Alright for all you people who compete in dB drag or anything else like that in a 3rd generation Maxima. I was just wondering what box specs you use and what size subs you have and also tuning frequency. I'm trying to do all this right the first time. Any info is much appreciated.

 

FFxMax and I competed in a Dbdrag in Maryland this past weekend. He has a 3rd gen. He hit 134.1 with a single Infinity Perfect 12 in a 1.5 cu ft sealed box with about 425 watts. Im pretty sure he used a 45hz test tone. Get your hands on the Bass Mekanik v5.0 cd, it gives great instructions on how you find your vehicle's resonant frequency and has great bass tracks.

 

holy mother f'er!!!!!!!!
I have Perfect 10's and they dont do crap....
I guess I know what i'm upgrading to

 

That 134.1 does not seem very impressive at all. I did a 137.5 with 2 old school rockford subs in a sealed box with a flea market Boss 600 Watt Max amp in a 1990 Geo Prizm. I have an AT Shocker X-treme on the way and a phd2 and i was hoping to get in then mid - upper 140's. But I'll try a 45 HZ freqency.

 

A Geo Prism and a Nissan Maxima are two VERY different vehicles, it's like half the size of a Max. Ofcourse you are going to hit higher with that car, more subs, and more power.

Again, try the Bass Mekanik CD. I used the 45hz tone and after re-figuring my car's resonant frequency, I found it to be actually 26hz and not 45hz. So that really would have improved my SPL. Dont know how I could have missed it, seems night and day now. Guess I had gone deaf temporarily from testing all that morning.

 

In my car (which is tuned for SQ, not SPL), I hit about 135 at most of my shows.. I'm running 3 JL 10w6s on a 600w PPI amp.

that's in a pretty large box (actually built it so I could port it later if I didn't like the sound of the sealed, but never got around to it.)

but with those same subs and box, I could probably easily get into the mid-140s had I ported the box, braced the car some, and found the right tuning frequency..


Another easy way to find the resonant freq of the car is to grab a CD with a 10-100hz sine wave sweep.. buy a cheapo sound level meter.. turn the sound up to about 90dB on pink noise, and then start the 10-100hz track.. Don't touch the volume ****, and watch the meter for where it indicates the loudest spl. record the time on the disc- most discs will have a way that you can tell exactly what frequency that is from the time on the track.

Most likely this will be your best frequency for SPL, but it may change tad when you crank it up and start clipping and distorting things..

and remember, in SPL, it doesn't have to sound good. I got the best SPL numbers by just maxing the volume **** and hoping nothing blew up. by going until I heard a fair amount of distortion, I would get 127-129dB.. if I maxed the volume and waited for fire, I'd get mid 130s..

Competition isn't some place where you're allowed to be scared of blowing up..
kinda like at the races though- don't ruin your car in the heat races.. you still have to be running for the final rounds. at big shows, you'll usually do several SPL runs with many different cars. if you blow a sub in the first round, you're f***ed. but when it comes time to get down and dirty, you gotta be willing to buy a new sub.

 

45Hz to 26Hz??? That's a pretty big gap, and I usually don't test in the 20-29 HZ range. But i could give it a try...(As soon as I get my headunit to work right)... But thanx for the input guys. Another thing i figured out... it really isn't the size of the car for SPL. I mean smaller sized does help but not always. My buddy and i went up to a show up in micigan and competed. We used a DD9512 with a PHD2 in a 97 Celica hatchback and did a 143.9db. But back home here in IL we but the setup back in his car and he hit a 145.7db in an '87 Cadillac Deville. I guess it's how you tun it and all that. Anyways, I really appreciate your help.

 

Uh oh....i'm in trouble. I can't even get the subs to work. I have an Alpine 7863 headunit with a temporary Alpine mrv1002 amp and temporary mtx extremes. Right now, i the subs won't even move!! The light on the amp is on, the subwoofer output on the headunit is to the max, and the rca's are good. If anything i was thinking it was the speaker terminals, but i changed the wires so it can't be that....HELP!!!

 

Take a multimeter to your sub's and make sure there's continuity through the voicecoil. If there is then probably the subs are fine and it's another problem....

 

I know the subs are fine because i hooked them up in my friend's car and they were working fine. So i still can't figure out what it is....

 

If that amp is like most Alpines it has numerous input and output options. Check all the switches to make sure they are flipped correctly. And check to see is you have the speaker wires connected to the correct amp outputs. I.E. bridged may not be the obvious choice you chose, but something less convenient. And is the really getting a signal? Do you have a second amp to hook to the same RCA's to test this? If not maybe a portable radio with RCA inputs?

 

I've already tested the system with another amp, the same outcome. I was thinking it was the headunit but i can't find any switches, and i've talked to other people who have alpine and they haven't had a problem with it.

 

You just answered the question. You tested the system with another amp and had the same results. No sound. So at least one problem is probably ahead of the amp in the signal path. Head unit, RCA's, EQ. What else is in the signal path? Check the RCA connections to the head unit and again to the amp and to any other processor in the line. If the connection is good check the fader settings. Make sure you are sending a signal to the channel you are using to feed the amp. If you are using a sub woofer output check the level settings for that. Last I would say park next to a friend with a system. Connect your headunit to his/her system and his/her headunit to your amp/system. Does his system now have 0 output and yours work fine? If so it must be the headunit or some section of the headunit.