Film-Tech Forum ARCHIVE: 'Cloverfield' may have killed the subwoofer

my profile | my password | search | faq & rules | forum home

»	Film-Tech Forum ARCHIVE » Operations » Film Handlers' Forum » 'Cloverfield' may have killed the subwoofer (Page 1)

This topic comprises 4 pages: 1 2 3 4

Author

Topic: 'Cloverfield' may have killed the subwoofer

Ross Oba
Expert Film Handler

Posts: 181
From: Kailua Kona, HI
Registered: Oct 2005

posted 01-19-2008 03:19 AM

I was finishing up my shift and decided to check out the beginning of our last showing of 'Cloverfield.' I had already screened it the night before. And the noises in the beginning (you know what I mean if you saw it) sounded flat and not boom-ey. It is in one of our two largest auditoriums. The volume was set to 5.2. Normally we run at 5.0 but I wasn't thinking that this would be excessively loud.

The subwoofer is JBL if I'm not mistaken. Not sure which model/type.

Anyone else have had any problems? I'll have to check tomorrow to make sure it wasn't just my imagination.

| IP: Logged

John Walsh
Film God

Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999

posted 01-19-2008 04:01 AM

Sure, subs can blow. But it was probably not the soundtrack that killed it; it was just a random thing. If the amps are properly sized to the subs, a film's soundtrack shouldn't be able to cause damage. Be glad it's a sub, not a HF driver, which is usually (though not always) harder to get at!

| IP: Logged

Peter David Bruce
Expert Film Handler

Posts: 187
From: East Anglia -England
Registered: Aug 2007

posted 01-19-2008 05:03 AM

just be hopeful you havent had some kid come and put their foot thru your sub.

believe me, it happens!

we are showing avp requiem now in the UK and the bass is rather extreme in the opening sequence... our subs seem fine... infact the bass is collossal. im really proud of our setup its coping so well.

i hope your subs are okay Ross, and please let us know whats happened.

| IP: Logged

Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 01-19-2008 08:45 AM

It would be smart to check to be sure nobody has been tinkering with the sound system.

I got a call to one theater because the sound was "bad".
(No information on what "bad" meant. Just that it "didn't sound right.")

I get there to find that somebody had tinkered with the electronic crossovers and reprogrammed them to send the same signal to ALL the speakers. Then, as if that wasn't enough, they decided that they needed to have a "midnight screening" of The Fast and the Furious with the master fader set on "11".

They blew out all three HF drivers and two of the mids.

quote: "John Walsh"

Be glad it's a sub, not a HF driver, which is usually (though not always) harder to get at!

Anybody seen the late 1990's vintage Cinemark "All-Stadium" theaters with the "Ultra-Super-Mega" sound systems?
(Orlando Florida. Military Circle @ Norfolk Virginia. Etc.)

In order to fix the speakers you have to climb up to a skinny, little platform made out of expanded steel grid that's only about 3 feet wide and stand up on your tippy-toes to reach the top driver... About 20 feet in the air!

Moral of the story: Double check to be sure nobody has been tinkering. Yes, sometimes subs do blow out but it pays to check.

If somebody has messed with the system they'll only blow out again if you don't solve the problem that caused it in the first place. (i.e. You throw good money after bad.)

| IP: Logged

Brad Miller
Administrator

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

posted 01-19-2008 09:15 AM

Well, assuming your grammar is correct...

quote: Ross Oba
It is in one of our two largest auditoriums.

and

quote: Ross Oba
The subwoofer is JBL if I'm not mistaken.

There's your problem. ONE subwoofer for your large auditorium??? Your designer or possibly someone who interfered with the proper spec'ing of your auditorium should be held responsible.

The fact you run most of your movies at 5 yet again shows improper setup.

| IP: Logged

Ron Funderburg
Jedi Master Film Handler

Posts: 814
From: Chickasha, Oklahoma, USA
Registered: Nov 2007

posted 01-19-2008 10:16 AM

Brad, wouldn't 5.0 being loud enough or not loud enough be determined by the size of the auditorium? I can't run my theaters at 7.0 because it is just to loud in our theaters. But we only have 130 seat theaters. Now if the large auditorium is say 500 or more the 5.0 can't be right it just wouldn't have the boom for it, unless it set way to high to start with.

With all that said we run our theaters at 6.0 so 5 does sound a might week to me!

No sub wolfer or week sub wolfer doesn't mean, necessarily, that the sub is blown you could have lose wires, some one could have turned the gain off on the amp (or worse in the processor or decoder).

But you do need to find out of if set up is right or has been fooled with before the speaker is replaced if it is bad!

| IP: Logged

Jack Ondracek
Film God

Posts: 2348
From: Port Orchard, WA, USA
Registered: Oct 2002

posted 01-19-2008 11:45 AM

quote: Ron Funderburg
wouldn't 5.0 being loud enough or not loud enough be determined by the size of the auditorium? I can't run my theaters at 7.0 because it is just to loud in our theaters.

Nope. Brad's absolutely right on this. Theatre sound systems have the internal means to calibrate level and equalization to a standard setting. You should be able to run a print in several screens and have equalization close, and level VERY close to being the same.

