AVS Forum banner

1 - 20 of 25 Posts

·
RETIRED theater builder
Joined
·
33,822 Posts
Discussion Starter #1 (Edited)
A lot of people have time on their hands, AV PRO Edge and Anthony Grimani did a nearly two hour webinar on home theater layout and sound design last week. It covers a lot of ground of what you normally spend hundreds of dollars at CEDIA to learn. They are planning more and hopefully they will be posted on Youtube. As I've often said if you ask 10 theater designers for an acoustical treatment plan you will get 12 different designs. One of the things that Anthony is a proponent of is asymmetrical layout of treatments, with the left wall different than the right. Other designers want them identical and I think most of the pro designs that I've worked on have been symmetrical. I'm open to discovering which one is best in my lifetime.



Enjoy:
 

·
Banned
Joined
·
4,171 Posts
A lot of people have time on their hands, AV PRO Edge and Anthony Grimani did a nearly two hour webinar on home theater layout and sound design last week. It covers a lot of ground of what you normally spend hundreds of dollars at CEDIA to learn. They are planning more and hopefully they will be posted on Youtube. As I've often said if you ask 10 theater designers for an acoustical treatment plan you will get 12 different designs. One of the things that Anthony is a proponent of is asymmetrical layout of treatments, with the left wall different than the right. Other designers want them identical and I think most of the pro designs that I've worked on have been symmetrical. I'm open to discovering which one is best in my lifetime.



Enjoy: https://www.youtube.com/watch?v=G90ekzfA92Y&fbclid=IwAR0qsLHMzQpMkcX0aLapZ8VtkCShlNeVtVXGUHH--fFpKncVVvF91UmgG20
Thank you for sharing very kind of you. I hope you and yours are healthy and safe

Sent from my SM-G965U using Tapatalk
 

·
RETIRED theater builder
Joined
·
33,822 Posts
Discussion Starter #3
Thank you for sharing very kind of you. I hope you and yours are healthy and safe

doing my best to stay alive, sometimes a truck full of tools is useful

 

·
Banned
Joined
·
4,171 Posts
doing my best to stay alive, sometimes a truck full of tools is useful

Sad but true. Thanks for the picture. Gave me a good chuckle. I saw a guy with a mask just like that pumping gas next to me yesterday. Strange times indeed.

Sent from my SM-G965U using Tapatalk
 

·
RETIRED theater builder
Joined
·
33,822 Posts
Discussion Starter #5
Problem is replacement filters are currently unavailable. I've been using cheaper masks at the store, saving this one for when I need to step over the dead bodies in the aisles at the grocery store.
 

·
Banned
Joined
·
4,171 Posts
Problem is replacement filters are currently unavailable. I've been using cheaper masks at the store, saving this one for when I need to step over the dead bodies in the aisles at the grocery store.
You made me spit out water all over my son. LOL. I just pictured you with that mask on literally stepping over bodies. Gallows humor is not for everyone but I can certainly appreciate it. Thanks.

Sent from my SM-G965U using Tapatalk
 

·
Registered
Joined
·
1,274 Posts
Thanks for the heads up BIG!

I'm about 2/3 through the webinar and I notice that Grimani's recommendations for speaker placements for both the bed layer and the Atmos layer are very different than the Dolby home theater spec (attached in two parts). His reasoning for his recommendations is related to certain psycho-acoustic effects with regards to surround and overhead channels and that the wider placement recommended by Dolby can result in "confusion" or cognitive dissonance (my term) in processing the sound sources.

For example, in a 9(11).x.6 system, Grimani recommends a rear surround angular displacement of less than 30 degrees (>165 degrees in Dolby speak) which is less than half the angular displacement recommended by Dolby of 60 degrees minimum (150-135 degrees). Similarly, he recommends a much narrower placement of the Atmos speakers, roughly midway between the center channel and the respective L/R channels. Furthermore, he advocates that the rear Atmos speakers should only be 10 degrees behind the main listening position ("MLP") rather than the Dolby recommendation of 45 degrees with the center row 10-15 degrees in front of the MLP rather than even with the MLP. He had a few other minor deviations from the Dolby spec as well, but these were the most significant differences.

