Got an Infinity 1042W, going to be fed by a Directed Audio 250D.

Subwoofer RMS is 250W.

I'm still contemplating *lol* ... should I go with a sealed box .. or a ported one ? I want deep.. and well.. yeah loud enough .. if ya know what I mean

 

I'm thinkin ported. Ported will give you a slightly 'deeper' more 'powerful' sound. Sealed will generally give you a little 'louder' sound.

 

That's what I was thinking, kinda *L*, thanks.


hmmm now I'm just wondering if I can fit the box in the very bottom of the well, if it sticks up, no problem, if I have to cut into the rear plastic panel, no problem

but.... how much space do I need around the subwoofer, to the edges of the box that is ?

Cutout diameter for the woofer is 9 1/8, will 10 1/2 inch inside be enough ? Which with 3/4 MDF would be 11 inches .. or can I go even lower on the inside, like mounting 9 1/8 with only 10 inches of space on the inside (that is depth, not width though)

 

I would go with the ported myself...Sounds alot more nice than sealed

 

Talk about a lot of misinformation.

Ported boxes play lower than sealed but they're far from ideal in a car environment because they're next to impossible to tune correctly. It's hard to mach a ported box’s rolloff with cabin gain so even if you design a box that's flat to 30 Hz ported it will still have a peek in output in the car because of cabin gain. Ideally you could find out what kind of effect cabin gain plays in your car and then walk away and design a box that’s absolutely flat, allowing cabin gain to pick up where the box starts to roll off.

For HT/music applications in a house, room, or even outside area ported is generally the better choice. They can be just as musical/good sounding as sealed if designed correctly (not an overly huge box and not tuned too high) and have significant gains on the low end.

Here’s a picture to show the difference. All drivers are the same. Green is ported, yellow is sealed, and red is the equivalent of IB since IB is really just an infinitely large sealed box. Smaller sealed boxes stay flat but roll off fairly high and do so at a fairly sharp slope. Larger sealed boxes roll off lower and do so at a more gentle slope while loosing some output along the way (compare the ‘large’ red to the ‘small’ yellow).



Ported will always sound louder than sealed. I'm not sure about 'deeper' but ported will sound more powerfull due to the fact that it's louder.

Unless you're a complete bass head this generally isn't the case in a car.

Given this post I would say stick with sealed for now. I think what you're trying to describe is box volume (length x width x height of the box). Generally speaking you're going to need about a cube sealed for your average woofer. Ported is an entirely different monstor, takes a lot of planning to build, etc.

 

Gummie =

Chill Kid.

 

not the first time I will be called that. I just don't like it when people post misinformation so I guess I come across as harsh sometimes. I know that I was in the same boat once upon a time (we all have to get started sometime) but it still bothers me.

GHETTO STORIES <-- hilarious

 

Ya remind me of a bud on Z28.com, he's real hardcore bout car audio stuff, doesn't give any slack to anyone, is very straight up with'em. I try to be nice and be nice bout stuff and explain it out. Obviously to those who ARE car audio knowledgable, my stuff may seem a little questionable, but I try to break it down instead of getting complicated.

 

Generally speaking I'm pretty nice and try to be helpful but it bothers me when people post things that are wrong. I also try not to get into thing I don't know that much about and will gladly point out when I don't have much experience/knowledge in a given area.

I'm in the process of building a new sub box for my home stereo and it will be ported but I'm pretty sure that I will stay sealed for the car. Cabin gain wreaks all kinds of havoc in a car and it’s next to impossible to get a nice flat response curve with a ported enclosure.

Ported boxes require knowing the box’s exact volume, which is generally a pretty easy task in a sedan with a square box but it’s a bit harder in a hatch like ours. Once that’s done you have to balance port area and port length so that the ports will physically fit inside the box. Ported boxes are not for a novice box builder because they're a lot easier to screw up. I almost always recommend staying sealed for the first box or two to get a feel for things and then advance to ported after that.

