It's not just the decibels. You have to get the right frequency. The easiest way to break glass is to match it's resonant frequency. With a high frequency glass can shatter from vibration with db's only around 135.
joe is right matching the frequency is one way but to answer the other part in car audio glass usually breaks from the seals of the glass like the windshield expanding
my friend built a HUGE box for his 15 inch X.XX and this box was basically like bigger than me...ported and he turned it on...played some songs...put on the song...woofer cooker...intense song by the way...and like 5 seconds into it...his front and rear window cracked in half and the middles of the windows fell in on us...idk it was sooo intense...GOD awesome
Most of the time when someone...(your average joe street pounder)...breaks their windshield, it was prolly weak to begin with. But all the "stories" you hear say that they where super-loud and thats why they shattered the glass.
I have personally ran cracks (that started like 4in long)in my windshield. Sometimes as far as 3ft in just a little while. I did this w/ a single L512 in a 1.1cu ft sealed box on a bp600.1. As a matter of fact...i have bout a 2ft crack in my windshield now.
At bass frequencies, you are prolly not going to be doing the glasses resonant freq., but if you found the glasses res. freq. it wouldnt be all that hard to break it.
Glass can flex more than you would think also. Watch a few of the vids on realmofexcursion.com, you will see w/ I am talking about. I have seen guys in my town brag about shattering their windows...but like a week b4 that they had a 2ft crack in the same glass.
I'm not saying its impossible to break glass...i'm just saying that some of the stories you hear are not the "whole-truth". Glass can and will break...just think about it, how many usaci extreme vehicles have plexy-glass instead of glass...lol
15" X.X.X.'s are capable of producing SPL around 150db in the right install. Depending on what vehicle it is in and how much the vehicle flexed...I wouldnt be super surprised that you could break glass.
it was a corrola i believe...or a camry one of the two for sure lol....but there was nothing wrong with it at all..i think it was a 2003 at the time...but then like right after he repaced the window..he totaled it lol...now he has a shelby cobra lol...drastic change...would you say?
Your not gonna get close to "really shattering" the glass with subwoofer frequency's. If somebody does blow the glass out from a sub than it's from too much stress on a crappy glass, or huge cracks. Most glass has a resonant frequency in the 4000 hz range.
A Shelby Cobra, wow! lol Not that much of a change. So let me see if I got this right... You match the glasses frequency, but glasses frequency is like in the 4k range so it is like almost impasable:-) I say just get 3 mt's and put 2000 watt's to each, and that should do the trick!:-) Who am I kidding, I couldn't aford that!:-)
I've pulled my windows away from the seals more times than I cared to fix with one 12" Alpine type X, never cracked one though. I have seen a buddy's Jetta crack with 8 MTX 10" Thunder 8500's though, car only hit about 149 dB, but it was a new car, windshield itself was fine, quite a sight...
Anonymous
Posted on
"my friend built a HUGE box for his 15 inch X.XX and this box was basically like bigger than me...ported and he turned it on...played some songs...put on the song...woofer cooker...intense song by the way...and like 5 seconds into it...his front and rear window cracked in half and the middles of the windows fell in on us...idk it was sooo intense...GOD awesome"
uuuum, how exactly did the glass fall in on you. all new cars have safety glass. it will break or crack but its not going to shatter and fall in on you. and if that box was so big how was it in the trunk of a camry?
like he built it while in the trunk...it cant be removed...like he putr in each bored singly and used a sideways screwdriver to attach it all...and the glass like cracked and made a circle...then the circle broke in...idk...it just happened
Bout 2yrs ago a buddy of mine tried to kill a fly that was buzzin round in my cab while we were at sonic. He had his class ring on when he swatted at the fly. It lit on the windshield and he kinda balled up a loose fist and punched it...put bout a 1.5ft diameter spider-web in the middle of the glass. The glass stayed...but it had that huge crack.
haha...actually taht doesnt disprove anything,..you guys dont have to believe me if you dont want to...whatever..but iwa s there...and i know wat happened...it was not supposed to happen...but it did..and iknow he had wrecked the car a few times before...but its notl ike i come on here to lie to you guys
...my buddy bout $hit himself bout 2sec after he broke the glass...lmmfao
subfanatic...i'm not saying the glass wouldnt fall...when i had that huge crack in my glass i could touch it and it would flex back and forth...if i would have turned my subs on (2 kicker 10's at the time) i wouldnt have been surprized if it would have fell in.
what i am betting is that your buds glass was weak already...thats the most likly reason that it shattered...the bass prolly keep playing after the window started to crack. i have seen guys do mid-150's and the windshields would separate from the seals.
I really don't either. Hey, I'm not calling you a liar, if just sounds odd to me. You could put brass knuckles on and punch your windshield, and it still wouldn't shatter all over. Have you ever tried to beat an old car with a baseball bat? There used to be old cars left back in our woods when I was younger, and I'd go back and play around, beat them up. Trust me, it took some energy to even get the window to break.