I wonder if any of our acousticians or calibrators have any comments or experiences they would care to share related to Grimani vs. Dolby speaker placement.

Mike
 

Attachments

·
RETIRED theater builder
Joined
·
33,822 Posts
Discussion Starter #13
Anyone that wants to review Grimani's placement recommendations he starts at about 1:11 of the Webinar here is a screen grab. Note this is a 11.x.6 layout.



 

Attachments

·
Registered
Joined
·
2,959 Posts
A lot of people have time on their hands, AV PRO Edge and Anthony Grimani did a nearly two hour webinar on home theater layout and sound design last week. It covers a lot of ground of what you normally spend hundreds of dollars at CEDIA to learn. They are planning more and hopefully they will be posted on Youtube. As I've often said if you ask 10 theater designers for an acoustical treatment plan you will get 12 different designs. One of the things that Anthony is a proponent of is asymmetrical layout of treatments, with the left wall different than the right. Other designers want them identical and I think most of the pro designs that I've worked on have been symmetrical. I'm open to discovering which one is best in my lifetime.

Enjoy: https://www.youtube.com/watch?v=G90ekzfA92Y&fbclid=IwAR0qsLHMzQpMkcX0aLapZ8VtkCShlNeVtVXGUHH--fFpKncVVvF91UmgG20
Having done a couple classes taught by Anthony, this video is an outstanding primer for people looking at doing their own theater. I'm more of a symmetrical person myself, but I'm always open to new methods. If I had the time, resources and space, it would be nice to have a room to do nothing but play around with treatments, equipment, speakers and their placement.
 

·
Registered
Joined
·
28,980 Posts
Grimani recommends a rear surround angular displacement of less than 30 degrees (>165 degrees in Dolby speak) which is less than half the angular displacement recommended by Dolby of 60 degrees minimum (150-135 degrees).
The 60° minimum spread for the Rears comes from old research into the back-to-front imaging reversal problem, where sounds heard equally in both ears will end up reflexively imaging directly in front of you (where the brain expects it to be), even when the source of the sound is directly behind you. The research into this psychoacoustical phenomenon found that the imaging reversal could happen with sounds behind the listener as far as ±30° from the listener's centre line but fell off rapidly after that, hence the traditional recommendation (not just Dolby) to spread the Rear speakers at least 60° apart.
Similarly, he recommends a much narrower placement of the Atmos speakers, roughly midway between the center channel and the respective L/R channels.
That's where movie theatres place the overhead arrays AND where the home Atmos decoder assumes those speakers are (on a pair of imaginary lines splitting the L/C/R speakers). Dolby's own Atmos install guide recommends a wider spread (in line with the L/R speakers), which makes it easier to hear left-vs-right separation above you, but not so wide apart (like Auro) that it diminishes the 'overhead' effect.
Furthermore, he advocates that the rear Atmos speakers should only be 10 degrees behind the main listening position ("MLP") rather than the Dolby recommendation of 45 degrees with the center row 10-15 degrees in front of the MLP rather than even with the MLP.
NHK in Japan was doing research for their 22.2 channel format and found that the ability of our human hearing to discern differences in height behind us flatlined above 45° elevation. So Atmos and DTS:X both recommend a rear overhead pair at 45° elevation. You can place height speakers 10° behind you (80° elevation) but understand what you're giving up.

Check out the last couple of pages of the NHK paper: https://www.nhk.or.jp/strl/publica/bt/en/fe0025-2.pdf

Also, Dolby recommends placing the centre row of height speakers around 80° elevation, which is 10° in front of the MLP rather than even with the MLP. See sweet spot in range below:

 

·
Registered
Joined
·
1,274 Posts
Hi Sanjay,

Thank you for your thorough reply. I have just a few questions to make sure I understand what you recommend:



The 60° minimum spread for the Rears comes from old research into the back-to-front imaging reversal problem, where sounds heard equally in both ears will end up reflexively imaging directly in front of you (where the brain expects it to be), even when the source of the sound is directly behind you. The research into this psychoacoustical phenomenon found that the imaging reversal could happen with sounds behind the listener as far as ±30° from the listener's centre line but fell off rapidly after that, hence the traditional recommendation (not just Dolby) to spread the Rear speakers at least 60° apart.
Anthony mentioned the back-to-front imaging reversal problem but then went on to specify the narrow angle... Just to be clear, do you recommend rear surround placement >60° apart?


