From: Brian, [206-48-63-209.caribsurf.com]
Subject: Re: You're confused in car audio.....
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>There's two ways you can hear bass - either through a >sound wave or through pressure changes in an enclosed >volume. Agreed, but remember that when you transition from the former to the latter, you can expect a rise in response of about 12dB/oct as the frequency decreases. >It would be interesting to try if the same happens >ina car - eg. does 20 Hz disappear when you open the >door? We're talking about two different things here. When you open a car door, you're basically converting the car from a leaky sealed volume with a speaker contained therein, to an unknown alignment (cabin volume with a vent the size of the door perhaps, or a badly loaded horn with the door as the mouth). You can't simply compare the difference between door close and door open, and say that because of that difference you lose 20 Hz bass in a car audio environment. Example:  The above is a graph of my car's transfer function, captured using TrueRTA in relative response mode (the mic was placed near to the driver, then relative response was enabled and the mic was placed at the listening position). Note the rising bass response, caused by the enclosed cabin. The rise extends to below 20 Hz, indicating that there is an increase in 20 Hz response when the subwoofer is used in a car audio environment.  This is the difference caused in bass response when one door is opened. As you can see, it's not anywhere near the inverse of the graph above. That's because we're still in a car audio environment, but this time we've shifted the parameters a little by opening one door. |
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Follow Ups:
- Re: You're confused in car audio..... Andy 06-Jul-2003 18:06:36 (0)