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Ported or Sealed?

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Old Jul 19, 2004 | 08:38 AM
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Ported or Sealed?

Alright, got my sub, amp and everything needed to hook it up, now i have to build a box for it.
It says for louder/stronger use ported. It has all the dimensions of how to make a ported or sealed box (came with the sub). When i make the box, would it make it any worse if i angled it with the rear seat, (making a few more cubic inches inside the box) if it was ported? Would it make it sound bad?

BTW, i have a gen1 4runner with a kayline in the summer months, and a hard top in the cold...
I hear ported would be best (i'm only using 1 sub so i want to get the most out of it, storage space isn't a huge issue either but i still want room to put ˟˟˟˟ back there).
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Old Jul 19, 2004 | 08:40 AM
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I have a sealed and feel it "hits" harder than ported boxes. No, an angle on the box wont screw up anything.
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Old Jul 19, 2004 | 08:56 AM
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It depends on the type of sound you want to get from your sub. For tighter, clean bass, you should use a sealed box. A sealed box would be good for rock music.

Ported will get louder, thumping bass, which would be good for rap music.
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Old Jul 19, 2004 | 09:11 AM
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Ported. Don't even mess around with sealed.

If you build the box properly it will have equal the sound quality, if not better sound quality than sealed, and it will have double the output...

Use 3/4" MDF or HDF, use Elmers Pro Bond wood glue, and #8 2" Coarse drywall screws to secure everything. After it's all said and done, fiberglass the interior, then play around with some polyfil (yes, polyfill in a ported box)...

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Old Jul 19, 2004 | 09:32 AM
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Originally Posted by Bumpin' Yota
Ported. Don't even mess around with sealed.

If you build the box properly it will have equal the sound quality, if not better sound quality than sealed, and it will have double the output...

Use 3/4" MDF or HDF, use Elmers Pro Bond wood glue, and #8 2" Coarse drywall screws to secure everything. After it's all said and done, fiberglass the interior, then play around with some polyfil (yes, polyfill in a ported box)...

Sorry, i missed the last two, fiberglass the interior and polyfil? Sorry, still a noob, where do you get this from/how do you use it?
What's the diff between MDF and HDF? (i only know of MDF)...

Thanks,
Greg
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Old Jul 19, 2004 | 07:15 PM
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Originally Posted by Greg_Canada
Sorry, i missed the last two, fiberglass the interior and polyfil? Sorry, still a noob, where do you get this from/how do you use it?
What's the diff between MDF and HDF? (i only know of MDF)...

Thanks,
Greg
Fiberglass, you know the same stuff you patch boats with, or do body work with? Home Depot, Lowes, and scotties all carry it. I comes in 16oz, 24oz, 64oz and 1 gallon tins. You really dont need to put any mat or cloth down over the interior seams, but you can if you want to. Instructions are on the can. All you do is mix the resin with the hardener in the proportions listed, and after the listed time, it will begin to harden.

Polyfil is the trademarked name for fiber used and marketed for audio use. Just go to your local Wal-Mart, go to the linens area, and buy a bag of polyester pillow stuffing. That stuff is poly fill.

MDF = medium density fiberboard. Some places mislabel mdf as HDF as in High Density Fiberboard. The stuff you want will weigh 108lbs for a 4' x 8' x 3/4" sheet. It's fiber is VERY VERY fine and the stuff is ultra dense.

Last edited by Bumpin' Yota; Jul 19, 2004 at 07:17 PM.
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Old Jul 20, 2004 | 08:04 AM
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I got some mdf (my local home depot doesn't sell HDF)...
Fiberglass.. or what i call bondo LOL... hell i should have known i have 2 big cans or por15 fiber sitting infront of me... but those are for the body!
Would it be ok to just use latex caulking to fill in the corner gaps?
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Old Jul 20, 2004 | 04:15 PM
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Dont mean to steal thread, but should i get a basic sealed box for $50 or get a ported box where the subs face each other with a plexiglass 14x14in cover in the front center for $50.
I like Rap and advice?
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Old Jul 20, 2004 | 06:05 PM
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Originally Posted by FUZION
Dont mean to steal thread, but should i get a basic sealed box for $50 or get a ported box where the subs face each other with a plexiglass 14x14in cover in the front center for $50.
I like Rap and advice?

