This is topic Dolby,level in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Devriendt Miguel (Member # 296) on 01-09-2000, 04:39 AM:
Normally , dolby prescribes to set te level at 7 on a dolby processor. But i think that's to loud. At wich levels do you put your processor whithout complaits of the costommers? tx
Posted by Michael Cunningham (Member # 210) on 01-09-2000, 04:52 AM:
Yes, you're right, 7 is waaay too loud for most customers. What level you should use depends on the size of your theatre. 5.0 is a good place to start. You then need to run several shows and both go into the theatre yourself to listen and pay close attention to any customer complaints. Hopefully you will eventually settle on a reasonable level that will be loud enough to reproduce effects (explosions and such) but will only generate complaints from a sensitive few. In my 9 plex, the large house runs at 5, the next two smallest run at 4.5, the next two smallest run at 4.0 and the last four run at 3.5. Hope this helps!-Mike
Posted by Devriendt Miguel (Member # 296) on 01-09-2000, 05:25 AM:
tx micheal
Posted by Stephen Jones (Member # 16) on 01-09-2000, 06:16 AM:
I agree that 7 can be loud at times, I have run at 7 and it sounds ok but I think it can depend on the mix.Usually tecs come in and set the levels to high in which case I have to run at 6 even though I prefer to run on 7 but you have to have a happy medium as its the patrons needs that need to be addressed,so most of the time its 6.------------------
Posted by Gordon McLeod (Member # 33) on 01-09-2000, 01:33 PM:
The techs don't set it too high they set it at Dolby's reference level which is at 50% modulation the house level is 85DBC Slow at a fader setting of 7
This will translate into most faders actually running at 5-5 1/2
There have been recently some films especially from Europe that run quite nicely at 7
Posted by John F. Allen (Member # 218) on 01-09-2000, 02:25 PM:
There is a great deal of confusion about the reasons that faders must be run typically at 5 1/2 and as low as 3 1/2, for the program levels in the theatres to be normal. If a fader is indeed running at 5 1/2, it means that the accumulated errors in the technician's measurement system and the techniques used for system setup totaled about 5 dB. In other words, when 85 dB was measured on an SPL meter, it was equivalent to 91 dB. This is hard for some to understand, but it is the case nonetheless. Since it is impossible to wave a magic wand and provide the technicians with the measuring equipment, training and speaker systems needed for everything to come out the way it should, allowing faders to be set at "7" for both calibration and operation, I recommend the following: If one finds after calibration done with the fader at "7" that a fader must be set at (say) 5 1/2 for films (not trailers) to play at their correct level, simply reset the levels with the fader set at 8 1/2. Then films will run at "7" and in fact the system will be calibrated correctly, at least as far as levels are concerned.
This reasons for all this are described in detail in an article that can be downloaded at:
http://www.hps4000.com/pages/special/missing.pdf
John F. Allen
Posted by Steve Guttag (Member # 268) on 01-09-2000, 04:18 PM:
Welcome John!Depending on the room, I will set it to SPEC, that is 85dbC at "7". These are for review rooms or premier situations where the deaf studio people will expect that "7" means what they are used to.
For the rest of us...
I try to get the comfortable setting to end up being "7" and this depends on the theatre and customer. Some customers like it quite while others like it loud. I find out where they think it sounds right and make that "7". This is normally about 78-80dBc.
The problem with having the fader at 3.5 - 5.5 as the norm (as most are) is that it is VERY sensitive in that region. At "7" a little adjustment is still a little adjustment.
Steve
------------------
"Old projectionists never die, they just changeover!"
Posted by Joe Redifer (Member # 3) on 01-09-2000, 06:46 PM:
I usually have no problem running my flicks at "7". True, we do get complaints from the sensitive few. If the system is over-EQ'd where the vocals are reproduced, then that will make you need to turn it down as well.The movie "Magnolia" came with a note from the directors to "Please please run it at 7.0. If it sounds loud then we meant it to be that way." Most of the dialog in that movie hurts my ears, and thus I had to turn that one down, even though every other movie in that auditorium sounds great at a higher volume level. Bad mix.
