Film-Tech Forum ARCHIVE: Theatre Volume

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Posted by Michael Brown (Member # 890) on 06-18-2001, 05:27 AM:

So in general in the USA do cinemas play films at the correct volume.

Saturday night I went to Along came a Spider and got my ears blasted off.
Sunday night I went to Autumn in New York and had to pay close attention into trying to listen to the speech.

------------------
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Michael Brown
Bradford Student Cinema
www.bradfordstudentcinema.co.uk

Posted by Aaron Mehocic (Member # 15) on 06-18-2001, 09:59 AM:

Depends on if you spent the right amount for the proper equipment. I don't know about most theatres but we set our sound at 5.0 on our non digital processors and 5.5 on our digitals. Thats a little bit below the recomended 7.0, but thats an arbitrary number in my opinion anyway. Theatre volume depends on one thing -- What do the customers want? Most middle age-ers and old people don't care about sound that much. "I just want to hear it" is usually the comment we get when we tell them their film is in a digital house. Young kids and Gen-X'ers like a lot of noise so we usually crank up the volume a half click or so. The key is remembering to check the sound quality and volume on Thursday nights just like you check your lenses and apertures after moving prints. We seat a little over 2000 people a week. Out of that I might get one or two sound complaint(s). I'll catch some flak for this, but it all hinges on your demographic, what does your customer want?

Posted by Antonio Marcheselli (Member # 373) on 06-18-2001, 02:30 PM:

Aaron,

If a theater is weel calibrated to 7, 5 IMHO is more than "a little bit below" the recommended volume. I would turn down to 6 at maximum if there were big problems with a particular audience but only in particular situation!!!
Also, I think that if a movie is well recorded, 7 is ALWAYS the correct volume. If the film is intended for old people, it will not have sound effects and the dialogue's level will be perfect at 7.
After the last equalization (very good IMHO) I never had the need to turn the volume below my calibrated level and sound compliances were minimal.
I've projected Pearl Harbor in a THX theater. For my ears 7.5 was perfect but also 7 could be perfect. For many reasons we had to turn down the volume to 6. It was too low for my concept of "movie theater".

Bye
Antonio

Posted by Aldo Baez (Member # 790) on 06-18-2001, 05:19 PM:

I'd have to disagree on the 7. We normally run out theatres at 5.0 on the weekdays, and between 5-6 on the weekends for the new movies. For kids movies we tend to raise it since they make a bit more noise, but we almost *never* go over 6, as it is just WAY too loud. 5.5 is very very comfortable in our theatre and we receive no complaints at all.

Posted by John Walsh (Member # 168) on 06-18-2001, 06:26 PM:

It's true that 7 (at least on Dolby units) is supposed to be the correct setting, but almost all of the theaters I've seen run it lower.

Posted by Darryl Spicer (Member # 711) on 06-18-2001, 07:47 PM:

I think the reason that you find a lot of systems running lower than seven, even those that are calibrated correctly, is do to these facts.

When the standard was set up by dolby you had a lot of auditoriums that held 600 700 as well as more than a thousand people in them. A lot of these theaters were not accustically able to handle sound without some kind of loss in quality.

Speaker systems at the time were not what they are now. What we have now can produce better and more audible sound.

Better mixing and productions of soundtracks.

Higher quality amps to handle the power to run the channels.

The problem is not in what we are doing it is the fact that the standard fader setting is based on 1970's information and situations.

Posted by Joe Redifer (Member # 3) on 06-18-2001, 09:02 PM:

It all depends on the EQ. If you have a super crappy EQ, a volume level of "7" will seem way too harsh. If you have a truly smooth and proper EQ, then that volume level should be comfortable for most purposes, unless you have a very small crowd. And even then it should still sound good.

Posted by Paul G. Thompson (Member # 655) on 06-18-2001, 09:19 PM:

I think it boils down to what the engineer's preference was when he set the output levels on the EQ cards. I referenced mine as close to "7" as possible. I like standardization.

Posted by Rick Long (Member # 213) on 06-18-2001, 09:34 PM:

Or it could be possibly related to the length of time since the installing technician last calibrated his/her sound pressure level meter.

Posted by Paul G. Thompson (Member # 655) on 06-18-2001, 10:00 PM:

Rick, you got that right!!!!

Posted by Brad Miller (Member # 2) on 06-18-2001, 10:46 PM:

It is generally due to the technician not setting up the system properly if you have to run any lower than 6.5, plain and simple. Sound level is sound level, regardless of auditorium size. The all important thing to note here is the proper balancing of the channels and a good EQ. Never have I heard a good EQ on a system where the tech dialed things to "the line" and walked away. Larger and smaller rooms require different levels of high frequency rolloff and if the tech does not adjust that accordingly, the sound will appear "way too loud" and "harsh" and will end up having to be played at 5. This is an improperly calibrated system any way you slice it. Unfortunately, I see it all the time.