Thats not a ported box, that is a prefab bandpass. AVOID prefab bandpasses like the plague.

A vented box will have the subs and ports firing into the air, not into a chamber.

I'd say buy the sealed prefab, and fiberglass the inside of it.

Last edited by Bumpin' Yota; Jul 20, 2004 at 06:09 PM.
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Old Jul 20, 2004 | 06:08 PM
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Originally Posted by Greg_Canada
I got some mdf (my local home depot doesn't sell HDF)...
Fiberglass.. or what i call bondo LOL... hell i should have known i have 2 big cans or por15 fiber sitting infront of me... but those are for the body!
Would it be ok to just use latex caulking to fill in the corner gaps?
Ideally there should be no voids in your box if you cut correctly. If there are, I'd use a LOT of fiberglass to fill it in...
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Old Jul 20, 2004 | 07:07 PM
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Naw, no big gaps, the caulking "just to make sure"... sound good?
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Old Jul 20, 2004 | 07:38 PM
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Originally Posted by Bumpin' Yota
Thats not a ported box, that is a prefab bandpass. AVOID prefab bandpasses like the plague.

A vented box will have the subs and ports firing into the air, not into a chamber.

I'd say buy the sealed prefab, and fiberglass the inside of it.


edit: what role does the fiberglass play inside the box?

Last edited by FUZION; Jul 20, 2004 at 07:41 PM.
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Old Jul 21, 2004 | 05:21 PM
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I'm gonna disagree w/ Bumpin' Yota. All the SQ and SQ + systems I've ever built/heard/tuned/scored used SEALED boxes. By nature, a sealed box has a better sound curve. You can't fight the efficiency of a ported box. That's why they're used a lot for lower watt systems and such. Bandpasses amplify this... but they also narrow the frequency response that much more.

I have no idea what size sub or type of sub this guy is using, so I can't recommend either way, but...

If it's an 8 or a 10 inch sub and you're running at least a TRUE 150 watts per sub, then go sealed. You'll get better low frequency extension and better transient response.

If it's a 12 or a 15 and you want to bump with 300 watts or less, go ported. If you're playing w/ the big boys and have high RMS subs w/ 1000 watts or more, then the world is your oyster. Sealed or ported, it depends on what you want. Transient response w/ tight, crisp bass, or BOOM? For the latter, go ported. For the former, go sealed.

I will agree with him about the box construction and such. Measure once, cut twice. I use drywall screws instead of brads, and I use liquid nail on the seams and silicone on the interior. Fiberglass always, and polyfill only for sealed.

Rock on!
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Old Jul 21, 2004 | 05:25 PM
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Bumpin-

Kinda OT, but I see you hit your highest numbers at or around 42 hz... I thought I was the only one... I did a 147.8 w/ 2 Stroker 18's and 2 MMATT's D2's. The enclosures were tuned to 40hz... Woo hoo! Gotta love the LOW bass!



J
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Old Jul 21, 2004 | 07:06 PM
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Alright, i've got a 12" 300RMS sub at 4 ohms, (200rms amp at 4ohm's)... running 4 gauge power cable... 4v preouts on the deck...
I'm trying out the ported box cause i'm gonna need more BOOM cause of the soft/no top... if it was a newer truck i'd probably go sealed...
Anyways, thanks guys,
Greg
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Old Jul 25, 2004 | 06:05 AM
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Originally Posted by WolfpackTLC
I'm gonna disagree w/ Bumpin' Yota. All the SQ and SQ + systems I've ever built/heard/tuned/scored used SEALED boxes. By nature, a sealed box has a better sound curve. You can't fight the efficiency of a ported box. That's why they're used a lot for lower watt systems and such. Bandpasses amplify this... but they also narrow the frequency response that much more.

