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

» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » 3D Wheel vibration is making too much noise

Author Topic: 3D Wheel vibration is making too much noise Michael Jamieson Film Handler Posts: 6 From: Sandwick, Shetland, UK Registered: Mar 2018 posted 03-03-2018 10:29 AM                     Hiya, our setup contains a MasterImage 3D system, with a motorised rail which automatically slides the 3D wheel in front of the projector for 3D shows. The rail and wheel are mounted directly to the concrete wall in the projection room, and there's a lot of vibration noise, which manifests itself as a low frequency hum, which goes on in the background for the entire film show. Very noticeable in the cinema, especially at quiet moments in the film. My question - has anyone experienced a similar problem, and is there a way to mount the rail and wheel with something which will absorb the vibration?  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 03-03-2018 02:07 PM                     I haven't seen one mounted to a booth wall. Most MI wheel systems are movable floor units with the 2D/3D movement vertical. We have one horizontal movement one in a ceiling box, it sits on rubber pads and is pretty quiet - sitting near the box you can tell if it's running but it is not annoying. There are vibration isolators for such applications but it will be simpler and easier to make a stand that sits on the floor for the assembly to bolt to. And this probably belongs in "digital", I don't think MI made a film 3D system?  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-03-2018 10:39 PM                     Carefully check the disk, it is out of balance for some reason or other. Replace it if you can't figure it out. I've had the early disks explode and do considerable damage to the lens and booth personnel, and although the current ones don't do that it still may if it gets far enough out of balance. Mark  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 03-04-2018 07:39 AM                     Since RealD did a 'unfriendly takeover' of Masterimage, their original products and webite diappeared. Is RealD still providing replacement parts/discs for Masterimage systems? I have never seen a wallmounted spinning disc system either. Can you supply a photo? Google doesn't seem to have one. - Carsten  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-04-2018 12:02 PM                     All the Masters I installed were floor standing spinning disks. Some of the last stuff they produced like the Wave was quite good. And it did not utilize a spinning disk.  |  IP: Logged Phil Ranucci Expert Film Handler Posts: 236 From: Carpinteria,CA, United States Registered: May 2006 posted 03-05-2018 02:37 PM                     If you have a spare disc swap it out. We had one that a booth person sprayed with alcohol to clean. The glue holding the plastic layer on the disc dissolved and cause an amazing amount of noise. Anybody know if discs will be available in the future?  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 03-05-2018 03:05 PM                     I don't know the specifics but I can tell you that any rapidly spinning machine/device that was once quiet but suddenly starts to vibrate and make noise has a problem that needs to be resolved post-haste. Left unsolved, this problem will likely result in an "Unplanned Rapid Disassembly," the aftermath of which will not be pretty. Anybody in the vicinity of such an accident will get hurt by flying shrapnel. Check the disk for anything that could throw it out of perfect balance such as chips, cracks and any other damage or dirt. Check the shaft to be sure that it is straight and true. Be sure that there are no rotating parts that are touching anything else that they aren't supposed to be touching. Check bearings, motors, gears, belts or other linkages to be sure that they rotate/move freely, the way that they are supposed to and are not worn, frayed or otherwise unsound. I'm sure that you've seen enough fans, rotors, grinding disks, saw blades and other such things which have come apart while in motion and I don't think that I have to tell you that it is not pretty. You wouldn't want that system to "rapidly disassemble" on s Saturday night with a house full of customers. Would you? Please shut it down until you can get somebody to look at it.  |  IP: Logged Michael Jamieson Film Handler Posts: 6 From: Sandwick, Shetland, UK Registered: Mar 2018 posted 03-09-2018 05:50 AM                     Hi guys, thanks for the replies, I appreciate it. It hasn't just started to vibrate, it's always vibrated, since it was installed. It's had a change of disc too. It's definitely the fact it's bolted straight to the wall with no isolation. We're not really able to move it and mount it seperately, as it sits in a 300mm gap between the wall and our server racks (which we can't move). We could probably move it out from the wall by about 50mm, but I'm needing a vibration absorbing mount of some kind. Anyone seen such a thing?  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 03-09-2018 07:38 AM                     There are disc, or 'puck' type rubber shock absorbers with either threads or screws on both sides. Without having seen a picture of your installation, it's hard to judge wether they are applicable, but that would be the first that comes on my mind for this. The larger ones should be strong enough to hold an MI. Here is an example: https://goo.gl/images/B8GUk5 Google/ebay/amazon for 'rubber shock absorber' ! Using just a rubber piece with a through-screw wouldn't help much, but these absorbers have no hard connects between either sides. - Carsten  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 03-09-2018 07:48 AM                     Yes. There are thousands of different ones. Search "vibration mounts". The designs tend to get very specific - mounting angle, device weight, frequencies to be isolated, etc. But pretty much whatever you can find - any type designed for wall mount use and for the MI weight - should be OK. Here in Canada there are places like Princess Auto with an assortment to pick through. This will naturally allow more vibratory movement in the mounted MI unit - if the isolated assembly resonates at the wheel RPM frequency... it may shake itself apart.  |  IP: Logged Michael Jamieson Film Handler Posts: 6 From: Sandwick, Shetland, UK Registered: Mar 2018 posted 03-13-2018 02:52 AM                     That's excellent, thanks guys  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 03-13-2018 01:59 PM                     quote: Dave Macaulay if the isolated assembly resonates at the wheel RPM frequency... it may shake itself apart. I was just thinking about that, too. If you could create a shock mount where the machine is mounted to a metal plate or bracket which is, in turn, mounted to the wall with two sets of vibration dampeners of slightly different stiffness it might prevent that. In other words, create something like a compound pendulum that never gets into a steady state. Two problems with that idea, though: First, it would take some experimentation with different stiffnesses, etc., etc., to get something that works right. Second, we've only got about two inches of space to work in. Time to fiddle and space to play in are not luxuries we have.  |  IP: Logged Michael Jamieson Film Handler Posts: 6 From: Sandwick, Shetland, UK Registered: Mar 2018 posted 03-16-2018 08:54 AM                     Nice idea  |  IP: Logged

All times are Central (GMT -6:00)

Printer-friendly view of this topic

Hop To: Select a Forum: Category: Operations -------------------- Digital Cinema Forum Film Handlers' Forum Large Format Forum Ground Level Feature Info, Trailer Attachments & REAL Credit Offsets Category: Community -------------------- Film-Yak Film Handlers' Movie Reviews The Afterlife Bob Maar's Joke-A-Thon Category: Classified -------------------- Equipment and Supplies Wanted/For Sale Help Wanted/Seeking Employment Category: System -------------------- Software Beta Testing Forum

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.