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Topic: Dolby A at fader 7

Michael Brown
Phenomenal Film Handler

Posts: 1522
From: Bradford, England
Registered: May 2001

posted 05-24-2002 06:56 AM

Is is totally accurate to say the the fader must be at 7 completely all of the time (just a Dolby A analog auditorium).

No matter what film. 7

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Brad Haven
Master Film Handler

Posts: 300
From: fremantle, West Australia
Registered: Aug 2001

posted 05-24-2002 07:20 AM

No!.
We have our dolby SR systems aligned by a good tech, cinema one settles at around 6 and cinema 2 (smaller) settles at 4. We also set our trailers at individual levels , even film ads, if dramatically diffrent, which does occur!.
Each film should be set for it's own volume, as i find that most films have very varying levels. I used to work with dolby A and we found the same result. Not having worked with digital sound (at work that is)i cant comment on those set ups.

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Michael Brown
Phenomenal Film Handler

Posts: 1522
From: Bradford, England
Registered: May 2001

posted 05-24-2002 07:28 AM

I tend to find that I need to run the set up at at least 7. The average setting is 7 and a half.

I supposed it depends on the film.

I'm sure that the system has been aligned properly. And the Dolby Level is definately correct.

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Brad Haven
Master Film Handler

Posts: 300
From: fremantle, West Australia
Registered: Aug 2001

posted 05-24-2002 07:49 AM

i find that it really depends on many factors ,amps ,speakers, acoustics e.t.c...
our other location (SR and dolby A) set theres at around 6 and 7.

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Greg Mueller
Phenomenal Film Handler

Posts: 1687
From: Port Gamble, WA
Registered: Jun 99

posted 05-24-2002 09:12 AM

On my system (CP65) I have to run "A" and Mono at 7, but SR and DTS at 5. No doubt I'm doing something wrong

------------------
Greg Mueller
Amateur Astronomer, Machinist, Filmnut
http://www.muellersatomics.com/

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Leo Enticknap
Film God

Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000

posted 05-24-2002 09:27 AM

In my cinema days I distinctly remember two venues at which A-type was usually played at half a notch to a notch higher than any other format. The only explanation for this I can think of is that within a cinema processor, the preamp gain for A-type is separate from that of other formats.

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Frank Angel
Film God

Posts: 5305
From: Brooklyn NY USA
Registered: Dec 1999

posted 05-24-2002 09:43 AM

Guys, there is a reason why Ray Dolby put a volume level control on the front of the processor - volume is not absolute. As mentioned, many factors in the theatre "B-chain" acoustical environment will impact the apparant sound level in the room. Everything from temperature and humidity to the number of bodies in the room will change have an effect, to say nothing of the type of sound mix as well as the age of the audience. Guaranteed a young crowd of rock and rollers watching ROCKY HORROR PICTURE SHOW will think a level 7 is much to low....a Sunday matinee of seniors watching ON GOLDEN POND will think a 7 is too loud. Audience comfort will not always pin out a Dolby reference.

If there were such thing as an "absolute correctlevel," then the level controls on the output card would be all you would need -- why put a manual level on the front panel at all? In a well calibrated system, yes Dolby 7 is the mean reference level -- but you use that as the STARTING point; you use your ears and the audience as the ultimate decision-making reference instrument.

Frank

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 05-24-2002 02:21 PM

No!

I heard somewhere that when the system is calibrated with the Pink Noise Generator, an error is "built in" with the generator. I have heard that at least a 100mv error is introduced. If calibrated with fader set at 7, the actual level of the fader will run around 6 or so.....Maybe Steve Guttag can shed some more light on this.

I have also heard that it is a good idea to calibrate Dolby Tone levels with the system punched up on MONO. I have heard several instances where the SRA adapter will perform much better without excessive "pumping".

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Antonio Marcheselli
Phenomenal Film Handler

Posts: 1260
From: Florence, Italy
Registered: Mar 2000

posted 05-24-2002 02:35 PM

Frank,

Yes your're right. On a well calibrated system, you usually play around 7 (6,6.5,7) depending of your taste, your auditorium, your speakers, the mixing.....

