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

» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » Baffle Walls - Need them or Not? (Page 2)

This topic comprises 2 pages: 1  2

Author Topic: Baffle Walls - Need them or Not? Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-24-2003 06:56 PM                     Bill, There are baffeletts available for many of the JBL speakers. You could also fabricate yourself them on-site as well. Use the same duct liner THX uses and make them extremely rigid. I've used layers of Drywall in past projects same as in the full scale baffle wall. The stuff is extremely dead. My condolences on being stuck with the screen dissaray speakers. JBL makes much finer products than those!! Mark  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 03-25-2003 12:03 AM                     RE: 3632...Consider the 4675C or the 4670D (2-ways) or if you insist on a 3-way...the JBL 5000 series is out there. Remember this...a good 2-way beats the heck out of a middle-of-the-road 3-way. If you aren't willing to spend $3000 or more a speaker on the 3-way, you should probably consider 2-way speakers. Now whereas you got the SST modules...you will have ALOT of work ahead of you. The SST is a basic 3-way crossover to be used in the Crown CE or CL series of amplifiers. My most successful 4632T (or 3632s for that matter) have been with DSP based crossovers (RANE RPM 26V). Being able to apply appropriate parametric EQ, and custom crossover points and such minimized phase anomolies. I don't think you can tune a 4632T with 1/3-octave EQ and not introduce substantial time-domain errors. The midrange horn is the trickiest part of it. Good luck and listen often as you attempt to tune them. Steve  |  IP: Logged William Bunch Film Handler Posts: 87 From: Misawa, Japan Registered: Nov 2001 posted 03-25-2003 03:55 AM                        Egads and Ommigosh! Please don't tell my bosses. Steve, I greatly value your opinions on this forum. But now I wonder what sort of monster I've moved in with. It is like a bad dream. If this system is so terrible why would they still make it push it on the market? I'm sure your opinions are based on solid experience. Well, there will be no turning back now. Just gotta dive in and make it work somehow. I do have experts in Tokyo that I can call in if the going gets tough. But they are partial to EAW systems. I did get the proper amps to go with the crossovers. This thread is supposed to stay on the topic of baffle walls so I will now go elsewhere to study up three way speaker systems now.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 03-25-2003 07:14 AM                     Who said anything about being terrible? If you read around the threads you will find that speakers/sound is VERY subjective. What I personally may like has nothing to do with what is best, persay. I've tried to keep my comments relating to the factual aspect of my experience with the speakers. That is, be very careful how you tune the mid-range section and give yourself listening tests to see how well you can make the analyzer and your ears agree. When I'm done with them, the customer has always been pleased. I've tuned them with all analog crossovers and digital crossovers without nar a complaint from the customer (after hearing them...he bought three more theatres worth of them). Another nice aspect of the digital crossovers is that now that I have sussed out the speaker...I can download my settings on any future installations and generally, without ANY 1/3-octave EQ...I'm already at the X-Curve. If you read JBL's spec sheets, you will find that they base their frequency response of the 4632T on using their DSC-260 digital crossover. However, given a choice, I'll take the JBL 4675 over it every day of the week. To my ears, it is superior sounding and MUCH easier to tune. So, wipe the sweat off your brow, go in with an open mind and take it slow and easy and let us know how you made out...preferrably with baffle walls! Steve  |  IP: Logged William Bunch Film Handler Posts: 87 From: Misawa, Japan Registered: Nov 2001 posted 03-25-2003 04:03 PM                        Thanks Steve, I feel better now. I just finished opening a new restaurant and am now working on a retail store renovation. Hope to take some time off on vacation before I start in on the theater project so it may be a while yet. Your points are well taken. Thanks to everybody here for their input. I'll report back later when the smoke clears.  |  IP: Logged William Bunch Film Handler Posts: 87 From: Misawa, Japan Registered: Nov 2001 posted 03-25-2003 10:48 PM                        Here is a picture of the 1954 Jim Lansing/Ampex model 5050. Mark, I'm assuming when you speak of "bafflettes" it would be something like this? The Army and Air Force still have some these speakers in operation. So simple they work.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-25-2003 11:06 PM                     Yea Jim, That sort of thing will work fine. Just extend these up to and above the HF horn. Cover it all with appropriate black duct liner of the type THX reccommends. Going above the hhf horn helps to reduce reflections that come back off the screen and improves MF, and hf clarity alot. Use 5/8" drywall, in layers, its cheap. No less than 2 layers and preferably three. I don't think I'd use plywood as they did back then, or HD particle board either. those are not dense enough. I've seen em made form all sound panel material, but I thought they were too absorbative, and too much loss of hf..... Sorry...I can't remember the liner number off the top of my head......anyone else here remember?? Mark  |  IP: Logged William Bunch Film Handler Posts: 87 From: Misawa, Japan Registered: Nov 2001 posted 03-25-2003 11:31 PM                        I finally got hold of some decent construction plans for a full wall. I will breeze by my contractors with it to see what is feasable. Much rather have the full deal if possible. There is no such thing as 5/8" gypsum board in Japan so will just need more layers of the thinner stuff I guess. Thanks, everybody. I'm learning alot in the past few days.  |  IP: Logged Rob van Ede Film Handler Posts: 25 From: Zeist, The Netherlands Registered: Sep 2002 posted 03-26-2003 03:17 AM                        Wasn't that Lansing speaker a frontloaded open baffle design? If so, the wings are for preventing dipole cancellation so there is some bass output. Antonio, a speaker radiates only from the drivers and ports, not from the cabinet walls. If mounted in a wall, there is no output behind the wall. The output can still be omnidirectional, but pressure normally lost in the space behind the driver is now reflected into the auditorium.  |  IP: Logged William Bunch Film Handler Posts: 87 From: Misawa, Japan Registered: Nov 2001 posted 03-26-2003 07:41 AM                        Rob, I have tested your theory. I have one of these very same speakers that we use for outdoor events. At first it was just the main box on wheels. Then I got smart and tried replicating the baffle wall with two large wood panels off to each side. What a HUGE increase in the lower frequencies and all directed forward. It is easy to fill a completely wide open soccer field. Lansing knew what he was doing. The waves from the back of both drivers is first combined and compressed then is bent three times in an ever widening horn like channel until it comes out the bottom. Like a folded foghorn. So what was happening without the wings was the the longer waves were exiting the throat and wrapping around the back and cancelling out. Now with the wings attached you can stand directly behind the box and "feel" very few sound waves. This box produces some VERY low frequencies effortlessly. I had to make the wings out of 2x4 with 3/4 plywood. All members glued and screwed. They attach with long 3/8" bolts with extra large washers and LOCKWASHERS. Earlier versions of attachment just rattled loose. Having learned all this before is why I came up with my original question about whether or not a baffle wall could improve auditorium projection the same as in an outdoor setting.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 03-26-2003 09:23 AM                     Properly done the baffle will improve the low frequency reproduction and the intelligability of dialogue  |  IP: Logged

All times are Central (GMT -6:00)

This topic comprises 2 pages: 1  2

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.