SPL Car


I’m currently building an SPL car with a mate which I will be traveling around with this year and competing, in conjunction with my car (PYROAY SQ car) which will be back to full competition mode and ready in April for Autosalon.

I thought I’d give people an idea about what is required to build a good SPL car and provide some insights and tips as I go through so you can pick up some good hints and learn as you go. A lot of SPL’ers don’t help others as it’s not in their best interests but I hope you can learn something from the project I am building and if your game build your own system and bring it out and compete. Just for fun of course….




Aim
Pretty ambitious and despite having never built an SPL car or even competed in SPL before I aim to build the car and get 150dB+ and get an Australian SPL record. I am designing the car so that I can easily change a few things and enter it into a number of different classes over the course of the year with the ultimate goal of getting at least 1 Australian SPL record and hopefully get it into the top 6 (ideally top 3) Australian SPL scores in some of the other classes in which I will enter it.


Car
1986 Ford Telstar TX-5 Turbo – owned by my mate Robert O’Mera
Gunmetal Grey nothing too fancy but good suspension as it’s going to have to take some weight


Audio Equipment
2 x SP15S, DLS quad (x4) 2ohm voice coils. Rated at 2,000rms per voice coil
4 x CAD-15, DLS Monoblocks 1,600rms @ 1ohm (Strapped 3,200rms pr @ 2ohm)

Configuration
2 CAD-15’s strapped with 3,200rms to each subwoofer (voice coils series then parallel) so 6,400rms total.





Other Equipment
Alpine headunit of some sort
DLS 4â€￾ front co-axials
DLS 2 x 6.5â€￾ midbasses for a 3 way front stage
DLS probably CA41 (4 x 70rms) 4 channel amplifier for front stage semi active


Battery and Cabling Supercharge Gold Heavy Duty Truck Battery 900CCA
(good battery, not the best but running out of money)
4 x 0g from front battery to amps.



Box
9c/f internal space about 11/c/f all up.
25mm MDF walls heavily braced, 25mm base, 75mm MDF top where the subs are mounted. All braced internally and with rounded off corners inc fibreglassing all corners

We will play with tuning but at this stage tuned to 40htz, with a peak freqwuency of around 54htz

Your thoughts?
Will we get the 150dB?




I will get some pics up tomorrow.

Last edited by pyroay on Wed Feb 08, 2006 8:05 am, edited 1 time in total.

running out of money on the battery hahahaha .. what is the prize if you win.

f**k thats nuts man

good luck!

What does SPL stand for?

Sound pressure level. Measurement of pressure (i.e. volume).

A car horn is about 120db... shotgun about 130db... (will damage hearing after about 4 minutes of exposure per day).... 140db is the threshold of pain for most people....

150+db is insane pyro!! lol.

Best of luck tho - im sure it'll be fun either way!!

Yeah thanks. Jsust to clarify people like most of my projects this will be a used daily driver but not with the system playing anywhere near that volume. the only time it will see 150dB is at comps.

What does the current Pioneer sedan reach, i thought is was around the 150db.

Also what about the Pioneer Ute thingy, i thought these cars already did do 150db.

I must have been lied to......Good luck it should sound rather loud

It depends on class too though.

The current loudest car is around 164dB but not in street class. Thjat is extreme class where you can fill the car with cement and use as many amps and batteries as you like.

Street Class (or int his case Street Max) mewan you must have have part of the car usable. In street class it the whole cabin from the trailing edge of the back sdoors in street max its fromt he B pillars back.

Not sure what the Pioneer Sedan, or Ute play at but i'll try to find out...

with that gear dude i reckon u should get 150+ definently....thats insane....id get a better batter setup tho... save abit dude look at ya cars lol and still heaps of time.

And what no caps or multiple parrallel batteries almost thought u would have gone one amp per coil

s**t dude i got 149.2 in my last car and that was 2 crossfire subs with a crossfire 1000d amp to each sub! and that was in a false floor! not even ported! if u dont get over 150 with that you doin somethin wrong!
good luck anywaz dude...
oh by the way my last car was an eb...not a small car!

Was the 150 on the new Term Lab not the audio control or the old lab system?

Big Kev - can't run anymore than one battery as it changes the class. You can only run one battery nit he standard location up to a mxaimum of 13,110cm sq.

So that's the size battery we are running. In our set-up with more than one battery you get bumped to Super Street Class.

In Street Max 3-4 (which we will also be competing in with 4 x SP15S and 8 x CAD15's) we can run a second battery and in Super Street 1-2 no wall we can run unlimited so there will definately be a few more thrown in their then.

Last edited by pyroay on Wed Feb 08, 2006 7:59 am, edited 1 time in total.

Ok
SPL Hint 1:
Avoid parallel walls. Sound waves can travel along them evenly and you can get cancellation. By slightly sloping the walls, the sound waves travel differently and you can avoid this problem


This box design is slightly sloping with a height of 380mm at one end and 310mm at the other. The sides are parallel but i have put some bracing inside the box on the sides to break it up a little so waves wont travel up and down inside it.

and this is where u know your dealing with a smart dude aaron sounds like its gonna be a wicked setup ithink you will get the 150db+ mark....sorry dude yeah forgot about battery limits and classes....only cometed once...cant remeber what i was in super street 3-4 i think...cause of the 4x 12" woofers and 3 batteries

Yeah 3 batteries puts you in SS class straight away even with only 1 woofer and amp..

The only other classes that allow you to run more than one battery are Street C (max of 2) and Street Max 3-34 (max of 2). Of course extreme class almost anything goes...

Exactly how much does this sort of thing cost?