My system was intentionally calibrated at 6.3 (for some valid reasons). I remember that I projected a movie at 5.0 but was just a movie, the other ones stays at 6.0-6.5 range. SR movies usually stays at 7.0.

But, I believe, if you usually have to project at 4... Well, something is wrong.

Bye
Antonio

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 05-24-2002 08:56 PM

This topic has been hashed over and over again
If the system is set up properly with 85bcs slow from the generator card and the ISO eq curve has been followed then the level matchs the mixing stage. To the average listener it is to high so typically most theatres run between 5 and 5.5
If you play to the standard John Q public and the fader is at 7 or up without complaints on most hollywood movies then something is wrong.

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 05-24-2002 09:02 PM

And I'll argue that as I always do. I run films all the time at 6-7 (but mostly at 7) with zero complaints. Everything is set up to spec. I find that theaters with bad acoustics and/or "not exactly great" speakers and most frequently an over-EQ'd B-chain have to run more at 5. Also, theaters where the tech calibrated the system and said "there you go, that's as perfect as it will ever be" end up playing at 5. The HF rolloff really needs to be double checked by ear before packing up and leaving the job, for no two auditoriums are alike. I believe it was Ioan Allen who has even stated this (as well as other forum members, some of which are THX certified but do not post on this subject because apparently this is a taboo subject). I have EQ'd my share of "crappy auditoriums" and end up leaving the fader at 5 myself. However I continually find that a well designed acoustical environment, good speakers with proper positioning and a good B-chain generally runs at 7.

Of course the bottom line to the question being asked at the start of this thread is to play it at whatever setting sounds best and does not bring about audience complaints. Treat the 7 as a reference starting point in determining the fader setting is what I tell most people. At least that advice I believe 99% of everyone will agree with.

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Steve Kraus
Film God

Posts: 4094
From: Chicago, IL, USA
Registered: May 2000

posted 05-25-2002 02:06 AM

Leo: A Dolby print would need to run at a higher fader settings on a mono system because the track is recorded at a lower level than a typical mono track. They're taking the improvement in noise floor that Dolby noise reduction creates and trading some of it for more headroom. In other words, lowering the overall level (and compensating with more gain in the processor) allows the peaks...an explosion, say, to be that much higher without clipping than they otherwise could. Dolby A optical stereo print runs at a lower level than mono and an SR print runs lower than Type A. Both would need to run at higher fader levels on a mono system. If you're talking about a stereo system SR will need to have the fader turned up if it was setup for SR by simply plugging in cards in place of the A cards.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 05-25-2002 09:39 AM

Well I as usuall disagree and a case in point
I service a fair number of dubbing and mixing stages and we took a print and its final mix to a theatre for a private and a public select screening
We Eq'd the room to speak ran the print it sounded exactly like what I and the crew heard on the dubbing theatre. THe mixers were also happy
The fader was at 7
When the public was admitted the fader was being constantly being lowered because of complaints until it was back at 5.5
The sound dept. then walked out as they felt there mix was ruined
That is why we have a standard. The fader setting is adjustable the rest should match the spec. Also the rolloff is specified based on room volume

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 05-25-2002 10:28 AM

It wasn't a "Mummy" movie, was it? Those mixes sound best at 0.

Well as usual we will disagree on this one, but it certainly is fun to debate it. In the meantime I will continue to run the faders at or near 7 without a complaint and won't even bother telling you that at Northpark we generally ran our movies between 7.5 to 9 without complaint! (For reference I do specifically remember we ran Titanic in 70mm DTS at 8.75 from the first day to the last.) Anyone who ever patronized that theater can vouch that the level was not too loud and the experience was phenomenal.

Anyone on the forums been to the Northpark in Dallas? Anyone see Titanic there?

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Michael Brown
Phenomenal Film Handler

Posts: 1522
From: Bradford, England
Registered: May 2001

posted 05-25-2002 10:44 AM

So if i find that 7 and a half is my average level. I'm not commiting a mortal sin?

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