Ok...

In the process of building a new sub enclosure, fibreglass of course. And I am porting it (RL-p 12). Now, I do not want to use a slot port, what options do I have for nice flared ports? What dia should I go with, is 4" large enough? I saw a couple options on partsexpress, wondering if it is possible to use normal plumbing PVC instead of the supplied stuff so that I can get lengths longer than say 17"?

I'll try to get pics up on the build, but, me being digicam poor, may not be able to get any up until it is completed (or I go through a complete film on the old-fashioned cam-era).

Ok...

In the process of building a new sub enclosure, fibreglass of course. And I am porting it (RL-p 12). Now, I do not want to use a slot port, what options do I have for nice flared ports? What dia should I go with, is 4" large enough? I saw a couple options on partsexpress, wondering if it is possible to use normal plumbing PVC instead of the supplied stuff so that I can get lengths longer than say 17"?

I'll try to get pics up on the build, but, me being digicam poor, may not be able to get any up until it is completed (or I go through a complete film on the old-fashioned cam-era).

a 4" round port works out to lil more then 12in^2 of port..so i'd recommend at least two of them

and yeah..u can use regular pvc..just round over ur edges...

and aero ports tune a lil differently...so be wary of that..

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

Another q..

You don't need as much port area when using round ports compared to slotted ones because of the surface area correct?

Another q..

You don't need as much port area when using round ports compared to slotted ones because of the surface area correct?

i believe it's the same...i'll have to graph some stuff to see if velocity changes...

that's a good question, one i do really have an answer too...but i would assume that u still would need just as much.

aero ports change it up a bit because of the increased area right at the end...but i'm not sure how the math works...

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

Well, my thought come from the fact that slot ports have more surface area, therefore more frictional surfaces than round ones. I'm waiting for Nick to chime in, because I recently remember a thread where we/he discussed this. I'll see if I can find it again.

*chime*

Sorry for the delay - lol.

Scotts right, mostly. You don't need as much surface area with round ports. generally of course Surface are of the vent opening > then surface area of the vent walls.

My question for You is what kind of vB are you looking for? One 12" so I'm guessing 1.5ft^3...? If so, (1) 4" shouldn't be too bad at all - tuning dependant. I'm at work or else I'd graph it for You.

With round ports - I look for a minimum of 7-8sq in of port per cube.

With slot ports outside of 4:1, I look for at least 10-12 sq in / cube.

Not a huge difference sometimes, but for smaller enclosures, 4 sq in means alot.

-Nick

*chime*

Sorry for the delay - lol.

Scotts right, mostly. You don't need as much surface area with round ports. generally of course Surface are of the vent opening > then surface area of the vent walls.

My question for You is what kind of vB are you looking for? One 12" so I'm guessing 1.5ft^3...? If so, (1) 4" shouldn't be too bad at all - tuning dependant. I'm at work or else I'd graph it for You.

With round ports - I look for a minimum of 7-8sq in of port per cube.

With slot ports outside of 4:1, I look for at least 10-12 sq in / cube.

Not a huge difference sometimes, but for smaller enclosures, 4 sq in means alot.

-Nick

<{POST_SNAPBACK}>

I am trying for 2ft^3 tuned to 28Hz ish.

I am trying for 2ft^3 tuned to 28Hz ish.

<{POST_SNAPBACK}>

2ft net to 28hz with 24mm xmax & 0.2 qts... I'd try for (2) 3" pvc -or- (1) 5" pvc.

It's gonna be tough tuning that low in that small an enclosure but still give the woofer enough port. Wait... you know that

I get about 19" depth for 14.13sq^2.

You might be alright with a single 4" aero @ ~14.5".

I'll throw them at BBP6 tonight, if You like.

-Nick

Sure, go ahead, I don't have my computer with me so I can't do it for myself ATM

The box size isn't definate yet, since it is going to be fibreglass, I will be measuring it after it is completed, probably using water.

Water or sand is the way to go IMO

Yah, I'll run a few for Yah after work. 1.75-2.5 ft^3.

In case you need one, I have a spare aero port deal from parts express I ordered last summer. I got 3 or 4 of them. They are about 4-5" at each end, but it narrows down in the middle, like a venturi tube or something of the sort. I dont see them on the website anymore, but if you need one, lemme know.

PE actually has the PSP ports in sale now.

I have 2 3" PSP( aeroport) ports in the SE enclosure i did for my friend.

No whistle at all.

The thing with buying el cheap-o PVC is that its not perfectly round.

The thin walled PVC that comes with the ports is pretty much perfect.

