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View Full Version : slot port vs. round port



hdave
03-20-2005, 05:12 PM
Whats the difference between slot ports and round ports?

What are advantages and disadvantages of each?

Acidburn
03-20-2005, 05:15 PM
the shape

slot ports are easier to incorporate into the design
round ports take up less volume since PVC isnt very thick

if both have the same cross sectional area, they will sound the same

BASS OUTLAW
03-20-2005, 05:19 PM
common PVC's cross diameter 4" to 5" ... so less cross sectional area, then less port length at a specific frequency... <------ loads of port noise though...

bri487
03-20-2005, 06:27 PM
common PVC's cross diameter 4" to 5" ... so less cross sectional area, then less port length at a specific frequency... <------ loads of port noise though...

port noise is cause by many factors.

pd298
03-20-2005, 07:12 PM
If you have a round port, make sure the port is big enough, because if not there will be ALOT of unwanted port noise, I had that happen with my box

joeldirt
03-20-2005, 07:46 PM
There is no difference between round and slot. YOu get the same tuning effects when tuned to a specific frequency.... People are under the impression that round ports give more port noise. THis isnt always the truth.... I can tell you why.
If you use a small round port, yes you are likely to have more port velocity then that of a larger diameter port. Imagine it like this. you have a garden hose..... putting out water at a normal rate the only thing you can hear is the water splashing in the grass..... lol work with me here. now put a nozzel on that hose and it is at a greater velocity shooting out of that nozzel you can now hear the water being pushed out of that little diameter nozzel. YOu want your ports to breath freely so air isnt being forced in and out cauding alot of port noise. Generally SPL competition is good with a port velocity of 5% or less. ( So I have heard)

People use slotted ports for a few reasons. They can easily avoid port noise by giving more port area with a slotted port, easily round over the port entrances/ exits, they can use the same material they are using for the box and the same tools and no matter how long the port needs to be they can bend the port allong the inside of the box until they achieve their correct length. In my own personal opinion, I think slotted ports are ugly as compared to round ports.

ROund ports can be rounded over just the same. I always brace the ports inside the box at the end and in the middle of the port to reduce port vibrations. I even go as far as adding a wrap of 3/4" weather strip allong the length of the port. Probably not necesary, but it acts as a vibration deadener, and I wnat to eliminate all vibrations and flex in my entire box. At the end brace flush with the entrance of the port, I round the port entrance over with a round over bit.

I hope this helped a little. I have an interesting way of looking at things and doing things. But my boxes sound bad ***. I do know that much. I can't wait to get out of the USMC so I can start taking my fabrication to the next level.

bcarpenterfhl
03-20-2005, 07:51 PM
joel dirt is completely right. to put it short, slot ports are only superior beucause you can make the port area to your satisfaction, and bed it so its longer. however, round ports can also easily be made into an "L" or labrynth shape, just no one does it.

traksta15
03-24-2005, 09:38 PM
plus slot ports add bracing......

InhumanAcura
03-24-2005, 09:52 PM
round ports are louder than slot ports...[/story]

....and sometimes you want the box to flex ;)

traksta15
03-24-2005, 10:31 PM
^^^yeah, don't u just love lost spl.....

joeldirt
03-24-2005, 10:49 PM
round ports are louder than slot ports...[/story]

....and sometimes you want the box to flex ;)

I also heard garden hose makes for good por tmaterial... :rolleyes:

InhumanAcura
03-24-2005, 11:00 PM
I also heard garden hose makes for good por tmaterial... :rolleyes:


^^^yeah, don't u just love lost spl.....

since ya both want to be asses...your both right. screw learning something :rolleyes: its not like i test every ****ing weekend

joeldirt
03-24-2005, 11:14 PM
since ya both want to be asses...your both right. screw learning something :rolleyes: its not like i test every ****ing weekend


Lol, what do you study? We have all seen you post befor, and we know you know your ****, we were just having fun since that thread was old and answered any way.