I have no idea what size sub or type of sub this guy is using, so I can't recommend either way, but...

If it's an 8 or a 10 inch sub and you're running at least a TRUE 150 watts per sub, then go sealed. You'll get better low frequency extension and better transient response.

If it's a 12 or a 15 and you want to bump with 300 watts or less, go ported. If you're playing w/ the big boys and have high RMS subs w/ 1000 watts or more, then the world is your oyster. Sealed or ported, it depends on what you want. Transient response w/ tight, crisp bass, or BOOM? For the latter, go ported. For the former, go sealed.

I will agree with him about the box construction and such. Measure once, cut twice. I use drywall screws instead of brads, and I use liquid nail on the seams and silicone on the interior. Fiberglass always, and polyfill only for sealed.

Rock on!
You mean measure twice cut once

BTW - ported can actually sound better than sealed if it is setup properly. Hence why B&K home audio towers that run 10,000+ usd are all ported. You also have to realise that any setup that utilizes passive radiators is also essentially ported. The mms of the passive = the weight of the air slug in the port so you tune the passive accordingly. The reason I mention this is because almost all of the home audio subs ive ever seen have passives used or are ported.

As to tight crips bass, that is more of a function of the driver to reproduce a higher frequency (lower midbass,) and most subs have too high of an inductance to easily do this, particularly any high power handling subs. There are some high power handling subs that can play rather high due to their low inductance courtesy of shortening rings used on the pole piece....w7 uses the shortening rings.

You are correct that a vented alignment is far more effiecient, but it also has far more output at low frequencys than a comparable sealed provided the ported is tuned low enough.

ps - I used poly fil to for some great results with some ported 8s of mine....

SPL wise they did a 145.1 legal on the dash from waaaaaaaaaaay back in my cargo area on the classic termlab meter.



NIIIIIIIIIIIIIICE setup btw.

What meter was that on and how did they meter it?

The 158 and change was legal when I had my wall and on the classic termlab (which is a soft mic.) The new termlab is about 8 dB down from that classic mic so it would have done a 150.x or so on the new TL. My last current setup was all from the cargo area and did a 151.6 @ 47hz on the new mic.

But yeah, these trucks LOVE low notes. My very first spl oriented install peaked at 38hz! :eek: It did 153.8 @ 38 on the old soft mic. Today it would have hardly hit a 146 on the new termlab, but my God that thing was FUN in parking garages. And boy howdy did it make everything FLEX...lol

Right now I'm still organizing my amp rack, then have to wire up the 4 zapco 9.0s and extra battery, then I start testing with these L7s....poor pooor subs...lol Thank god for warrentys cuz these little 2" coils aren't going to like 2200 watts each, even if only for burps...LOL

Last edited by Bumpin' Yota; Jul 25, 2004 at 06:22 AM.
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Old Jul 25, 2004 | 06:07 AM
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Originally Posted by Greg_Canada
Alright, i've got a 12" 300RMS sub at 4 ohms, (200rms amp at 4ohm's)... running 4 gauge power cable... 4v preouts on the deck...
I'm trying out the ported box cause i'm gonna need more BOOM cause of the soft/no top... if it was a newer truck i'd probably go sealed...
Anyways, thanks guys,
Greg
What sub are you using? I can help you out on that part if you need it. I'll be AFC till august 3rd, unless my motel room in London has ethernet....
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Old Jul 25, 2004 | 06:08 AM
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Originally Posted by FUZION


edit: what role does the fiberglass play inside the box?

To seal it up and strengthen it.

Ideally you want a box that you can quite literally use as a jack stand for your truck and not have the box fail - getting them that overbuilt is kinda hard though.
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Old Jul 25, 2004 | 10:53 PM
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My best frequency was also 42Hz in my 3rd gen.
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Old Jul 26, 2004 | 11:44 AM
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Hey dbikeman... do you ever get minor dimming with that HO alt? I have the same one btw in a 97' Limited.
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