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Author Topic: Do high-frequency speakers deteriorate over time? Or is it just my ears? Mike Blakesley Film God Posts: 12767 From: Forsyth, Montana Registered: Jun 99 posted 03-21-2012 08:50 PM                        This is a sound question, but we have digital equipment so I guess it should go in this forum. (Maybe we need a sound forum?) Anyway. Lately I have noticed that our sound seems to be kind of muddy, and the sibilant sounds aren't as strong as I think they should be sometimes. I notice this especially in action scenes. It makes the dialogue harder to understand. I also notice it in music segments...there doesn't seem to be enough treble. When we've played movies with lots of British accented actors (Harry Potter, for example) I've had a couple of comments from people saying they had a hard time understanding the dialogue. I attributed it to the accents or maybe a lousy sound mix, but...now I'm not so sure. We have Peavey 2-way speakers for our main stage speakers -- they each have two, 15" woofers and a horn mid/tweeter. We have two Peavey 18" subs. We do not have a baffle wall yet (although it's on my to-do list). For amps, we have (4) QSC DCA1622s, and one QSC DCA3422. The 3422 runs the subs. Our surround speakers aren't really the issue here of course, but just in the interest of completeness we have (10) EV 2-way speakers, don't know the model number but they have an 8" woofer and a 2" dome tweeter. In the balcony we have (2) JBL speakers which are slightly smaller (6" woofer). Our processor is a Dolby CP650. And, our sound gets EQd every 6 months or so, so I don't think it's an alignment issue but maybe that's it too. Last year we had a nice visit with the QSC guy at CinemaCon and almost went to 3-ways right then, but then I remembered I don't like to "impulse buy." So here we are. Any ideas, thoughts or suggestions (if we need to upgrade something) would be appreciated.  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 03-21-2012 09:19 PM                     Mike: It is possible for HF drivers to deteriorate over time...usually by the metal diaphragm shattering or flaking apart. The Peavey stage speakers suck in general...if you go to QSC's with the proper crossovers (or use a DCM monitor) you and your customers will be amazed at the difference in the sound quality. Getting the QSC's would be a very wise expenditure. If your budget won't let you replace the surrounds, leave them alone for now. The Peavey subs are ok, but again if you can, replace them with QSC. Keep us posted on this..  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 03-22-2012 01:05 AM                       Even used JBL 4675 or similar are much better choices that Peavey for this application. I would bi-amp for sure.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 03-22-2012 02:27 AM                     I've replaced quite a few HF diaphrams-hair line cracks at the edge of the fold can easily develop. HF diaphrams have the thickness of very thin alum foil where all the flexing they have to go through, they can split and go raspy.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 03-22-2012 06:45 AM                        I would leave the surrounds and subs alone; they are OK enough and you won't hear much change. That said, I agree with Sam that good used JBLs (or new QSCs) are what the doctor ordered. Only the 3 stage speakers. Louis  |  IP: Logged David Buckley Jedi Master Film Handler Posts: 525 From: Oxford, N. Canterbury, New Zealand Registered: Aug 2004 posted 03-22-2012 07:43 PM                        Horns tend to fail much more than they degrade, and when they do degrade, they generally do so making the sound not quieter but just uglier. A Peavey 2x15 plus little horn isn't really the right tool for this sort of job. Fifteens aren't real good with voice ever, but for many purposes are an tolerable compromise. These are bar band territory. So you either need to spring for "genuine" cinema speakers, or much higher quality sound reinforcement speakers. Cinema main speakers are only able to get away with fifteen inch drivers because of the qualities of the cinema horn, which is a very different animal to a bar band speaker horn.  |  IP: Logged Mike Blakesley Film God Posts: 12767 From: Forsyth, Montana Registered: Jun 99 posted 03-23-2012 11:00 AM                        quote: So you either need to spring for "genuine" cinema speakers, Well, these are "genuine" cinema speakers, or at least they were purported to be when we bought them in the late '80s. The horns aren't "little," they are almost as wide as the main cabinets (they sit on top of them). At the time, we had 3 choices of systems and opted to go with the middle one due to the cost. The top system had JBL speakers if I remember correctly. The middle system had the same electronics, but substituted the Peavey speakers. The lowest priced system was only a center-surround setup. Glad I was smart enough not to go that route at least.  