Monitor output has each satellite's LP sent -3dB to each sub (normally 0dB to one sub)
- LFE sent +7 dB to each subs. (Normally 10dB to one sub).
- Satellite gains all set to 0 dB.

Process:
1) Time align satellites/subs to listening position with MTRX Studio delay.
With the satellites equidistant, this should probably amount to aligning the subs with each other and then aligning all satellites with the same delay.
2) Run some REW samples on one channel to see how sub response lines up with satellite response. Play with sub phase angles and gains to see if can flatten the LF response and minimize the deviation of the average between highpass and lowpass bands. Repeat this for whatever sub locations I'm considering. Select a sub position and sub gain and call it good.
2) Add dolby room curve into REW
2) With both sub's enabled, REW each channel (other than LFE) at several positions in vacinity of listening position. Mic pointed at each satellite's acoustic center.
3) Averge readings for each channel and generate PEQ filters for each channel. Probably limit correction to maybe +2dB max. Input PEQ parameters to MTRX Studio SPQ for each channel.
4) Retest at listening position to see how the response looks just to check.

Does this seem reasonable? Any suggestions.

You need to get with Dolby on this on everything. It took me months to get my room done with plan approvals to say the least. They have plenty of info on the professional site for how to set things up. G

[ric982]

Yeah, you're probably right about getting back to Dolby. I"ve been through most of their "learning' stuff. I've been in a few discussions with Dolby before I had any hardware in place. Last time I tried, they more or less said they don't certify setups on DAB/DAPS - only if you have a remote RMC. I'll try them again soon, but I was hoping to try to get things sort of up and running before I bug them again. I'm not sure how much bandwidth I'll get from them, and want to be prepared to ask things that I really need help with.

Bringing up a MTRX Studio at this point and waiting on a Mac Studio to arrive, hopefully within a month, and then I'll probably get DAPS and try to get it running. Will probably try some room EQ stuff as well just to get familiar with SPQ on MTRX Studio. I can relate to the 'months' comment.

Thanks for the input.

[Mike Thornton]

Check out my series on using REW together with my MTRX Studio on EQ my 7.1.4 system. Although I don't cover bass management, it will be relatively easy to pick up the instructions from the REW manual. Hope it helps. Mike

[ric982]

Well Hello, Mike Thornton!

First, let me express a BIG thanks to all you folks at Pro Tools Expert. Alan Sallabank's "Using The Dolby Atmos Audio Bridge - An Alternative Workflow - Free Expert Tutorial Part 3" was a major help in my thinking on how I was going to implement ATMOS. And also, yes, I have seen your post on EQing with REW and MTRX Studio and it pretty much guided what I originally posted (and I will review it more than once again once I get there).

It is on the dual-sub with bass management that I was hoping to get some direction. As I was collecting used monitors that matched my existing blue sky 2.1 pro desk, I ended up acquiring another sub. I figured that two subs with some attention to placement would probably help even out room mode nulls and peaks and if nothing else give me another 3dB of headroom, thus the 9.2.4.

In particular, as I've got my MTRX Studio more or less up and running, there are a few important points I'm trying to confirm:

1) I've set the initial trim on the subs to -3dB in the monitor profile output (2 subs @-3dB = combined subs @ 0dB). Will adjust as needed when I calibrate.
2) Assuming (1), I'll send each satellite's bass to both subs with 0dB gain.
3) Assuming (1), I'll send LFE to both subs with +10dB gain.
4) Calibration is done without any PEQs other than the bass management filters.
5) When I run REW to measure a given channel, the satellite and both subs will be active.

I'm probably going to end up with a front and a rear sub. The front sub is on the front wall facing it. The rear sub is actually about 3 feet off the back wall because its in front of a rear wall bass trap/diffuser and this seems to be better for room modes than two on the front wall.

Apparently some people put different satellites to different subs. With the small room I'm in and an 80 Hz crossover, I don't think I'm going to get much localization of bass that a front/rear split or a left/right split would give much effect or benefit. So I was planning to just send all to both.

I have some other questions on house curves, but I'll save that for my next post.

Any feedback or comments would be helpful.