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Author Topic: Baffle Walls - Need them or Not? William Bunch Film Handler Posts: 87 From: Misawa, Japan Registered: Nov 2001 posted 03-23-2003 07:56 PM                        I have searched the history threads here on the subject of baffle walls and only find the term mentioned indirectly with speaker topics. My question is: Does a baffle wall offer significant improvement in sound dispersal/fidelity or is it a nice-to-have in only really LARGE auditoriums? I will be rebuilding one of our older military theaters soon. New projector, new processing, all new JBL speakers along with a new screen. Now is the chance to add any extras that can set us apart from the others. The building is constructed of all wood. Acoustics are good and the only hard surface is under the seating. There is a sloped floor (not stadium) with 500 seats. Room is a little wider than the screen is wide. Screen is on a stage made of hardwood flooring and is 16 x 35 ft. There is about 10 feet of blank space behind the screen and then a blank wall. Lots of border and bracket curtains. This room is often used for briefings and such but never for theatrical so the screen and speakers never move. I could easily afford the labor and building materials. Is this an effort worth having or not? Thanks a BuncH Bill BuncH Misawa, Japan  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 03-23-2003 08:26 PM                     The baffle wall effectively increases the radiating area of the speaker extending the lowfrequency response It also stops secondary sound reflections from the back of the screen reducing the loss of inteligablity of dialogue  |  IP: Logged William Bunch Film Handler Posts: 87 From: Misawa, Japan Registered: Nov 2001 posted 03-23-2003 08:30 PM                        I forgot to mention that my screen channels will be comprised of JBL 4632T speaker arrays. Bill BuncH Misawa, Japan  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 03-23-2003 08:31 PM                  I agree Gordon, I always push to use baffle walls in all installations. Be sure to put sound-absorbing material on the wall as well as the speaker boxes. Ummmm...Don't cover the radiators! >>> Phil  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-23-2003 11:23 PM                     Baffle walls make a huge difference, but be sure to build them to THX standards or better. Building to less than their specs may get you more bad results than more good. Stick with the reccomended baffle wall acoustic covering too. There is a big difference in available coverings there. Just because its black doesn't mean it will work appropriately. Use of good quality acoustic panels or acoustic treatment of some sort for the auditorium is also a very necessary item. The back wall is the most important and usually requires at least double the thickness, or more, of the side wall coverings...assuming you're doing an average auditorium..... Mark @ CLACO P.S. I forgot to mention that doing all of this the right way is VERY expensive....just to prepare you.....  |  IP: Logged William Bunch Film Handler Posts: 87 From: Misawa, Japan Registered: Nov 2001 posted 03-23-2003 11:52 PM                        Where would a person find a list of materials that would be considered suitable acoustical surface material for the baffle wall? If you are talking low or high density fiberglass wool then, I can get that readily here. The wall itself would not be a major cost for me but when you start talking about covering the building itself then that would be prohibitive since the building does not belong to my company. Only the projectors, screen and sound system are in my control. (It's a government/military thing) Could I build a decent wall only and reap a significant benefit? Did I forget to mention that the screen is slightly curved? That should not be a major finding, right? Thanks for your inputs! I'll digest any and all.  |  IP: Logged Antonio Marcheselli Phenomenal Film Handler Posts: 1260 From: Florence, Italy Registered: Mar 2000 posted 03-24-2003 03:45 AM                        A question about baffle: Reflections: If I have no sound wall but I put the sound treatment stuff on the back wall (that is, say, 2 meters behind the screen) shouldn't I have the same result? Bass frequencies: If I correctly understood put the, say, subwoofer against a wall increase the SPL response because since bass frequencies are omnidirectional, I take advantage of the rear emission without having them out of phase in the seating area. Right? But if I put the subwoofers on a sound wall, what is the end of the bass frequencies that come from the rear of the speakers? They're trapped in the wall-soundwall space and not useful? I'm sure that I didn't understand something! Bye Antonio  |  IP: Logged Darren Briggs Master Film Handler Posts: 371 From: York, UK Registered: Dec 2001 posted 03-24-2003 06:51 AM                        THX mentioned the introduction of a Bafflete, which just goes around the speaker array, this is a cheaper way of doing things, probably to try get the cost of installing THX cheaper?? Ill try dig out some more details on it. Darren  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 03-24-2003 08:36 AM                     The baffelet design requires a cross over that does bass management like the new THX one  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 03-24-2003 08:37 AM                     Consider using the JBL 4675C/4LF (or 8LF if want) over the 4632. To my ears, the 4675 is significantly better. If you want a 3-way, look towards the JBL 5000 series. Steve  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-24-2003 09:26 AM                     Whoa, I missed that he was going to use the Screen Dissaray speakers.......Definately go with Steve's reccomendation.....it will be ALOT better overall!! Mark  |  IP: Logged Per Hauberg Jedi Master Film Handler Posts: 883 From: Malling, Denmark Registered: Jul 2000 posted 03-24-2003 10:36 AM                        I'm about to do something to my front in Screen #1 this summer, too. For my only 88 seats, and from what i read in brochures, i believe JBL 3632T would be a top-investment, together with a baffle-wall. -Any of You familiar with this particular model ? As far as i understand, the 3632 can be ran bi as well as tri coupled. -Just how big a plus will the expense for extra amps and wiring give...? I have enjoyed those great pictures from the Film-Tech Screening room. This must be exactly to do it right, i guess - but the THX specs, Mark is mentioning -- can they be seen anywhere without being THX custumer ? -And anything else on print about the proper bafflewall installation ?? Thanks for any advise on this. Per  |  IP: Logged David Stambaugh Film God Posts: 4021 From: Eugene, Oregon Registered: Jan 2002 posted 03-24-2003 10:38 AM                        There's a formerly-THX-certified theatre here in Eugene that uses the bafflette (sp?) design. From a listener's perspective, the results seem to be very good, and low-end articulation is excellent. (Happens to be EV speakers though.)  |  IP: Logged Darren Briggs Master Film Handler Posts: 371 From: York, UK Registered: Dec 2001 posted 03-24-2003 01:00 PM                        I Can highly recomend Martin Audio systems Darren  |  IP: Logged William Bunch Film Handler Posts: 87 From: Misawa, Japan Registered: Nov 2001 posted 03-24-2003 06:23 PM                        Steve, Too late. Already locked into the JBL 4632T with SST modules. Just unloaded the truck last week. Only took ten months to get here. Guess I'll just have to make them work somehow. Anything will be an improvement over what we have existing. Does anyone remember the Jim Lansing Ampex theater speaker Model 5050? That unit used what could be called a "bafflette". It was a small 2x4 and plywood wall that surrounded the entire enclosure. This speaker system is still in use in some of our older theaters running mono. My shipping documents say they were shipped over here around 1954. This is a horn reflex type box. Many twists and turns. A small person can actually sit inside the port. But they better have hearing protection.  |  IP: Logged

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