os stroker 15d2s airspace and port calculations anyone

[bogart]

Well, I've procured two of these subs now and I do beleive that I'm gonna run em....found one tid bit that said they were run in 4.25net, 56.5 port area tuned to 40hz....they are rated at 1200 but these are monsters..have heard the 18s start to cycle down and the standing wave felt like it was going to lift you up in the car....was impressive to say the least...but this was years ago...anyway I've ordered the new recones for both with the improved surround and the extended coils...supposedly ten db per watt greater then the new ones which I've run and thought it was ok till the amps went down...b stock on a four amp bridge...not for the exl1200's let me tell ya...

anyway...if anyone has run these let me know what worked for you and what didn't. each will be run on a pca2000d...lots of overhead...and they will be in a trunk....can ekk out about 12 ft and still have room enough for the amps and such....thanks fellas

[Jacampb2]

Did you get the info you needed from the manual? If not, what freq are you planning to tune the box to. What are you trying to do with it, just pure and simple SPL? We can probably help, but we need more info. I put 1 of my 4 12d2's in my truck just to see how it sounded, and I am under the recommended air space I think, 2.9ft^3 (gross iirc) and tuned at 39hz. Anyhow, my point is, you don't have to do the box in the manual, but it is a good starting point.

About the re-cones, got a link? You have piqued my interest.

Later,
Jason

[bogart]

the recones havn't arrived yet....we'll see what they are all about. Got them off em ebay...there is a company that sells the kits and read abit about em....so we'll see....supposedly...they up the powerhandling to about 1500 rms...and add enough length to the coil to push the xmax up to around 2 inches....ordered them earlier this week so they ought to be here soon. Neither sub needs it as both are functional but they have the original cones in them and they seem as if they've gotten brittle with age. One has a small tear in the baffle but could be siliconed quite easily...if you just run stroker on ebay you'll see them. using rf cones and foam from the old old 15he2's and winding the coils....seem to be okay....once in the I'll write a reveiw of em here so poeple will know...

I've not seen the kits for the 12s....just the 18s and the 15s...but you can talk to em....

I just wasn't sure where to start...want them to be somewhat accoustic. currently running a one note wonder and I am getting tired of paul wall and such so I'll probably tune them to around 38 to 40hz...the recommended 36 hz seems pretty low....are you running slot ports or tubes...did you experiment with them at all? I may run external ports and run em up through the rear deck...so each enclosure would be right under 3 3/4 foot. I did it with rfls a few years ago and cut the old back seat to run the port through and it ran well but the tuning was off a bit...

so I've got a ball park...may go bigger with a higher tuned port....just want to see how the driver is going to react to the recommended box first and go from there....I've heard the 18s in huge boxes and it was badass...but a trunk is a lot different then a hatchback and the reasonance and cancelation in the trunk is terrible in my car....the solo's have broken all of the stock trim clips and the tirewell bracket and now it just goes nuts...plus the trunk now pops open from vibration and compression...adding electromagnets from security system to deal with that issue at present... and yes the manual was a big help...been on the web for days looking for it and it was here the entire time....

[Jacampb2]

I am by no means an expert on this, and the stroker 12d2 in my p/u right now is the first ported box I have ever built. My understanding is that for a more musical ported enclosure, you tune to as low a frequency as possible (within reason). The enclosure will have more gain near the tuning frequency than at any frequency above it. The boxes recommended by CV maximize this peak to get the highest SPL at the tuned frequency. For a more musical enclosure, the goal would be ideally to minimize this peak and keep the frequency response as flat as possible across the subs frequency range.

Playing the sub at frequencies LOWER than the tuning frequency will sound terrible and can actually damage the sub. At frequencies bellow the tuning frequency the port unloads and the enclosure acts similar to infinite baffle.

IIRC to flatten the frequency response, and tune to lower frequencies, you need to actually increase the volume of the box. This may not be feasible depending on your space constraints.

I built my box with a 4x5x16 rectangular port. This is much smaller than the recommended CV port, but I did the math both manually and modeled it in WINiSD and both agreed that it would have low enough air speed to be sufficient. As you decrease port size, air speed goes up until you get very noticeable port noise. My design was more forced by space constraints than by finding the perfect box. 16" long was about the longest port I was going to be able to cram in the box, and 4x5 put it at a reasonable tuning frequency.

Keep in mind that you can look though other manufactures box recommendations, and see if you can find something with a frequency response that you like. When you port a box, you are tuning the enclosure, not the sub, mechanical differences in subs will have an end effect on the over all tuning, it will similar to the enclosures response but likely not as flat.

Later,
Jason