If you want to use a nice posr calculator www.psp-inc.com has the best one ive used so far on the net

Yes, I've seen the ports on PE, but the problem is they don't come in long enough lengths, and I am leary of using aeroports because of the in-accurate tuning caused by the shape.

Yea, they need to make them longer.

I just tuned to w/e i could get without making mine longer

ok, i've learned something..lmao...

so do to the interior walls not having as much surface area, u can use smaller round then a compareable slot? so i'm guessing less friction, less chance for noise, correct? hence the ability to use smaller area...

kewl...

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

In theory, Less surface area = Less friction = Less velocity loss = Less noise, more output.

So... yes.

werd...

..it works in theory of laminar(sp) flow

hee hee hee, sorry. Got awefully sidetracked last night.

Lemme know which box ideas You want graphs for

I'll be in & out all day, but I;ll get 'em up.

Soooory.

-Nick

hee hee hee, sorry. Got awefully sidetracked last night.

Lemme know which box ideas You want graphs for

I'll be in & out all day, but I;ll get 'em up.

Soooory.

-Nick

<{POST_SNAPBACK}>

Like you said yesterday, 1.5-2.5 ft^3 tuned to 28Hz. No rush either, I ran out of fibreglass matte, so I can't work on it anymore until I pick up some, and I don't have any time to do that until at least middle of next week.

Interesting: bbp6 is giving me an odd vent mach graph. Basically, You're vent is peakiest ~15-25hz. If that is accurate (I have NO experiance with SS drivers), then Your ssf et al will negate any problems. Weird... So, knowing that You know what You're doing, I'll list vent mach @ 25hz, unless it peaks higher in frequency.

RMS per the SS site is 500, with the Brutus I'll imagine that You are using ~750wrms.

Also, bbp6 considers 35m/s the audible floor.. anything less is good. For reference, in Your sig is 2.0ft, tuned 28hz w/30sq in of port. bbp6 calc's a vent mach of 8.32 m/s @ 25hz.

1.5ft, 3" pipe 14.5" long: 31.5 m/s @ 25hz

1.5ft, 3" aero 15.5" long: 31.2 m/s @ 25hz

1.5ft, 4" pipe 27.2" long: 18.6 m/s @ 25hz

1.75ft, 3" aero 13" long: 34.3 m/s @ 25hz

1.75ft, 4" pipe 22.7" long: 20.7 m/s @ 25hz

1.75ft, 4" aero 23.7" long: 20.5 m/s @ 25hz

1.75ft, 5" pipe 36.7" long: 13.3 m/s @ 25hz

2.0ft, (2) 3" pipes 22.7" long: 20.3m/s @ 25hz

2.0ft, 4" pipe 19.4" long: 22.6 m/s @ 25hz

2.0ft, 4" aero 20.4" long: 22.3 m/s @ 25hz

2.0ft, 5" pipe 31.5" long: 14.8 m/s @ 25hz

2.25ft, (2) 3" pipes 19.8" long: 21.8 m/s @ 25hz

2.25ft, 4" pipe 16.8" long: 24.1 m/s @ 25hz

2.25ft, 4" aero 17.8" long: 24.0 m/s @ 25hz

2.25ft, (2) 4" pipes 36.8" long: 12.6 m/s @ 25hz

2.25ft, 5" pipe 27.5" long: 16.1 m/s @ 25hz

2.5ft, 4" pipe 14.7" long: 25.4 m/s @ 25hz

2.5ft, (2) 4" pipes 32.6" long: 13.6m/s @ 25 hz

2.5ft, 5" pipe 24.2" long: 17.2 m/s @ 25hz

2.5ft, 6" pipe 36" long: 12.1 m/s @ 25hz

Side note - f3's. With the 1.5' box, the f3 is 26.65hz. With the 2.5' box, the f3 is 28.78hz.

In summary, keep in mind that this prorgam, while better then some others, is still a lump sum calculator.

Hope this all helps.

Nick

That works

Thanks

So if i don't have to use as much surface area, what you guys recommend if the manufacturer suggests 20sq. in. of port area with a slotted port.

I"m trying to make a box 12x13.5x20 tuned to 26hz. I figure i can put 3 1" diameter ports that are 6" long. I don't know if that includes flair or not. Can anyone help me out? Cause i'm only getting 2.36" of port area, which is pretty far off.

Thanks for your time.

I would never use 1" ports... like trying to suck a jellybean through a straw.

What subs?

rl-i 10". Maybe 2.5 thats 13 inches long? Any help is apperciated

I like your jelly bean refrence.

a single 3.5" or dual 2.5" is what I would use.