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 03-23-2012 12:05 PM                       I'm assuming you have the dual woofer boxes. If so, you could maybe save the bass cabinets and speakers and go with JBL or EV drivers and horns, either long or short as space behind the screen permits. You could then Bi-amp if it's not already done. Sound will get much better.  |  IP: Logged David Buckley Jedi Master Film Handler Posts: 525 From: Oxford, N. Canterbury, New Zealand Registered: Aug 2004 posted 03-23-2012 02:37 PM                        quote: Mike Blakesley Well, these are "genuine" cinema speakers, or at least they were purported to be when we bought them in the late '80s. The horns aren't "little," they are almost as wide as the main cabinets (they sit on top of them). Time for me to eat some humble pie; that description does indeed sound a long way from bar band boxes. I wasn't even aware that Peavey Archetectural did cinema stuff, but yes, they did, and still do, and some of it has the THX stamp of approval. But having said that, even their current THX approved horn only goes down to 400Hz which (in my opinion) isn't low enough by most of an octave. They also have a 16 inch wide horn that would certainly look the part, but it only goes to 800Hz, nearly two octaves short, and that is almost in bar band territory. That horn is not THX approved! Although Peavey is a brand that has always concentrated on value, their kit always worked and did what it said on the can. Thus I have no idea why your intelligability has gone. But rather than guess, one could measure. The best diagnostic tool I know of for dicovering sound problems is Smaart and its transfer function analysis. If you have or can acquire a reasonable mic and and a USB mic preamp then you can download it on a 30 day trial, and have a play, but it may be quicker, cheaper, easier and get a better result to find someone who has the tools and has done the training (Smaart is a dumb tool; it is the operator that makes sense of it) and have them come and evaluate the system. If you get stuck in cinema world try your local sound providers, anyone with a decent size ad in the yellow pages probably has Smaart. Biamping as noted can make a difference, simply because an electronic crossiver is much easier to adjust than the passive thing in the back of a speaker box, enabling a much better mact of signal to the driver elements, and also modern DSP based corssovers allow time alighnment. But... if the system used to sound acceptable, then it shouldn't need biamping ito restore it to where it was.  |  IP: Logged Mike Blakesley Film God Posts: 12767 From: Forsyth, Montana Registered: Jun 99 posted 03-23-2012 03:43 PM                        quote: David Buckley Thus I have no idea why your intelligability has gone. It's not exactly GONE, it's just less than I feel like it should be. We watched "The Lorax" last night and had no problems hearing everything. But, even so the sound just didn't sound as "crisp" as it should, to me at least. We are already bi-amped.  |  IP: Logged David Buckley Jedi Master Film Handler Posts: 525 From: Oxford, N. Canterbury, New Zealand Registered: Aug 2004 posted 03-23-2012 05:05 PM                        quote: Mike Blakesley We are already bi-amped That changes things quite a bit; there are a lot more elements in the path, and thge chances of it being a horn problem are diminishing.  |  IP: Logged Victor Liorentas Jedi Master Film Handler Posts: 800 From: london ontario canada Registered: May 2009 posted 03-23-2012 06:49 PM                     Mike,I would try ordering a new tweeter diaphragm.I bet it will get you back to that like new crispness and at least it rules that out. I have used some of the more expensive sound re-enforcement speakers from Peavey and they may not be the best but not crap either.  |  IP: Logged Darryl Spicer Film God Posts: 3250 From: Lexington, KY, USA Registered: Dec 2000 posted 03-24-2012 03:33 PM                    Have your tech come in and check your B chain. High frequency problems will show up if there are problems with the horns. The EQ may be off a bit or something changed about it. I would do this before investing money into new equipment or replacing parts.  |  IP: Logged Dominic Espinosa Phenomenal Film Handler Posts: 1172 From: California, U.S.A. Registered: Jan 2004 posted 03-24-2012 04:28 PM                     Depending on the degree of degredation it could even been dust plugging up the holes in your screen or clogging the end of the driver assy. Agree with Daryl on checking your B-Chain. If it is a natural decline due to environmental issues he may be able to eq it out.  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 03-24-2012 05:49 PM                       I would substitute the hf driver from the left or right channel to the center channels as this is where most of the dialog comes from and our ears are most sensitive to distortion from human voices. See if that does the trick. If not, change the amp from the left or right and then the crossover if all three are the same type. If you do get a tech out, have them use an audio sweep generator to check for crackling, rattling, etc. FWIW, all the eq. and pink noise in the world will never find a distortion source, it has to be done with audio tones.  |  IP: Logged

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