Something I have been seeing a lot of as lately is improper balancing between the channels. I know of at least one tech who is quite old and has lost a substantial amount of his hearing (but of course won't admit it) and his complaints are that there is too much bass and the dialogue is buried in music and sound effects. What does he do? Why he adjusts the systems for HIS impaired hearing, of course! Check these SPL levels out after his calibration...

LEFT...85db
CENTER...93db
RIGHT...85db
LEFT SURR...79db
RIGHT SURR...79db
SUBWOOFER...74db

Anyone else care to comment on why these settings are horribly wrong? I would like to hear what other sound techs think of this. The systems are being played at 4.5 to 5 (because the level must be set upon dialogue) and they play like mono sound systems now.

Posted by Joe Redifer (Member # 3) on 06-19-2001, 12:37 AM:

Anyone who sets their systems up with THOSE levels has no business in the cinema industry whatsoever. It is obvious that this person doesn't have a clue as to what he is doing. My question is - How do such morons get jobs in the industry to begin with? Can't we screen for stupidity at the door?

Posted by Kevin Crawford (Member # 469) on 06-19-2001, 12:59 AM:

I know of another tech that sets levels according to his impaired hearing. He can't even hear the continuity buzz on his meter. I also heard that he fell asleep in Pearl Harbor and slept throught the attack. I don't know how you could do that.

But at the theatre I am at now, it is not due to incorrect EQ or SPL, it is because the people in that town complain for every little thing. Which in reality is probably only about 6 people. The other day I found Pearl set to 4.5 on the fader. At that level, what does it matter, you can barely hear it.

Part problem lies in placating the few people that complain. The other part is the sound mixers that keep turning things up. It seems that the worse the movie is the louder they record it. Like that makes it a better movie.

Posted by Rory Burke (Member # 512) on 06-19-2001, 01:51 AM:

Brad!!!

I recommend 20 lashings and a 7 year stint at a dollar house for that technician!!! Good God !!! I cant believe this volume thing seems to be such an ordeal.....from what ive seen the following is true....

-Proper calibration of microphones to be used for room B-chain.
-A multiplexing spectrum analyzer is recommended for best results.
-Proper speaker placement and positioning/aiming along with correct crossover/amplification is also a must!!
-Correct spl levels along with SMPTE/THX recommended frequency response.

Despite all of the correct procedures to setting your theater audio to be correspondent with the industry standards and to be representative of what one hears at the mixing studio....The volume is still turned down!!!! Sometimes you can get away with having the fader at 7.0 <like a starwars movie or the contender> but generally complaints keep em down. There is not much more to this volume dilema than just plain that. Until the industry figures out as a whole a true solution other than just testing trailers....i would venture to say that the volume "what r your faders set at?" dilema is here to stay.

Rory

Posted by Joe Redifer (Member # 3) on 06-19-2001, 02:57 AM:

Well perhaps the sound mixers are going deaf listening to all of that loud sound everyday, so they have to compensate. Or maybe not, but I always wonder about fun things like that.

Posted by Demetris Thoupis (Member # 833) on 06-19-2001, 04:10 AM:

CORRECT THEATER VOLUME????????!!!
Yeah Right. At the cinema which I am working, I have to play all DTS Movies below 3!!!!! just because my boss comes screaming that is too loud and that we are sending people away!! Anyway. I have to admit. The system needs recalibration for the sound levels of each channel but not for re-equalisation. It depends on the sound system you use.
Take Care
Demetris Thoupis

Posted by Gordon McLeod (Member # 33) on 06-19-2001, 09:25 AM:

When set at 85dbc and proper EQ the more vocal of audience members (the ones who riht letters to management and newspapers) find it too high
Most theatre run with the fader at about 5.5
A well mixed track (crouching tiger) runs at 7 with no complaints
as to Joes comments about hearing loss of mixers. Temporary deafness is a problem and it is not uncommon to see during the course of a session to see the faders slowly rise up higher and higher.
At one point there was talk of OSHA limiting the max shift to 4 hours to prevent long term effects
As for the levels set in the theatre Brad mentioned why bother haveing anything but the centre channel amp on for in effect it is big mono with those levels.
I think a public ridicule of the theatre and the engineer is in order

Posted by John Walsh (Member # 168) on 06-19-2001, 09:27 AM:

While anything is possible, I think the fault is with the film' sound. The directors have the same disease as the guys who make trailers... they want to impress people and just make it too loud.

