37 replies to this topic

[Ben DePellegrini]

Evening y'all,

With only 5 or 6 days between here and Thomastown, I just wanted to know what Pro-tips could be given out to someone wanting to improve on their score by 0.1 or 0.2 dB in a few days.

Without giving away too many personal secrets, is there something a newbie can do to their system to do a little better? Take myself for example; all i've done to the new box is dropped it in and turned it up (and that netted me 4.2dB gain off the previous score).

How much gain is too much? My amps are 1200w rms @ 1ohm, my subs are 1000w rms each (1 ohm). How much of a whoopin' can they take without cooking them.

Hopefully this will benefit other newbies besides myself.

Ben

[bobo333]

its hard to say without getting your car on a meter to test everything because every car handles differently

the FG ive done peaked at 46hz but it was miniwalled behind the seats, try stuffing things around the box to seal off the boot from the cabin to get your setup acting more like a miniwall

also depending on your local comp rules try opening/closing windows and doors, the rear drivers side window about 4" down was the loudest for us

[Ben DePellegrini]

Good answer!

The MEA guys at Traralgon were great, they were happy to tell me and my mate Dan that an open / closed window can make a difference. My 136 a few weeks back peaked at 45Hz, but my recent 140 peaked at 40Hz, so that's a bit strange :S

Grab a whole heap of pillows blankets and fill the boot and try and get all the port air entering the cabin? A FB mate has also told me that the carpet in my port is also detrimental to my score (240x250x200 port, and I carpeted it because looking at raw wood is unsightly)

[bobo333]

yep blankets rags etc will help, then cover the lot in duct tape for optimum air tight smoothness , if you do it black i might look ok too

and yes carpetted port wont be helping, pull the carpet out and paint it if you want it to look good

[Lunchbox.inc]

+1 on everything bobo has said so far, the man knows his louds!

sealing up the boot as best you can, as well asde-carpetting are a couple of great things to do, and you'll find that song choice can play a big role in things too, in Damologists car we gained around 1db simply by finding a better song... you'd be surprised how some songs, even if they peak at the same frequency can be louder than others... so it's always worth having a play around with song choice...

[blanketman]

seat positioning
vents open / closed

[089JAY]

seat positioning
vents open / closed

Cabin heated/cooled/niether
Sunvisors up/down/combination of both
People pushing/not pushing on panels and windows
Being in/out of the car

In all honesty any combination of things may or may not work, and your car compared to your mates car that is exactly the same (as an example)can or will act differently.

My personal favourites are the ashtray and glovebox tricks. I have seen gains in a few cars from 1 or both being opened.

[Charger]

Duct tape.

That is all.

[Big_Valven]

1. Read forums endlessly - build threads of loud cars
2. Find a termlab
3. Test and tune
4. Test and tune
5. Test and tune
6. Blow something, replace it
7. Test and tune
8. Test and tune
9. Profit

[RAD]

Remove the port on your band pass, and just run a loading wall. The Port acts as like a low pass, not a high pass like ported boxes. Round over everything.

[Fever.tapaz]

how many 1200rms amp pushing how many 1000 rms subS?

Edited by Fever.tapaz, 29 May 2012 - 12:53 PM.

[Ben DePellegrini]

2x 1200w rms amps in master/slave configuration pushing 2x 1000w rms subs

[woodzyspl]

i have seen score go up and down from the rubber on magnet on or off..if can try take off without wrecking it lol

annd cover up the hole at bottom of subs, ment help magnet strength, most time gain..but it will badly effect cooling, so be carefull lol

[Lunchbox.inc]

annd cover up the hole at bottom of subs, ment help magnet strength, most time gain..but it will badly effect cooling, so be carefull lol

DEFINITELY not advisable... if you had a wall where you can basically climb in and out to apply a cover of some sorts just for burps it may be worth trying, but in your instance it would basically mean the death of your subs, playing music woul dbe out of the question really...

as for the motor boot, i've seen gains from this personally, but considering your running a 4th order, i can't see it helping in the slightest... as the rear chamber is sealed...

[RAD]

Roundover over, and applying PVC roundovers to every vertical join would help here. Rounding over the rear of the baffle, and flush mounting the baffle _may_ help.

Biggest gains i could see here is ditching the port, sealing off the cabin (including the parcel shelf) and removing carpet; that means making the back of the folding seats smooth too.

