sound level inside car

[M3M3]

just curious if anyone else has checked this. i used an android app call "sound meter" on my motorola atrix to check interior sound level on three of my cars. droid held near my right ear, 60mph, top gear, windows up, stereo off.

97 M3 w/ AA exhaust system - 67db

87 325e - stock - 71db

75 M2 - nothing stock........79db.

(remember..every three db is a doubling of the sound pressure level.)

[jimk]

Not checked, but not suprising. Earplugs are required at sound levels greater then 85dbA.

[TobyB]

At 85 dB a weighted, you have an exposure limit of 8 hours,

after which you can expect (over time) to suffer hearing loss.

Problem is, lots of car noises are frequency- specific, and your

inexpensive sound pressure level meter averages them, and integrates

them over time. A modulated, intermittent or spectrum- limited sound will usually

under- read.

So if there's a nasty drone at 400 hz, but not an inordinate amount

of sound energy anywhere else in the spectrum, that can

cause hearing loss at 400 hz... even though the meter says you're safe.

It's relatively complicated...

my 2002 is too loud for long trips, so I wear earplugs so that I can listen to the radio.

heh

t

[M3M3]

lol...yeah, you get what you pay for with free apps! yes, i keep a set of earplugs in the m2 for trips. and a set of bose qc15's for after dark. interesting laws that i can wear cheap foam earplugs, but it is illegal to wear modern noise canceling headphones to achieve the same effect....

also for ref, using much better sound equipment my e36 235is race car was 102db by scca measurement. (full tilt, 50ft to left of car). not driveable without custom ear molds and a helmet to muffle the sound...

[Colin]

my 2002 is too loud for long trips, so I wear earplugs so that I can listen to the radio.

heh

t

In my younger days I worked as an audio engineer. I remember recording this rock band where the drummer kept asking me to turn up his headphone mix to the point that it was just at a ridiculous level. I couldn't figure out how he could tolerate the SPLs.

After the session, I discovered that he was wearing ear plugs INSIDE his headphones.

Makes sense?

[jgerock]

Marshall -

Funny how your E36 M3 is quieter than the eta E30.

My company makes vacuum and pressure blower packages.. some have simple exhaust mufflers and others have a fully insulated cabinet to reduce the noise from the belt-driven Roots brand centrifugal pump. Some of the 15 and 25HP fully insulated packages run about 80dBA @ 3 ft. perimeter. We use an ancient hand-held SPL meter to randomly check the noise levels.

Wish I knew what some of our 75 and 100 HP pressure blowers measured - they are really loud when we test them in our building.

[Koblenz]

What? I'm sorry, I can't hear you.

[TobyB]

After the session, I discovered that he was wearing ear plugs INSIDE his headphones.

Yeah, I've seen that, too. Especially with headphones that can get quite

loud but don't isolate well.

Makes sense, tho- take ambient from 90dBSPL to 75- then add back 10

of what you WANT...

The proper cancellation headphones that the jetway techs use are fantastic... 50+ dBSPL of reduction, but someone can talk at a normal level right

in front of you and you can hear them clearly.

t

[Colin]

The proper cancellation headphones that the jetway techs use are fantastic... 50+ dBSPL of reduction, but someone can talk at a normal level right

in front of you and you can hear them clearly.

Yeah I actually work at an airport now and my first experience with those was mind blowing.

But back to cars, I've put quite a lot of effort into quieting down my daily. I keep meaning to stick an SPL meter in there but haven't yet, but I reckon its pretty good. It's quieter than my wife's old 1994 corolla, but loud enough that I can usually get away with a fart or two without getting punched.

[nbristow01]

Lost a lot of my hearing in the military after 12 years of service. So my 02 is just a whisper to drive! But actually it is amazing how much ambient noise there is. So much so that on the drive to Mid America we could not understand each other on the 2 ways or CBs

[willys]

Has anyone done a before and after Db measurement after soundproofing their 02?

Jeff

[redphu72]

Marshall, thanks for the tutorial on Esty's carpet install. Great help. Got mine done and looks dare I say professional . Wish I'd known about the side panel where you can add the extra vinyl flaps that go over and wraps aroun the seat rails. Oh for the kicker panels, I used super velcro and stuck them in place just in case I need to access the wires, which I had to do for my electronic relay upgrade.

[tim385]

How about .....Doof Doof music that you hear before you see it pull up next to you or i pod ear phone music you can hear over the other side of the room , give me 85 dba at 7500 rpm any day even though it only for a while .Anyway as I get older my cars get quieter ....WHAT WAS THAT DEAR ..... may be it is my hearing ??