Chadxton

iTrader: (1)

Ok, so on we are with a build up thread about ports. This time it's on the port that I'm prototyping for my system...I posted this thread on another forum, but thought it would be interesting to share here too:


This is the sub tub that is used. Thanks go to Hakujin for making the tub for the most part.


Here's the top cover which I will be mutilating.


Here's a close up of the cutout that will be done. It will be cut to accommodate the 3"x9¼" port, as well as the ½" MDF rectangle all the way around. Essentially the port is designed to effortlessly and snugly fit in.

More to come. Stay tuned. Literally. [img]smile.gif[/img]

[ January 29, 2004, 08:58 PM: Message edited by: Chadxton ]

Chadxton

iTrader: (1)

Here's the aforesaid port I built, and the following pics show a mockup of it on the enclosure top.







Here we have the section of the top cut out, and the port is glued and pinned together. For now, it is suspended in the cutout to show illustration for how it's going to be set up.



Here it is sitting in the car.



It may not be all that clear, but the port right now sits 4" from the bottom of the tub. One corner of it just touches one corner of the port where it rests for now. All it needs is to be lifted maybe a ½ inch, and a base applied to it so that it can be firmly screwed to the MDF top.

Further plans call for different length ports, and a port plug for sealed use.

[ January 29, 2004, 08:59 PM: Message edited by: Chadxton ]

Blu

iTrader: (7)

Not sure if it is just this way for illustration sake... but shouldn't the T-Nuts be on the underside of the baffle?

Team_Obsession

How long is that port?

Team Shadow

whatever result you get with that port, i would round as many edges as possible, get rid of hard corners and soften up all square looking pieces. At least that way you don't get any port noise, or any un-needed hang ups of sound. One of the best looking slot ports that i have seen(i haven't seen to many) is rob VO's. just by looking into his port you can tell that he rounded the boxes interior to accomodate the flow of air and sound.

Picture this(maybe this thought can help)
ever water the lawn. And the stream coming out of the hose is the same shape of the hose? And then you put you finger on it and the water sprays every where . sort of the same concept. the sound needs to come out of that port and will contour to the port. if there is a 90 degree angle that it needs to pass thru , it will limit it's ability to come out of that port(bringing your number down) but if you accomodate the ease of that sound coming out(rounded edges) it will increase your score, sound, quality, etc. now this isn't the only way, and i'm sure that other can help you with their opinion, i'm just trying to help you with it's shape. seems to look a little bit too square. I do not think that i myself can build an SQ car that sounds good(so hopefully no body's panties get in a bunch over my post) but i do know that the nicer and cleaner the wave , the nice and cleaner your sound is gonna be.

maltesechicken

How close does that port come to your trunk lid? Do you have a really deep trunk or is that port really tight with the lid?

TomK

Surprised that "Quack" hasn't shown up here to comment on his favourite topic............... Dukk [img]graemlins/thumb.gif[/img] He's the port king.

Only thing I'd add is the spacing between both the inlet and the outlet sides of the port and any other adjacent surfaces is important. For example for round ports, the min distance from either end of the port to an adjacent surface should be a minimum of one diametre of the port itself. That what an old installer buddy of mine, and now brother inlaw, told me as far as a rule of thumb. Has that changed or was never true to begin with !?!?!? That's what I've always gone with......... although my ported 12" in the truck now isn't following that rule. Cosmetics overruled that issue, and the cosmetics still suck as far as I'm concerned. Come warmer weather, that's going to change without a doubt. Cosmetics are for girlz not car audio............. ha, ha, ha.......... I made a funny [img]graemlins/boring.gif[/img]

Team_Obsession

Maybe just do a smaller port and make it alot shorter...................... [img]graemlins/dunno.gif[/img]

Chadxton

iTrader: (1)

Ok, in answer to questions here, the T-nuts are in the right place. The sub is going to be invert mounted and just a simple MDF ring is going to be placed to cover it up. Final finishing is yet to be decided upon.


As far as rounding the ports goes, I had already planned to do so, but I only built the port yesterday!! It's still a work in progress.

There's about 4" at the closest point from the port to the trunk lid. The port is 18½ inches long and protrudes about 10" from the enclosure base. Target tuning for this port is 32-34Hz.

Yes, I do plan on making similar shorter ports, mainly for SPL use. Team Shadow, I gotta get some time off so we can figure out the resonance freq of my car.

Chadxton

iTrader: (1)

I see your point. I do strive to make it more of a property of function rather than form. I don't entirely care for cosmetics concerning there's a mountainous port protruding out of the box like that. [img]tongue.gif[/img] But it appears as though there is sufficient area to clear the port, it being square, I'm told it doesn't quite follow the rule of one full diameter of the port for clearance. I guess we'll see how it goes. I feel like I'm entering unchartered territory doing this setup.