How loud to break windows?
Originally posted by BootlegGuySQi:
Rob, in Edmonton at that dB drag, how loud was that mustang that blow apart the drivers roll-up? That may have been pure SPL and timing.
Rob, in Edmonton at that dB drag, how loud was that mustang that blow apart the drivers roll-up? That may have been pure SPL and timing.
X
2000 Watt CAFz'r
Joined: May 2003
Posts: 2,819
Hey...does anyone remember that movie "DC Cab" with Mr.T??
Remeber thatcab dude put a system in and him and his buddy sat in it and screamed at the top of their lungs making the back window blow out...do ya??
That was cool!! [img]graemlins/headbang.gif[/img]
Remeber thatcab dude put a system in and him and his buddy sat in it and screamed at the top of their lungs making the back window blow out...do ya??
That was cool!! [img]graemlins/headbang.gif[/img]
50 Watt CAFz'r
Joined: May 2003
Posts: 244
I think SPL has alot to do with it but for the most part it has to do with the frequency in which you are doing it with. To be honest I don't whether it's lower frequency or higher frequency that does it. From what I can remember from back it the day when the reinforced windshields starting popping up they were barely over the 160db mark. From another source I recall they were also hitting frequncies in the range over 100hz too. But I've also seen a local kid with his 1988 Isuzu Impulse Blow out all his windows with 12 JL Audio 12" subs and he regesterd only 148db.
All in all I think it has to do alot with the frequency that is being used and not so much to do with the SPL. If we can look back to the DB Drag finals of 2002 we found that guys in the Super Street Classes were hitting over 170db, and the rule is "stock windshield".
The cause of a broken windshield is STANDING WAVE. You know your system is louder than our buddy's but the mic tells you otherwise. When your windows are down your system is louder but when they are rolled up it's alomost non-exsistant. That is when you don't know the tuning frequency of your car and you are too far off the frequency it can't adapt without something giving way, such as rolling down or blowing out a window.
Rob
All in all I think it has to do alot with the frequency that is being used and not so much to do with the SPL. If we can look back to the DB Drag finals of 2002 we found that guys in the Super Street Classes were hitting over 170db, and the rule is "stock windshield".
The cause of a broken windshield is STANDING WAVE. You know your system is louder than our buddy's but the mic tells you otherwise. When your windows are down your system is louder but when they are rolled up it's alomost non-exsistant. That is when you don't know the tuning frequency of your car and you are too far off the frequency it can't adapt without something giving way, such as rolling down or blowing out a window.
Rob
Guest
Posts: n/a
Back when they used unfiltered mics frequencies as high as 2k were used. It is not necessarily the pressure that cracks the window but the window resonating and cracking itself. If you want to see what I mean on an extreme case search for some footage of the Tacoma Narrows bridge. It literally shook itself to pieces when the wind got it going at its resonant frequency.
