posted
Why does the loudest frequency in a setup rise as the two "enclosures" in a vehicle( the box and the air in front of it) get closer to the same size?? IE bigger box/smaller cabin.
I have noticed the loudest measured frequency in this situation rise from 13-14 over tuning with a ratio of 4 to one and above(cabin to box), and that change to 24-30 hz above tuning when the ratio is 1 to 1.
As the resistance of each side of the speaker goes to equal, the energy driving the speaker is more and more capable of driving the speaker an equal amount in each direction, making a wave of greatest possible amplitude for a given power input.. Also, this increases the lower energy "resonance" by the aforementioned equalization of air resistance.
ShadowStar
At least, I think so
ShadowStar
------------------ HEY! I'm looking for a CHEAP used Clarion Thunderdome.. Hook me up!
If the sub moves, use it. If the tweet's metal, lose it. If you car doesn't have Oz, I just can't excuse it.
Posts: 2579 | From: Somewhere In the Northeast | Registered: May 1999
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posted
OK, I see your point. But I do not see how this could raise the freq. It seems to me this would mainly help lower freq where the subwoofer needs to move more, but I am talking about freqs going from 55-60 hz up to 70-75 hz. How could this phenomenon occur due to the point you made?
I was thinking about this earlier while out on a bike ride. I couldn't come up with an explanation that made any sense. On a somewhat related note: does anyone know where I could find the equations that govern the frequency response in different enclosures. I know that you can model the box, port, speaker interaction like an electrical circuit, but I haven't been able to find the equations.
posted
with a 4to1 you have more room to play w/ lower frequencies. but with 1to1 you have much less space (and probably distance) to lower freqs don't respond as well as a higher freq would.
am i close???
------------------ I respect any sub that can make me pass out.
posted
I dont think that has much to do with it. I have taken the response plots for several test setups,with several different ratios, and in same test/different ratio tests, the response curve( when entered in spreadsheet form and graphed) is always the same curve just shifted up in frequency and spl. If what you mentioned was playing a part, the actual curve would change shape, having a faster rolloff on the low end, and this doesn't occur.
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