im now off the road till frign 2014 dont ask me why but yeah silly me F'd up SO got soem time on my hands and was about to throw the pulsar at the local sims metal then Devinchy gave me an idea!


the car isnt too far gone and better than doing it to something re sellable so why not?

ill be ripping the whole interior out soon and starting within the next 3-4 weeks (gotta gather parts etc)

so based on the woofers i plan to use (still using the T4 15s i think they are under rated and a decent sub) pumping around 5k rms roughly

how large should the chamer be and how will i calc the port size for it?

Cheers (need something to do at home lol)

been offered something instead all good i will take over from soembody else its going to be fun ;-)

good stuff.

Generally speaking, just make the box as big as possible, then fit the baffle allowing for the biggest port area possible (whilst still fitting the woofers in properly)

my mate is running 5500-6000watts into t4-15 in a 5.5cu ft box with 2 6in ports, hit a best of 147.6. Still more in it yet, but good luck with your system.

im taking a known members car

5-6k into how many T4s was he running?

i will be running 4 on 2 XXX6500's

you bought billys old car ay

I wouldnt be putting that up until he gets alot louder, with a single 15 i was doing 148.3 with 1500rms and that was the 1st box I built for my car.

i love wall cars good luck and make sure you take heaps of pics of the build so we can see

yea trism you got it

sorting out this week
cant wait though will be changing the appearance somewat it will be basically all his work that matters

O i forgot to add that his car is not walled, hey roo since ive got your sub now and going to feed over 5000watts into it what do you think i'll get

That would all depend on a couple of things...... Will Roo screw the sub in and will he wire up both voice coils correctly????

i think thats great, should be loud

brad shhh

Beacuse this is the SPL section ill guess its a one note box.

Ive been looking for a link that allows you to plot impeadence rise on a graph, giving you a sharp peak at tuning freq.

All you need is a multimeter, a resistor, a tone cd with 1hz increments, and excel and you can graph it.

Its the easiest way ive found so far to check tuning freq. When i find the link again ill throw it in here.

At your service – I hope you enjoy this thread.

Everyone has heard of the mystical term impedance rise, but more & more I read and hear people saying “I’m not worried about that yo…”
Well, sad to say, but that person will not see what they expect from their Acme 9000.
Why? Impedance rise.

Now, I do not understand all of the physics behind this… But I do understand the end result and a portion of the process. Hopefully, someone will take something from this post and make use of it

First, and foremost: Immediately following is how you go about mapping a given loaded enclosure for impedance shift (rise or fall). If you are brave, keep reading for a little background on Impedance shift (both thermal & EMF related).

This procedure also can be used to find the real world tuning of any ported enclosure, in a given install.
More importantly, in my opinion, the second method gives the example of the best way to go about seeing what you amplifier ‘puts out’. With regards to this, any given amplifier will produce different results in different install.

With either method, You are going to need a few basic things:

*At least one Voltmeter (VAC) –or- DMM.
*A supply of test tones. Preferably 20-80hz - NOT a sweep
*An audio system: Signal source, amplifier, drivers, enclosure
*A calculator of spreadsheet program.
*Pen & Paper

Throw in a clamp meter –or- a resistor (Radio Shack) and you’re in business.

Resistor method:

You are going to need the items mentioned above, but, in addition:

An additional VOM/DMM would be helpful.
* A 10 ohm resistor. Preferably non-inductive and able to handle 10 watts or better.

That’s it, the resistor should cost no more then $5, and you probably have a DMM or two by now. You’re going to be amazed what you find out for a $5 investment.

To map any enclosure, you need to measure the impedance. Unfortunately, Impedance changes as the driver’s coils travel. Thankfully, Ohm taught us a few different ways to find impedance. Enter the math:

QUOTEVr(resistor) = Va(amp) * [R(resistor)/[R(resistor) + Rs(speaker)]]
We want Rs(speaker), solving gives...
Rs(speaker) = [[Va(amp)* R(resistor)]/Vr(resistor)] - R(resistor)
Confused? Open up Microsoft Excel. Copy & Paste:
QUOTERs = (Va*(R/Vr))-R
Where:
Rs = in box impedance of the driver
R = the resistor that you’ve purchased (10ohm in my example)
Va = Voltage at amp output terminals
Vr = Voltage at resistor
As for the physical how to:
Make a voltage divider circuit:

->A 10ohm resistor in series across the speaker wire / terminals
->Connect the speaker wire to an amp that is connected your source unit
->Secure your VOM’s leads into a.)The amplifer’s output terminals b.)The resistors terminals (or ends) c.) Set both to VAC
->Power up and play your test tones AT A LOW VOLUME.
->Record the readings from each VOM (or switch leads quickly from amplifier terminals to resistor terminals quickly)
->Power down and plug your readings into the spreadsheet

annnnd You’re done.