[woodzyspl]

oh yeh he got a 4th..my bad LOL i just no alot guys do it on DD subs over in states..only burps tho.. i wouldn't recomend it unless your playing for a few secconds lol

[Ben DePellegrini]

Awesome ideas guys, thanks.

A friend on FB has also told me to make a massive flare between my port opening and the ski-port opening of the backseat (ducttape and cardboard). Since this will probably be the FG's last stand, I don't want to cover heaps of crap in tape or seal up factory holes. Great suggestions for the EF though, i'm getting stuck into prepping her this weekend

[woodzyspl]

OHH biggest thing with a trunk, look around the rear bar, and cover up where the air escapes when close it..mate did and gaind a db..i never got cover mine up but burp could feel the air rushing out

Edited by woodzyspl, 29 May 2012 - 08:07 PM.

[~Samuel~]

1. Read forums endlessly - build threads of loud cars
2. Find a termlab
3. Test and tune
4. Test and tune
5. Test and tune
6. Blow something, replace it
7. Test and tune
8. Test and tune
9. Profit

[kedgenz]

size of port and shape and matrial that the port is made from, and box design make a huge differance.

download a spl app for your phone and play test tones at low frequencys around 90 to 100db you will see the peak of the car as you play different notes, then remake a cd with a set of frequencys around the gain of the car

On the day of the comp just burp with 1 frequency then change track and do another burp and see if you get a differance. make sure car is cold and dont run your equiment untill you need too.

upgrade the earth from you battary to the body of the car. also using the spl meter try moving the box around the boot of the car and see if you get a increase or decrease. the spl app you can use as a tool to get an idea off were the loudest notes are at low volumes.

upgrade the battary to the largest cca size you can fit in the car. upgrade power cables to welding cable size 50mm or thicker.

move the amps to under the seat off your car and and shorten the power cables to increase the voltage to the amps.

upgrade size of speaker wire going to subs

push on door closest to teamlab mic i did one day by mistake and got .1 db extra

kedge

[SQXPRT]

one thing I found most effective was to ensure the voltage at the amplifier was kept as high as possible.

no point having a big battery and big alternator, and then running a single 0ga to the amplifier.

you need 2x 0ga or more to reduce the voltage sag on big bass hits.

I used 2 runs of 2/0ga on my old setup, and it still dropped to 11V on a run. (mind you , that was pulling 500A from the battery )

[bigwillystyle]

Cardboard port flare is possibly a bad idea... everything that moves is converting sound energy to movement and taking away from your woofer... except in the case of your car's res freq.. this adds to your score but due to the car singing at the same freq ur playing...


Power cable DEFF the best idea... And earths... EVERY peice of cable coming out of the battery must be returned... 2 0ga runs of power you need 2 0ga earths added to the earth of batt to the body..

[hardyards]

2x 1200w rms amps in master/slave configuration pushing 2x 1000w rms subs

You could try running each amp stand-alone as well. I have this memory that back when the jaycar 1500 watt monos were quite prevalent that people found when running the amps strapped that they weren't producing as much power or weren't as loud. Your amps may not suffer the same issue but possibly worth a shot?

[SQXPRT]

Power cable DEFF the best idea... And earths... EVERY peice of cable coming out of the battery must be returned... 2 0ga runs of power you need 2 0ga earths added to the earth of batt to the body..

I disagree with this on 2 points:

1. most cars' body resistance is waaaay lower than 0ga or 2/0ga
2. rule 1 is based on experience, but may not apply.
3. you'd need to measure the volt drop from the battery ground to the amplifier ground terminal to see if that's the problem

You could try running each amp stand-alone as well. I have this memory that back when the jaycar 1500 watt monos were quite prevalent that people found when running the amps strapped that they weren't producing as much power or weren't as loud. Your amps may not suffer the same issue but possibly worth a shot?

I had the 1500W Jaycars strapped, and they were 3dB louder than separate. I was running 2 ohm plus Z rise though.

[~Samuel~]

I disagree with this on 2 points:

1. most cars' body resistance is waaaay lower than 0ga or 2/0ga
2. rule 1 is based on experience, but may not apply.
3. you'd need to measure the volt drop from the battery ground to the amplifier ground terminal to see if that's the problem

I had the 1500W Jaycars strapped, and they were 3dB louder than separate. I was running 2 ohm plus Z rise though.

At the highest levels of SPL competition competitors will have matched + and - runs, always. I have never seen a world level car built any other way.