The guy who tunes our theaters is a real audio guy.. he runs a recording studio, but likes free movies. So, he does only the audio for us with an R2 unit, and we let him in free.

The point is: even after a good tuning, the volume still needs to be lower.

Posted by Antonio Marcheselli (Member # 373) on 06-19-2001, 03:03 PM:

Brad,
LEFT...85db
CENTER...93db
RIGHT...85db
LEFT SURR...79db
RIGHT SURR...79db
SUBWOOFER...74db
---

GOSH!!!
I could understand a little correction after the standard EQ but... 93dB?????? How could he made it????

Regarding poor EQ, perhaps I post this example again, in this case pls excuse me.

Once I have a very bad tech to EQ my theater. After the EQ the theater (an old theater with "normal" acoustic and good digital sound system) sonded terrible.
We tried with TITANIC. When the sailor saw the iceberg and they sounded the bell, the bell seemed far, closed in three boxes...

We projected in these condition for few weeks. When I had to project "INSTINCT", I had big troubles with sound level. If I put the volume to 6 or 7, the sound was so bad that was noisy. If I set the volume to 5 or lower, I had problems to understand dialogues.
Peoples complained that volume was too high, but when I tried to turn down the volume, pople complained that volume was too low...

Than, I had a true equalization, made with an R2 RTA by a THX tech. My system, for many reasons, was calibrated to 6.3 instead of 7. After that EQ I set most of the film between 6 to 6.5 and all sounded perfectly. I had 1 or 2 sound compliants during the next year while I had 1 or 2 sound compliants a week with previous EQ...
Ok, sometimes I had a movie recorded to impossible levels... But just few times.

Oh, that day, we tried TITANIC again. The bell was just behind the silver screen, where it should be.

Bye
Antonio

OT: just to realize how my english is bad: how would you rate my english, between 0 to 10? Can you understand easily what I write?

Posted by Randy Stankey (Member # 64) on 06-19-2001, 10:45 PM:

Parlate molto più meglio inglese di parlo Itallian! Parlo Itallian affatto! (Devo utilizzare un motore di traduzione.)

(Sneaky Trick: I used a translation engine! )

Seriously, I have no problem understanding you. Sometimes I see that you use English words with Itallian grammar but I don't have a problem with that. When I graduated high school, I took a summer vacation in Italy. (La Toscana) My friends, who spoke Itallian, told everybody that I spoke a little bit of Spanish so everybody thought I could understand them.... if they spoke LOUD ENOUGH!!! When I look back on it years later it's funny, but it wasn't a joke back then! I spent most of my time pulling my hair out just trying to understand people.

I think your English is molto bene!

Posted by Antonio Marcheselli (Member # 373) on 06-20-2001, 08:41 AM:

Randy,

I live in Tuscany!!
Thanks for your reply, I'm more relaxed now... I can continue posting here without the fear that anyone could understand me!

Ciao
Antonio

Posted by John Pytlak (Member # 331) on 06-20-2001, 09:56 AM:

John F. Allen wrote an article in the July 2001 issue of "Boxoffice" on "The Mythical "X" Curve" that discusses the pitfalls in EQ procedures and how they could make sound "harsh". He contends that room acoustics (especially reverb) require modification of the procedure for "tuning" a room, since human hearing tends to concentrate on the direct sound from the speakers, but the RTA microphones "hear" the entire room including the low frequency reverb, often making the objective EQ sound too "bright" and "harsh":
http://www.hps4000.com/pages/articles_page_.html

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Posted by Joe Redifer (Member # 3) on 06-20-2001, 01:53 PM:

Like Brad advocates, final tweaking of any EQ must come from the ear and not the RTA, even if it is an R2.

Posted by Gordon McLeod (Member # 33) on 06-20-2001, 05:26 PM:

Funny how Mr Allen stands alone in the Cinema Audio industry regarding the issue of near field vs far field equalization
In extremely reverberant rooms It has some good ideas but I think bursts of noise with comparisons in the decay would be more advantages but that can get into some very complex test gear

Posted by Mark Gulbrandsen (Member # 72) on 06-20-2001, 05:30 PM:

I disagree with both Brad and JFA on this. I let things run pretty much right off the R-2 and have hardly had to touch up any eq settings afterwords. With modern speakers it is not usually necessary to have to go back and color the sound to your taste. You are then doing something for your customer that has little or no meaning, and really no benefit. Only on a few occasions could I remember having to do this. If you calibrate your R-2 mics and have the unit calibrated at least every two years it should sound great right off the R-2. There are instances of encountering older speakers that have poor hf response. Some techs will have a tendency to push the hf to have it there when the speaker, and phasing plug are not designed to do it. This can produse very harsh sound at times. The best thing here is to see what the flat response is and base your eq situation on that. It stupid to try to make a speaker do something that it can't do. This also will eventually probably blow the diaphram as well.

