upcoming spl competition help

[Smanleyman 15]

So last time I entered an spl I tied a guy with two 10" solo x's and a rockford fosgate t3000, and there's another in 2 weeks and im sure he will be there. I dont want to risk damaging my sub by upping the gains or voltage any more than i did last time, but perhaps i can adjust the box/ place it in my car differently?

The box is a little over 4^3 at 31, and it is about a foot back in my trunk facing into the car. Only ideas i have now are putting 45's in my corners to help flow and raise tuning, and face the sub towards the trunk. Are there any little tricks anyone knows about to give me just a .1 or .2 db gain?

[johnecon2001 82]

Honestly.. the thing that's hurting you the most is not knowing your resonant frequency of your car and tuning close to it.

31hz is going to be hard to get good numbers on.

[Smanleyman 15]

Yea i was trying to avoid building an spl only box, and hoping to just upgrade this/fine tune things as much as possible. In this box I peaked at 36hz, so im thinking 38-40 would be ideal for spl, but again I dont think I want to build another box... what is an average spl tuning in a mid-size sedan, if there is an average?

[akjay907 0]

The only thing I would suggest is to put 45s in the enclosure, but you have to take apart your enclosure.

Other than that, you should just build an enclosure and use round ports, switch them out for music when your not competing as I am assuming you have the system in your daily driver.

[Smanleyman 15]

I have absolutely no clue how to use round/aero ports, im assuming you mean have two sets of the same diameter but varying lengths for different tuning? how do I tune those I've only ever used RE's calculator...

also the owner of my local shop said its louder facing the trunk instead of into the car because of what i think he said was "quarter roll effect"

does anyone know anything about this?

[rushnrun 14]

LOCATION of meter, type of car, ect.. would help a little as well... with your tuning I'd say rear firing should be louder....

[Smanleyman 15]

sorry i guess it would help to say its a honda accord, so midsize sedan, with the mic in the windshield on passenger side, and its outlaw so windows can be wherever is loudest

[Smanleyman 15]

darn internet lag double posted...

Edited November 12, 2008 by fiq15pwnsnoobs

[rushnrun 14]

most I stress MOST of the accords I've dealt with peak at 45 hz on the dash-sealed... no clue on outlaw... probably close to the same..

drivers window down would increase spl given those requirements... what ORG?

[KU40 173]

try raising your tune a few hz (shorten the port). If, for example, you raise your tune to 35 hz and are still loudest at 36 hz, you can usually pour more power into it because the note is closer to tuning, where the cone moves the least.

If you don't want to do that, try facing your box to the rear. If your box doesn't take up all of the cross-sectional area leading into the cabin, it will be louder facing the rear almost every time. set the box so that the sub is on the passenger's side, port on driver's side.

How did you modify from being totally sealed up in your car last time? As rushrun said, usually rolling down the window on the driver's side will help the score, as will opening the door in some cases. If they allow it, you should even try fanning the door in and out while the note is playing. Also, did you have your foot on the gas to keep your RPMs up last time? Check the rules of the organization on this, as they all vary. Sometimes they let you rev up your car to 2,000 RPMs, which will get more current from your alternator for your amps to use.

Try using winISD to model your sub in the enclosure and ones like it that you may be able to modify your current box into. But don't just look at the SPL graph, check impedence, too. That's one trick that almost nobody talks about. shh.

[Smanleyman 15]

Thanks for the tips

The comp is just at a local store, so anything goes for rules pretty much, and im gonna try to get my current box as loud as possible.. the only mod I can think of without tearing it apart is to 45 all the corners by cutting the pieces and fitting them in through the sub hole and putting them in place, which should raise me 1 or 2 hz. Last time I had it revved up some, lol the guy that tied me had a focus with a fart cannon and he was bouncing of the rev limiter it sounded so bad... all I can figure is his box is horrible if he has two ten inch solox's and 3000+ watts and tied my low tuned q... but it would be awesome to win especially since I just ordered an fi shirt and no one in my town knows about them.

[Thorshammer 1]

From the box size you posted it prob takes up most of your trunk No? when you face it rear its gonna choke itself. It will create tight small areas for the air to get through into the cabin. Let it breath. Face it front port on drivers side and try to seal it to the cabin.

I found my best no's with box forward, port on driver side, centered in the trunk with it pushed all the way back against the trunk lid.

If your willing to seal it you'll gain a full Db or more. Pretty much can gaurantee it. LOL

[Thorshammer 1]

I'm gonna guess but your prob in the 43-47hz range.

[Smanleyman 15]

thanks for the placement ideas, do you mean pushed closest or farthest from the cab? i have the port on passenger side right now, so if that makes a difference you may have just won for me ... actually in the last comp since im tuned at 31 my peak was at 36, If I can manage some 45's in the corners that should go up to 37 or 38...