 

why are you giving gummie **** for posting a bunch of completely true statements? the only remotely hostile thing he said was that there was a lot of misinformation, which there was. i'd be willing to bet gummie is one of the top 3 most knowledgable people when it comes to car audio on these forums. as far as "getting all complicated," if you aren't ready to tackle this stuff, you aren't ready to build a ported box for one of these cars unless someone else designs it for you, and you know how to build.

i'm sorry cam-aro, but you are not another of those top 3.

 

and going by this post, you dont know what the hell you're talking about. explain to me, how a sealed box sounds louder in any way shape or form than a properly designed ported box. because in the last week i went from sealed to ported, all other factors remained constant, and its a HELL of a lot louder, at all frequencies, as any other sealed to ported change should be.

 

Well I got the specs for the box, only thing I would be changing is going from one 9 inch long 3 inch diameter port at 28 Hz to two 8 inch long 2 inch diameter ports, tuning it to 32 .. 33 Hz.


I was concerned whether the ported box would fit in where I want it to fit, after all, it's a single subwoofer box, not a dual one.


Although later on I'll probably end up going dual 10's anyway. And the amp will be the Profile California MSX600 or whatever it's called. RMS of 300W at 4 ohm, and can't beat the price *L*


So, still thinking lol .. sealed.. or ported, but it looks more like I'm going ported, and will take my time and build it nice and slow.

 

Mean, thanks for backing me up. I can see both sides of the issue and it's not the first time I've come across as harsh. I didn't mean to come off that strongly (and didn't say anything that mean) as you pointed out. That's all I'm going to say on that topic

Back on topic...

It's not really a matter of building the box slow; it's just a matter of checking the math (box volume, port area, port length). It's hard to know exact volume when you're building an odd shape to fit into our hatch area.

As for your ports, I would recommend at least one larger diameter port to try to avoid port noise. The 3" port has more port area than the two 2" ports so if you're dead set on those two choices I would go with the 3" port. Be sure that your ports are going to have a decent amount of clearance before they meet a wall of the box too.

 

Well as big as the box will have to end up being, should I just go with two 3 inch ports instead ? I'd prefer two ports, yes, it's about the look of the box too *l*, oh and I'm actually going flared on both ends of each port.


I'll have to be careful too when running the subwoofer, didn't think enough when I bought the woofer and ordered the amp.

It's a 4 DVC, so have to run it at 2 ohm, but the amp will be putting out 410W RMS at 2 ohm, the woofer is 250W RMS, but peak handling is 1000W, while amp is 600W, so as long as I am very careful about the gain settings, and bass booster, I should be fine, right ?

 

Don't worry about peek output, only RMS. It's generally a good idea to have too much power on tap vs too little to avoid clipping so I would say you're fine. Just don't go too crazy on the gain.

2 - 3" ports will have to be 17.5" long to tune to 30 Hz for your application (working backwards from your earlier posts I'm guessing your box volume to be 2.1 cubes). You will need about 20" total for those ports including clearances. As long as you can physically fit them in your box you could do it.

 

Box will be 1.75 cubic feet, that's the volume including volume for one subwoofer and one 3 inch diameter 9 inch long port.


Now if I would go with two 2 inch ports, and tune it to around 32 33 Hz I should have hmmm around 8 or 8.5 inch long ports ?

 

*re-reads your post* ok ok *lol* got ya

So 10 inch for each port ? If I would go 3 inch big ports, although then I'll have to move up a tiny tiny bit in size from 1.75 cubics

 

No, you would need 20" for each port total including clearance at the end of the box. But I was working off a larger box (2.1 cubes). 1.75 cubes requires two 21.5" ports if you want to run 3" diameter, which will require about 24" of total length (you don't want a port ending a 1/2" away from a wall of a box).

All I'm doing at this point is plugging numbers into winISD. It's free. You can download it here.

An enclosure with one port will require less port length than an enclosure with two ports of the same diameter (say 10” for the single port and 15” each for the two ports with port diameter staying the same). Also, smaller diameter ports = less length but greater chance of port noise.

 

For some reason I can't figure out how to use WinISD to calculate port size/length. I think I'll go with two 2 inch ports though .. how long should they be, to keep it all at 32 Hz or so

 

Each port needs to be 7.8" long for two 2" round ports in a 1.75 cube box tuned to 32 Hz.

