I have a 2000 Trans AM with IVA-C800 head unit, boston pro series components in the front and rear and a JL Audio 300/2 going to each pair. I also have a JL Audio 1000/1 Amp running in mono to 3 JL Audio 15" W6 subwoofers. 0 guage wiring, extra battery and 3 caps. Why am I only hitting 143Db's? I have 1.92 cubic feet going to each subwoofer...and I found out they call for 1.00-1.50 cubic feet per speaker...would the extra .4 cubic feet make this big of a difference and make me lose that much DB? Can someone please help?? I had 3 12" W6 subs in my old 96 camaro and it hit 144Db's with half the size amp and 3 smaller subs. Please someone help, I need the input!!

 

Where was the measurement done at in the car?

 

The Microphone was hung from the rear view mirror...

 

first of all.....thats the wrong place for the mic to be


secondly.........this years dbdrag official mics are about 6-7db lower than last years............and other mics that other sancioning bodies use are all different..........you can score a 150 on one mic, then a 145 on another.

 

No. This should HELP you actually.....as Got HP mentioned already, you have to take into account that all mics are not the same. Do you have access to the same mic that was used to measure your three 12"s? Damn, three 15"s in an f-body. I gotta see pics. Hook it up!

 

Three 12s should hit more than 144, let alone three 15s. Maybe it is the mic, but sounds low to me. How does the output compare audibly? Do the 15s sound louder to your ear than the 12s did? I wonder if it isn't something else...

 

Did you make the box yourself? Did you have a shop do it? Sure the box isin't leaking? Are you REALLY sure? That is a really low score..... I do 145's with three 10"s!

 

ditto, with single 12...

 

Yeah but your runnin a sub with about a mile and a half xmax..... cheater....

 

lol half a mile... I think I could approach that number with my single 12 magnum d2 and definately get there with my 15A, now I need the 15 to show up Good Luck with your problem

 

What are the sensitivity of the speakers and the ohms?

 

Are you running sealed or ported enclosure(s) for the subs?

If you're ported, what's the tuning frequency and what's the peak frequency for the box?

Placement will have an effect on output as well, however in our cars the hatch tends to minimize this effect.

What type of meter were you measured on?

For example: I meter out at 147.8 on USACIs recalibrated AudioControl meters, when tuned to 35Hz (Peaking around 40), but I metered at 143.5 on MECA's Linear-X recently with the same setup tuned to 45 Hz (Peaking around 50). The weather was cooler at the USACI show (it was in April) and the MECA show was just last month it was HOT and HUMID (rained half the day). With my last setup (sealed enclosure) I metered at 141.0 on the Linear-X and 142.9 on the recalibrated AudioControl. Very similar weather.