You can see what it does to the windshield. You can only imagine what it does to the tympanic membrane and the inner ear.

Extreme sound system bends the windshield glass

 

I've even had the mirrors rattling. Not to mention roof, doors.
Makes for a great massage.
Love a good excuse to post a pic! Thanx!
Amp moved and no longer have second battery, 15" woofers still there!

 

How can you enjoy the music when it's that loud??...

 

It's all about the bass. I was told that bass must be about 5-10 times louder than singing. Goes to power and speaker size. Bass speakers must be bigger becuase the frequencies are lower and require more power to drive them. Small bass speakers underpowered sound like crap. You should be able to feel and hear the bass.
I can understand that really loud is excess, but it's cool once in a while to shake everything!
Go big or go home.
I don't drive around full blast but maybe @ 7 out of 10.

 

The tympanic membrane vibrates with the sound waves that enter the ear canal. There are 2 muscles (not shown)that attach to 2 of the ossicles. These muscles will tighten or relax depending on the sound pressure level. That mechanism protects the tympanic membrane and the membrane in the cochlea.
The vibration gets reduced in amplitude, but raised in force by the ossicles much like a crowbar increases force by mechanical advantage. The footplate sits in a window of the petrous bone and pushes on a liquid inside the cochlea. Thus the vibration is transferred to the hydraulic portion of the ear.

There are hairlike nerve endings laying over the tectorial membrane. Excessive sound levels will damage the nerves and that means hearing loss at the frequencies these nerve endings used to capture.
Then the brain realizes something is missing and tries to compensate by augmenting the signals from the adjacent nerves. That leads to "static noise". That condition is called tinnitus and it will drive you nuts because it is a buzz, hum, hiss or squeal that you cannot turn off. You will hear it every waking second of your life.

 

Here's a place where you want to turn your stereo down: LongBeach, California. They installed a decibel meter reader on the street. Headers and straight pipes look out!
Spurred on by a citizen group in Long Beach, California, the local area police have dispatched a sign to monitor sound levels emitted by passing vehicles. The electronic sign functions much like the automated road-side speed-measuring signs that flash up an LED-lit warning showing your real-time road speed as you pass by. The sign features microphones that pick up the maximum decibel level reaching the sign, and then flash the decibel level on the LED screen.

The average vehicle emits around 55 to 60 decibels (when traveling around 60 km/h), and the officers monitoring the sign are looking out for those that strike the 70 to 75 decibel level. Those with aftermarket exhaust systems ought to shift up a couple of gears and lean up on the throttle when passing by...
FROM: Police use electronic sign to measure if cars and motorcycles are 'too loud'

 

from Wikipedia:
Acoustics

Main article: Sound pressure
The decibel is commonly used in acoustics to quantify sound levels relative to a 0 dB reference which has been defined as a sound pressure level of .0002 microbar, or 20 micropascals.[17] The reference level is set at the typical threshold of perception of an average human and there are common comparisons used to illustrate different levels of sound pressure. Sound pressure is a field quantity, so the formula used to calculate sound pressure level is the field version:
where pref is equal to the standard reference sound pressure level of 20 micropascals. The human ear has a large dynamic range in audio perception. The ratio of the sound intensity that causes permanent damage during short exposure to the quietest sound that the ear can hear is greater than or equal to 1 trillion.[18] Such large measurement ranges are conveniently expressed in logarithmic units: the base-10 logarithm of one trillion (1012) is 12, which is expressed as an audio level of 120 dB. Since the human ear is not equally sensitive to all sound frequencies, noise levels at maximum human sensitivity—somewhere between 2 and 4 kHz—are factored more heavily into some measurements using frequency weighting. (See also Stevens' power law.)


With this range of human hearing, why push the envelop and risk the possible damage? BTW we loose high frequency hearing as a matter of aging. Past 40 most people are no longer able to hear the sounds bats make for sonar navigation.

 

Good thing I don't explore Caves!

I cracked 142 decibels with stereo below while playing 1 of Metallica's songs. 1987 p/u extended cab with rear small seats removed. My current car has rear seats removed too! Case on floor is for a pool cue!
Haven't bothered to test my current system but it should be 135-140 anyway.



Current Car, no rear seat:

 

Noggin: you are a freak (your own words in an other thread) 142 dB

For every 3 dB the SPL doubles. Hearing damage may occur at 120 dB.

You will pay for this kind of an exposure down the road with hearing problems.

 

Actually to get another 3db you need to almost double the volume.
Speaker efficiency is usually rated @ 1 watt @ 1 meter away somewhere around 90 db.
2 watts = 93 db
4 = 96
8 = 99
16 = 102
32 = 105
64 = 108
128 watts = 111 db for 1 speaker (driver)

I had like 10-12 speakers in that truck in a very small area and extremely efficient speakers in the 95-98 db area for 1 watt 1 meter. That was also with windows closed. When driving i always had my windows opened and the loud stuff behind me so i never got it directly in my ear!

130 dB represents the threshold for pain, 140 dB causes irreparable hearing damage, and 150 dB can cause instant deafness, anything greater than about 192 dB can kill you.
FROM: Relationship Between Watts and dBs | Audioholics

I've had loud stereos in my vehicles for many years. My ears don't ring anymore! There was a time where they did hurt. Currently i have pretty good hearing.

Sound dB-SPL (beside it)
Jet engine at 3m 140
Threshold of pain 130
Rock concert 120
Accelerating motorcycle at 5m 110
Pneumatic hammer at 2m 100
Noisy factory 90
Vacuum cleaner 80
Busy traffic 70
Quiet restaurant 50
Residential area at night 40
Empty movie house 30
Rustling of leaves 20
Human breathing (at 3m) 10
Threshold of hearing (good ears) 0