JP said that JA said "He contends that room acoustics (especially reverb) require modification of the procedure for "tuning" a room, since human hearing tends to concentrate on the direct sound from the speakers, but the RTA microphones "hear" the entire room including the low frequency reverb, often making the objective EQ sound too "bright" and "harsh".
My experience with this is that it can be true in some instances but is usually not true. Probably more true in an HPS system because JFA has no reverb standards that are specified anyway. In fact I can remember JFA telling me many times that he liked a room that was a little on the live side. I always felt that this covered up the problems that were inherent in the high end response of the HPS speakers. As I have said before hearing a 70mm film with a great mix at the Chinese #2 in Hollywood was the confirming arm of this,at least for me and for a number of others I know.
If a room is built to The specified THX standard it will end up with quite little reverb, sometimes almost none, then what ever small bit reverb there may be is not nearly as big of a deal as the mics are not picking up much of it and the amount that might have to be factored in to readings is pretty irrelavent. Should standards be changed just to accomodate JFA's non-standards...I don't think so. His methods and designs are already a bit far to the left for most of us and probably justifiably so since he has other factors to deal with in his systems and rooms that most of us don't experience. Quite simply, his systems require a set of standards all their own.
Mark @ GTS

Posted by Gordon McLeod (Member # 33) on 06-20-2001, 06:21 PM:

Another area is the source of the pink noise that is used.
I have found I get better results with the Component Engineering Pink Noise unit than the original 85c and I find some of the internal pink noise sources in SDDS unit a bit suspect.

Posted by Scott D. Smith (Member # 821) on 06-20-2001, 06:25 PM:

As a sound mixer, this is a subject I have groused about for years. Based on my experience both mixing and viewing films in various size theaters and dubbing stages, I have come to the conclusion that the standards for calibrating levels need to be revisited.

Despite all the best intentions, the perception of what is comfortable in terms of volume varies widely with room size and acoustics. This, of course, assumes that everything else is properly calibrated (which is a BIG assumption!). As a point of reference, in our preview theater (49 seats, short decay time), we typically find we have to set the fader around 5.0 to 5.6 for most commercial titles. This varies slightly depending on whether it is a digital or analog track.

In conversations with other mixers who have been working in smaller rooms, they have stated that they typically have to set their monitor level about 4 db below 85dba, to maintain a good correlation to the apparent loudness in a larger house. While I still find that 85 dba works in theaters of about 250 seats or larger, the situation changes as the room volume shrinks. The other paradox is that on better quality systems, I find that the level usually needs to be a little lower. This could be due to better speech intelligability, high peak power capacity, etc.

In any event, even under the best of circumstances, with identical systems, the perceived volume level is going to vary based on the room volume, acoustics, and overall background noise level. It's still an improvement over the bad old days of Academy, though!

Posted by Mark Gulbrandsen (Member # 72) on 06-20-2001, 06:34 PM:

Scott is absolutely right. Level standards are really more of a problem these days. Some work has been done recently to tame the levels on trailer mixes but the overall effect has yet to be felt, and or little or no change has come of it. Overall volume of a normally run film needs to be gauged by the apparent level of the dialog in the mix. Not by the level of the music and effects. Too many base level setting on peak or loud levels. If levels are set this way then dialog is frequently lost to oblivion. Its very easy to tell when dialog is too loud!
Also, ultra high quality playback systems are a must even in normal theatre environments. This makes a big difference as Scott mentioned and if the sound is seamless, uncolored, and clean, even slightly higher than normal playback levels will usually get little or no complaint at all. This has been my experience when putting in top notch playback systems. Usually complaints come from someone with a hearing aid.

Gord also makes a good point as well. Pink noise SHOULD ALWAYS be suspect and you should use a known good pink noise source only! Some inexpensive processors have really lousy built in PN generators and I generally refuse to use them for B chain alignment. I use either the Ivie PN generator or the C.E. card. Be careful here!!!!!!
Mark @ GTS

Posted by Gordon McLeod (Member # 33) on 06-20-2001, 06:46 PM:

Scott why are they useing 85dba not 85dbc that is the standard weighting. would that account for the 4db

Posted by Rory Burke (Member # 512) on 06-21-2001, 02:08 AM:

