|
|
Author
|
Topic: 7.1 surround speaker placement
|
|
|
|
|
|
|
Harold Hallikainen
Jedi Master Film Handler
Posts: 906
From: Denver, CO, USA
Registered: Aug 2009
|
posted 09-17-2016 11:28 AM
Each of the surround channels (Lss, Rss, Lrs, and Rrs) should produce 82 dB(C) at the reference position (see SMPTE RP200) when SMPTE pink noise (about -20 dBFS) is played. Another method (SMPTE ST0202 Appendix A.9) is to set each 1/3 octave between 500Hz and 2kHz to 70 dB for screen channels and 3dB less for surrounds. It appears that the mathematically accurate 1/3 octave levels are 71.5dB (500 Hz to 2 kHz) for screen channels, 68.5 dB (500 Hz to 2 kHz) for surround channels, and 81.5 dB (25 Hz to 100Hz).
One thing to keep in mind is that when you play 5.1 content in a 7.1 room, you will typically use Ls to drive Lss and Lrs, and Rs to drive Rss and Rrs. The gains need to be reduced by 3dB since the level will be up about 2dB when you combine a side and rear surround. For example, the USL JSD-60 does input routing using a mixer. When playing 7.1 content, the mixer coefficients are set to 100%. When playing 5.1 content, the mixer coefficients for the surrounds are set to 71% (-3 dB).
Good luck!
Harold
| IP: Logged
|
|
|
|
|
|
|
|
All times are Central (GMT -6:00)
|
|
Powered by Infopop Corporation
UBB.classicTM
6.3.1.2
The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion
and agrees to release the authors from any and all liability.
|