The comment about only one sub also makes sense. Sounds like you need a qualified service check (at least).

BTW, there are VERY long threads in here that cover both topics well.

| IP: Logged

Ron Funderburg
Jedi Master Film Handler

Posts: 814
From: Chickasha, Oklahoma, USA
Registered: Nov 2007

posted 01-19-2008 12:50 PM

If you set each theater to the standard at 7.0 and 84DB it is louder to the ear in smaller theaters than in larger theaters no matter that they are set the same. The standard was set 30 years ago for 1000 seat auditoriums with 700 people in them. So 7.0 is softer in the 1000 seat theater than in the 100 seat theater!

Not trying to be argumentative here but the standard is really to loud in smaller theaters and just fine in larger! The standard is more to insure each speaker is at the same volume output than the general level of sound in the theater. Equalization on the other hand is to insure that each frequency is the same level as the others with a roll off on the high end!

| IP: Logged

James Westbrook
Phenomenal Film Handler

Posts: 1133
From: Lubbock, Texas, Usa
Registered: Mar 2006

posted 01-19-2008 02:19 PM

Someone could have swiped the horn out of the sub. We have had that happen a few times. I suspect they ended up in the trunks of kids with the "booming" car stereos.

| IP: Logged

Cameron Glendinning
Jedi Master Film Handler

Posts: 845
From: West Ryde, Sydney, NSW Australia
Registered: Dec 2005

posted 01-19-2008 02:20 PM

quote: Ron Funderburg
If you set each theater to the standard at 7.0 and 84DB it is louder to the ear in smaller theaters than in larger theaters no matter that they are set the same.

| IP: Logged

Brad Miller
Administrator

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

posted 01-19-2008 02:35 PM

Ron is absolutely incorrect. I can interlock a movie between a very large auditorium with an 80+ screen and walk across the hall to one with a 20-something foot screen and the apparent volume to the ears sounds the same, and both play perfectly fine at 7 on the fader...provided the systems were set up properly in the first place (which most cinema sound systems aren't).

Ron's problem is that most often in multiplexes I see the smaller theaters "cheapen out" on the quality of the gear, ending up with harsh-sounding rooms (which is often considered "louder" by many). I also see those small auditoriums tend to get rushed with a "good enough" attitude during the installation and calibration. Remember too that the rolloff has to be altered slightly depending on the size of the room.

There is far more to a sound system than just setting a level.

| IP: Logged

Mike Blakesley
Film God

Posts: 12767
From: Forsyth, Montana
Registered: Jun 99

posted 01-19-2008 04:24 PM

Some people are going to think 7 is too loud no matter how good it sounds. I don't mind listening to movies at 7 in our theatre but my wife thinks that's too loud.

quote: Ron Funderburg
No sub wolfer or week sub wolfer

But is it "nosy?"

| IP: Logged

Mike Olpin
Chop Chop!

Posts: 1852
From: Dallas, TX
Registered: Jan 2002

posted 01-19-2008 05:18 PM

quote: Ron Funderburg
If you set each theater to the standard at 7.0 and 84DB it is louder to the ear in smaller theaters than in larger theaters no matter that they are set the same.

A decibel(dB) is a measurement of sound pressure. 84dB is the same volume no mater what the size of the room.

Now to clear things up, this measurement isn't made by measuring the sound right in front of the speaker, but rather the sound from the seating area of the listener. Dolby Reference Level 7.0 should reproduce the same sound pressure level to a listener seated regardless of auditorium size.

7.0 should be comfortable for most listeners, although you will always have complaints about the volume, because different people have different listening preferences.

| IP: Logged

Marco Giustini
Film God

Posts: 2713
From: Reading, UK
Registered: Nov 2007

posted 01-19-2008 05:51 PM

Sounds like people that thinks that with room full of audience, the temperature has to be kept lower; room with few customers, the temperature has to be kept higher!!! 20°C is 20°C, regardless the number of patrons!

As Mike.O pointed, 84dB (BTW the standard says 85!) is 84dB regardless the size of the auditorium

quote:
Not trying to be argumentative here but the standard is really to loud in smaller theaters and just fine in larger! The standard is more to insure each speaker is at the same volume output than the general level of sound in the theater. Equalization on the other hand is to insure that each frequency is the same level as the others with a roll off on the high end!

No, the tech that was setting up the rooms had no idea of what he was doing.
A correctly equalized screen is confortable at 7.0 (or around 7.0) and there will be NO difference in fader settings between a 1000 seats screen and a 100 seats screen.
This assuming that the sound system is correctly dimensioned and the acoustic treatment well done.
Ciao

Marco

| IP: Logged

Ross Oba
Expert Film Handler

Posts: 181
From: Kailua Kona, HI
Registered: Oct 2005

posted 01-19-2008 05:51 PM

I went back today to check it out and it looks like it was blown. But now I am wondering if it may have been punched out by someone because I have never seen a blown subwoofer before. The way it looked was it was torn on the left edges and then there was another hole towards the center of it. Pardon my lack of technical words. If it was blown, would it be blown outward and not just torn and oriented inward?

| IP: Logged

All times are Central (GMT -6:00)

This topic comprises 4 pages: 1 2 3 4

Printer-friendly view of this topic

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.