Movie Theater

CaligulaPolk

I was at movie theater several times this month, and i was wondering about their subwoofers. I do not see any sub at all, only see 4 giant **** speakers hanging on the wall. I was wondering about subwoofer, and i am curious if they conceal it somewhere under seats or do not use subs at all? I could feel movie effect with the speakers they have.

This made me wonder.... if they use subs or not...

Ron-P

Typically, most all speakers (other then surrounds) are located behind the screen, including the subs.

Jstas

Yeah, behind the screens are gigantic speaker walls not so much meant for sound stage but volume and impact. The subs are very often folded horn designs with multiple large drivers and wattage numbers that will make your head spin. The newer DTS and THX certified theaters require those kinds of systems to reach the levels that the certifications require.

Some older theaters, especially those built in the 40's and 50's actually still have Altec Lansing VOTs or old Electro-Voice systems hanging behind the screen (VOT = Voice of the Theater). I have seen some speced theaters having low frequency emitters, not necessarily subwoofers though, mounted under the stadium seating to vibrate the seats and such. A few IMAX theaters have that kind of stuff too.

Movie theater speakers are not designed necessarily for clarity but rather SPL and impact. Besides, in rooms that large, the space is so vast that clarity gets lost in the mix of reflections anyway. Much of the newer "digital" theaters use time alignment processors to alleviate the crosstalk on the channels and clean up the muddiness. This enables them to put massive amounts of power in to large drivers that are more capable of pressurizing the vast space in the room to give that impact that people expect in a theater.

If you see speakers hanging on the wall, they likely are full range and much more powerful than most stuff you would find in a home but they are not as accurate in the sound reproduction. The "digital" part of theaters nowadays has nothing to do with sonic clarity but more to do with the theaters capability of giving that big impact sound.

Theater speakers more closely resemble the gigantic public address speaker stacks you would see at a rock concert or festival rather than what you have sitting in your home.

Jstas

This is a movie speaker from Klipsch:



This is a PA speaker that I have seen in theater and concert setups from Behringer:



These are speakers from one of Electro-Voice's several lines of cinema geared speakers.

Full range cabinet


Subwoofer



And this is an example of a low frequency transducer that gets mounted to set frames or floor supports and stuff to vibrate things and "enhance" the experience.



There are other companies that make stuff like this out there. SEAS is a big supplier of public address systems as well as other places and unlikely companies lie Siemens. Well, Siemens used to be, dunno if they still do.

Here are where I found some of these speakers:

http://www.behringer.com/EN/Products/VP2520.aspx
http://www.electrovoice.com/markets/3.html
http://www.klipsch.com/products/commercial.aspx

Jstas

Just to get an idea of size, this is a Klipsch KPT-MCM-4-T Grand from their commercial theater speakers lines



Here are some specs on this beast.

* Low frequency by a KPT-MWM dual, 15-inch, high efficiency, horn-loaded woofer enclosure
* Separate, single, 12-inch, Tractrix® Horn-loaded mid-bass device
* High frequencies by the Tractrix® Horn two-inch exit titanium compression driver

KPT-MCM-4-T Grand Specifications
frequency response 40Hz-19kHz ± 3dB, -10dB @ 35Hz
delay LF- 0ms
MF- 5.0ms
HF- 4.4ms
UHF- 5.7ms
crossover slope 24dB/Octave
system components LF- KPT-MWM-LF – 400 watt/driver
MB- KPT-XII-MB – 250 watts
MF- KPT-402-MF – 50 watts
HF- KPT-GRAND-HF-T – 55 watts
power handling 1155 watts
sensitivity 108dB
crossover frequency 300Hz, 800Hz, 4kHz
coverage angle HORIZONTAL 80°± 20° 200Hz-16kHz
VERTICAL 50°± 30° 350Hz-16kHz
height 98" (249cm)
width 67.25" (170.8cm)
depth 45" (114.3cm)
weight 526 lbs. (238.7kg)


Yes. Those speakers are 8 feet tall and handle almost 1200 watts with a sensitivity rating at 108 dB. They only dig down to about 40 Hz but that's on a 3 dB slope which is due to enclosure tuning.

Then again, that's why they make beasts like this:



KPT-684 Specifications
frequency response 34Hz - 1.8kHz±4dB (-10dB @ 25Hz)
power handling 600 watts (65V) per woofer 25-250Hz
recommended amplifier power 600 watts continuous / 2400 watts peak per woofer
sensitivity 105dB @ 1 watt/1 meter
nominal impedance 8 ohms, 3.6 ohms minimum at 22Hz
max continuous output 130dB
dimensions 48.5" (123.2cm) x 24" (60.9cm) x 31" (78.7cm)
weight 190 lbs. (86.2kg)



That first speaker has a horn loaded subwoofer. The only subs I have ever seen be louder are sonotubes but sonotubes are insanely inefficient.

zombie boy 2000

Excellent posts, John. Some say my brain grew three sizes this day. Good stuff.