A couple of important points:

*Use LOW volume. The resistor probably cannot handle very much wattage. You smoke it, bad things could happen.
*Though tedious, you should try to use 1hz increments. 5hz at the most. A lot can change in your driver over a 5hz band.
*The average DMM sample twice per second (iirc), so you will need each tone to be at least 5 seconds long – this’ll give you a chance to glance at both and write them down. At each frequency note the voltage at the amp terminals and voltage at the resistor.
*I would put the results into Excel then plot Rs and frequency... make a line chart in your worksheet, it’ll be so much easier to grasp once you have a visual.
*I dunno how much the listening area (car interior or room shape) come into play… If you are testing in-car, open the windows to simulate your normal listening space. Unless You are only concerned about the sealed interior (a la dBdrag)

Now… to move onto the physics…

By now, you’re either heading to your amp with tools in hand –or- wondering where the heck impedance rise comes from.

This is where I’ve gotten to in my studies… so I don’t have all of the answers. Please read on with this in mind. These are my findings & summations. The following is only a jumping off point… I am not an Electrical Engineer.

-Nick

EMF, Motor cooling, and enclosure design. These are the three biggest causes of impedance shift.
*Back EMF is not a complete negative, it provides a measure of checks & balances… but that’s over the head of this thread and Me.
*Motor cooling obviously affects the nature of the coil. The hotter the metal coil, the higher it’s impedance. A well designed motor cooling system (top plate vents, vented pole pieces, pole piece type, etc…) will greatly help the driver’s stability and longevity. I’ll stop here and refer you to the link below.
*Enclosure design will obviously affect a driver in many ways. Port area, port tuning, port coupling, vB, etc… Cone speed has a whole lot to do with the ability of the motor to work efficiently. Again… I’ll refer to a link below



Tis a good read,
source: <a href="http://www.soundsolutionsaudio.com/forum/i...?showtopic=2690" target="_blank">http://www.soundsolutionsaudio.com/forum/i...?showtopic=2690</a>

well its official the suzuki was picked up today and should be arriving at its new home in about 1 hour. it was a little sad to see it go but its going to a good home where it will continue to be a sweet SPL car.

good luck with it DW_1 luck im sure you wont need as its going to be loud with the gear you plan to run. i look forward to seeing it in the lanes with its new look once you have it ready.

i hope it stays a record setter, which im sure it will be if you finish of the little things that i never got around to completing with the enclosure.

when ya have it ready and bring it out for its first comp. will tell you and show you all the little fiddley bits within the car that make it go louder.
but anyway take care of the beastie and i will see you around.



cheers billy

tks mate will be in touch with both you and Leo
i cant wait mate

tks billy and devinchy the car arrived this arvo and i cant wait to get to work on it

i will more than likely be giving it a new look though but everybody will always know the work was billy's

look fwd to sharing ideas with you guys both top blokes

ok my next quest is starting ive located all my parts

going ot be running 4x soundstream T4-15's and 2x SS XXX6500's

have 2 D34 yellow tops i just dont know what class i should be in to be competitive so where i should have batteries and should i have another or not as im told the class rules have changed now

also how many runs am i going to need to the back so far have about 5 runs of each but im thinking ill need many more now

need some help

Ok Ali your yellow tops are the d31 series and yes if you could located a couple more it would be more in your favour i would have one up the front and run at least 8 + and 8- from front to the back and that would put you in
super street 3-4 but if you wanted to go street max you will need to drop a battery but i will call you later today.
Sorry i didn't call last night we just had a few family probs last night.

all good Leo mate i will get some more runs i just need to get the busbars and figure how to put them on the batteries
2 subs in just fibreglassed the corners i little so they are rounder on the back walls and painted it all black inside (i dont want it glowing from the street )


so 8 runs each way? wow man lol

drifte.au none of your links are working?

The links in the tute are 3 or 4 years old.

The link to the thread (source:) works

installing everything probably this weekend
so over the next 10 days should have given it a go though im gonna need a semi decent head unit with remote (not after anything wow just something sufficient for SPL)

2x D31 yellow tops
16 runs of 00g cable
4x soundstream T4 15 subs
2x XXX6500 goliath Amps

and a peice of crap pioneer cd player for now (does muck up sometimes)

will post pics shortly in install/rides forum

will have some important tech support from both billy 79 and Devinchy and really cant wait to get it happening!!!

wish me luck

Sounds good dude

pics or ban

pics in rides / installs man