Remembere that spectrum analyzer mics especially those with the R2 must be calibrated regularly....What happened to that mic calibration kit that THX was going to make for the R2? Since were are also on the topic of pink noise....remember that those pink noise generators also have to be calibrate regularly as well....as far as tuning a room with a R2 and then making EQing/adjustments with your ear after the fact is a ridiculous concept in my book Joe Redifier!!! Please tell me that your ears are better and that some how you possess the perfect pink noise template in you head? please!!!! if you follow all the proper guidelines to EQing a room .....300mv etc, calibrated EQ kit and have good acoustic reverb response, your speakers are adequately amplified and horn aiming is good...im afraid you cant get any better than that!!!
Rory

Posted by Brad Miller (Member # 2) on 06-21-2001, 02:38 AM:

Geez Mark, would you even attempt to EQ a room without your R2? You mention it so often I would think you were having sex with it. Granted the R2 is in most everyone's opinion the best possible tool a tech can use to achieve the best possible sound, but a good sound tech IMHO should be able to achieve excellent sound with a variety of RTAs. Also, just because someone may be the bearer of an R2 does not in any way mean that he/she can automatically achieve good sound. I'm sure most people here will agree with the "over-EQing" argument that has been discussed in the past. In the end, achieving a really good EQ relies at least somewhat on the talent and listening ability of the sound tech to transform the final adjustments into a great sounding system. For those who haven't read Mr.Allen's article that John Pytlak mentioned earlier, it is good reading regardless of whether you agree with "near field" measurements or not and there are valid points made in it that affect both styles of EQing.

Overall I think Mark, Gord and Rory are missing the point and taking a single comment to the extreme here. No one ever said that an auditorium should be EQ'd by ear. I've never said it. I don't think Joe ever has. Before you try and say that John F. Allen claims to have, I do not believe he has...and come to think of it, I don't think I've heard anyone EVER say that. To clarify, the entire argument here is whether the HF slope should be fine-tuned / tweeked by ear AFTER the entire EQ has been carefully set with whatever kind of analyzer system or pink noise generator a specific tech prefers to use. I know when I personally finish an EQ, I play several reels of film that I have heard time and time again without ever taking the mics out of the auditorium or packing up the RTA. If it seems that the HF needs to be tweeked just a touch, I do it WITH the RTA and not literally "by ear". (The use of the words "by ear" is where I think the confusion is residing in this discussion.) When I say "by ear" I am referring to using real human hearing and not a machine to evaluate the overall tone of the playback, but all initial and "tweeking" adjustments are still performed with the RTA in front of me. I honestly do not think anyone is that good as to be able to set an EQ without at bare minimum an RTA and one mic.

And getting back to the first question of the thread, if tweeking the final HF rolloff a tad up or down by ear is such a bad thing, I find it interesting that my faders sit right at 7 while other systems EQ'd by various techs sit on 5; both systems being set to the same SPL levels. Kinda weird how that works, but sound is all subjective anyway.Still I agree 100% with Mark's earlier comments about setting the fader to the dialogue. The dialogue should be clear and during scenes where the actors are talking at a normal level, the volume should be not be loud nor soft. The rest of the mix will fall right into place from there.

Posted by Michael Brown (Member # 890) on 06-21-2001, 06:39 AM:

We are having a mono to Dolby SR upgrade in a few months, so we will be doing EQ's and stuff like that.

Our Boss person(chairman) seems to think that we will be able to play everting at 7 and not have to think about volume level after the instalation. It should be interesting to see what turns out.

------------------
------------------
Michael Brown
Bradford Student Cinema
www.bradfordstudentcinema.co.uk

Posted by John Pytlak (Member # 331) on 06-21-2001, 08:02 AM:

I agree with Brad. IMHO, "tuning" a theatre is equivalent to "tuning" a piano. A really good piano tuner uses objective tools to tune the piano, but also uses an experienced ear to do the final "tweek". The final step is to sit down and actually play some music.

Of course, this method depends on having a piano tuner who is not tone deaf.

Posted by Gordon McLeod (Member # 33) on 06-21-2001, 10:02 AM:

The mic calibrator is available from THX I think I was probably one of the few who shelled out the bucks for it
Brad as for having sex wit R2 I would rather have Princess leah

John how would you stand on balancing two projectors illumination by eye rather than rely on a meter
At several labs I service we can get the light dea on by the metre but the timmers are not happy when doing side by sides

Posted by John Pytlak (Member # 331) on 06-21-2001, 10:18 AM:

The final "tweek" in matching two side-by-side projectors for color and uniformity is always done "by eye", from the position where the color timer would sit. The meter is used to verify that the screen luminance meets SMPTE 196M, but is not used as the final judge.