Airplay355

Ya know what I hate? When you go to the theater and their center channel is blown so you have to listen to farting noises throughout the movie. Happenedto me when I went to see LOTR and when I saw Terminator Salvation. Very sad:(

Face

A good HT rig should blow away most theaters.

zingo

Airplay355 wrote: »

Ya know what I hate? When you go to the theater and their center channel is blown so you have to listen to farting noises throughout the movie. Happenedto me when I went to see LOTR and when I saw Terminator Salvation. Very sad:(

Can't you complain and get a refund? I would have as the holistic theater experience was ruined.

Jstas

Face wrote: »

A good HT rig should blow away most theaters.

Depends on what you mean by "blow away".

In clarity and sonic accuracy, yes, you are right.

In sheer SPL and impact, no way.

Sherardp

Excellent posts and good read. I was considering JTR or JBL speakers for that SPL impact. I've always wondered where they kept the subwoofers also. I thought perhaps under the stage, never thought about behind the screen.

ryanjoachim

CaligulaPolk wrote: »

I was at movie theater several times this month, and i was wondering about their subwoofers. I do not see any sub at all, only see 4 giant **** speakers hanging on the wall. I was wondering about subwoofer, and i am curious if they conceal it somewhere under seats or do not use subs at all? I could feel movie effect with the speakers they have.

This made me wonder.... if they use subs or not...

I'm curious...why would yo go to a theatre anyways? Aren't you deaf? (no disrespect, i'm honestly curious)

zombie boy 2000

"Subtitles" come to mind....

muncybob

We have 2 local theaters. One (the Mall) just kills my ears in the higher frequencies. The other much more pleasing....but neither have the "impact" that my home rig provides. Both almost sound to me like they lack subwoofers? I MUCH prefer to hear movies at home....I just wish I had a big(or at least larger) screen!

CaligulaPolk

ryanjoachim wrote: »

i'm curious...why would yo go to a theatre anyways? Aren't you deaf? (no disrespect, i'm honestly curious)

oca :d

Jstas

muncybob wrote: »

We have 2 local theaters. One (the Mall) just kills my ears in the higher frequencies. The other much more pleasing....but neither have the "impact" that my home rig provides. Both almost sound to me like they lack subwoofers? I MUCH prefer to hear movies at home....I just wish I had a big(or at least larger) screen!

See, this is a single instance. Alot of things depend on the theater experience. The largest factor is how modern that theater is. If you live in a area where population density isn't really high, theaters don't draw the income that theaters in more densely populated areas do.

For example, the Atco Multiplex in NJ just closed. It was 23 screens at least. When it opened almost 20 years ago, it was state of the art and everybody wanted to go and see movies there. The biggest problem was that it was out in the middle of nowhere and people didn't want to drive a half hour to see a movie when a smaller 10 screen theater was within walking distance. So among declining attendance and lack of distributor support because they couldn't afford to upgrade any theaters to newer digital standards (they were denied releases of recent blockbusters because they had no THX certified theaters and like 4 out of 23 theaters were DTS), they closed. meanwhile, 3 of teh 10 screen theaters closer to civilization have flourished with one expanding to 16 screens and another expanding to 27 screens after the Caldor next door closed.

Older and out of date theaters tend to lack in sound because the amount of space in audio tracks even 20 years ago didn't require gigantic systems that could provide the performance that modern movies with digital, multi-channel soundtracks require. Your theater at home probably beats the public theaters because you have the facility to provide support to a full 5.1, 6.1 or maybe even a 7.1 channel soundtrack.

The DTS theaters near me, yeah, they will shake your kidneys until they turn to goo. When I went to see LOTR: The Fellowship of the Ring in the theater, the opening sequence when Sauron is cut down and the shockwave goes out across the battlefield...yeah, the frequency response was so low and loud it made me dizzy and the girl I was with at the time actually had to go to the bathroom 'cause she thought she was gonna spew. The ONLY time I have been able to reproduce sonic impact like that was with massive slot loaded subwoofer enclosures in vans for competition and we were hitting the 150-160 dB range.

Just because the theaters near you don't have the "impact" as you say doesn't mean it doesn't exist. It more likely just means that your local theaters are either lacking in the audio department or not tuned properly. If that's the case, sucks to be you, man.

I think I'm gonna head down to the theater up the street from my house and watch "Up!" tonight. My HT is nice but nothing beats goin' to the movies! Everybody can be a kid again when you get to go to the movies!

muncybob

Well, it is our local set up that sux....and sux to be me for that, but I wouldn't trade our "rural" life for a better sounding cinema.....funny you should mention UP, went to the town cinema to see it last night but walked away, was not showing in 3D. Sux to be me again in cinemas! Looks like decent cinemas and good restaurants are too much to ask for around here!

Jstas

muncybob wrote: »

Well, it is our local set up that sux....and sux to be me for that, but I wouldn't trade our "rural" life for a better sounding cinema.....funny you should mention UP, went to the town cinema to see it last night but walked away, was not showing in 3D. Sux to be me again in cinemas! Looks like decent cinemas and good restaurants are too much to ask for around here!

Open one up.

Better yet, combine the two with a restaurant and a movie theater. Put a hotel in and make it one stop shopping for date night! Low frequency vibrations could enhance the hotel room activities.