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Show your subwoofers "movies" blowing out candles!

Andysu

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I start with the ultimate best. Would be interesting to know how much air was in the fake speaker in 'back to the future' to lift and throw marty, some 15 feet across the room at what 10 miles per hour whatever without breaking his neck against the bookshelf.

JBL 4645 18" with candle few inches away. Well if it was more then the JBL sub would get damaged due to carelessness and even if I lined the floor or area with candles, the SPL dB would be unrealistic and unnatural sounding. I seen candles lined out on a floor but at end of the day it just port air turbulence flowing around inside the box at a certain frequencies to blow a candle flame out.

 
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Mart68

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I start with the ultimate best. Would be interesting to know how much air was in the fake speaker in 'back to the future' to lift and throw marty, some 15 feet across the room at what 10 miles per hour whatever without breaking his neck against the bookshelf


Good question! Here's a starting point:

"For a person who weighs 100 pounds (45.3 kilograms), it would take a wind speed of 40 to 45 miles an hour, or tropical storm force, to move them''

Marty's only little and he's not overweight so 100 pounds is probably in the ballpark. So the speaker would need to move air at at least 45 mph to knock him over - but I'd guess more to blow him back across the room like that. Good job that comfy chair was there.
 
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Andysu

Andysu

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Good question! Here's a starting point:

"For a person who weighs 100 pounds (45.3 kilograms), it would take a wind speed of 40 to 45 miles an hour, or tropical storm force, to move them''

Marty's only little and he's not overweight so 100 pounds is probably in the ballpark. So the speaker would need to move air at at least 45 mph to knock him over - but I'd guess more to blow him back across the room like that. Good job that comfy chair was there.
Good points on that.

Yet again even at the so called 45MPH speed hardly the rest of the lightweight paper is blowing around in gulf of air! And it lifts up and blows him back.
I guess they must have filmed the gag at upside down so the stunt double is dropped backwards or which way? There have to be wires here but it is cleverly done. And wonder if the cab box once the gigantic speaker has been obliterated would the box lose some the air pressure and Marty should just stumble backwards and fall over.

Also we have all experienced gale-force winds in the UK up 80MHP but I never seen people or myself getting picked up and blown down the road. sure enough at times to even try and unbalance when walking though it to fall over backwards.

Anyone care to make a mini sub or use a toy figure and start tuning the Amplifier level and gain level up to see if the toy gets blown across few inches or test with wind fan or maybe some fireworks stuffed into an enclosure sealed with a passive subwoofer and watch it get blown-up to smithereens lol.

Also it would appear that Marty now has tinnitus as that would have to be easily over 150dB and no one is gonna walk away from that without ringing ears. But this is all a fantasy movie make believe but still, interesting.

So here is how it was done. There is device that stunt people use it is like a catapult you stand on it and it has I guess a hydraulic that simply flips up that is why you can just barely tell it is behind all the boxes paper in the camera shot.
 
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Andysu

Andysu

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I been looking around for more answers on the type of device that stunt men use to flip them up so they go flying. I seemed to have landed on something else that is interesting the link has advertisements so click them off and have small read which is all it is. And makes point that Marty would be deafened by that speaker blowing up! BUT there is a type of ramp in one shot you see Marty clearly standing in position with his feet. Next shot you see camera angle with boxes covering the Ramp gag otherwise the gag , is like a spring I guess with wooden platform stand on it and it flips!! So the speaker would have some pyrotechnics fitted and on cue, filmed. Also the shot would be few takes one showing stuntman flipped backward - the next shot stuntman landing into the couch and whole scene edited. So it is all storyboarded and then worked out how to film it.

https://www.themarysue.com/physics-of-guitar-powers/
 
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Andysu

Andysu

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Andysu

Andysu

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Another thing about Back to the Future, where it was exhibited in USA in few THX cinemas and HPS-4000. There hardly any videos showing the set-up of these THX and HPS-4000 and yet lots of video of men allegedly walking on the moon. Usually today everyone has home video showing this and that home theatre cinema build and what can do. But I never seen Big bass at a cinema blowing the audience out of the seats.

back_01.jpg
 
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Andysu

Andysu

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Normally under any circumstances, I wouldn't care to post anything about Liemax, since they ruined the Empire Leicester Square.
So there is some smaller Liemax subs I think these are the smaller 12" clusters of them as the new Liemax don't use the 18" even at Liemax Square, they only use clusters of smaller 12". Sure I can a video like this one. bit hard mind you since the projection screen mostly covers my JBL 4645/C direct radiator 18", I could move my Oled to one side to do one with the JBL 4682 TCB with a candle blow out and even used a smaller JBL control SB-5 TCB.
 

Mart68

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Good points on that.

