Fi options and detailed specs

[ncc74656]

I went through on this forum a month ago and the information i was given as I understand it is as I posted above.

the sub is an 18 that I plan to put 5500w basecleff at .5ohm on. its a daily that I want the best fs I can get from it while being fucking loud.

i designed a box with far less backing, maybe 6 2x2 prices of wood running from front to back and side to side. first posts following my design ideas were "that sp4 18 will need much more bracing" so I'm getting frustrated at so many 'experts' telling me different things one month to the next.

my understanding is the sub box is a pressure vessel in the since that air never flows through it. rather it pushes and pulls air into itself in such a manor that the inside bracing does not effect any air flow because air does not flow inside. it is pressurised and forces the port air in and out so long as there is equal distance under the end of the port which is clear of obstruction as the port is wide.

what am I missing? does anyone have Skype or voice chat? I'd love to have an active conversation.

thanks

[Real96SS]

i had a rough box design on here a while ago, ill try to find a basic picture: this is a concept design, not a final build but the final is the same general setup just a bit different dimentions. its all 3/4MDF,. you can see in the center a ring around the circle, the ring is a peace of hard plastic like rubber that will be attached to the 4 wood stand offs to support the rear magnet.

The way you come off to people giving you suggestions, shows that no matter what we tell you about this contraption your still going to think its gods gift to that sub.

[Kranny]

that is literally overkill. you might as well put concrete in your door panels instead of sound deadener if you want to have something that solid.

link to the first design (pictures or whatever) that you're talking about? i really dont understand how you take a "needz moar more bracing" comment to this...monstrosity?

air doesnt flow inside? have you ever put a piece of paper inside a port and had it suck back inside? yeah....

if the air inside the box cannot move freely, which it will be hard to with all those friggin internal braces, then performance will be limited.

[TeamHT]

Even IF they didn't restrict air, the biggest thing is completely useless especially if your intention is to brace. I don't Skype but maybe you are a little open to finding out why. Even if it's an 18" that's not how to brace an enclosure.

[ncc74656]

i was told taht Xmax is not the maximum distance travled but rather some measurment called Gmax or idk somthing like that was the real masurment. i seem to recall being told that Xmax doubled is generally the distance the sub will move out from the mount point. is this not true?

33mm xmax one way man. on website.

[ncc74656]

im looking to figure out what kind of a box i need. i thought i had it nailed with this one but i guess not. what should i build for this then? double baffle front i think is a given right?

rounded corners on the port but the rest does nto matter?

resen the inside of the box for strength?

use wood glue and screws

what should i use to brace a sub box? beams, bars, corner peices on the edges?

the posts i have made everyone has told me to brace as much as possible, i was linked to pictures on google of people with built up cradle mounts for magnets, full sheets of wood being used to build a latace work inside of a box. now that ive done that im told its too much?? im so confused right now if i had the money id pay 500.00 to have a shop build it.

all i want is a box for an SP4 18 that will fit in the back of my truck and produce loud, clear, smooth bass from songs ranging from god smack to ferry corsten, tiesto, distubred, rihanna, kaskade, ect. i want a wide frequency range and was intending to tune it starting at 30hz and work my way up from there untill i found the sound i was looking for. i intend to have the sub face forward in the cab and have single slot port on the top about ear level.

what information do i not have correct? what do i need to change?

[DylanBunch]

Dude put like a 2x4 on both sides of the sub or get some threaded rod or something lol I dont know shit about box bracing but seriously.... thats overkill for any setup, let alone 1 18. And why .5 ohms for daily? Just wire to 1 ohm so you dont stress your amp and electrical system. What is your electrical gonna be like anyways?

[bkolfo4]

I never realized the air only moved at the port.

My bad.

Edit - and yes, Xmax is the shorter of two distances - max mechanical movement and 70% BL point (but you should still just use the published Xmax).

[ncc74656]

i had a rough box design on here a while ago, ill try to find a basic picture: this is a concept design, not a final build but the final is the same general setup just a bit different dimentions. its all 3/4MDF,. you can see in the center a ring around the circle, the ring is a peace of hard plastic like rubber that will be attached to the 4 wood stand offs to support the rear magnet.

The way you come off to people giving you suggestions, shows that no matter what we tell you about this contraption your still going to think its gods gift to that sub.

im not trying to come off as anything, i need help with this as it would seem i dont understand quite a bit in the box design department. i was simply asked what kind of a brace setup i planned so i gave one. it was not my intention to come off as anythong or to portray this as 'gods gift' to the sub.

[ncc74656]

i only know what im told and this is what i was told. i had asked on here and on the12volt and both forums agreed that air flow across bracing was a non issue. this is why im getting so frustrated right now. i feel like i understood this and now im back to squar one.

so Xmax is the max distance the sub will move in or out so if i measure Xmax from the top of hte mount ring i should be safe with room to spare as Xmax is measured from the surround glue point under the mount ring correct?

I never realized the air only moved at the port.

My bad.

Edit - and yes, Xmax is the shorter of two distances - max mechanical movement and 70% BL point (but you should still just use the published Xmax).