I dont know what the mic is and I mean its outlaw... but I got 148.2 last time I had it port passenger side about center of trunk drivers window halfway down. I would love to break 150, just dont know if it's possible

[fritosaregood 0]

i have a honda accord too and its peaks frequency seems to be 45ish. my box is big like yours so its facing forward. I found the biggest box that will fit with the sub not facing up is 32"x20"x16" outer, which gives an inner volume of 4.75cubes before woofer and port displacement.

[Smanleyman 15]

what year is yous? externally im 38x17x19 and It has a lil breathing room, after displacement its maybe 4.1... I really dont want to build an spl only box just because I dont want to spend the time for a one or two time use box and then need somewhere to store it, otherwise I could just have fun and build a 4^3 42 or so hz box and kick some arse, but its even more fun to hit high in the mid 30s with flex while everyone else is doing 42-45's and just rattling.

[fritosaregood 0]

what year is yous? externally im 38x17x19 and It has a lil breathing room, after displacement its maybe 4.1... I really dont want to build an spl only box just because I dont want to spend the time for a one or two time use box and then need somewhere to store it, otherwise I could just have fun and build a 4^3 42 or so hz box and kick some arse, but its even more fun to hit high in the mid 30s with flex while everyone else is doing 42-45's and just rattling.

Ive got a 95, you think a lot like me. not wantin to just tune a box high for better numbers. the last comp i was at had almost 10 different kids all with pro boxes bought from the local shop. all peaked at 51ish hz some hittin 141-3 with two 12s, i think a 147 with two 15" L7's. i pulled up with my low tuned box (later found out my eq was set to only use 1500 or my 3000watts, found out even later that i had a blown coil durin the comp. so about 800 watts now), with this box it peaked at 41 hz and i did a 144.1. pulled up for a another run, wanted to show all the kids that went out and bought all there stuff what a real box would do, rolled down the windows played a 25 hz tone, and got a 140.1. I cant wait till the next one to see what it really does.

here is the vids of it:

[Smanleyman 15]

nice thats a really sweet setup, Is the box some sort of modded TL?

[fritosaregood 0]

nice thats a really sweet setup, Is the box some sort of modded TL?

yea, except my port area is about 20% what it should be, but that box is the best box I have build for very low frequencies

[BenHemp 1]

Putting 45's in your corners doesn't always help. Actually, a lot of times it doesn't help. I have yet to have a box in my truck where 45's have helped; often times they have hurt my score by .5 dB or less. So far, my team has only had one box so far where 45's were successful and we only gained .3 dB from it.

[Thorshammer 1]

Putting 45's in your corners doesn't always help. Actually, a lot of times it doesn't help. I have yet to have a box in my truck where 45's have helped; often times they have hurt my score by .5 dB or less. So far, my team has only had one box so far where 45's were successful and we only gained .3 dB from it.

x2 Lost .3 whenever I put them in this current box. It might be diff. if the 45's were in first and then tuned box to vehicle . I'll find out on next box.

[Thorshammer 1]

what year is yous? externally im 38x17x19 and It has a lil breathing room, after displacement its maybe 4.1... I really dont want to build an spl only box just because I dont want to spend the time for a one or two time use box and then need somewhere to store it, otherwise I could just have fun and build a 4^3 42 or so hz box and kick some arse, but its even more fun to hit high in the mid 30s with flex while everyone else is doing 42-45's and just rattling.

I do everything i can to eliminate rattle and any excessive noise other than the sound of retarded clean Bass. A lot of people like the flex and think rattle means your loud but for me its all about what I can accomplish on the meter and still be Musical. No you don't feel 30hz and under with my current box tuned in the 40's but in real world daily radio there's not a whole lot thats 30 and under.

Just my opinion. lol

[Smanleyman 15]

the 45's in corners wouldnt be for flow purposes, but more so to decrease my volume to raise tuning, since im a little oversized and at 31hz right now, and i figured 45's made more sense than randomly sticking wood in places...

In this local comp no one has any form of sound deadener for the most part so they sit there and rattle, I have a roll of deadener in my trunk the rattles are much better and windshield flex just looks cool

[BenHemp 1]

The only way to know if they will help is to test. Sometimes you wouldn't think that they will distract airflow, but it can:) I've placed 45's under my sub, which you would think is a dead spot for air flow, but I lost. Even a small corner that takes up very little volume can hurt your score by a few tenths.

[KU40 173]

the 45's in corners wouldnt be for flow purposes, but more so to decrease my volume to raise tuning, since im a little oversized and at 31hz right now, and i figured 45's made more sense than randomly sticking wood in places...

Be careful with this. smaller boxes lose efficiency. So while raising tuning is good, lowering box volume is not.

To give a reference, I had four 12's in a sealed box a few years ago. I tried porting that box to maybe get a higher score, and I scored the exact same. 4 cubes sealed scored the same as 4 cubes and about a 42 hz tune.

Also, try duct tape. It works!