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[Mark "Bass Pig" Weiss]

I've finally been convinced of the value of a 1080P large screen flat panel display for the Bass Pig's Lair because of what I have seen it do for NTSC footage. I want to install one in here, but I have a concern because of the size of the panel and the fact that it will cut across significant portions of audio wavelengths due to its size.

The concern stems from the fact that LCD and plasma panels are made of large sheets of glass. While this won't be in front of any speakers, it will be between the center speakers, and the SPLs there can easily hit the 150s. My existing CRT weighs about 180lbs and "walks" off its platform regularly, but the CRT itself is too small to have any resonances in the bass range. But a larger flat panel display is likely to catch a good portion of a soundwave and I'm concerned that the glass might crack.

No doubt, some of you have worked with large screen panel displays in high SPL situations. I was wondering if anyone has tested to find out how much vibration these panels can take without damage?

I love the gorgeous film-like output of the LCD my wife just got, upstairs, and now my "old" CRT looks like a coarse set of venetian blinds when viewing video. I don't know how they do it, but that Faroudja technology in there does wonders with stard definition video, and I'm looking forward to shooting 1080P in the coming year, so I have the impetus to convert some of my unsused equipment to cash and get this flat panel display installed. It will be a sizeable investment, so I want to make absolutely sure that I'm not making a 'witches brew' of mixing high SPL sound with fragile flat panel video displays.

I'd like to hear comments from those who have worked with panels under extreme SPL conditions. Thanks.

[Matt Vivlamore]

I don't know the answer... but go with an LCD...

Plasma is old tech, and won't be around much longer (1-3 yrs).


I'll ask at work on Monday about SPL and vibrations...

[Mark "Bass Pig" Weiss]

I purchased a 47" LCD (yes, it looks much smoother and more filmlike than plasma displays) last week and am cautiously observing how much it vibrates. I put an SPL meter up close to the front of it, where it sits between two speaker columns, and at about 130dB range of readings, the lens vibrates about 1mm. But I realize this is a plastic lens and not the LCD itself.
What I'm worried about is a repeat of the lens shattering I regularly deal with on the overhead fluorescent lighting. I don't really care about that--it's just a few pieces of plastic, but the LCD is costly and I'm concerned about how much it can take before catastropic failure happens.

[Brad Weber]

I suggest checking your meter, making sure you are reading dBA or dBC with slow metering, or turning it down.  The sound levels you note, especially since the were apparently measured almost 90 degrees off axis of the speakers, would likely cause permanent hearing damage with short exposures, in fact instantaneously at 150dB, so something seems wrong.  Either that or past exposure is why the levels now have to be so high!

A 47" HD format display has about a 23" high image and for a true 1080p display is really meant to be viewed at maybe 6' away and they are probably assuming meeting THX criteria at the viewers, so the video display manufacturers are definitely not expecting to be dealing with major outdoor concert type levels at the display.

Of course, you are free to run whatever levels you want, but I wouldn't expect the display manufacturers to have accounted for such high levels or to even necessarily consider any resulting damage as being the result of the display being used in a "consumer" or "residential" application.

[Gabe Nahshon]

I had a look at your home stereo system.  Impressive!  But why do you want to listen to music that loud at home?  Don't get out much?


Gabe

[Mark "Bass Pig" Weiss]

Thanks for your replies, gentlemen.

In chrono order:

I choose fast and flat settings, as I want to know the actual peaks SPLs, since a brief transient is all it takes to break something.

Since I am constantly shattering 2 by 4 troffer lighting fixture lenses, I naturally conveyed that concern over to my new LCD panel, due to it's large size being in such an enviroment.

No, those aren't my regular listening levels. They are occasional, and also make room for 'accidental' or unintentional high levels in my tests. I normally listen at about 115dba (127dbc) and use ear protection.

The high SPLs are for the physical sensation. If you ever visited Redstone Arsenal in Alabama to see the testing of the Saturn V rocket engine, you will understand the sensation I am recreating here. Yes, I'm a bit eccentric and some have referred to me as "maniacal" even. But I try not to abuse sound. However, the potential is there and I want to understand what these LCDs are able to withstand--how much safety margin I may have.


I have had this affliction for over 30 years. Yes, there are other things in my life that take up my time, but my old friend Bass Pig can satisfy me in ways that no one else can. And I still enjoy that thrill.

[Andy Peters]

Mark "Bass Pig" Weiss wrote on Mon, 26 March 2007 15:11

I normally listen at about 115dba (127dbc) and use ear protection.

That statement speaks volumes.

Quote:

The high SPLs are for the physical sensation. If you ever visited Redstone Arsenal in Alabama to see the testing of the Saturn V rocket engine, you will understand the sensation I am recreating here.

So, simply put, you don't listen to MUSIC, do you?

-a

[Ladd Temple]

Quote:

The high SPLs are for the physical sensation... you will understand the sensation I am recreating here.

"Sounds" like you might be using it as an audio laxative?   Got a bathroom close at hand?

[Mark "Bass Pig" Weiss]

Actually, I do listen to music, in addition to pyrotechnic recordings, helocopters and a variety of electronic music with very deep bass sounds.

In fact, when I listen to real music, a symphony orchestra, I set the levels such that a crescendo is about 97dBc, or 88dBa. I record symphony orchestras from time to time (am in the middle of editing 14 channels of audio and three camera angles of a concert I recorded on March 25th) and I bring a sound level meter and take readings at the edge of stage, first row and balcony locations for later playback reference. It's amazing how accurate the playback is when the levels are set correctly.

I played back some of the 24/96 concert audio on the full surround system and it was like being back in the first row at the concert again. It was quite a demonstration of Bass Pig's accuracy, which is in quite a different mode of use than what it was built to be capable of.

So, yes, I do listen to music, on occasion.

[Tom Howard]

Have you not considered tactile sound transducers?