Honestly though, you're better off going with the single 3" port (8.23" long) because it will give you more port area, which will reduce the odds of port noise. Two 3" diameter ports would need to be 18.65" long each if you're set on installing two ports for aesthetic reasons.

 

hmmm contemplating *l*, my amp arrived today, so I need to start the build, I may go with a mix of MDF and fiberglass though, brace and ring out of wood, bottom as well, everything else fiberglass


the 7.8 for 2 inch ports is for straight ports though, correct ?

 

If by straight you mean cylinder shaped with straight walls, then yes.

 

OK, well I need to get this project done, so for now I'm building a sealed box, since 0.75 cubics will fit just nicely in the very bottom of the trunk.

And once that's done, I'll do some proper calculations, and design a ported box.

That way I'll be able to test both, to see what works best for me.


The bigger the port, i.e. diameter, the less chance for port noise ? Because the electronics store has 4 inch ports, not real flared though.

 

You can use PVC pipe if you wish. The more port area the less chance of noise. Keep in mind that you will be displacing a decent volume of air at louder volume levels. In a smaller port that air can move quite fast and cause noise.

 

The build of my sealed enclosure, 0.75 cubic foot, actually probably a tiny bit less now due to the bracing.

1991 Chevrolet Camaro - Olaf's Chevrolet

 

With the exception of drilling holes for the mounting of the sub plus drilling the hole for the plug, the box is done. I didn't smooth it 100 percent, but it's close enough, especially since the truckbed coating does cover it nicely.

I'll post some pics later.

Now I also have to figure out how to bolt it down or something, so it'll stay.


On the side note here though, I HATE using Bondo's glazing putty, it works worse than regular bondo, even though it's supposed to fill in the tiny holes nicely, horrible product.

 

Done, and installed. Ooops forgot to post new pics oh well.

This was my very first subwoofer box build and actually very first subwoofer install as well.

At first the woofer made almost no sound what so ever, I had to check it, to make sure it was even doing something, amp was lit up everything. Eventually it fired up, is this normal ? A brand new sub needs "charging" or something like that ?


I haven't adjusted it yet, any advice how to adjust the gain ? Not even going to touch the bass boost.

And what about poly fill ? How would it affect the sound ? Make it "woofier" or tighter or what ? Reason I'm asking, is the enclosure may be tiny tiny bit smaller inside than the recommended 0.75 cubic foot.
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The amp/sub should fire right up once the amp is turned on. There can be up to a ~5 second delay from the amp while everything turns on inside it though. I know my component amp turns on faster than my sub amp. Eventually I will wire up a delay circuit to fix this but I’m broke at the moment and the amps aren’t in the car anyway.

Polyfill/fiberfill is a way of tricking a box into thinking that it’s bigger than it actually is, which is good in the case of a box that’s too small.

Be careful when using words like tight/punchy and woffy/boomy. The majority of people tend to associate boomy speakers with larger speakers, which isn’t the case. Boomy generally means lack of cone control, which is caused by too large a box, a high tuning frequency if ported, and/or loose suspension of the sub.

 

OK, thanks.

So does polyfill do anything SQ wise ? Besides making the sub think the box is bigger ?

 

Bigger box = looser, smaller box = tighter. If you don't think the sub is playing low enough add some polyfill. If you think it sounds sloppy then take some out. It's not going to make that drastic of a difference IMO.

 

ah ok, thanks


I guess I'll leave that alone until I have the sound system setup and adjusted properly

 

Sealed box, 0.75^3, I'll try a ported box soon, but that will be tricky.

Here's a few pics of how I made it (used fiberglass on top, right away, no fleece):

1991 Chevrolet Camaro - Olaf's Chevrolet

And because I'm going to build a ported box anyway, I didn't smooth everything as much as I could have done, it's good enough the way it is, considering it's my first sub install ever.

Also not quite sure whether I'll build an amp rack for the amp where it's at for now, or if I'll try to mount in the spare tire well. Considering I live in San Diego, well ... spare tire well would probably be safer

 

Not bad at all. Vary good especially for a first time out.