CadillacMatt

Hey all It seems the general consensus is to use 14"-16" or port area per cube for slot ports, and that flared round ports (aka aeroports) are recommended @ 8"-12" per cube... Now I was thinking about fabricating a port out of Sonotube or the like, and possibly creating some flared ends using fiberglass... What would be a good port area to shoot for? I was figuring if I used a 10" tube that would give me ~78in² Av which for a 6.5ft³ enclosure after displacements nails it right at 12" per cube. For an 18" driver. Thanks

Commenced building of the box today. Outside dims 24D x 16H x 39W. Net volume will be around 6~6.5ft³. Only thing I didn't pick up today was the PVC for the port. Going to do that tomorrow. My makeshift workbench All sliced up

Thanks Steve I hear you, I trust your judgement Thanks, I have followed GMonk's builds for a while, he does know a hell of a lot. All things considered, I might be better off just building a wide, shallow ported box @ 5-6ft³ and if I crunched my numbers right then I can have both the driver and the port facing upwards deep in the trunk, firing straight up at the hole in the rear deck. This would also allow me to build a "dam" between the cabin and trunk that would seal the trunk off. Loved the way my old setup sounded and it wasn't even sealed off, so I have high hopes.

But I thought you ran it in 6 cubes on an SAZ-3000D?

Thanks Chop glad to hear from you it's been a while! The rear deck is already wide open, with my last setup I had subs and port facing forward not sealed off but sounded killer. I was really looking forward to one as well, but it seems that nobody seems to know anything technical about this sub I have, and short of going out and purchasing precision audio measuring equipment to determine the T/S parameters of it building a bandpass would be a shot in the shit. However, all that studying up I did will come in handy however, I figure the extra stiff suspension that begets greater power handling will allow me to design a larger-than-average ported enclosure (maybe 7 cubes or so) and tuning @ 32Hz... after plugging some numbers into WinISD things look promising, but then again I'm using the stock measurements for the sub. Sooo basically what it comes down to is all I can do is build it and see what happens? Maybe I should stop thinking so hard.

Anybody?

That red carpet reminds me of old school Astro van carpeting! Beautiful attention to detail man I'm lovin' it.

Thanks for taking the time to explain, it's helping me out as I've really been trying to tackle the details behind it all... Well, just for giggles and to help myself learn I crunched the numbers for that off-the-shelf 18" Nightshade with the params listed on Sundown's page through the equations on DIYsubwoofer, and I got 1.16f³ for the vented chamber and 1.34ft³ for the sealed enclosure, a gain of 2.12dB, and a top freq of 62Hz... this is assuming an F1 lower dB of 30Hz, and an S Factor of 0.6. I was also hoping you could help clarify things for me... when you plug a number for the lower cutoff into the equation it is likened to choosing a tuning for the box of a ported setup? Like a box that's tuned to 32Hz means the -3dB cutoff is at 32Hz? And as for the upper freq if my goal is to nail the lows on a daily setup, is that a good top end for a fairly wide passband and not a one note wonder? And also, is there any way for me to determine the amount of Vas/Fs/Qts I should add or subtract based on the current info? Thanks again for the help

Hey Ed know this is an old thread revive but as time goes by I find myself knocking at that 4th order door... just wanted to know how you arrived at all your calculations, I've been researching non-stop for the past two days on 4th orders and getting familiarized with WinISD, but it keeps recommending an enclosure about the same size as yours for the 18" I have! I'm waiting on a response over in the Sundown forum for the T/S specs of my Nightshade but after that I'll be ready to rock and roll. I loved the way your setup sounded at the last meet man, but I think when I design mine I'm going to make the sealed portion a bit bigger and the ported a bit smaller just to widen the passband a little bit... or at least from what I hear. Meh.

Another thing I found strange is that when I plug those parameters into WinISD and several other box calculators for a 4th order, it gives ridiculously small enclosure recommendations like 2cuft sealed, 1cuft ported. I'm looking to design an enclosure with an S factor of about .6, a compromise between narrow and wide bandwidth (although I would prefer to have a somewhat wider passband at the expense of efficiency, especially one that would add greater low end extension). I realize that the smaller the enclosure the wider the passband but that would be an awfully small box!

I'm thinking of designing a 4th order in my trunk for a D2 18" Nightshade, and after rooting around the web for a while I found some T/S parameters for the stock speaker, however, this speaker has been reconed with an extra stiff suspension built to handle about 3KW daily. How would this affect the T/S numbers, if at all? The website I found here lists the Qts @ 0.44, the Vas @ 36.7 and an Fs of 38Hz. Thanks!

