Sub placement, does it matter?

[MellowHype 10+ year member]

33 x 19 x 15 is actually a bit bigger then the 34 x 19 x 14 I was discussing earlier. The Rs will do just fine. But yes, do an aero port to save space. They're more efficient then slot ports. They are indeed PVC or cardboard (sonotube) pipes with flared ends. One 6" will be fine.

Ill give that a go then, could you tell me what the ft^3 would be at 33 x 19 x 15 with a 6"x16" like you said earlier? also what the htz would be? just as its a bit different from the measurements you gave before.

Its not a bad idea to go aero as ill have more room to mount the subs, just i have no experience on them so ill have a look around

And one more thing, if im not looking to get extreme lows and im more interested in SPL, is a higher tuning frequency a good idea? like would 38hz be louder than 32 hz?

 

[ancorp 10+ year member]

Youd be at around 3.84 cubes and 31.2hz or so. If you're looking for a higher spl then yes, tune higher. Its easier to adjust tuning with an aero port. Just take it out, chop off some of the pipe, reattach flared ends. If you go with a 6" diameter 9" long port, you'll be tuned to 38hz with about 3.95 cubes of net volume after all displacements. Start with a 16" port first and see how she sounds, and then shorten it piece by piece until it sounds good to you.

 

[ancorp 10+ year member]

If you can locate a 8" flared port (or make one), then make it 21" long and you'd have 38hz with about 3.5 cubes of net volume. The larger port area and smaller box might help you peak for greater SPL. Tuning above 38 might be beneficial too, depends on the vehicle.

 

[MellowHype 10+ year member]

If you can locate a 8" flared port (or make one), then make it 21" long and you'd have 38hz with about 3.5 cubes of net volume. The larger port area and smaller box might help you peak for greater SPL. Tuning above 38 might be beneficial too, depends on the vehicle.

Thank you for your help bro, gonna crack on with this over the weekend. I just need to find some PVC and learn how a aero port is correctly made and im good to go

 

[psych0ticnemes1 5,000+ posts]

At 3.6 cubes net you're better off getting a single 15", which is unfortunately because you just bought the pair of Rs, but 1.75 cubes per 12" R is plenty.

As for a 2k 1 ohm amp, what is your budget? I'd recommend this: Q1-2200D

Those subs will take the power well and it's a great amp. I run a 15" Type R off 1.5k right now. They're tough to beat for the price.

Good luck.

 

[MellowHype 10+ year member]

At 3.6 cubes net you're better off getting a single 15", which is unfortunately because you just bought the pair of Rs, but 1.75 cubes per 12" R is plenty.
As for a 2k 1 ohm amp, what is your budget? I'd recommend this: Q1-2200D

Those subs will take the power well and it's a great amp. I run a 15" Type R off 1.5k right now. They're tough to beat for the price.

Good luck.

Surely two R's will out perform a single 15" even if the enclosure is on the small side??

Also, ive realised 2k 1ohm is definitely going to need an alternator upgrade so im gonna stick with 500 each for now, but thanks for the recommendation

Im hoping to go and get the materials tomorrow, just im not 100% on how to make an aero port. Do i just need one tube of 6" and then flare one end? Surely i need the ends slightly larger than 6" so that they can be stuck on the straight pipe to change tuning, and also to have the inside end flared?

Can they just look like this?

So i grab one 6 inch radius 16 inch long tube, flare one end, slightly file the other and slide it in the box and screw it down?

Also, the port is supposed to look like this? not sticking out of the box.

 

[psych0ticnemes1 5,000+ posts]

Two 12"s won't automatically be louder than a 15" simply because of the extra cone area, but in proper boxes you could guess that they would be.

The port can be internal or external, but if it's internal, it'll take up space in the box so you have to figure that in when determining net box volume and tuning.

 

[MellowHype 10+ year member]

Two 12"s won't automatically be louder than a 15" simply because of the extra cone area, but in proper boxes you could guess that they would be.
The port can be internal or external, but if it's internal, it'll take up space in the box so you have to figure that in when determining net box volume and tuning.

