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Author Topic: Dolby Fader Levels Ken Lackner Phenomenal Film Handler Posts: 1907 From: Atlanta, GA, USA Registered: Sep 2001 posted 01-01-2003 10:58 AM                     What do the numbers on the Dolby faders mean? Are they decibels, or some other unit, or just some arbitrary numbers that Dolby came up with and decided to make "standard"?  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 01-01-2003 11:09 AM                     Are you referring to the 0-10 numbers? If so, then they predate Dolby by quite a long time...it merely breaks the frader's travel into 10 equal amounts and nothing more. The desire for 7.0 to be the reference has to do with keeping the traditional analog fader from the most sensitive part of it's travel (the lower numbers). Where as the difference between a fader setting of 7 versus 8 might be on the order of 3 dB , the difference between say 3 and 4 might be as much as 20 dB. You can think of the area around "7" as the sweetspot of the fader's range. I'm sure another issue was the ability of the earlier VCA's to track with each other...as one got down the sensistive part of the range, I'm sure the channel-to-channel balance was more likely to be erratic. Now having 7.0 corresspond to 85dB was fine for analog with only 6dB more of level (91dB)...with Digital and nearly 20dB more level left...many are reducing their faders down to the 4-5 range...which is not what the original intention was. So Ken, was your question about the 0-10 scale? Steve  |  IP: Logged Ken Lackner Phenomenal Film Handler Posts: 1907 From: Atlanta, GA, USA Registered: Sep 2001 posted 01-01-2003 11:21 AM                     That's exactly what my question was about! Yeah, my theater has most of it's faders down in the 5 range. We get way too many volume complaints when we go much above 6. Our tech does have the processors properly calibrated. So if films are intended to be run at 7, why so many volume complaints?? So if I understand you correctly, a jump from one level to the next (3 to 4, 4 to 5, 5 to 6, etc...) does not correspond to any specific dB level? quote: Now having 7.0 corresspond to 85dB was fine for analog with only 6dB more of level (91dB)...with Digital and nearly 20dB more level left...many are reducing their faders down to the 4-5 range I really don't understand what you mean by that. (Not the part about people reducing their faders, I just said that my theaterd does that too!) quote: If so, then they predate Dolby by quite a long time So whered did this standard come from?  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 01-01-2003 11:44 AM                     It isn't so much of a standard as a convienient way of numbering any gerneric fader...even THIS IS SPINAL TAP made fun of the way faders are numbered by making note that Marshall amps have their faders go to 11! To which the reporter asked...well why not make that "10" and renumber it? So yes, the numbers have no correllation to a dB change. You will find knobs having a 0-10 scale though out their history. Some have called their faders "attenuators" and number them from -infinity to 0dB (no attenuation). For a simple pot that is correct. People don't normally work well with negatives so you wouldn't want to tell people to "set your faders to -5". It is easier to set to 5 or 7. Sony decided to have their fader on the dB scale with "0" being normal, or equivalent to "7" everywhere else. They only gave you a +/- 10 dB range and a knob resolution such that you needed a Makita to spin it down to -10 as fast as you could to get people's ears to stop bleeding. When they came out with the 3000 series they now have +10 but -30 dB. Note the Sony method hasn't taken in the Cinema Industry....Peavey tried something similar with their CinemaAcoustics stuff...a "0" ref with +/- from that. The pro sound guys try to just bring in their ways and this industry just doesn't change that fast. SMART took a rather interesting approach on some of their processors...the ModIII only had ONE marking on it..."CAL"...which was used for calibration only. After all, you will turn the knob up or down to satisfy whatever complaints you are having. Since the numbers have no correllation to anything anyway, what difference does it make? (The ability to set things uniformly comes to mind) So as to digital...if you are mixing a film you are going to get your dialogue levels right and hopefully that will be right for any format of sound...mono though digital. Then the music and effects are added, and added, and added...I little known feature of film mixing consoles are the fader rachets...just like on a roller coaster, once a fader has been slid up... it may never be brought down again ! Thus films only get louder from there. As the recordest is exposed to these insane levels longer, the less sensitive they get to it and they climb yet higher! Even the dialogue will start getting boosted so as to not get lost on all of these expensive and impressive music and effects. When you only had 6dB more of range from reference, well that is all you could go up. With 20 dB more, you have a lot more sound you can put down and, unfortunately, they do! I love a loud "sting" as much as the next guy but when the whole damn film is loud...it actually takes away from the track...nothing is emphasized since it ALL is. So what does 90% of all theatres do...they reduce their