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projectors damage with massive subwoofers - Page 2

post #31 of 46
http://www.seaton-sound-forum.com/post/Art-Sonneborns-Sun-Cinema-updated!-5952583

Art
post #32 of 46
Quote:
Originally Posted by MississippiMan View Post

Jason,

I suppose my responses were due to seeing posts alluding to there being no reason or justification to expect SPLs to have any effect whatsoever on a PJ's welfare. By my reasoning, even if Lamps don't fail and parts don't shake loose, a vibrating PJ / Lens only shows a lack of foresight and planning. But I have come into such situations often enough to know they exist...and are not exceptional circumstances.

FWIW, I only posted on DIY Screens for some time because as professional A/V Design Installer w/35 years experience, it was understood back in 2002 that I could not offer advice without violating Forum Rules, in the eyes of those who felt I had ulterior motives.

A few, but not many on AVS know I cut my virtual eye teeth designing and building Mobile PAs and Stadium Audio systems since 1973. But as far as Home Audio...that only started in 1978. smile.gif A lot of the issues I mentioned can / are directly attributed to poor acoustic considerations as well as sub standard PJ mounting solutions. When I design a high db Theater, you can be sure I use robust Mounts like the Chief RPA- Dedicated units, sturdy Drop Pipe assemblies, as well as build in real acoustical support for the Audio installed....when warranted.

But absolutely, I have avoided posting in the Speakers Forum because I have seen over the years that it can be a very cantankerous forum, full of some pretty opinionated & nasty commentary and even nastier retorts. Also, for some reason, people seem to accept it, and there doesn't seem to be the level of Moderator intervention as there is elsewhere. Speakers is not by any means the only Forum that suffers, but at least over the last few years...things have gotten a little better all around because the Mods have been doing a much better job controlling the worst offenders..


I apologize for coming off in a less than courteous manner, I just find it very hard to conform to and accept "absolutes" when experience tells me differently. As someone who has had his share of bombastic attacks, I should have been even more restrained than I was trying to be.


It is obvious you do have the background for such a discussion but I don't think any of us were talking in absolutes. wink.gif

Quote:
Originally Posted by Bohanna View Post

Hey MississippiMan, Being from Mississipp My guess is that you have spoken with Hartley on several occasions. I Have traveled a parallel path as you designing and building several sound reinforcement systems one of which had MIT students scratching their heads. Its almost comical reading the opinions of people involved in Home theater sound who think they understand Pro audio and what LOUD really means! Anyone who doesn't think that a high power driver wired to a High powered amp with a high slew rate can't PULVERIZE a projector just doesn't get it!

Bohanna

Again be careful with those assumptions on what you think others understand and have personal experience with. Your mistake is thinking that the two of you are the only ones in this thread that know what 'LOUD really means'.

I DJ'd in clubs with 30,000+ watts that utilized 10+ 18" Bass bins (along with several projectors, big screen tv's, lasers, etc.) enough to rattle the teeth in your head from just about anywhere in close proximity to the building.

Also if you think that what Art has (posted above) does not exceed that single Fi 18" mentioned in the OP then you are seriously mistaken and maybe it is you that needs a real 'un-distorted' HT experience.

That said, is that not what we are talking about here... bass in a home theater. wink.gif

Jason
Edited by DaGamePimp - 7/16/13 at 5:36pm
post #33 of 46
Actually Gamepimp we WERE talking about Bass in a Home theater and the negative affect it might have on a projector That was the WHOLE POINT of the discussion. I don't believe any of us were implying that we were the only people who understood what "loud" is. What some of us were saying is that the people who don't seem to think it would have any effect on a projector don't understand what "loud" is. There is a HUGE difference.

The HT sound system with the pretty pictures looks to be quite a nice home system but its not being used to producing the kinds of High sound pressure levels described by the OP. If it were they would not have mounted the speakers behind the screen since the screen would look more like a kick drum head once the volume was turned up. What is also missing from this home theater set up are mid range horns and any tweeters of consequence that would be needed to compliment a "LOUD" Bottom. I'm guessing that its a passively cross overed system that must sound great indoors but if you took it outdoors and tried to run a live band through it you would not get anyway near the SLP needed to do the job. I hope this clears things up.

BTW as the guy who had to maintain several earth shattering EV and JBL drivered systems The LAST thing we would do is let the DJ's anywhere near the Main amp racks or the main volume controls. Left unchecked on their own they would have destroyed ever driver in the house inside of 10 Minutes. That's why compressors were invented! Just ask ANYONE who owns a sound company!

Bohanna
post #34 of 46
Can it damage a projector, YES of course, carefully moving a projector and barely bumping it can damage it if something is loose or poorly constructed. No projector is EXACTLY the same in regards to the ability to take sound waves or shock waves. I never said it was impossible for it to damage a projector, I said it MIGHT damage something on certain projectors, but it is doubtful it will damage the IC's.