Ok thanks, got me a bit worried now though lol, i could go return the R's and get a 15" sub @ 1000wrms 1ohm and have it in a 3.5 slot ported box, not sure how that would compare to 2 12" R's @ 500 each.

And yeah i understand a 15 could be louder depending on the setup / brand etc, i think ill have around 4ft^3 before displacement of subs and port so i hope the box should just about be big enough.

The port has to be internal aswell as i dont have the room for external.

Im thinking of just filing and smoothing one end of the pvc, and sliding it in with the aero/flared end on the outside as i dont see any other way, other than using a coupler which just means more displacement.

 

[ancorp 10+ year member]

Well two 12 Type Rs should definitely be louder then one 15" Type R in the same box. More cone area and motor force, and less power compression. You need to flare the port or you risk port noise and choking. But it might not be noticeable. My calculations were with the port inside the box. Don't see the point of making the port external, unless its just the flared part. Yes, flaring both ends is best, but if you can only do one, do the one on the outside.

This is what you need Precision Port 6" Flared Port Tube Kit | 268-354

 

[MellowHype 10+ year member]

Well two 12 Type Rs should definitely be louder then one 15" Type R in the same box. More cone area and motor force, and less power compression. You need to flare the port or you risk port noise and choking. But it might not be noticeable. My calculations were with the port inside the box. Don't see the point of making the port external, unless its just the flared part. Yes, flaring both ends is best, but if you can only do one, do the one on the outside.
This is what you need Precision Port 6" Flared Port Tube Kit | 268-354

I was looking at that earlier, however im from UK and cant find anything decent here.

My friend has a peice of 6" PVC pipe for me, so i know i can have one flared edge, i just dont know how im going to get both ends flared and then get it through a 6" cut out..

Maybe flaring both ends of a long pipe, cutting one end, and with the cut off flare the other end of it ever so slightly so that it might slip on to the other longer peice, if that makes sense. But even that i doubt would work.

 

[ancorp 10+ year member]

You could indeed make the outside flare bigger, and cut a bigger hole. Or simply make a flare separately and then insert it into the box through one of the sub holes and glue/tape it onto the pipe inside.

 

[psych0ticnemes1 5,000+ posts]

If you have the 12"s, use them. They'll work great for you. Report back when you get this thing built and post a video.

 

[hispls 5,000+ posts]

I have seen pictures of people flaring their PVC pipes by heating the tip in a pot of hot frying oil and building a jig to press it onto to stretch the end into a flare. Seemed a bit of a process to do but the results looked excellent.

 

[MellowHype 10+ year member]

You could indeed make the outside flare bigger, and cut a bigger hole. Or simply make a flare separately and then insert it into the box through one of the sub holes and glue/tape it onto the pipe inside.

If using tape is fine, then thats what ill do, makes the job nice and easy i just was unsure whether tape is good enough. Got strong blue gaffa tape and might even use a bit of sealant round the cut.

If you have the 12"s, use them. They'll work great for you. Report back when you get this thing built and post a video.

Will do, hopefully have the box done then get it in the car with subs in a day or two later. Just might have to buy another run of 4awg though as my amps are moving further from the battery and im not sure how much slack theyve got in them.

I have seen pictures of people flaring their PVC pipes by heating the tip in a pot of hot frying oil and building a jig to press it onto to stretch the end into a flare. Seemed a bit of a process to do but the results looked excellent.

not sure what you mean 'building a jig' but i have a heat gun and should be able to find a metal bowl anyway.

All the cuts done today and had a bit of an accident with the front peice

going to have to use it still so ill just sand it down flush, it will just be a bit weaker than the rest..

I also have #6 1 5/8 Drywall coarse screws, what size should my pilot be?

 

[hispls 5,000+ posts]

Heat Moulded Port Flares

Something like this to flare ports. Ive seen a thread where someone used a pot of hot oil to evenly heat large PVC he claimed that you need a lot of pressure to force the pipe open so he built some sort of lever press to smash down the PVC onto the mold.