Rational Acoustics



jwyatt805
February 6th, 2019, 01:56 AM
Trying to think of a good use-case for the Octacapture integration, particularly over the input gain controls. Could it be used to "level off" the gains of the mics to get a truer spatial average of a seating area (in my case a movie theater) or is going with dB Averaging setting sufficient?

I think in some of the older the multiplexors & rta software used in cinema calibration had a "gain leveling" process where first the input gains of mic #2-4 would get zero'd to the magnitude of the #1 mic (in the mix position), then a 20-30sec time window would run for the spatial average plexing. Was this a means to an end with the technology of the time? Does the dB average achieve the same goal of keeping the mic closest to the source from influencing the average too much -- or should be recreate the "gain leveling" with this new feature?

TerryLewis
February 27th, 2019, 06:10 AM
Hi,

Not sure if I can help you with the answers, cause I'm not a tech guy at all. What Smaart version do you have, btw? I'm trying to make heads or tails of Roland OCTA-CAPTURE with Smaart v8.3 (engineering projects (http://yourhomeworkhelp.org/do-my-engineering-homework/) for a movie theater).

gluis
May 24th, 2019, 11:34 AM
Trying to think of a good use-case for the Octacapture integration, particularly over the input gain controls. Could it be used to "level off" the gains of the mics to get a truer spatial average of a seating area (in my case a movie theater) or is going with dB Averaging setting sufficient?

I think in some of the older the multiplexors & rta software used in cinema calibration had a "gain leveling" process where first the input gains of mic #2-4 would get zero'd to the magnitude of the #1 mic (in the mix position), then a 20-30sec time window would run for the spatial average plexing. Was this a means to an end with the technology of the time? Does the dB average achieve the same goal of keeping the mic closest to the source from influencing the average too much -- or should be recreate the "gain leveling" with this new feature?

The reason to integrate gains of the Octacapture within Smaart is to conserve your absolute SPL calibrations, even if you have to move the gains. How would it serve on your movie theater scenario? Well, as the theater has to be calibrated at a set SPL (85dB SPL if I remember correctly), you can actually move the the gains of your preamp and conserve your previously set SPL calibration on the program.

I'm not sure about the gain leveling procedure you mention though. The old and still current (as far as I know) cinema calibration procedure does not include any leveling off. It basically assumed constant SPL as cinema theaters used to be fairly reverberant, so that reverberation helped maintain SPL thought the space. I'm not saying this is good, is just the way I believe was supposed to be. Nowadays good cinema systems had their horns designed to have more gain to the back of the theater, trying to compensate a little for the distance, and also reducing horizontal coverage angle on top of them, which help on not to excite the room as much.

I hope this helps. GS