DGP always gets a big ego if anyone disagrees with him, it will suddenly be everyone elses EGO that is at fault rather than his own. I am personally tired of his "underhanded" comments directed at people, as if no-one has the right to voice an opinion on a subjective matter, and he is the only opinion that matters...

Will it damage a projector, MAYBE, but then just get a good warranty. Everyone in here is acting like a know-it-all right now because no-one actually knows the specific limitations of a specific projector. I would surmise however that in most cases, many projectors will keep going out of focus (some with tight lenses may not) before damage occurs. What I am saying is that more than likely you will notice other side effects before the force is strong enough to damage the projector, but of course there is no absolute guarantee.

Also, the sound waves required to damage a projector (unless the PJ was very close to the speakers) would likely vibrate the mount so much that the first side effect noticed would be a SHAKY image. I am just saying that you will probably ruin the viewing experience before you even get to the point of damaging anything, ok even this isn't guaranteed, but it makes some sense.

I don't know the specific levels it MAY or may not damage a projector, neither do any of you, but what I can tell you is that it is unlikely to damage the IC's unless the boards are severely warped or cracked. How do I know, because I've seen enough electronics beat up and dropped to know this, after 20 years of being in electronics, and I've done it myself on old boards. Scratches or cracks are really bad for electronics because it will break the connection of the soldering points on the boards, but evenly exerted pressure (even applied at large amounts) or blunt force or vibrations, well then it is usually not nearly as sensitive to that (NON-SS can be, but I am talking the IC's themselves).

I've literally thrown electronics down the street and played baseball with them and plugged stuff in after doing so, some things still work, some don't. You can bang some of these electronics across the wall many many times before they break, but as far as will it damage a projector, MAYBE, no idea how much BASS we are talking, but it is unlikely to damage any SOLID STATE PART. Of course if you bang it against the wall, it might break it right away even from mid-level force, but it just depends on the angle and how you do it. So the same rules apply to all blunt force, depends, it could. The vibrations very well might affect the lamp life, but then again I don't know the specific levels at which this occurs.
Edited by coderguy - 7/17/13 at 8:23am
post #35 of 46
Quote:
Originally Posted by Bohanna View Post

Actually Gamepimp we WERE talking about Bass in a Home theater and the negative affect it might have on a projector That was the WHOLE POINT of the discussion. I don't believe any of us were implying that we were the only people who understood what "loud" is. What some of us were saying is that the people who don't seem to think it would have any effect on a projector don't understand what "loud" is. There is a HUGE difference.

The HT sound system with the pretty pictures looks to be quite a nice home system but its not being used to producing the kinds of High sound pressure levels described by the OP. If it were they would not have mounted the speakers behind the screen since the screen would look more like a kick drum head once the volume was turned up. What is also missing from this home theater set up are mid range horns and any tweeters of consequence that would be needed to compliment a "LOUD" Bottom. I'm guessing that its a passively cross overed system that must sound great indoors but if you took it outdoors and tried to run a live band through it you would not get anyway near the SLP needed to do the job. I hope this clears things up.

BTW as the guy who had to maintain several earth shattering EV and JBL drivered systems The LAST thing we would do is let the DJ's anywhere near the Main amp racks or the main volume controls. Left unchecked on their own they would have destroyed ever driver in the house inside of 10 Minutes. That's why compressors were invented! Just ask ANYONE who owns a sound company!

Bohanna

The pictured system uses a tensioned AT screen and would not act like a drum head with the 18" Fi behind it, the output it has currently would best the single 18" any day of the week... period.

What you are doing here is debating the point because you have a background dealing with pro-audio, and that's excellent but I think your lack of experience with higher end HT is where you are likely misguided. The system in the picture is very well 'complimented' and designed by one of the best in the industry and is capable of getting very LOUD while being very clean (unlike those outdoor gigs that require insane SPL at all levels in order to reach the hippies in the back forty enjoying some herb).

Well I always had control of the systems that I DJ'd and never once destroyed any gear, if anything I usually had to turn things down a notch or two due to the type of music being played (which was bass heavy).

I'll say this once again... nobody here is saying that extreme levels of bass cannot have an impact, what we are saying is that it is not something to be too concerned with... enjoy. wink.gif

I'm done here and not even sure why I bothered posting in the first place. confused.gifbiggrin.gif

Take Care,
Jason
post #36 of 46
Hey Jason!
Thanks for your input. As a reader looking in, I see talk about a single 18" subwoofer highly powered and maybe even overdriven, vibrating drywall at whatever resonant frequency the room likes. I believe, too, that at this limited level, projector damage is not the issue, or an issue. Lets all talk again when we want to address line arrays of 10 18" subwoofers driven by 30,000 watts in a 20' by 20' living room. That would be different. Probably.

I'm a drummer too. Percussion is a beautiful thing, and everything should be able to take it.
post #37 of 46
Just so you guys know I had to have the ceiling mount reinforced to stop the projector from shaking with certain frequencies that one could clearly see on screen.I was less concerned about the projector than the effect on the image. My theater is on the second floor so the whole structure shakes at times which gives a very visceral feel to the LFE not just the air or seat but the floor as well.