OK after spending the better part of my day researching on Google... I might try a 4th order BP setup, aero-ported through the rear deck. After all the reading I did I could not find one single website that had a straight-up tutorial on how to build one, but I did find a few websites that were pure mathematical equations and theories so I guess my only option is to dig my Calculus book out and study like a schoolgirl. If anyone has knowledge on the subject I am all ears, I am all about doing this 100% legit and correct, thanks!! Another ghetto picture to explain. The little black circles are aeroports going through the rear deck

Against my better judgement I sauntered over to ca.com forums and asked this question and so far they laid out two possible solutions: 1. Two seperate slot ports on either side of the box, or 2. Aeroports! I have no experience with them at all as we speak I'm Googling Aero vs. Slot ports and soaking in all the info I can.

You mean the other way around? Well, I'm sort of basing the idea that my old box sounded much better faced towards the cabin than turned around facing the back (but I think that's mostly due to the box being so big it practically sealed off the trunk lol). Plus you know I don't really care about numbers man just like you said in the Navi it scored hella good but it doesn't sound too well on music lol

I second the idea of the alt putting a strain on the engine... I'm guessing as the alt tries to deliver more power it creates more rolling resistance against the rotation of the pulley. I had the same problem even with my MechMan alt, due to a weak battery... at full tilt every now and then the car would misfire and the belt would slip a little

Wow, this might need to be sold with a coolant system lol! That would look hella futuristic too

yeah thats what im saying why is it so bad to have rims at 16. but man thats sucks your rims got scratched No biggie, just remember to watch out for potholes and curbs. Especially while drinking tequila.

I got rims when I first started driving and everything was fine Until I let my girlfriend at the time borrow my car and she scraped a curb lulz

That's a perfectly valid point Aaron... I had thought about that... hmm. Seems like it wouldn't be a big deal but it's a technicality. Maybe I'll come up with some other ideas

Lulz!! Amen to that!

Hey all So I'm going to be installing an 18" Nightshade in my trunk, and I have been trying to come up with a workable solution for a box design. Been sifting through threads but haven't really seen too many builds with a sub back/port front design or vice-versa. It seems that any other design would take up the entire trunk with little room for any other equipment. This is what I'm proposing: Top down view of the trunk. The yellow dashed line is the rear deck, about 19" total height clearance. The grey dashed line is the recessed spare tire well, about 6" or so deep. Box sides and top would be built as to contour around the wheel wells. This would be the view from the back, I apologize for the shitty drawing.. it gives the impression that the box is sealed off from the cabin but in reality it would have about 5" or so of clearance (what I'm shooting for...). The woofer is recessed down into the tire well, I could fabricate the bottom of the enclosure out of fiberglass I'm thinking to contour to the floor pan. Last but not least here is an actual picture of the trunk taken before the sound deadening for visual clarity I would want the box to be about 5 cubes of internal volume... I've long since forgotten the trunk measurements and haven't gotten into the specifics of it yet but this was just a preliminary idea I was tossing around... anybody worked with a design like this? Thanks a million guys

Looks good man, any vids of that Firebird in action?

Classic SPL vehicle

Sorry I guess it would be helpful to post a real pic of the trunk lol

Hey all ! I'm only about ankle deep in my new build... lol... well, I actually was hoping to get some preliminary advice from you guys, especially in the area of box design. So I'm trying to explore my different options for trunk setup this time around. The 18" Nightshade is a fresh recone done by Steve built to handle 3k daily, with heavy duty spider & tinsel leads among other things... Here are some pics next to one of the old 15" Q's Closeup of the tinsel leads My goal is simply to be balls-to-the-wall loud, of course. Not for SPL competition, but strictly for music. I really liked how low the Q's got off 7 cubes so my key points in designing the trunk setup will be to give the sub as much breathing room as possible while still retaining a little trunk space, and this is where I came up with two possible designs: #1 The first design I thought about, this is viewing from the top. Sub back, port front config. The grey dotted line represents the spare tire well, it's recessed about 6 inches. The yellow dotted line is the rear deck. The box would be contoured around the wheel well. This is the view from the back of the same setup. As you can see it utilizes the tire well for airspace. Now, I'm wondering how this would sound. If anybody has had experience with a setup like this please chime in! #2 Sub up, port front configuration. As of this moment I don't know if this would be the most feasible option as Jon told me the excursion is pretty high on this sub, and I only have about 19" of clearance under the rear deck. Couple that with a double baffle and I don't know if it would all fit... lol... but here goes Have a plexi window or something The rest of the build will be coming in the next few months so I'm going to be focusing on this for now... Shoot your ideas at me thanks guys!