Garmer

Can somebody please explain this to me? I know its a dumb question for you people that know a lot about car audio, well i dont! So can anybody help me?

Jim85IROC

iTrader: (2)

SPL. Sound Pressure Level. Basically it's just what it says. It's the level of pressure created by the sound. Sound waves don't move through the air like the traditional sine wave you think of going up and down. It actually moves through like a shock on a slinky would, with a series of compressions and rarefractions. When it compresses the air, it creates a high pressure region, and when it rarefracts, it creates a low pressure region. A special microphone hooked to an RTA measures this pressure in a fairly conventional way (i.e. it's a regular microphone).
In different competitions, the rules vary which makes it hard to compare SPL readings from one car to another unless they were both done in the same sanctioned style show. For example, IASCA requires the microphone to be in a very specific position on the passenger side of the dash board, and that a certain track from a specific selection is played. This ensures consistancy. If you roll down the windows it gets higher in many cases, so this is not allowed. In other types of competitions, usually called "outlaw" the mic can go anywhere, including right next to the sub. Obviously this creates BS numbers that don't mean anything. Other local style shows simply drape the mic over the rear view mirror. This is fairly useful to compare one car to the next, but the results will not be compatible with IASCA style results, so they still can't be compared between events. Complicated, hey?


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The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

Garmer

Damn that crap is confusing!!! So I am assuming that SPL is a good thing?!?! Can you have to much?

Jim85IROC

iTrader: (2)

It depends on what "too much" is. Can you have too much horsepower? It depends on what you're using it for. In terms of hearing damage, you can absolutely have too much. Prolonged exposure to 90dB can cause perminant hearing damage. Momentary exposure to 140+dB can cause INSTANTANEOUS deafness. 140dB can be reached with 2 subs and a strong amp. There are even some cases where cars have reached those levels with 1 sub.

------------------
The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

Garmer

Jim, how do they measure db? What do you think my system hits.

2 12' Kicker CompVR's
IX702 Kicker Amp
Clarion Head Unit(30 X 4 channnel)
the other 4 speakers are stock.

[This message has been edited by Garmer (edited February 03, 2001).]

Jim85IROC

iTrader: (2)

They measure it just like I stated above. With a microphone feeding into a RTA (real time analyzer). It's tough to say what your system will hit because there's a bunch of variables, but I hit 141.1 with 2 12" Oz subs being powered by a Kicker ZR600. Had I tuned it for SPL I could have approaced 145, which is pretty good for a pair of 12s. In general, 2 good 12s in a good box, pushed by a good amp will get you in the range of 135-140.

------------------
The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

Garmer

Thanks Jim, this summer I think I might go and get that measured! How much do they cost?

Also how many watts and RMS,does your amp put out?

Jim85IROC

iTrader: (2)

How much does what cost? An RTA? About $3000. Just find a shop that has one or join a local dB Dragrace.

My amp is rated at 150x2, but according to the birth certificate, the amp put out 871 watts into 4 ohms bridged. I'm running at 2 ohms bridged though

------------------
The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

Garmer

How much would going to a car show, where you can bring your own car in and get it checked to see how many db's it can put out.

Jim85IROC

iTrader: (2)

I paid $10 for the Kenwood dB Drag Race when I entered my car a couple years back.

------------------
The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

85TA-AZ

hey i was juts wondering if two rockford 12 inch rfz pushed by an orion cobalt 304 could do any ear damage?

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85 Trans AM
305 5sp
180,000 miles
KYB sturts front shocks rear
polyurathane bushings
solid panhard bar
new world class t-5
new clutch

Garmer

85TA-AZ, I am by no expert on this, but i would say anything can give you hearing problems, if you turn them loud enough!

Jim85IROC

iTrader: (2)

Your lawnmower can do damage, so Yes, 2 12" subs can most definately do damage.

------------------
The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

stingerssx

What? Huh? NO I DON'T WANT ANY CHEEZE!!!


If you have cheap quality equipment, and it pumps lots of distortion, you'll cause more damage.

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'82 Firebird, dead stock, 9 bolt disc rear, over 200,000 miles and still going strong, more to come...
http://www.spinfrenzy.com/stingerssx...easures.html#4

myposcamaro

'cheap quality'?????

stingerssx

In my opinion, audio bahn, thump, jdl, flea market equipment. The amps that are rated at 1900 watts, that measure out to be 2"x4", and use 22 guage power wire. Stuff like that will pump out alot of distortion, and kill your hearing faster. Even at lower volumes than better quality stuff.