I have a storage room in the back behind the theater with wall mounted shelves. One day I went in and eveyrthing was on the floor (boxes, cleaning supplies, DVDs etc). I thought my kids had gotten in and then I realized it had been the movie watching the previous weekend that had caused it. I
put in a disc that has freqencies from 10Hz to 200Hz and played it at reference.I opened the door and watched till it reached the frequency (about 35Hz as I recall) and the shelves started to flap violently ejecting everything again !biggrin.gif

Art
Edited by Art Sonneborn - 7/18/13 at 5:57pm
post #38 of 46
Yeah, Art knows.

Every instance is different. And many times, it's all about the content itself. Also, the effect caused by such transferred "non-sympathetic" resonance can be cumulative, and amplify itself via structural harmonics going ape-crap crazy. Once a material's resonant frequency has been matched, many unexpected results can occur. Propagation and amplification tendencies exist in many rigid materials, and can lead to structural deterioration or even outright failure. As stated before, many...if not most individuals can really have no clue as to what can...and does often happen under such assaults. That's not to be considered an insult, challenge, or conceited expression of "know it all-ism". It's simply a statement that it has happened, and will happen under many varied circumstances if sane choices are not made, and/or proper steps are not taken

Myself, it's the "jiggle" of an image, and the loosening of Lens Shift settings that have been the most frequent issues to deal with. Lamp Failure is what seemed to some to be tied with any tendency for a hot filament to be subjected to enough vibration so as to make the image stutter. As for IC boards cracking and/or a component's solder points cracking....well anything obtuse enough to cause that will also be causing a lot more issues even more easily recognized. A case in point....I've actually seen Can Light trim rings come loose and fall down in the middle of a Movie. The battle off Pelinor Fields comes to mind. So does Saving Private Ryan. (...I hate that movie....it can kill a system...)

If anything good can come of this discourse, it certainly should be that readers will at least "consider" what they have wrought, and be looking to as if they need to take any additional steps to mitigate potential issues.

That ain't so bad...is it?
post #39 of 46
If you have not had any vibration problems by the time the warranty has expired, I would not worry about it. If you have damaged the projector by sound vibrations before the warranty expired, then you know what to do, since neither you nor the MFR can be sure what caused it (and really you still cannot be sure even if you suspect bassy sound), then it's still fair-game to send it in to get an RMA.

So I don't see it being a real issue for most people.
post #40 of 46
Quote:
Originally Posted by coderguy View Post


So I don't see it being a real issue for most people.

Dude..... eek.gif

I know you've been around the Forum long enough to know AVS'ers are not to be considered "Most People". rolleyes.gif

If it's something weird, queer, illogical, improbable, even impossible. Or just plain one individual's bad luck, our valued membership will report it. tongue.gif

Worse still....we're all gonna debate or argue about it. wink.gifbiggrin.gif

....and who benefits?

Why....the Advertisers, of course. cool.gif
post #41 of 46
Quote:
Originally Posted by MississippiMan View Post

Dude..... eek.gif
....and who benefits?

Why....the Advertisers, of course. cool.gif

Finally we agree 100% smile.gif

Yes, there is an alarming amount of Aspee like traits in this forum, not sure if that makes us smarter than most people, or just more obsessive.
post #42 of 46
I'll start worrying about projector damage when I read the 1st post I've ever seen of someone reporting damage due to too much bass in the speakers/subs DIY thread. If it hasn't happened yet I don't think it's going to.

I have 8 18" subs never had an issue, a avs friend has 16 of the same subs never an issue. I haven't seen one person in all my years in the audio forum have a problem.

post #43 of 46
That a nice looking system. The only thing I think its missing are sub woofers. Have you ever thought about adding a few? eek.gif
Bohanna.
post #44 of 46
Thanks. Haha, yeah I know it's a sickness.
post #45 of 46
I'd be more worried about needing a pace maker after listening to that setup for a couple years.
post #46 of 46
Thread Starter 
Thanks everyone for all the input. Seems this question has stirred a lively debate. Its funny that cracking sheet rock came up because in my previous home we did just that with the same Peavey amp running a 18" JL audio woofer and two 12" Infinitys running off an older 2 channel Adcom amp. My friend and I were roommates for a time after our respective divorces and thats were the big bass experiments began. When we placed the 18" into an a built in alcove originally designed for the equipment rack the bass energy split the seams of the wall around the opening. So that really does happen in the right or "wrong" installs.

Since dampening has come up several times I thought I would mention that my dedicated theater room is entirely wood, the walls and ceiling are yellow pine. Carpeted floors and I made some sound absorption panels from 3" fiberglass ductboard we use in the HVAC industries. ( off topic, but if you look up the products sound absorption characteristics they are great).

Thanks again, great forum, always enjoy what everyone has to say.
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