While you are right Simon prehaps it is not about having the lowest resistance but rather equal resistance on both + and - runs.

My understanding on the mono's whas that they did indeed make rated power strapped, interestingly though in SPL doubling the power does not have to be worth 3db. On a theoretical level yes but in a car is ends up being lower or higher depending on the setup. Just because you gained 3db strapped does not mean you doubled power.

[089JAY]

The new(est) Jaycar 1k's make 1800w Strapped @ 2ohm (1ohm per board) or 2kw individually wired at 1ohm each...

[Fever.tapaz]

I disagree with this on 2 points:

1. most cars' body resistance is waaaay lower than 0ga or 2/0ga
2. rule 1 is based on experience, but may not apply.
3. you'd need to measure the volt drop from the battery ground to the amplifier ground terminal to see if that's the problem

your car loom wasn't done by idiots.. a original loom will have the same power input + as -ve.. they need to be equal to not restrain current flow from your battery ... i dont see you doing 9 run of 0 gauge on positive to the amp and putting only 1 run of 0 gauge to ground..

Things on here is that, multiple run of +ve from battery to the amp will give u a full clean constant current to the amps as for their specs and power output... AND this return power need to flow at the same rate no matter wat.. E;se you getting your cable heaten up of battery failing to do his work / draining to rapidly

so i will agree with bigwillstyle on here and say if you do 3 run of 0 gauge from battery to amp there will have to be 3 run of 0 gauge from amp to earth.. not putting 3 run of 2 or 4 gauge ..

respect the physics

Edited by Fever.tapaz, 01 June 2012 - 07:39 PM.

[089JAY]

As Will (bigwillystyle) explained to me when I first started out in SPL, it's a matter of thinking of your battery like a house, you don't pump water in via a 6inch pipe and out via a garden hose... It just won't work...

[~Samuel~]

Guys it might be worth remembering that Pulse is entitled to his opinion, he has been loud... His method was just different, still worked for him

Fever.tapaz, Pulse's loom was done by Pulse and i can assure you he is no idiot, in fact quite the opposite. He has probably gotten a lot louder than you ever have either so maybe just cool it a bit

[TMM]

Sometimes you don't need as thick a cable (or multiple cables) grounding various components. Short runs only need to handle the current, since the resistance and therefore voltage drop of a short run is negligible.

For instance, i'm going to run 0ga from my batt to the boot, then into a distro block and a short 2ga run to an amp. I only need 2ga ground cables on my amp and battery because i'm not going to be drawing any more current than 2ga can handle, and the ground cables are going to be short - therefore there is negligible difference in using 0ga ground cable. The reason you use thicker (or multiple) cables for long runs is because the voltage drop is proportional to the and length of the cable and resisitance per meter of the cable. Long cables = big voltage drop. Thicker cable = less voltage drop, even if you aren't anywhere near it's current capacity.

It doesn't matter how big your system is you can use the same logic. Spend your money where it's going to net you the biggest gains - put the thickest/most cables on the longest runs where most of your voltage drop is coming from, rather than beefing up a 30cm ground connection which isn't contributing a significant amount to the overall voltage drop. There's also the point where you are exceeding the capacity of the battery/alt, in which case adding more cables isn't going to do anything. If you try and draw too much power from a battery the voltage will drop to compensate (Power = voltage*current - if you want to draw more current the voltage will drop because the battery can only put out so much power)

Sure if you are chasing every last 0.1db go nuts and put the thickest cables you possibly can everywhere, but if you're like me and your system only costs $1500, then adding $200 of cable to get 0.1db seems like a waste of money.

annd cover up the hole at bottom of subs, ment help magnet strength, most time gain..but it will badly effect cooling, so be carefull lol

The hole provides airflow to cool the motor, and prevents pressure building up. Blocking it would probably alter the T/S parameters which could be beneficial depending on the application, but i'm imagining the tendency for the sub to cook more easily would far outweigh that...

Cardboard port flare is possibly a bad idea... everything that moves is converting sound energy to movement and taking away from your woofer... except in the case of your car's res freq.. this adds to your score but due to the car singing at the same freq ur playing...

Resonance is resonance, just depends if you can use it to your advantage or not. Not all panel resonance is good. The guys hitting 170db+ go to great lengths to STOP their car resonating at the frequency they want to burp.

Edited by TMM, 01 June 2012 - 11:29 PM.