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Author Topic: Room levels Antonio Marcheselli Phenomenal Film Handler Posts: 1260 From: Florence, Italy Registered: Mar 2000 posted 09-24-2003 12:31 PM                        Hi everyone. I have a question that it's a long time I would like to share with you. Dolby and all sound manufacturer says that channel's level in the theater has to be LCR: 85dB Surrounds: 82dB Subwoofer: 91dB or +10dB in band gain. I'm talking of digital formats of course. However all equalization I've heard following these standards had a very lack in surround sound. In my experience the "correct" level for surrounds speakers is 85dB or, better, the same level of front channels. With this setting surround sound is clear, not too high, clear enough to be clearly heard in all situations. If I set my surrounds at 82dB usually during louder scenes surrounds die and cannot be heard. I remember a post where Brad says that to have good surrounds they have to be set 1,5dB higher than specs. So 83.5 What is your opinions? Bye A  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 09-24-2003 01:46 PM                     I will frequently do 82.5, as that sums more accurately to 85db, but it would be a rare case when the surrounds would need to be raised to 83.5. I don't remember ever recommending that. If I did, it was quite possibly a typo. If you are having to set each surround zone at 85db, something is wrong.  |  IP: Logged Larry Zuverink Film Handler Posts: 98 From: Caledonia, MI, USA Registered: Nov 2002 posted 09-24-2003 01:54 PM                     I disagree. I have heard surrounds set to 85 and find it very annoying. Now maybe that is just our set up. Depending on distance between surround, type of speakers, and power handling head room might make a difference.  |  IP: Logged Antonio Marcheselli Phenomenal Film Handler Posts: 1260 From: Florence, Italy Registered: Mar 2000 posted 09-24-2003 01:58 PM                        Brad, I saw surrounds set at 82 and 85dB in many theaters. Both with ARTA 80 and THX R2. 82dB is, at my ears, not enough. You can see surrounds only in quite scenes or only surrounds that are very very loud. I believe in dolby standards but in this case I cannot understand how a theater can be set at 82dB. 82.5, you're right, it was my memory, you said 1/2 db and not 1.5 dB! I cannot understand. It's not a single theater, it is all theater I worked for!! Michael, do you remember Supercinema in florence? That had the surrounds at 85dB. You told me that surround was very good.. (just FYI, Supercinema is closed now... ) Bye A  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 09-24-2003 03:17 PM                     I usually go to 82.5 or 83db. Whatever it takes to get me to a sum of 85db. I've never had to go higher than 83db per channel. I remember when I was first starting out; I misunderstood the spec's and went for 85db per channel and I could tell immediately that I had made a terrible mistake because the screen channels became hard to understand. It was a mess. Look at what you wrote... quote: I saw surrounds set at 82 and 85dB in many theaters. Both with ARTA 80 and THX R2. 82dB is, at my ears, not enough. ...and consider the possibility that your personal taste disagrees with the standard. I thought my theatres sounded just wonderful until I visited a cinema in South Florida with very good sound. Rather than get depressed about my ignorance, I became very excited about starting from scratch in hopes of obtaining similar results. I think it is possible to continually improve at this so long as we resist the temptation to become too opinionated as to how a room should sound. Someone on this forum once noted that although our ears play an important role in setting up and evaluating our sound systems, we have to take care that they are "calibrated" just like the rest of our equipment. In other words, we need to keep ourselves reminded of what a theater is really supposed to sound like. Otherwise, we are just guessing. I don't know the theatre to which you refer -- the one with the surrounds at 85db each -- but even if that is true, there may be peculiar factors in the design of the space that impacted the decision to set the system up in that manner. Then again, maybe not. It may have been a bad setup that you got used to hearing.  |  IP: Logged Antonio Marcheselli Phenomenal Film Handler Posts: 1260 From: Florence, Italy Registered: Mar 2000 posted 09-24-2003 03:42 PM                        manny I fully agree with you!! That's why I said "at my ears". I'm not saying that 82dB is wrong, just that I've had the chance to hear different setup of equalization and I found that, for my personal taste, 85dB of surrounds is better. Of course too many surrounds are not a good idea, front channels has always to be clear. However I put myself in customer's head. Customers are not so used to surround sound (they don't work in a theater!) so, like myself first time in theaters, they note surround sound less than me that I'm able to concentrate on both side of a movie: sound (front and rear) and image (first movie, years ago, I had to close my eyes and concentrate on surround sound to clearly hear them!!). So, I wonder, What is the audience hear if I can barely hear surround sound? I realize that we should hear a movie in the same theater to understand our personal taste, but I can assure that i DON'T like too high surround, when majority of sound come from rear instead of front. I like perfectly balanced surrounds, where you can clearly hear surround from rear but when they don't cover the stage channels. Hwo do you equalize surround speakers? Same X-curve of the stage channels? Bye! A  |  IP: Logged Rick Long Jr Expert Film Handler Posts: 211 From: Toronto, Canada Registered: Jul 2000 posted 09-24-2003 08:07 PM                     As far as Dolby goes, 82 db is correct for all processors except the CP 65, which has them at 85 db each and 88 db summed. (due to the cat 441 card). If set to 82, the surrounds become practically inaudible.  |  IP: Logged Martin Brooks Jedi Master Film Handler Posts: 900 From: Forest Hills, NY, USA Registered: May 2002 posted 09-25-2003 08:47 PM                        In most NYC theaters I attend, I never think I'm perceiving the surrounds. I always think they're set too low. Now sometimes, the end-credit music is mixed only to the front and then I'll hear the difference. There's a local theater near me in which I saw American Splendor. It's a relatively small theater and there I heard the surrounds quite clearly. When I've been on the left coast (which hasn't been for some time), I've always felt that the surround levels were higher and sounded better.  |  IP: Logged Matt Zeiner Expert Film Handler Posts: 146 From: Windsor, CT USA Registered: Sep 2003 posted 09-26-2003 09:06 AM                     Hey folks - new guy chiming in... for what its worth, I approach the surround array as a near-field system and the screen speakers as a mid/far field system - totally separate. As such, I generally treat each differently. I will apply the X-curve to the screen channels as room reflections (or lack thereof at certain frequencies) will color the sound. The listener perceives predominantly direct sound from the surrounds and as such, I tend to leave them flat - 82 - 82.5 DBc works fine as long as you don't go rolling off the high end...  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 09-26-2003 09:14 AM                     Hi Matt. Welcome! You're a controversial fella, aren't you?  |  IP: Logged Matt Zeiner Expert Film Handler Posts: 146 From: Windsor, CT USA Registered: Sep 2003 posted 09-26-2003 09:20 AM                     Yeah, maybe... doesn't it kinda make sense, though?  |  IP: Logged Antonio Marcheselli Phenomenal Film Handler Posts: 1260 From: Florence, Italy Registered: Mar 2000 posted 09-26-2003 12:52 PM                        I know someone that set surrounds flat. Surrounds are brighter and more... funny but they're not balanced with front channels, IMHO. However my thought is: if at 85dB you can hear sounds that at 82dB you cannot hear... How can the mixer put this sound if it shouldn't be heard? Bye A  |  IP: Logged Matt Zeiner Expert Film Handler Posts: 146 From: Windsor, CT USA Registered: Sep 2003 posted 09-26-2003 01:04 PM                     quote: I know someone that set surrounds flat. Surrounds are brighter and more... I think the word you are looking for after your periods is "present." the ear is much better at discriminating sounds above 2k than it is at 200hz. This is why I beleive it is appropriate to set them flat - it seems to me that if you roll off the surrounds above 2k per the x-curve, you are actually not compensating for an acoustical coloration because the ear is latching on to more of the direct sound than the reflections, and as such, you are causing the perceived sound from the surrounds to be predominantly midrange-heavy. In order to make them more clear and distinct to the listener, one would have to set them to a higher average SPL than the spec demands - hence the reason that most techs find the need to boost surround levels above 82 DBc. IMHO, of course.  |  IP: Logged Alan Haigh Film Handler Posts: 45 From: Watford, UK Registered: Jul 2003 posted 09-26-2003 03:21 PM                    I think Antonio has hinted at the key to this one, and it applies equally to high end hi-fi. Should a playback system be set to reproduce the master tape as accurately as possible, or should it be "tuned" to personal taste? For myself, I'm with the former option. So surrounds at 82, with the curve, just like in the dubbing theatre (also level on "7"!). This is what you are matching. Maybe the mixer wanted the surrounds to be unobtrusive, to "fill" the stereo image. You can't really hear them, but it would sound worse without them. Or perhaps they are only really audible at reference level. If you deviate from the curve or other settings, it must be for size of room/ acoustical factors (see other thread) and not for personal taste. Mind you, having said all that, the audience chooses to pay your wages (by choosing your cinema), not the director. But surely if you set the surrounds loud, then eventially there will come a film with REALLY loud surrounds...  |  IP: Logged Matt Zeiner Expert Film Handler Posts: 146 From: Windsor, CT USA Registered: Sep 2003 posted 09-26-2003 03:51 PM                     quote: If you deviate from the curve or other settings, it must be for size of room/ acoustical factors Yes. acoustical factors are the reason I would set the surrounds flat (or utilizing less rolloff, if you like). The audience perceives a greater proportion of direct sound from the surround array than they do from the screen. Balance of perception in this case (as I see it anyway) is more important than what your test equipment may tell you...Obviously, the larger the theatre is, the more reflected sound will come into play, and the need for more eq is required. The litmus test is to play back a mono mix through each channel and compare. I bet that on a conventionally eq'ed theatre, the surrounds will sound muddier AND louder than the screens - I do this as a matter of course and 9 times out of ten (especially in smaller houses) I find this to be the case.  |  IP: Logged

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