No LFE channel audible but system passed sound test?

[Jonathan Smiles]

My local VUE's largest screen (formerly THX now Dolby Audio 7.1) has no LFE channel content audible, local staff say screen passes sound test and sounds the same as the other screens.

Super obvious that there is no low bass, only bass is with music via screen channels, the big action moments (Black Widow, Shang-Chi) have no LFE at all.
I guess it's possibly a processor glitch and the sound test plays fine or blown/turned off sub array/amplification.
One usher suggested that the subs had been turned off to stop the screen flapping, if correct could point to a blown sub array.

Shang-Chi was laughably weak sounding at times with missing LFE.

Hope everyone is doing okay and attendance is going up.

[Leo Enticknap]

A bad amplifier would be my guess, because a processor glitch would be unlikely to take out more than one channel, and a blown sub array would sound bad, not no sound at all.

I have tuned one house in which the subs at reference did indeed cause the screen to vibrate a little, which was notably visible on light shots with little or no camera movement. The subs themselves were fine. A combination of increasing the low pass a little (I think from 25Hz to 30, but I can't remember the exact figures), and riggers retensioning the screen, fixed it.

It is possible that one big amplifier (e.g. a QSC DPA4.5) is driving all the subs, and that has gone bad. Local site staff may also have decided that they were receiving far more complaints about the screen ripple than poor bass (in fact, yours may have been the first), and that switching off that amplifier was the easiest way to stop those complaints. Either way, one of the chain's techs needs to check this out; though the fix could lie more in the mounting of the sub(s) and the rigging of the screen than any tuning or calibration changes.

[Mark Gulbrandsen]

I have lost gobs of woofers where the system was never updated for digital, or had been purposely under-designed to save a few bucks.

[Armand Daiguillon]

I have 2 auditoriums where one channel just stops working.(Left rear in one, and left surround in other) If I play a sound test that isolates each channel I find that the silent channel is actually just so muffled that I cant hear it in regular shows. Turning the processor on and off fixes it every time. I find that this happens around once a month in each affected auditorium. As they said above though, a bad amp or wiring would be more likely. But when you are told that it "passed a sound test" - I would question the quality of that sound test.

[Randy Stankey]

But when you are told that it "passed a sound test" - I would question the quality of that sound test.

That's like saying, "I filled my car with gas," then wondering why it doesn't start. If you filled your car with gas last week then drove 300 miles, the tank is probably empty. No wonder it doesn't start!

When was that sound system tested? I can guarantee that all the auditoriums at the theater in Erie, PA have had their sound systems tested. I did it myself and they were all perfect...twenty years ago!

By now, if nobody else has done PMs on those systems, they'll all sound like crap but, yes! They passed a sound test!

[Leo Enticknap]

Sorry - typo - first line of my post above should read likely, not unlikely.

I suppose CP750 level drop disease might be the reason; but again, I've never seen (or more accurately, heard) that affect just the one channel.

[Carsten Kurz]

There are official test DCPs that would at least allow to check wether there is signal on the LFEs. You could take such a test DCP on a stick to the cinema. Wether they would be willing to play it, is a different question.

[Leo Enticknap]

If the theater is controlled by a locked down TMS that has playlists and schedules built from a head office 200 miles way, the site staff might not even know how to do that.

[Jonathan Smiles]

VUE UK head office customer services were not interested when contacted and just replied with a stock response about sound levels, so I don't have much confidence in the issue getting fixed anytime soon.

[Leo Enticknap]

VUE UK head office customer services likely believes that a subwoofer is a four-legged creature you take for a walk and feed Pedigree Chum to...

[Randy Stankey]

VUE UK head office customer services were not interested when contacted and just replied with a stock response about sound levels, so I don't have much confidence in the issue getting fixed anytime soon.

My response to such a stock reply would be, “I am a professional movie theater technician and I offered my comment as a professional courtesy.”

Then, depending on my mood of the day, (which can be pretty variable) I might have added something like, "I'm sorry to have wasted your valuable time."

[Jonathan Smiles]

Thank you for getting in touch with Vue...

I am terribly sorry to hear that during your most recent visit to Vue Plymouth you believe that your experience was lessened due to a suspected issue with the sound facilities.

At Vue, we always look to provide the best Big Screen Experience with the ultimate Seats, Screen and Sound. In order to achieve this we regularly check all of our facilities to ensure that these are all in working order and to standard.

Having checked with our facilities team and the venue directly, I can confirm that both the sound system is in full working order and was on the day of your visit. Therefore, I am sorry to hear that incorrect information may have been provided to you by a member of our team. I would like to further reassure you that we will bring this to the attention of the management at the venue to ensure that all team members are correctly briefed.

Again, we would like to thank you for bringing this to our attention and look forward to you returning to Vue soon.

.....
Customer Service Manager
Vue Entertainment UK & I

[Randy Stankey]

Ooh! That reply just hit a nerve!

I would have to go outside and have a cig to calm down or else I might let loose with a real "fireball" in response!

In either case, it would be a snowy day in August before I went back there!

[Jonathan Smiles]

The first reply from VUE to report of no LFE,

Thank you for contacting the Vue Customer Service.

I apologize that you were dissatisfied with the sound levels in your recent Vue experience.

Our technical team regularly test sound levels and set them within an acceptable range to comply with Health and Safety regulations. We will also adjust the volume for specific shows if we receive feedback from audience or crew.

We do set the volume during the adverts and trailers lower than the volume for the main feature, often the pre-show content may seem louder as these are mixed to mainly use the front speakers only, rather than the surround sound which may vary from advert to advert.

If you ever find the volume too loud in the future please do speak to a member of staff who can provide further assistance into resolving this issue at the time of the screening.

We do hope this has helped assist you and add clarification to your query.

Should you require any further assistance, please do not hesitate to contact us.


Kind regards,
......
Vue Customer Service Team

[Randy Stankey]

Dear Little Miss Muffet;

I have been a professional technician, employed in movie theaters and legitimate theaters for over twenty years.
I can assure you that the sound system in your venue was NOT in full working order at the time of my visit, thus the reason for my message to you.

Even though I work for one of your competitors, I offered my comments to you out of professional courtesy.
I expected you to forward my comments to one of your technicians and I would have been happy to have received a reply to the effect that you had done so.

I am not encouraged to have received such a stock reply from you.
As such, I feel confident in reporting to my superiors that we have nothing to fear with regard to the quality of our presentation in comparison to that of Vue Entertainment.

etc. etc...

And, THAT is the NICE version of my reply!