Got glass?
 

So there are a few kids going around in my town claiming they've broken their glass by burping their dinky little subs. I know breaking the front windshield is possible, but I really have no idea at what dB/freq. If anyone has, would you plz be so kind as to inform me at the numbers you were hitting when it happened or at what freq? I'd like a little more info before I just go around claiming they haven't.

The number I've seen on various forums repeatedly is 160+dB, with a perfectly good (chip-free) windshield. But a few people claim that the windshield breaking seems to be caused by the seal letting go (which allows the windshield to flex alot more) and not simply by the pressure.

With chipped windshields, I've seen them spider and grow rapidly in the high 140s (50-60Hz). Probably could happen even lower but I've never noticed or paid attention.

Personnaly, it depends on a lot of factors. I do have my OEM windshield (1995 car) with a small dot/crack on it since 1999, and it has endured ever since everey burps that i've made thru 155'ish. However, i've seen windshield broke at less than that, but that was because the microphone succion cup was too heavy (remember those old TermLAB or AC Mikes?) and that was the cause of the break.

So give or take evereything, if you are under 160, unless you have a post-WW1 designed russian-manufactured windshield made from irregular leftover MiG cockpit glass recycled from an old German BF109, it's doubtfull that a puny 12 will break a windshield. Maybee with the right resonant frequency, with low low sub-zero a$$-freezing temperatures (like -30 celcius), it might be easier to break...

Now i would like to study if a replacement windshield is more or less subject of being broke due to SPL compared to an OEM windshield (the fact that the replacement windshield might be thinner, more flimsy, badly installed or the adhesive is not properly put, whatever reason...) compared to the OEM sibling.

Getting glass to break is hard work,
The only one that I seen ever is pipo sanchez' truck!! All soundstream and very loud,

[IMG]http://www.youtube.com/watch?v=rTjx19zvyFI[IMG]

Im sure there will people disbuting this, but this is proof!!

I had a small chip/spider crack in my windshield, and it hasn't budged since last winter. This sumer it has been ing slowly with every show I go to. So far my highest has been a 146.6 at 49Hz.

Other than that A guy cracked his windshield at tnespl finals. Nothing shattering though. Just one line top to bottom. I forget his score, but it was in the 150 with a crazy setup in a pickup truck.

well for the record i had a 15 inch kicker in an 86 chevette runnin on 250 rms just squeakin by the 130 mark and my hatch window let go and shattered on the ground it was impressive to the ppl not understanding bad glue lol

i Lost 2 sunroofs for my explorer.Bass busted the clips that hold it on and they went for rides, 1 on the highway @ 120kmph

do you still have the vette?

there really has to be a defect in the glass or the glue not done properly, the center of the glass is pretty flexable, the edges are very easy to crack ....... usually theres some thing that makes the glass flex and it hits a imprefection on the edge and it cracks, you really need alot of pressure to make laminated glass break

No man but i wish i did

my car had a small crack which got bigger and i only do 135 ish at 20-23 hz.

but then again my car is a honda and it may have just gotten bigger over time but in 2 weeks i saw it gain 4-5 inches in length.

Don't forget that driving can affect windshields too. Spirited driving and chassis flex can make windshield cracks longer.

to make a long story short your looking at about 165-168db at 40+hz to crack the front windshild. a rear hatch window will pop at about 145-150db. IF the ports are close enough.

I have pulled into a car wash with only a little chip, washed the car and jumped back in to find a crack half way across the windshield. Lots of factors can cause the windshield to break easily.

Later,
Brad

Defroster, Body flex ( also panel flex from stereo) hell, i know people that have hit the window from inside the cab where the chip is to make a crack grow...

You guys need to watch mythbusters for when they tried to bust a good piece of glass with that huge "sub"

All glass on a vehicle is tempered. Meaning any change in shape can cause breakage,, but it is also very strong when curved, as in most of vehicles windows.

But, it can be very brittle, if you chip the edge slightly it'll cause a crack and then start to spider on you.

A lot of rear glass on new trucks, the edge is not protected and when throwing stuff in the bed, hits the edged and shatters the glass.

The windshield is most durable to flexing because of the plastic center keeping the two layers together, which is why when you break a windshield it does't shatter to peices.

Next time you're at a wrecker,, bring along a spring loaded center punch.

For those who know,, you know what happens,, for those who dont?

A center punch is used to indent metal, or plastic so that your drill bit won't wander when you start to drill.
A normal punch, you need a hammer/mallet and punch.
A spring loaded punch, is that,, you find your spot, press it and it automatically punches a point for you.
Hold a spring loaded center punch up to a windshield, press and "POP" the whole glass is shatterd, but stays together because of the plastic center.

Do it to the side or rear glass, near a corner preferably so your hand doesn't go through and cut you up bad,, and the glass shatters to thousands of peices.

Tempered glass is used on vehicles so when it does break it doesn't create shards of razor sharp objects ready to cut you up.

It's hard to get seriously cut up bad from shattered tempered glass unless you pick it up and roll it it your hand, or you punch through it with your fist!

So, back to the origional statement,,, I've never heard of side glass going out.

I've seen rear and windshield going out,, but as mentioned, the perfect resonant frequency has to be hit and at the right volume,, or enough air has to be displaced to "warp" the glass to the breaking point.

So I call BS on your friends statement,, and call it BS until he can prove it to you!!!