Posted by John Keegan (Member # 290) on 06-21-2001, 11:35 AM:

Generally, we keep our volume at 6.0 to 6.5 for most releases unless we find that the film is loud (car chases, loud music, etc) then we bump it down. Children's movies are generally 5.0 or 5.5, maybe reaching 6.0 if we have a full house. Our tech generally comes in once a month to check calibration and levels.

Posted by Rory Burke (Member # 512) on 06-21-2001, 01:47 PM:

Brad, Thanks for the clarification!!! I understood that once all the EQing was completed that you physically continued tunning to what you "ear" was most accustomed to hearing. As you stated then....you do fine tuning adjustments and minor tweaks to your high frequency roll off. I dont trust my ears however, if the humidity is up, if i went swimming the day before and i have water in my ears still, what if you went to a dance club the night before and your ears are ringing. In some way i still dont necesarily agree with making "ear" tweaks due to its subjective nature.... what do you use as criteria? help me understand what you listen for and what you aim for. I myself make sure that my equipment is properly calibrated and ofcourse i play familiar material in the auditorium and do what i call subjective listening to make sure that everything seem presentable....no boomyness, no rattles, etc. but unless i had perfect pitch i just dont understand how a typical guy does it? It was mentioned that changes might be made if the HF sounded harsh but shouldn't that also be reflected on your spectrum analyzer? to some degree at least?
On another note, I have noticed with great consistency after EQing over 300 rooms in my ventures that speaker aiming/placement is directly related to over EQing..... I have been to many screens where so long as I took the time to climb behind that dusty baffle wall and reaim the speakers to their correct locations < most theaters still lack this im afraid > The EQ changes significantly. Youll be amazed as to how many EQ cards I have turned the 500hz trim pot down simply because of the crossover/time alighment between the HF and LF speakers. That hole disappears so long as you follow specs. Less EQ is Best EQ and the subtle little things you can do to affect it are definately worth it. I would say these subtle things are alot more critical and in the long run you might be satisfied as to the results you spectrum analyzer gives you. There is nothing more satisfying than putting in 8 hours aiming horns, A-chaining, B-chaining, adjusting lamphouses etc per screen when that reel of "WOW" comes on the screen!!! RORY

Posted by Brad Miller (Member # 2) on 06-21-2001, 03:17 PM:

Rory, I absolutely agree with speaker aiming, but this is not a realistic possiblity in many situations. (Such as old UA THX installations that requires moving the screen out and cutting through 1 inch thick wooden boards that are bolted in the cement walls only to climb back into a tiny little box that hangs outside the theater wall!!!

)

When I say that I play familiar source material, I have a small collection of rejected reels of film that were never picked up by the depot for whatever reason. After a random reel sits in the booth for 6 months, I will go back into a known good sounding auditorium and play it to decide if I want to claim it to my collection. Most of them I reject, but some of them I end up keeping. One of these days, I am going to sit down and edit 5 minutes here and 2 minutes there and assemble a compilation reel for tuning. (Fortunately, all of these reels have all digital formats on them.)

One of the best reels I have come across was from Detroit Rock City. While the movie only ran for 2 weeks in theaters, it actually has a very good track to check EQ by. There are bits in there that are supposed to be just a touch harsh (loud electric guitar music), others that should not be, variations in bass that are directed only through stage speakers and others that only come through the subwoofer (which both should appear at the same intensity) as well as good use of the surrounds and their levels in respect to the stage channels. After playing this reel in several theaters that have always had excellent sound, I made mental notes of which parts should be reproduced which ways and can now play that reel in an auditorium and tell if the subwoofer is too low, too high, if the surrounds are at a correct level and if there is a peak in their EQ as well as the overall stage channel's EQ settings. This film won't sound really smooth if the system is lacking and frequently will sound harsh in many auditoriums that are over-EQ'd or do not have the correct treble rolloff. If you are particularly proud of a certain installation, contact New Line and see if they will loan you a print to play (or get a dts timecode generator and a set of discs). If you agree that the film mix is fantastic (which on a good installation should), then go play that film in a theater that doesn't sound all that great, but sounds good and you will be shocked at how bad it sounds. I try and find films like this, that basically require a perfectly tuned theater to sound great. Does that make any sense, or am I not explaining my reasoning well enough?

As to the final "by ear" EQing, frequently an adjustment of only one little "bump" on the course treble pot a cat64 EQ card will make WORLDS of difference! The test reels which I was playing at 6 or 6.5 on the fader always end up playing at 7 perfectly after even just a tiny adjustment like that. This is why I still maintain that the final rolloff must be carefully tweeked by ear to achieve this.

