Enclosure design RE MX-12 in CRX for Street A

7 years 11 months ago - 7 years 11 months ago #1 by Tezzating
Takin' it to the *ISD :P

If you dont have it.. Download WinISD Pro here (registered members).

RE-MX12 WinISD Driver Files
RE-MX12 in 1.85 cubes Project file

Copy the driver file to the DRIVERS directory of WINISD & the MX12 project file to the PROJECTS directory.


If you're too lazy to download 2 little files, or register to download and install WinISD Pro. Here's some graphs..

Transfer Function Magnitude @ 52hz (exhibits total transfer gain of 11dB @ 58hz):

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Impedence rise based on RE 1.7ohm @ series wiring @ 52hz (exhibited 6.2ohm @ 58hz):

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@ 500W input exhibits Linear Excursions:
@52hz 3.2mm
@58hz 5.7mm

Of cource all of this doesnt mean all that much until its in the the car and then the laws of physics play merry hell with the perfect world projections of WinISD :P

Which is to say as long as we find a total system peak somewhere in the vicinity of 52-58hz we should be OK.. but I'd prefer to see it lower than higher.

Its 1.85 cubic foot with a single 6" port, 9.5" long + a 1.5" flare. Gunna make a 11.5" + Flare port just incase 10" was too lairy :P.

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7 years 11 months ago - 7 years 11 months ago #2 by Tezzating
Crunched some numbers.. Using our super cool online enclosure volume calculator (for registered members !)
14x19.5x20 gives me 2.19 cubes with 1" walls.
accomodating 0.3 cubes of woofer, 45's and misc bits, 2.19 cubes comes down to the 1.85 I want.

So I guess it'll end up looking like this:

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Only about half the size, with less port :P.
Ya'll might remember this was Jason's CRX setup with one amp..
2x 9512", 1x Z1, 8x 0g runs (4 positive, 4 negative).. made from 32mm MDF with a 10" storm water drain pipe flared. We never tuned the port or the box ! haha.

150.8 with a screwed old Blue Top G34.
151.8 with an Odyssey 2150.
152.8 with a second Z1 and we did something else I cant remember now ?

[edit: The headunit skipped & shutdown @ 151.8. We put a 1 farad cap on the headunit, added a stacker and added the second Z1]

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7 years 11 months ago - 7 years 11 months ago #3 by Tezzating
Actually I was just sniffing around a thread by Terry Brocks over on TermPro.com about HIS red CRX and came across this shot:

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In which you can quite clearly see his old 158dB with 4x 10"s enclosure and his newer 159dB with 4x 10"s enclosures both DONT use 45's ???

Anyone have any feedback on this ? I'll gladly not waste 2 hours doing 45's if they're not gunna be helping me :O


[edit: train spotters will note Jasons box & Terry Mk2 box are almost identical.. IIRC Terry designed Jason's enclosure ;) ]

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7 years 11 months ago - 7 years 11 months ago #4 by Tezzating
To add to this... He also slapped Dynamat into his CRX.
Ignored the outer skin, one layer on the inner frame, then a second layed on the back of the door cards. Repeated in the back/plastics, and did 2 layers of dynamat on the floor pan.. which equated to 1.3dB gains. INTERESTING.

As I need to take red's door skins out anyway (replace window, replace mirror), I might give this a lash on the front doors :D. Depending on cash levels :(

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7 years 11 months ago #5 by zion187reigneth
nice info, curious which of the 2 boxes in the pic is the newer one?
7 years 11 months ago #6 by Tezzating
The New box is the darker (resin covered) one. :)

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7 years 11 months ago - 7 years 11 months ago #7 by Andy
45s dont work IMO......only thing they do is take up internal volume.

Right before finals i built another box and didnt add 45s, 150.5. Added 45s and score went to consistent 150.3s. ;)

Dont bother, or if you like test it.

Probably alot of the gain in those boxes was the single port.
7 years 11 months ago #8 by Dylan
It would be interesting to test how much of a gain the port flair adds. As well as the box shape.
7 years 11 months ago #9 by Andy
Well with my single 10" port i gained 1.5db by flaring both ends, and a further 0.4db by making the port exit area VERY smooth, which involved several coats of resin and surfboard wax ;)
7 years 11 months ago #10 by Dylan
Maybe I should work on some flared ports for the box I have here then. as +1.5dB would put me in the 149dB+ territory.
7 years 11 months ago #11 by Andy
Unfortunately i lost all my pics of the box build, showing the work i did internally.....but its still in the HDD that dosent crash - the brain (well, minor crashes sometimes haha).
7 years 11 months ago #12 by Tezzating
Yeah my problem always was running on a truncated time table, so didnt really get a chance to test a lot of stuff.
I do know we gained in Jasons CRX with the flare on the 10" port, but how much I cant say. Nothing huge, a few points, but everything counts.
To go from 148.1 to 150.8, all we did was remove the one dead Z1 ;), add 2 more 0g runs (4 total), upgraded the 4g earths to 0g (engine bay), flared the port, moved the box forward 4", and re-arranged the seats & sunvisors.

There's 2 big differences in Terry's 2 designs. One, two ports versus one. Two, split chamber versus common. The split design changed his note a bit, and the woofers/car liked that more.
He also resined the new one which probably helped.

I'm picking up some plywood sheets from work (packaging materials from pallats LOL) today and having a lash at this box design on the weekend.

Thinking of dropping some dollars into a Dynamat pack and doing the floor pan and doors. Need to remove the seats (they're on the wrong sides !) anyway, same as opening the doors to fix the glass and mirror.

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7 years 11 months ago - 7 years 11 months ago #13 by Tezzating
CRX maximum enclosure size, whilst remaining under window line and behind B pillar with full trim:

Width 35" (maximum between wheel arches)
Depth 41" (from B pillar to tailgate area)
Height 15.5" (from floor to window line)

Distance from front of battery, to back of tool box, along floor pan:
254cm (2.5 meters)
8.3 foot

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7 years 11 months ago #14 by Andy
Nice, atleast now i know i can fit 15s front firing in a CRX and still be under the window line ;)


LOL @ a 2.5m power cable run, half the length if my car :laugh:
7 years 11 months ago #15 by Dylan
You going to buy a CRX mate?
7 years 11 months ago #16 by Tezzating
If you take out the toolbox and floor cover you'll get another inch or so (and keep the carpets), but thats getting a big dodgy :P

Advantages North American CRX have over Jap/Euro/Oz:

1. Shorter cable runs by 3-4 foot.. battery is on the Right. No drivers controls there in an LHD :P
2. Vinyl backed seats (instead of plush)
3. Vinyl door cards (instead of velvet)
4. Vinyl dash (instead of velvet)
5. AC optional means not many have AC.. which leaves a HUGE 2.5" x 3" hole plugged with a grommet

Mostly I posted those sizes 'cos I knew I'd forget my notebook at work (which I did) :P

Picking up Phillips drivers today, chipboard screws, adhesive and duct tape.

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7 years 11 months ago #17 by Dylan
WOO, sounds like the start of a build!!
7 years 11 months ago #18 by Tezzating
Yeah headed to Home Depot to pickup pipe and adhesives.

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7 years 11 months ago #19 by Dylan
That excites me!
7 years 11 months ago #20 by Andy
Dylan wrote:

You going to buy a CRX mate?


Yeah eventually, just gotta find one for the right price.
Buying it mainly for performance, but when im happy with the speed / handling im gonna throw in a street C setup. Ive always wanted to beat George's 155s, the only way to do that is go CRX ;)
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