fader...for the most part that works but the big explosions are less big and more importantly, the dialogue is reduced to the point where I find it too soft. Steve  |  IP: Logged Christopher Seo Jedi Master Film Handler Posts: 530 From: Los Angeles, CA Registered: Jun 99 posted 01-01-2003 12:32 PM                     Steve, I don't understand the relationship between the headroom of the soundtrack and the level reserve on the fader. Are you saying that given the increased headroom of digital soundtracks, technicians are purposely calibrating systems at 4-5 on the Dolby fader? What would be the purpose of this? Certainly, digital tracks rarely need to be turned up past reference.... So how precisely should Dolby's guide (from the CP650 manual) be taken-- that each increment from 4 to 10 represents 3-1/3 dB, and each increment from 0 to 4 represents 20 dB? Are the digital faders better calibrated than the analog ones?  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 01-01-2003 01:10 PM                     Nope you are missing the point.... The people mixing the films have the ability to make LOUD sounds LOUDER and they do....too much. You could probably run your Woody Allen films at 7.0..even in digital even though you probably run your normal digital films at 5 or so. As to the Dolby manual and the CP-650....in all seriousness...the CP-650's 7.0 is actually 2 dB louder than any other Dolby processor in the past. So yes if you set the CP-650 to 85dBc...it will actually be louder than anything else. As to a digital fader...that is entirely up to the designer...You can set the scale anyway you want. As I recall, the CP-650 has a double knee...a rapid assent up to something like 4.0 then it changes its slope up to around 7.0 and finally changes its slope again. I think Dolby publishes the actual fader characteristics. They didnn't publish the CP-500s...and for good reason...I don't think there was any level change below 3.0 or above 9.3 But as has been hashed above...it doesnt really matter what the slope is...what matters are two things...what is reference (that is what was the film actually mixed to) and what level is comfortable to your audience. It is good to know if the level will change drastically below a certain point, I agree. If that level is 5.0 or +1.8dB or "11", who cares? You know what reference is and you know what level your audience will tolerate. Steve  |  IP: Logged Christopher Seo Jedi Master Film Handler Posts: 530 From: Los Angeles, CA Registered: Jun 99 posted 01-01-2003 02:21 PM                     I understand your general arguments... I am, rather, confused about a specific statement you made, the same one that Ken mentions: quote: Now having 7.0 corresspond to 85dB was fine for analog with only 6dB more of level (91dB)...with Digital and nearly 20dB more level left...many are reducing their faders down to the 4-5 range...which is not what the original intention was. You are implying that the increased amount of headroom available with digital makes 7.0 a poor fader setting choice, whereas it is acceptable for optical analog. What is specifically wrong with "having 7.0 correspond to 85 dB," and what do you think would be a better choice? As far as the Dolby fader characteristic, I was just wondering how well the faders are calibrated; i.e., can I really expect lowering the fader from 7 to 6 to yield a precise 3-1/3 dB reduction in SPL, especially with analog faders. I would imagine a discrete shaft-encoded digital fader to be more precise in this regard. I know the precision is not critical as long as one knows what is relatively good levels, but it's nice to know that when the editor of a film yells for 2 dB more, one can set the fader accordingly.  |  IP: Logged Howard Johnson Film Handler Posts: 87 From: Felpham , West Sussex, UK Registered: Jun 99 posted 01-01-2003 02:27 PM                     We just had a second screen added with 120 seats and DTS we opened with Die Another Day. This film is so loud that we were running it at 3 1/2 we just couldn't stand it louder. The dialogue is a little soft but if we ran it louder audiences complained, there are so many guns and explosions. We now have Harry Potter which is fine at 5 we can hear all the dialogue and effects so I agree about the sound mixers they must be deaf!  |  IP: Logged Adam Martin I'm not even gonna point out the irony. Posts: 3686 From: Dallas, TX Registered: Nov 2000 posted 01-01-2003 02:42 PM                     I think that the room acoustics and equalization also affect what the audience perceives as volume. Severe echo and poor equalization will make the audio sound "harsh", which the audience will equate with "loud". Poor audio characteristics may also originate with the wrong equipment chosen for the room, a crappy soundrack builder, or improper installation of equipment.  |  IP: Logged Antonio Marcheselli Phenomenal Film Handler Posts: 1260 From: Florence, Italy Registered: Mar 2000 posted 01-01-2003 03:23 PM                        Howard, If your system was right at 3.5.... I believe that something was wrong! It cannot be right, also with a very loud movie. I would say that, with a "difficult" audience, 5.0 is the lower volume I can set with any kind of movie. And, I fully agree with Adam. About what Steve said: I believe that he meant that if you set the fader at 3.5 you'll loose all of Digital Dynamic. Let's suppose that 7.0 is 85dB and you have a +20dB of headroom. If you set the fader at 3.5 most of the softer sound will be lost because too low. So the total dynamic is reduced rather then projecting a movie at 7.0 Steve, am I right? Bye  |  IP: Logged Howard Johnson Film Handler Posts: 87 From: Felpham , West Sussex, UK Registered: Jun 99 posted 01-01-2003 03:31 PM                     Hi Antonio, this new screen was properly set up just before christmas with a Vic5B and DTS. The installation engineers felt we should run the Bond film louder but we felt locally that it was too loud for our audiences and us in such a small screen. The Harry Potter film sounds great at 5-5.5 because it hasn't got the continuous bangs you can appreciate the quality of the soundtrack.  |  IP: Logged Antonio Marcheselli Phenomenal Film Handler Posts: 1260 From: Florence, Italy Registered: Mar 2000 posted 01-01-2003 03:40 PM                        Howard, There is a LOT of difference in volume between 3.5 and 5.5. 3.5 is, I believe, the minimum fader you can set on the dolby. At 3.5 the dialogue should be barely audible. I had once the privilege to project a show at 3.5 (an action movie) and with 10 people in the auditorium 7 was out to complain. I understand that 007 is a very loud movie but HP has its loud scenes too! I cannot understand such a difference in fader with two DTS movie. Bye  |  IP: Logged Howard Johnson Film Handler Posts: 87 From: Felpham , West Sussex, UK Registered: Jun 99 posted 01-01-2003 03:55 PM                     Antonio, Perhaps the print of Bond wasn't very good although the timecode shouldn't be affected. We are new to DTS so we are learning as we go I am looking forward to some more DTS films booked "Rabbit Proof Fence" "The PIanist" "Gangs of New York" and "Chicago" I think that "Gangs" will be noisy but we will see. At the moment we are running Harry in mono instead of DTS as a card has gone in the Dolby unit, I am hoping to receive a new one in the post tomorrow, today being a public holiday.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 01-01-2003 05:21 PM                     The number means nothing other than a reference one could set up a system with 85dbc at 8 and then most theatres would run at 6 instead of 5 and so on Bottom line it is the fact that with the increased overused capacity for LOUD that the faders get turned down. The average dialogue is still the best at 7 As fo EQ it is not really the problem as when set up following the ISO curve it is way the mixers did it and you know I have had many ocassions when the manager and audience say turn it down and the mixer says absolutly no  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 01-01-2003 05:30 PM                     Obviously, something is being lost in the ASCII translation here. I am NOT advocating lowering the reference level at all. What I am saying is if the recording engineer only has 6dB available of extra headroom for explosions, music and effects, that is what they seem to use...with digital, they have 20dB and that is what they seem to use ALL THE DAMN TIME. The problem isn't with the reference level...it provides a wonderful dynamic range to give the ability of the recording engineer to make loud things loud, soft things soft and everything in between....by lowering the fader, you have, in effect, squashed the dynamic range of the system. This is not the exhibitor's fault. The problem lies with the recording engineers! They don't leave that 20 dB of headroom alone and keep it in reserve for the really BIG LOUD STUFF. So if you have a guy that records dialogue at a comfortable and natural level but will always record music and effects at the top-end of whatever medium he has, then with a digital track it will be way too loud...with an older optical track it will only be 6dB louder...the track in effect, put a "governor" on his mix board. Dolby made a nifty gadget which has been dubbed the "annoyance" meter. It merely gives an ongoing account of the relative level of a film over time. It doesn't correspond to dB persay but some propritary level called Leqm. What it does is measure the soundtracks for the entire length...and comes up with a single number represenation...the higher the number the louder the film overall. Its nifty since the weight of any part of a film is proportional to the length of an entire film. If you have a 3 hour epic, then a short 1 minute bang em up sequence will not drive your number up substantially. This device has been in use now with the mixing of trailers and has contributed to lowering the overall level....with a trailer the entire feature is only a couple of minutes so each loud passage represents a major portion of the score. If the industry adopted the use of this device on mixing features and put requirements on its use in order to receive an MPAA rating and basically put a watch dog on the recording engineer, the excessive levels would come to an end. Yes, Adam does bring up valid points...the acoustics of the theatre and tuning definately contribute to the harshness of the track too. As to accurate...the analog faders can be quite accurate...the older ones made with discrete components were less so. Digital faders offer the flexibility of programing the exact response of the fader over it's entire range. With an analog fader, you are even depending on how well the index line was put on the knob. Steve  |  IP: Logged

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