Posted by Gordon McLeod (Member # 33) on 06-21-2001, 03:56 PM:

As Rory mentioned there are too many variables for that too work In fact the most important I get off the plane and for several days my ears are popping what then.
The Smpte standard is pretty clear as to the amount of rolloff vs room volume.
I can only remember 2 complaints after finish in 22 years.
The key is know your instrumentation and it usually doesn't let you down

Posted by Brad Miller (Member # 2) on 06-21-2001, 04:09 PM:

Gord, Well I've seen many a tech EQ a theater and leave without ever bothering to listen to their work and thus far they have a 100% success ratio of having poor sound IMHO. I know I am not alone on this, but I think generally people are tired of debating the point, just as I am. I give you the benefit of the doubt that you are either the exception to the rule, or you are not as picky about sound. However, I still have a very hard time believing that after you perform an EQ that the auditorium is "perfect" every time, R2 or not. Perhaps THX needs to implement a "ground time" rule for techs to stay on the surface of the earth for X number of days before they are allowed to touch their systems. I hardly ever fly, so this really isn't an issue with me.

Sound is all subjective anyway. <yawn>

Posted by Rory Burke (Member # 512) on 06-21-2001, 08:17 PM:

Ground time? With 3000 + screens world wide not to include studios and the now PM3 rooms.....impossible!!!!! Didn't someone mention in past posts how some theaters havn't even been recertified once since initial certification? Im afraid its too much to ask. at the end of the day no matter what you do with your sound in your theater....the volume still goes down down down. HF roll-off or not....EQed by ear<<ill call it "Brad's pink HF curve coeficient">> or not.......someone is always going to complain its too loud and the fader is going to move despite the best of the best of our efforts!!!!! Rory!!!

Posted by Brad Miller (Member # 2) on 06-21-2001, 08:53 PM:

That whole ground time thing was a joke Rory. I'm surprised you took me seriously on that, for I thought the mere mention of such a thing was ridiculous enough that a

was not necessary. Regardless, faders run at 7 without complaints if the HF rolloff is set carefully. Sorry your experiences have not been that way.

By the way, what's up with all of the exclamation points!!!!!!?

Posted by Rory Burke (Member # 512) on 06-21-2001, 10:42 PM:

Hey Brad!

I knew you were joking....I said it in a serious tone but as a joke as well....no worries from here!!!!!

You must tell me where you theater is located so that I may come by and visit you in person. Sounds like you run a tight ship where ever you are. Do tell!!!!

As for me punctuation.....I always say you can never enunciate enough!!!! hehe

Rory

Posted by Brad Miller (Member # 2) on 06-21-2001, 10:49 PM:

I do engineering for independent theaters around north Texas. Bring your equipment and we can play in the new screening room I am building.

Posted by Mark Gulbrandsen (Member # 72) on 06-21-2001, 11:19 PM:

Brad,
I have owned no less than 8 different analyzers. I still have 4 of them. I am sort of a test equipment junkie, thats for sure. Do I have sex with them?.....well, thats a kinda personal question that I won't delve into right now but all I can say is that the other 4 analyzers that I used to own definately caused me some pain at one time or another so thats why I divorced them. The R-2 is the one that has given me the best results, and the best repeatable results. And more importantly the most satisfaction for my customers. There are many things about the R-2 that I hate but if I couldn't have one or at least the use of one I would not tune any B chains at all. In my experience with it on all types of systems including HPS it is the only analyzer that one can tune a room with and rely on the results, and not have to go back and tweek. Brad, next time you are in the area have a listen to some of the systems I have installed and let me know what you think. I would be surprised if you said you wanted to tweek them.
John,
Indeed panio tuners do voice a paino after tuning it with a meter but on most occasions it is voiced for a certain performer or for that performer to play a certain type of music. It is also coloring the instrument, which sometimes certain types of music calls for but it is the same as if one made adjustments after setting a B chain with and relying on just the analyzers results. Weather its a paino, speaker, or some other thing with adjustments any deviation from the reference is just someones opinion or desire. With a B chain you have to have it go down center of the lane as you will be reproducing all types of music, among other things, and thats what the R2 allows one to acheive. Personally Id rather drive down the center of the lane than deviate from that and perhaps have a serious problem at some point. Frankly, coloring, or tweeking a B chain for one thing may lead to poor sound for another type of playback material.
Mark @ GTS

Posted by Randy Stankey (Member # 64) on 06-21-2001, 11:28 PM:

Well, the way I see it, doing any kind of test/adjustment involves the use of test materials that put signals of known origin through the system and then adjusting to that standard. I look at it from the point of view that no test signal is the same as a real-world signal, therefore any work you do needs to be checked against real world conditions.

Therefore, anybody who does an EQ job and doesn't at least go down to the auditorium and listen to the results isn't doing his job. Maybe, just maybe, the results will be just fine. Then again, maybe they won't be. There is one sure way to tell... go check.