That's where movie theatres place the overhead arrays AND where the home Atmos decoder assumes those speakers are (on a pair of imaginary lines splitting the L/C/R speakers). Dolby's own Atmos install guide recommends a wider spread (in line with the L/R speakers), which makes it easier to hear left-vs-right separation above you, but not so wide apart (like Auro) that it diminishes the 'overhead' effect.
If the Atmos decoder is expecting a narrower spread, but the Dolby Install Guide is recommending a wider spread, what angle do you suggest we place the overhead speakers?


NHK in Japan was doing research for their 22.2 channel format and found that the ability of our human hearing to discern differences in height behind us flatlined above 45° elevation. So Atmos and DTS:X both recommend a rear overhead pair at 45° elevation. You can place height speakers 10° behind you (80° elevation) but understand what you're giving up.

Check out the last couple of pages of the NHK paper: https://www.nhk.or.jp/strl/publica/bt/en/fe0025-2.pdf

Also, Dolby recommends placing the centre row of height speakers around 80° elevation, which is 10° in front of the MLP rather than even with the MLP. See sweet spot in range below:
I reviewed most of the various Atmos configurations in the Dolby Install Guide and the only time Dolby spec'ed 80° for the Overhead speakers was in x.x.2 systems using in-ceiling speakers. In all of the x.x.6 configurations, whether Atmos-enabled speakers or in-ceiling speakers, Dolby always showed the placement at the 90° elevation.

Do you find the 80° elevation sounds better than the 90° elevation for the middle row? As a corollary, a number of AVS members prefer their side surrounds slightly forward vs. even or slightly behind the MLP as in the Dolby spec.






Thanks again,
Mike
 

·
Registered
Joined
·
28,980 Posts
Just to be clear, do you recommend rear surround placement >60° apart?
Yes, at least 60° apart for multiple reasons: minimizing reversals, greater envelopment, easier to hear stereo separation behind you (where our human hearing is not so great), etc. Any wider is up to your preference but I've found that a roughly 60° spread does all of the above AND keeps the Rear channel sounds firmly anchored behind me. Good compromise. You lose that if you spread the Rear speakers too far apart.
If the Atmos decoder is expecting a narrower spread, but the Dolby Install Guide is recommending a wider spread, what angle do you suggest we place the overhead speakers?
Again, comes down to personal preference. I like them wider because it makes it easier to hear left-vs-right separation overhead, so I'd line them up closer in line with the L/R speakers than the midpoints of the L/C/R.
Do you find the 80° elevation sounds better than the 90° elevation for the middle row?
You already know that our human hearing is better in front of us than behind us or directly above. So having the Top Middles a couple feet forward of the MLP (haven't measured degrees) really makes it easier to hear imaging from those speakers.
As a corollary, a number of AVS members prefer their side surrounds slightly forward vs. even or slightly behind the MLP as in the Dolby spec.
Guilty (was one of the early advocates). Imagine a surround field created between your Side and Rear speakers. You can either sit outside of it (Sides behind you), sit at the edge of it (in line with the Sides) or sit INSIDE the surround field (Sides slightly forward of you). I did the latter to end up with greater wrap-around envelopment AND better side-vs-rear separation.
 

·
RETIRED theater builder
Joined
·
33,822 Posts
Discussion Starter #19
Guilty (was one of the early advocates). Imagine a surround field created between your Side and Rear speakers. You can either sit outside of it (Sides behind you), sit at the edge of it (in line with the Sides) or sit INSIDE the surround field (Sides slightly forward of you). I did the latter to end up with greater wrap-around envelopment AND better side-vs-rear separation.

It probably makes a difference if you are implementing 9 base layer channels or 7. With 9 you already have something ahead of you giving you the sit inside the surround field experience
 
1 - 20 of 25 Posts
Top