Vented or sealed enclosure?

[Dammed 12]

Title says it all. I can build a enclosure with about 11 cu ft (internal volume, displacement of the subs has been removed). I read on a forum a while ago that you get the best SQ if you go with a big vented enclosure. I want to hit the lows but not to loose the highs completely. I listen to almost everything that's called music. That means from Queen to ATB to Bob Marley. My goal is SQ.

The car is a Toyota Celica GT, this one:

I will be using a Hifonics BXi 2610D amplifier pushing 2600W rms on to two Fi Q 18" subs.

The optimal vented enclosure as I have read is from 6-10 cu ft for one, meaning 12-20 cu.ft. for two subs. Or 4-8 cu.ft. for a sealed enclosure, 8-16 cu.ft. for two subs.

My first Idea was to go with a 11 cu ft vented enclosure filled with polyester, tuned to 28hz using a rectangular port.

I'm not 100% sure you call it polyester, but it's stuff you can cover the walls inside the enclosure to trick the subwoofer to think that it's a bigger enclosure. And If I remember correctly you can get the same effect as from a 20% larger enclosure. Meaning about 13 cu. ft. (please correct me if I'm wrong on this one, long time since I have read that article)

If it matters, I was thinking about closing my trunk completely, my front baffle will be like a lid going from the top of my seats and all the way back to my plates. So the rear window will be pretty close, I haven't measure it yet, but I think it will be around 8-10" from the subs. And with my amazing paint skills I illustrated it for you guys:

'

So what you think, should I go for vented or sealed if I have only about 11 cu. ft to use?

[The enD 467]

Why do you begin with subwoofers for a SQ car? You should look for deadner first. And two 18 is too much for SQ. A ported enclosure has a peak, but SQ needs to cover all the low freqs.

What about the front line ?

Edited December 27, 2009 by The enD

[kirill007 52]

What is you're front stage?

2600W with 2 18's and SQ?

I think it would be better to have a sealed enclosure, because you would be choking those subs in a ported enclosure.

The net volume of the enclosure needs to be around 12-20 cu ft, you only have 11cu ft, and you need to first distract the port volume and woofer displacement which would put you below 5 cu ft each.

Just build a 10-12 cu ft sealed enclosure for the Q's.

[Dammed 12]

The enD, Who said that I started with looking at the sub woofers? I have deadened the whole car using Dynamat extreme and Hushmat. Infinity Kappa Perfect 6.1 in the front and back, amplified by two ZXi 1010D amplifiers. These pictures are 2 years old. The only thing left is the subwoofers. I'm also going to buy a 180A alternator from Iraggi soon and there are two kinetik batteries a HC600 in the front and a HC1800 in the back. The big 3's are upgraded with 0/1 awg cables. So the rest is sorted out, only thing left is the subwoofers.

The reason for two 18's is simple, I want a 18" subwoofer because a friend of mine had one, and I loved the way it hits the lows. I want to use my BXi 2610D to the fullest, so I need a 18" SQ subwoofer that could handle 2600W rms and had a maximum price tag of 700$. (I'm a Uni student, so money doesn't come easy). Through my web surfing I didn't find any subwoofers that could do that. So the choice became two 18" instead. I read NDMstang65 thread (Q Enclosure Recommendations) where DosOne used a BXi 1606d on a 15" Q subwoofer, meaning a Q subwoofer could handle 1600W rms, again meaning two 18" Q's would have no problem with a BXi 2610D (1300W rms on each). DosOne got good SQ and some SPL, which is the same thing I am after, with a vented enclosure.

On other forums, this it was on realmofexcursion or *** forum that I read if you wanted a Q sub to hit lows and give you nice SQ that you needed to build a vented enclosure.

The only reason I made this thread is because my car isn't a big Chevy Van, so I have limited space to build a enclosure.

edit:

kirill007, front stage?

the 11 cu. ft is internal volume after I have subtracted the displacement of the woofers, but the port volume hasn't been taken in consideration.

Edited December 27, 2009 by Dammed

[Adrian_D 520]

in 11cf you won't fit a good ported box for 2 18's. Stick with sealed, they will sound very good sealed and still have plenty of output.

[Dammed 12]

Ok.

so, with a sealed enclosure, how big should I make it, around 12-13 cu. ft?

[kirill007 52]

The max you can, so 11cu ft.

if you can make it bigger then around 12-13 would be good.

Front stage=The speaker's you have and what amps you have on them.

