unexplained loss of spl

whats up everybody, i recently went through the line at a usaci sponsored competition for the first time in about 3 years. im running a RE SX18 in a 6ft^3 ported box tuned to about 36hz and all that is sitting in the extented cab of my ford ranger. but anyway, i used to hit right around 150db plus or minus a db, and this was about 3 years ago. i still have the same exact system, nothing changed except i had to install a new active crossover. 

this time around, i went through the line and actually turned up the boost on my crossover even more than i ever usually do even for a comp, and only hit a 142.4! a loss of about 8db. my question is, does anyone know if a well broken-in, 3 year old subwoofer, which still plays perfectly on any music i throw at it, can cause such a huge drop in decibels.  or can you think of anything else that could be the cause.

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hey im taking a shot in the dark here but what kind of meter was it each time and do you think that the technology of meters has changed over the past 3 years giving you those different numbers and making it more accurate? like i said this is just a shot in the dark pls dont grill me for asking. lol

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-ETS-
Escape The Scilence

nope, it was a term-lab meter every time. my score is usually less if they use some other meter.

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Two things: first, yes it is not only possible but certain that the gear changes as it ages.  And second, you changed your system when you changed the crossover.  Anytime anything in the signal changes, the results cannot always be predicted.

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DYohn] wrote:

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wo things: first, yes it is not only possible but certain that the gear changes as it ages.  And second, you changed your system when you changed the crossover.  Anytime anything in the signal changes, the results cannot always be predicted.

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i know what you are saying but i really dont think that the crossover had anything to do with it and the reason is simple, its a better crossover with a higher voltage output than my old kicker crossover and at the time of the competition it was turned way up, probably way more than it should have been.  i did a little research on the difference between the crossovers and all i found out was that the new crossover outputs 7.5 volts and the old one only did 5 volts. and the other difference was that the crossover slope on the new one is 12db and the kicker had an 18db slope. so when you think about it it doesn't make any sense to blame the new crossover.

any other ideas?

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 Do you still have the old x-over?  If so could you hook it back up, Have your system metered and if its 150 db+-Then you would Know it was the new X-over .....But I dont Know if that is feasible for You to do.

I stand by my statements.

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boogeyman wrote:

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 Do you still have the old x-over?  If so could you hook it back up, Have your system metered and if its 150 db+-Then you would Know it was the new X-over .....But I dont Know if that is feasible for You to do.

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the old crossover is shot, it self destructed at the competition in question, so i had to make a quick swap to the crossover thats in there now. which by the way is a Cache CEX 3-way crossover. 

DYohn, do you think its possible that there is some sort of output limiter/protection if you send it a clipped signal?  yeah, it sounds stupid but i figured i'd ask because it is supposed to be more of a sound quality device than a bass processor.

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Is this the exact same vehicle? Did you replace anything like the alternator or anything like that? I would think a power issue could be a cause.

Like I said before, after three years you cannot expect the exact same performance.  Also, whenever you change a component it is impossible to know exactly how it will effect the system until you test it.

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whiterob wrote:

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Is this the exact same vehicle? Did you replace anything like the alternator or anything like that? I would think a power issue could be a cause.

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same vehicle, same alternator, same amp, same woofer, same box, same wire, same locations, same battery.   im starting to think i just need a total overhaul.  thanks everybody for your input. im not too worried about it because my system is more about sound quality anyway but i guess im not entering it into any more competitions

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Doesn't Fi Sell Re-cone kits?
That could be cheaper than a total new system

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UNLABELED Custom Car Club President

blackcivichatch wrote:

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Doesn't Fi Sell Re-cone kits?
That could be cheaper than a total new system

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id rather buy a new sub than re-cone it.  and i didn't mean i was going to buy a whole new system, i just need to fix all of the small problems that i was always just too lazy to address. i know i have always had a voltage drop when i really turn the sub up so i need to do the big three and maybe get a new alternator, check my grounds to make sure they are still good, just minor stuff like that should get me at leats back into the high 140's

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