Posted by Michael Cunningham (Member # 210) on 01-09-2000, 09:41 PM:
I'm not sure if it is an error on the part of our Technicians or a problem with thier equipment or something else entirely but I cannot run any of our processors at 7. We have tried this, the volume level literally blew horn drivers and shook ceiling tiles loose. Because I am not allowed to play around with the tech's internal settings of the processors, we must overcompensate to the low settings. This is probably typical of most large corporate chains, unfortuneately.-Mike
Posted by Brad Miller (Member # 2) on 01-09-2000, 10:24 PM:
In the simplest form, it is quite entirely possible the SPL meter the tech is using is not accurate. Personally, I prefer to stay towards the middle mark of the needle (analog meter) as it is the most accurate for channel balancing. This can easily be accomplished by setting the fader to 8 1/2 and calibrating for 90db. I'm sure if a thread on SPL meters was started it would be filled with everyone's pros and cons over the different units available, but in my opinion it all boils down to two things.
#1 is the equalization. Many techs tend to "over-eq" their auditoriums. I find this extremely common with SDDS units and Dolby CP-500s because somewhere, someone said "this eq is all digital so one frequency will not affect the adjacent"...which is bullshit. The end result of such thinking is one frequency is up and the next slider is down and up and down and up and down..."but just look at the RTA!!! It's perfect" they say. Well, it may look "perfect" on the RTA, but big deal. It sounds like pooh in the theater!
I am a big believer in cutting when needed and ONLY boosting when absolutely necessary. Even after eqing, the cards should be visually inspected for any obvious flaws (such as one or two frequencies high next to a few turned down low) and corrected. Also, for everyone who rolls off the low end on the stage speakers below 80hz "because that's the subwoofer's job", just listen to that great shrieky sound that always accompanies such thinking. The ears need the low frequencies to increase the sound pressure in the room to be able to "shield" themselves from the ear splitting upper frequencies (typically 4-8K) if played loud...much like the iris of the eyes "closes down" to protect itself from bright sunlight. Sound shouldn't hurt to listen to, but at the same time should have the capability to be powerful enough to shake the viewers.
Also of importance here is the size of the auditorium. Just because that RTA shows a perfect reference "X" curve doesn't mean anything. In very large rooms and very small rooms the rolloff angle MUST be fine adjusted by ear. (If anyone knows of a mathematical way to do this, then please post it here.)
Posted by Andrew D'Vrey (Member # 285) on 01-10-2000, 12:28 AM:
With so many houses and such differences in acoustics, I don't bother with a specific volume level. I check each one whenever a new print gets played in that house. Auditorium faders are so nice for this. We RARELY get loud volume complaints. Well, except for Pink Floyd--The Wall, which I kinda like to crank up to 8 
. I like to give those SR tracks a little kick!------------------
"And the monkey flips the switch."
- Major Don West, "Lost In Space"
Andrew D'Vrey
IATSE Local 219
Posted by Gordon McLeod (Member # 33) on 01-10-2000, 07:41 AM:
If you measure the SPL at 2/3 back in any dubbing room you will get 85dbc slow at fader setting 7 and if the theatre is EQ and has a similar reverberation time then the level in the theatre will match the dubbing room. And that level is loud and usually gets hotter as the day progresses. In fact that is why they are regulating the length of shifts that mixers work due to temperoray hearing loss.
In fact the public doesn't like it that loud and that is why many manufactures usually recomend that at 7 it is set for 79dbc.
But errors do not account for that and the most respected engineers in the industry T Holman and Ioan Allen have mentioned that many times
Posted by Tim Reed (Member # 137) on 01-11-2000, 03:02 PM:
There's nothing magic about the "7" on the dial, beyond Dolby wanting a certain sound pressure level achieved at that setting. As to what setting should be used for day to day performances, that's a highly subjective matter, and I don't think that can be specified. After all, the fader will naturally have to be run higher with an auditorium full of people, and lower for just one or two persons.