Yet again even at the so called 45MPH speed hardly the rest of the lightweight paper is blowing around in gulf of air! And it lifts up and blows him back.
I guess they must have filmed the gag at upside down so the stunt double is dropped backwards or which way? There have to be wires here but it is cleverly done. And wonder if the cab box once the gigantic speaker has been obliterated would the box lose some the air pressure and Marty should just stumble backwards and fall over.

Also we have all experienced gale-force winds in the UK up 80MHP but I never seen people or myself getting picked up and blown down the road. sure enough at times to even try and unbalance when walking though it to fall over backwards.
.
I have seen a man blown off his feet in Snowdonia, very high up in atrocious conditions. I can also recall some cases of troops doing SAS selection in the Brecon Beacons being blown off the top of a peak and killed. So it does happen but possibly it needs to be at altitude in a very exposed location

I recall watching a documentary some years ago where they stood a bloke in a wind tunnel and wound it up to see what velocity it would take to blow him over. Can't recall what the name of it was so might be hard to find even if it is out there.

My guess would be no drive unit regardless of how large or how much power could move enough air fast enough to accomplish it. Needs further investigation though.
 
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Andysu

Andysu

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I have seen a man blown off his feet in Snowdonia, very high up in atrocious conditions. I can also recall some cases of troops doing SAS selection in the Brecon Beacons being blown off the top of a peak and killed. So it does happen but possibly it needs to be at altitude in a very exposed location

I recall watching a documentary some years ago where they stood a bloke in a wind tunnel and wound it up to see what velocity it would take to blow him over. Can't recall what the name of it was so might be hard to find even if it is out there.

My guess would be no drive unit regardless of how large or how much power could move enough air fast enough to accomplish it. Needs further investigation though.
I been to Wales in '79 on school trip, one week so I know of the park as we had tour of it very missty with vapour clouds. Thou was a calm day.

There are dozens of videos wind tunnels but BTTF isn't it is a ramp flipping the stuntman and edited from three camera shots to look like one scene. Otherwise Yes standing in front of jet engine, thou stupid would blow One around a bit but that isn't sudden and with loudspeaker exploding into pieces.

the scene in face/off maybe a stuntman falling backwards to create the impression of a being blown backwards horizontally.

Well maybe those mythbusters can bust it, cos I simply do not have the money to waste on it. I just do it with candle flame that is lot safer.
 
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Andysu

Andysu

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The smoking man, from x-files - candle blow out, wow the episode had some low end below 20Hz.


I can place a candle few feet away and blow Hard it will take few seconds for the wind air to reach the candle and fluctuate the flame, not enough to blow it out that would take a bit more effort for a few feet like 5 feet. A subwoofer is going to struggle and going to sound unrealistic due to SPL dB cos blowing it naturally is opposite of subwoofer.
 
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Andysu

Andysu

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LMAO the same music used in that BS Maxwell tv ad. Yeah sure the ports on that JBL is gonna be blowing wind turbulence in your face, unless it was a jet engine. LMAO and the guy jumps up while jet engine is blasting air energy at distance shorter the BTTF speaker and only falls flat on his face without being below backwards. Maybe stand closer and thou that would be carelessness, yes the guy would be AE at the hospital.

Now place some candles in direct line over a hundred feet of the jet engine. One by one the candles will be utterly blown out. Cos there is a lot of air blast! Which is why, Warning never stand behind the Blast Barrier at an airport, by all means stand over there and you'd be fine.

 
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Andysu

Andysu

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Try to find a birthday scene.
You mean this one. LAMO oh no got strip that sub down clean it out as that will all go mouldy within a week.
 
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Andysu

Andysu

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Another Liemax cinema and yes I have the same movie but don't care much for nolan movies with muffled dialog. I do have a I think a video? I think these are 18" subwoofers in the video where the other video was the 12".

 
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Andysu

Andysu

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Just found the video in my private collection. The reason why my candle flame doesn't fluctuate before rocket engines fire, is cos Liemax doesn't use a discarte sub bass track they take the bass from all other channels hence why you see those Liemax intros speaker and here and subwoofer is Here. They use the six full range channels and passive sub not like Dolby six-track that uses LCRS SW - Liemax uses LC Upper C R and Ls Rs and now it has used up all six channels.

My THX cinema wins over liemax I saw one candle flame blown out and the other about 1 second later and the liemax didn't blow them all out at once, how liemax disappointing.

 
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Andysu

Andysu

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^ ha, ha dog submarine subwoofer that's funny.

JBL control SB-5 the smallest of the TCB range thee smallest would be the SB-1 TCB, I don't have one of them. I do have the pro version JBL 4682 TCB, I may do same Apollo 13 scene again with THX Laserdisc dts. Coming soon...
 
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Andysu

Andysu

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Apollo 13, again I did few of these years ago.

 
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