I worked on a stage for a couple of years and have seen piano tuners at work. The good ones (who will earn repeat business) will always go find the person who is going to play the instrument (or his representative) and have them play a few notes on it before he packs up and leaves. If there are any requests for "final adjustments" they are done right then, before all the equipment is packed up. The same goes for sound systems. It's just the "right" way to do business.

Posted by Mark Gulbrandsen (Member # 72) on 06-22-2001, 11:45 AM:

Of course you go have a listen! Dah.....
The only thing I can relate is that when using the R2 I have not heard anything that I didn't like when listening afterwords.
I can relate though that on at least several dozen instances of setting up room eq for location dailies screenings and the sound mixers have intentionally had me eq it to the ISO curve for them and leave it as-is. I alwaws have them present though when doing it and they have as of yet to monkey with the final results after listening.
Mark @ GTS

Posted by John Pytlak (Member # 331) on 06-22-2001, 12:34 PM:

Regarding the "near field" vs. "far field" effect, has anyone ever tried and published results of different mike placements to EQ the auditorium? In particular, has anyone ever tried directional mikes or mikes mounted in a "dummy" head to simulate the ear placement, directionality, and head density of a real person?

Posted by Brad Miller (Member # 2) on 06-22-2001, 01:09 PM:

I for one would like to see someone take a multiplexer and equalize an auditorium and get a "screen shot" of the RTA. Then utilizing one single mic, move it around the auditorium and take pictures of the RTA in a dozen different locations, including the front row and the back row. I have a feeling the results would be worse than expected.

Has anyone done this?

Posted by Rory Burke (Member # 512) on 06-22-2001, 02:30 PM:

John P!

I believe that THX has also addressed your very question. They have been certifying PM3 rooms for over a year now. They are your smaller post monitoring mixing rooms typically used in broadcast, telecine etc etc. Maybe someone with the powers to be can answer your question as to how they have addressed the near field environments and as to how to proceed with EQ. AT some point I would assume that the ISO curve no longer applies when room volume levels get too small. Would be good to know!!

As far as Eqing a room and moving the mics and comparing the results.. I believe the R2 software already offers features for such A-B testing and comparison. Gordon might know better I'm sure!!! Again moving mics around wouldn't show me anything other than how fragile EQing a room and how really subjective the process really is ultimately. Think about it...with out moving mics even the test can be performed. Take measurements diring the coldest time of the day and compare them with measurements from the hottest part of the day. Try the same comparison with different humidity extremes as well. I wouldnt be surprised if differences in altitide also affect mic readings so long as you can have a mile high elevator/studio to do the test in.
Rory!!

Posted by Gordon McLeod (Member # 33) on 06-22-2001, 05:29 PM:

With the R2 comparrisons are easy asyou can do comparison file between any to rta files
I find humidity makes the biggest difference. Manly because Condensor mics are humidity sensitive and the room will absorb diffently as the fabrics absorb moisture
That is one reason I don't worry as much about the eqing of a room for opening night of a complex as the room will radically change as the drywall and tuff dry out over the first two weeks
I usually put it in the ball park and then come back a few weeks later when things have stbalised
Also the only film I run when it is done is Jiffy

Posted by Francis Casey (Member # 514) on 06-22-2001, 09:39 PM:

Gordon
Who did you get your R2 calibrator adapter from at THX ? I have enquired about this a couple of times over the past year but have not heard back from them yet. How much did you pay for it and is there a part number for it ?
thanks
Francis

Posted by Mark Gulbrandsen (Member # 72) on 06-23-2001, 09:17 AM:

Brad,
I have made those comparisons quite a few years ago. I didn't record the findings and can't quite remember what they were but they were so far different that I sent my PC-40 back to Ivie to make sure that it was working correctly. On the ivie there was a consistant midrange hump or dip or something like that..and I talked to Ivie about it and their engineer said that it was not really taking the whole room into account like it would if it were fed from a multiplexer. He also said that Ivie ahd planned to build a multiplexer but never got around to it then the R2 was introduced and they shelved the idea. The Ivie engineer did not reccommend me EQ'ing a cinema with just one mic and that if I had to to use the record/averaging feature of the PC-40 analyzer and walk it while recording to do so. I tried that with much better results but still not nearly as good as a 4 mic setup.
I'm in the middle of doing a 5 plex right now and I'll record the screens of the analyzers and e-mail them to you if we have the time for this. I also feel that the EQ'ing of the HPS systems with the R2 sounded better due to the room being more factored into the readings. There was none of the "horn"type sound on dialog or in the midrange after R-2'ing them that I always disliked about them.
Mark @ GTS