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View Full Version : building a ported box with a round port question...



g30ffr3y
12-16-2004, 02:33 PM
i was thinking up building a ported box
for one of my SE's but trying a round port
this time...

i know most people use PVC pipe for
the port but which diamter is better?
3" or 4" i suppose are the common
choices???

also where should be port be in relation
to the sub?

what are the benefits or disadvantages
to going with a round port over a slot
port???

thanks.
-g

DFW40
12-16-2004, 03:52 PM
No advantages with either, they sound they same assuming you have the same port area. With that sub I would go with no less than dual 3 inch pvc pipes. The dual 4 would be good too but then you get into length issues and space etc. I had/have a box that had an 12 inch SE in it which was 2.25 with dual 3 inch ports tuned to 27hz. Mine was like this with the sub in the middle and the two ports in the bottom corners like so.

-----------------------------------

sub

O O
-----------------------------------

DFW40
12-16-2004, 03:54 PM
My attempt at a diagram fell short. But like I said the sub was in the middle on the front baffle with one port in each of the bottom corners.

g30ffr3y
12-16-2004, 05:00 PM
why dual ports???

bbp6 had me with a simple 3" diameter and around a 7" length...

Acidburn
12-16-2004, 05:09 PM
more port area = less chance for port noise + louder

nosaj070
12-16-2004, 05:11 PM
What sub are you running? If it is going to be displacing a lot of air definetly go 4" , i don't know if I would bother running dual ports.

DFW40
12-16-2004, 05:16 PM
I wound not use a single 3 inch but you can get away with a single 4 inch without any noise. I had a 10w7 with a single 4 inch in a box and it sounded great. I just like the look of dual ports.

g30ffr3y
12-16-2004, 05:23 PM
ill have to work on my bbp6 file to adapt it for
dual 3" ports but i figure i could do that... just
one more cut after all...

im running an RE SE 12"...

would the single 4" or dual 3" be best???

DFW40
12-16-2004, 05:31 PM
You are looking at either

dual 3 port area 14.13 square inches
single 4 or 12.56 square inches

either way you would be ok

Acidburn
12-16-2004, 05:31 PM
the dual3s have more port area...

g30ffr3y
12-16-2004, 06:48 PM
dual threes it is...

i bought some MDF on my lunch break and im
going to get to building after work...

what does port noise sound like??? how can i avoid it???

is placing the ports on the same face of the box with the
sub the right way to go??? or should i port out the
back or one of the sides???


what got me thinking about this round port is my new
home theatre sub [harmon kardon 10" 100 watt do dader]
is downfiring with the port out the back of the box... and
it sounds awesome!!!

DFW40
12-17-2004, 10:18 AM
I think ports facing the same way as the sub makes sense. You start putting them in the back you could possibly screw up the timing on the front wave and the rear wave. The timing of the sound coming out of the port and off the sub is important. I could be wrong but I usually play it safe. Port noise sounds like a chuffing of air or a whistleing. To avoid this number one you need enough port area which you should be fine with dual 3's. Another way is to sand or grind down the ends of the ports (on the inside) so they are more rounded and smooth. You also want to be sure that the end of the ports inside the box are not right behind the sub where the back air off of the sub pumps directly into the port opening without pressurizing the air inside the box first or to close to a wall etc.

Acidburn
12-17-2004, 03:28 PM
The dual 3s have more surface area and, therefore, more resistance ;)

Two 3" = One 4" ...
ya know what James, you just always have to be soooo right
ahh you're such a party pooper!!

g30ffr3y
12-17-2004, 03:33 PM
ya know what James, you just always have to be soooo right
ahh you're such a party pooper!!


but he seems to know a sh1tload about box building...

Moe Lester
12-17-2004, 04:08 PM
I built a box w/ 2 3" ports and put my SE in it a while back, port noise out the ***... do 2 4"

Nikuk
12-17-2004, 04:36 PM
For 2 cubes You should really run with (2) 4" or better if you plan on putting 600rms to it.

Nikuk
12-17-2004, 08:27 PM
I personally say slot port with 25 square inches or more ... ;)

i agree but he's insistent on using pipes. I ended up pointing out that (3) 3" would be nec... Much rather slotport.

Str8Up
12-18-2004, 05:01 AM
Maybe try using Lightning Audio Aero Ports?

Btw, are two 3" Aero Ports in 3.5 common chamber ported box good enough for 2 ID Max 10's?

I know the 10" Brahmas can displace a lot of air, and Adire recommends a 3" port for a SQ application in the 'tech' section of their website.

An ID Max 10" has about 88 cm2 more surface area over a Brahma 10", but the Brahma has about 10mm more total linear travel than the ID Max 10. So shouldn't they move about the same amount of air? And if so, shouldn't the 3" Aero port be ok for each sub since Adire recommends 3" for their 10?

DFW40
12-18-2004, 08:13 PM
See if you can use dual 4' s, it will have to be a big box with all that length for those ports. The 2.25 box tuned to 27hz I have now with the dual 3's has very little port noise even with your head right next to it. This is with a Brahma running at around 800-900 watts. You will not even hear a peep if it is in your trunk. The easiest way is the slot port, I know you tried this earlier but I think your box was too small and maybe needed some tweeking. Do not be afraid to try the dual 3's.

Str8Up
12-18-2004, 11:59 PM
See if you can use dual 4' s, it will have to be a big box with all that length for those ports. The 2.25 box tuned to 27hz I have now with the dual 3's has very little port noise even with your head right next to it. This is with a Brahma running at around 800-900 watts. You will not even hear a peep if it is in your trunk. The easiest way is the slot port, I know you tried this earlier but I think your box was too small and maybe needed some tweeking. Do not be afraid to try the dual 3's.

Thanx for your reply :)

I think you have me confused with someone else though on the bottom half of your post.

My 10's will be in my reardeck firing at the back window, ported @26.5 hz. And the volume chosen is what ID recommends.

thanx man...

DFW40
12-19-2004, 04:29 PM
sorry, that was intended for the original poster.
But to answer you question I would not use jsut one 3 inch aeroport, 2 for sure.

g30ffr3y
12-19-2004, 11:49 PM
ive got the box installed now... just the single three
inch round port... its only like six and a quarter inches
long... and if i put my ear up to the port i can hear
some wooshing... but not much over the bass... and
hardly at all if at all in the drivers seat... so for now
i dont see a need to make lots of ports with curves
taking up my box volume...

the box overall sounds awesome!!! i probably
wont keep it too long although i want to build
another one for my other SE and be ridiculous
before i get to work on a box for a 15" XXX...

how big an what tuning are those supposed to be???

Str8Up
12-20-2004, 12:24 AM
sorry, that was intended for the original poster.
But to answer you question I would not use jsut one 3 inch aeroport, 2 for sure.

I have 2 ports. In a soon to be common chamber enclosure. Plus, a tuning of 26.6hz is pretty low, and there is much less turbulance than a higher tune, say, 30hz or greater. And coupled with the fact that they're not regular 3" ports, but Aero Ports, I think I'll be fine now that I've thought it over.

Thanx for your replies ;)

Nikuk
12-20-2004, 09:59 PM
geoff - good to hear that its good to hear. faith in RE's paid off... ? ;)