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View Full Version : Round off end of port?



accuab
11-06-2011, 10:54 AM
I've read somewhere that it is better to round off the board at the end of the port and if it is an L port to put a corner piece at the turn to smooth out the air traveling through the port. Is this needed for a port?

wenn_du_weinst
11-06-2011, 10:56 AM
some times it does good some times all it does is look pretty

SPL Blazer
11-06-2011, 11:04 AM
It reducess or eliminates port noise. I use a router to all the edges of the port opening and the inside edge of the port wall. You can hear the difference in the clarity of the bass, it doesn't help it get loud to the ear, but you will notice it when testing it on a meter.

wenn_du_weinst
11-06-2011, 11:07 AM
It reducess or eliminates port noise. I use a router to all the edges of the port opening and the inside edge of the port wall. You can hear the difference in the clarity of the bass, it doesn't help it get loud to the ear, but you will notice it when testing it on a meter.
some times, not always.

SPL Blazer
11-06-2011, 11:16 AM
some times, not always.

what part of that is sometimes?

accuab
11-06-2011, 11:45 AM
For a normal build does it matter? The sub will be in the trunk of a car. And would I do anything for where the port turns.

wenn_du_weinst
11-06-2011, 11:48 AM
what part of that is sometimes?

when your port is big enough to not need it to be rounded off, or the angle of the port walls makes it not needed. Noise comes from either restriction or the walls making the wind spin backwards creating noise.

SPL Blazer
11-06-2011, 12:56 PM
There will always be noise, you may or may not actually hear it. I large port will make noise just as a smaller one will. Rounding the edges will deduce the restriction and turbulence in the air thus reducing the port noise to a level you will no longer hear over the output. Most prefab boxes don't do it cause they're crap and made as cheap as possible. A good custom box will have a 45 degree angle inside the back inside corner of the port, or something to smooth the flow of air coming in and out of the port, and will also round off all the port edges.

wenn_du_weinst
11-06-2011, 01:04 PM
lol if you really are a spl competitor you should know NOTHING is foolproof. Every thing is test and tune, a correctly designed box will not have noise. The 45 in the port corners is not to smooth the transition, it's to make sure the port is the same width all the way through instead of getting larger in the corners. Also a good box will not always have everything rounded, a GOOD box will only have the transitions and corners rounded where they are supposed to be rounded and the others left alone.

accuab
11-06-2011, 01:40 PM
So what should I round if any? I'm just wanting it for normal bass. Not competition level.

wenn_du_weinst
11-06-2011, 01:43 PM
put a 45 in the corner of the port and leave it at that. it will be fine and be much less work then rounding everything over

goingdef
11-06-2011, 01:47 PM
well I have been in hvac(heating/cooling/air flow) for about 12yrs and that 45deg. angle at the back corner of the port helps smooth out the flow verses hitting a flat wall before turning 90 and trying to go back into the box as for rounding the edges it might make a tiny difference but not as important as the inside construction.

---------- Post added at 01:47 PM ---------- Previous post was at 01:47 PM ----------


put a 45 in the corner of the port and leave it at that. it will be fine and be much less work then rounding everything over

in short that^^

SPL Blazer
11-06-2011, 01:51 PM
lol if you really are a spl competitor you should know NOTHING is foolproof. Every thing is test and tune, a correctly designed box will not have noise. The 45 in the port corners is not to smooth the transition, it's to make sure the port is the same width all the way through instead of getting larger in the corners. Also a good box will not always have everything rounded, a GOOD box will only have the transitions and corners rounded where they are supposed to be rounded and the others left alone.

true, it's all in the testing. One of my comp boxes had all but one inside edge rounded with sections of plastic pipe, that was using areo's and not a slot port. I tested after I added each new piece and then removed some and retested with each piece that was changed. With my finished slot ported boxes I never used a 45 in the port corners, but another section of pvc pipe to make it smoother. I tested with a 45 and with the pvc and was louder with the pvc. Both sides of the port wall in the back corner ended up being rounded over, between using the router on one side and the pipe in the other corner.

SPL Blazer
11-06-2011, 01:54 PM
put a 45 in the corner of the port and leave it at that. it will be fine and be much less work then rounding everything over

Or he can round over the end of the port wall inside the box in addition to adding the 45. If he wants to later he can round over the edges on the outside of the port, but it'll be a lot easier to do that before he builds it rather than trying to do it later on.

accuab
11-06-2011, 02:23 PM
how large of a 45 should i be looking at adding? I'm looking at around a 4" wide port. Should it be as small as possible as to not take away from the port volume? Also, should I extend the port to factor this in?

dB-SPL
11-06-2011, 02:28 PM
how large of a 45 should i be looking at adding? I'm looking at around a 4" wide port. Should it be as small as possible as to not take away from the port volume? Also, should I extend the port to factor this in?

The point of the 45 is to keep the same distance throughout the port. So measure 4" from the inside corner of the port and that's where the 45 should land.