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post #31 of 38 Old 10-27-2012, 01:18 AM
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The point is that spl measurements in vehicles are valid and yes you can get 30db of gain and more. There is overwhelming evidence to support it.
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post #32 of 38 Old 10-27-2012, 06:29 AM
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Quote:
Originally Posted by Ricci View Post

The point is that spl measurements in vehicles are valid and yes you can get 30db of gain and more. There is overwhelming evidence to support it.
Just as valid is the evidence that when blowing into a meter I'm creating 140 plus dBs. If the meter says so it must be true. rolleyes.gif

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The Laws of Physics aren't swayed by opinion.
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post #33 of 38 Old 10-27-2012, 08:16 AM
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Apparently JBL was blowing into the mic too in all of those vehicles that result in that average in vehicle sensitivity gain graph that you linked? How about nearly every other audio manufacturer and organization that recognizes vehicle cabin gain?

If what you are claiming were true then changing the distance of the microphone from the speaker or changing the environment that the measurement is taken in from 1/8 to 1/4 to 1/2 to full space changes the efficiency of the system itself. It does not.

Are you making this claim? That the inverse square law and boundary reinforcement both do not exist and that efficiency of a system constantly changes depending on the environment and your proximity to it? Your stance cannot be true otherwise.

You cannot put an voltage sensitivity spl cap in place associated with a particular efficiency % without knowing the environment that the measurement occurs in. If the efficiency ceiling resulted in 110dB 1/2 space at 1 meter that only occurs at 1/2 space at 1 meter. It will not be 110dB at 10 meters or inside of a vehicle.
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post #34 of 38 Old 10-27-2012, 09:01 AM
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Quote:
Originally Posted by Bill Fitzmaurice View Post

Do the calcs, when you exceed 100% efficiency collect the appropriate prize. Do it with a Chevy Volt and you can power the car with the leftover juice.

"The Laws of Physics don't bow to opinion."

Right. This coming from the same person who claimed in room sensitivity of 110 db/w/m down to 1hz>? rolleyes.gif

Have you ever measured something, truly. and been able to interpret the results without smoothing, and stretching the scales to make it look better? Have you any MDAT files you care to share? Inquiring minds would like to know.

Here's a measurement of an Acoustic Elegance AV12 driver both outside of a vehicle, with the mic at 1m, and the same device located in the trunk of a Honda Accord. Nothing was changed in the gain structure at all, the sweeps were back to back. The microphone was clamped lightly into the driver's headrest, with cables going outside to the laptop for the second test.
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post #35 of 38 Old 10-27-2012, 09:09 AM
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I guess that the same argument would be used when a highly tuned road race naturally aspirated engine can exceed 110 percent VE at some RPM ranges.... since the math doesn't support it, it doesn't exist. wink.gif

Here's some reading: http://en.wikipedia.org/wiki/Volumetric_efficiency

In an engine, you can have too much of a good thing, if the exhaust is scavenging too much or there is too much overlap, it's pulling the intake charge partially out of the cylinder.
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post #36 of 38 Old 10-27-2012, 06:55 PM
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"Just as valid is the evidence that when blowing into a meter I'm creating 140 plus dBs. If the meter says so it must be true."

it is.

if you want to prove yourself in error, stand 1 meter back from your spl device, blow as hard as you can, register the reading, and report back.

Listen. It's All Good.
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post #37 of 38 Old 10-28-2012, 01:45 AM
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"In an engine, you can have too much of a good thing, if the exhaust is scavenging too much or there is too much overlap, it's pulling the intake charge partially out of the cylinder."

so? ;-)

Listen. It's All Good.
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post #38 of 38 Old 10-28-2012, 04:36 PM
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In car audio SPL comps the SPL sensor is placed on the dash. In the street trunk class the world record is 153.9 DB. The subs are more than a meter away from the sensor.

Edit:

Blowing on the Term Lab sensor will not affect the reading. You cannot blow on it and get a 140 DB reading.

http://www.termpro.com/storefront/page605.html

Term-LAB is not significantly affected by airflow. Try it yourself. Take an air hose and blow air onto a microphone. Notice the effect the airflow has on the measurement. Next, do the same thing on a Term-LAB sensor. You won't see an appreciable change in the reading.
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