Edited December 27, 2009 by kirill007

[Dammed 12]

Damn, I need some coffee... I read only the recommended size for the enclosure, forgot about how much room I have...

So back stage would be back speakers and amps on them or?

11 cu.ft . sealed will be the enclosure then. Will it hit the lows and will it be loud if I crank the volume button all the way up?

Edited December 27, 2009 by Dammed

[///M5 2,833]

No such thing as back stage or sub stage as there is only a stage in the front. Front stage and sub/s.

[Impious 1,476]

And two 18 is too much for SQ.

Poppycock. Two 18's can be excellent for sound quality. I would use 18's myself if I could fit them....in fact I had a pair I was planning to use but decided against it due to the amount of space they would consume.

As to the original topic, I agree; Don't go ported with that amount of space.

[Dammed 12]

Like one old professor I had said, you learn a new thing every day.

Anyone with some experience on how this will be like? Was thinking about hitting the lows and being loud. Because if they don't hit the lows, I might as well go for two 15" in a vented enclosure if they will play better at lower freq.

[The enD 467]

And two 18 is too much for SQ.

Poppycock. Two 18's can be excellent for sound quality. I would use 18's myself if I could fit them....in fact I had a pair I was planning to use but decided against it due to the amount of space they would consume.

As to the original topic, I agree; Don't go ported with that amount of space.

Thank for your very kind reply !

I just don't get it how two 18" ported would sound good at all freqs no matter if it is playing rap or metal.

[Adrian_D 520]

On other forums, this it was on realmofexcursion or *** forum that I read if you wanted a Q sub to hit lows and give you nice SQ that you needed to build a vented enclosure.

Blanket statement coming from kids who think 35hz is low.

If the q's are anything like the old xxx's, I can tell you that in 9cf one 18 on 750w was killer. Loud or not depends on what is loud for you.

And two 18 is too much for SQ.

Poppycock. Two 18's can be excellent for sound quality. I would use 18's myself if I could fit them....in fact I had a pair I was planning to use but decided against it due to the amount of space they would consume.

As to the original topic, I agree; Don't go ported with that amount of space.

Thank for your very kind reply !

I just don't get it how two 18" ported would sound good at all freqs no matter if it is playing rap or metal.

In the same way as 2 ported 12's will sound good in a well designed box. Tuned low enough you can avoid having a ridiculous peak in the frequency response. And you also have to have midbass that can keep up with the subwoofers.

[Duran 387]

Go Adrian!

[lee 2]

id seriously recomend sealed if you listed to that many different genres of music.

[jcarter1885 995]

It seems like you have two different goals, you say you want SQ but you keep screaming you want loud. I dont see how two 18"s on 2600 (2300 watts actually) wont be loud, stop worrying about loud because it is subjective (you might get them and want louder or they may be louder then what you wanted). Worry about doing this right if you want some good SQ, size of sub does not really matter when it comes to hitting the lows (they all will hit the lows).

[Dammed 12]

Why did you blank out the *** forum? (New here, so kinda good to know, as I see it isn't commercial if you mention something, like Nike. Did I advertise now? lol)

True, 2600(or 2300)W rms will be loud either way. So yeah, it's gonna be good, gooooood.

The amp that will be powering the Q's will be mounted so that, the heat from the amp can not go straight up but it would have to go through the sides of the enclosure because the front baffle would be like a lid on the whole trunk. Will this be a problem? If someone wonders why I want to do it like this, it's because I think it would look much better then to make a small gap for the venting of the amp.

Edited December 27, 2009 by Dammed

[Duran 387]

SM[) is blocked, as well as his name.

[Impious 1,476]

Thank for your very kind reply !

I just don't get it how two 18" ported would sound good at all freqs no matter if it is playing rap or metal.

Why couldn't it? A properly designed enclosure is required, as in any other situation.

The benefit is the large surface area of the drivers which reduces excursion requirements for a given output level, which keeps the driver's excursion further within it's linear operating range which will reduce distortion compared to similar drivers with less total surface area operating at higher excursion levels.

[Duran 387]

Thank for your very kind reply !

I just don't get it how two 18" ported would sound good at all freqs no matter if it is playing rap or metal.

Why couldn't it? A properly designed enclosure is required, as in any other situation.

The benefit is the large surface area of the drivers which reduces excursion requirements for a given output level, which keeps the driver's excursion further within it's linear operating range which will reduce distortion compared to similar drivers with less total surface area operating at higher excursion levels.

Very well said.

[Dammed 12]

That sounds promising. Can't wait to get subwoofers.