what are the most efficient ports to use? obviously round ones, but flared not flared, flared at one end? any help would be great. thanks

4" Aeroports (flared both ends and round) are aparantly THE most efficient port there is.. Something to do with PI I've been told..

But yes, a round port with flares on both ends is the most efficient for air flow.
Slot ports are the most efficient for surface area and depth (you get more port face for the same "lost" space on the baffle, and slots are shorter as they use a wall of the enclosure for the port).

as usual with SPL it will differ from install to install, but with round flares definately flare both ends.

The day before Autoshowdown I spent some time testing with DD Phil, and we started with a single 6" pvc port unflared, once our score peaked we flared both ends and got a 1.3db gain.

I know Sheildsy uses the 13-14(something like that) sqin of port per cubic foot of box, he seems to do alright too.

i just thought to myself. if i flare both ends how do i get the port in the slot. do i just flare the second end once its in the hole?

yeah, just flare it while its in the baffle.

adam, where u competing at jamboree in the green civic?

yeh that was me. i saw your car there. probably spoke to you a couple of times that day.

the port length doesnt include the flared ends does it? or do i cut the port to correct size and then flare the ends?

the flare will actually increase your tuning freqency, so if you want a freq that youve worked out to a certain length, unflared.. you will want to make the port a bit longer, then flare it

great i think im set then! iv got some testin to do tommorow now.

Or use aeroports - they're flared ends you attach to your normal port pipe.

aero ports are great!
very easy to use.
saves alot of hassle and very easy to pull off cut and retest.

also not done so much but worth trying...
Dimple the surface (inside the port) with a right angle drill, surface should look like a golf ball. This will create turbulance on the surface resulting in a faster more volume airflow vs pressure resulting in extra output. Basically making the port larger and longer for free. Something new for you to chew on...

wouldnt that make the surface rough? when i made the ports smoother on both ends i picked up spl...

THINK OF it like a golf ball- dimples create turbulance on surface resulting in less drag=less resistance=ball will go further.
heres a dimpled port

Think of a golf ball.. dimples = turbulence. Turbulence helps make the ball fly straighter as the turbulence helps equlizes the wind resistance around the ball. A smooth golf ball will fly faster hence further, but be far less accurate in its placement. As the ball travels large distances you need that accuracy.

Conversely, look at a baseball. It needs to travel fast, over a short distance, hence they're mostly smooth (aside from stitching which you can't do away with) 'cos the need for accuracy is reduced by the shorter distance it needs to travel.
The "spitball" was a baseball pitch where they'd slag on one side of the ball, as the ball rotated the spit side would have less resistance than the rest, causing it to travel erratically.. it was banned because of this.

We're not talking about something travelling thru air, we're talking about air travelling thru something. With SPL you want to maximise air flow, and turbulence won't do that. Dont believe me ? Make a slot ported box, meter it, then resin the insides of the box dead smooth and meter it again. SPL goes up.
This is the same reason people see gains from duct taping around ports and subs.

Not arguing with you many top end companies in home audio already use dimpled ports-the one above is Bose and B&W also do it. A baseball is not optermized for speed and distance otherwise it would have no stitching and by the way golf balls were smooth years ago. It doesn't matter if the air is moving or the object is moving, the air is moving over a surface regardless. There are even surfboards that have a rough coating as this creates a turbulance with the waters contact creating speed. All in all though it will only give your port more effiency=a larger size port. Smoothing a port may work in some cases as it may twist the flow of air in favor of the mic but it will not increase air flow effiency.