How much net volume would i need to go ported?

[06RTCharger]

While waiting for the never ending list of equipment to be aquired, been brain storming and drawing up ideas for my subs. Im wondering what would the ideal net volume would be for my subs to be the most efficient in a ported box? My goal for the system is to have them play deep as they can (fs is 23) with a flat and wide sub-bass bandwidth (not mid-bass) if possible, knowing ill sacrifice spl. I dont imagine these subs are ideal for spl comp type of situations anyway. I want to make the most out of them with my vehicle, willing to assemble box inside the trunk. I looked at the recommendations from the owners manual and i dont think they are considering power and tuning freq, it seems more of a general idea that they give you. 

Just for fun i was sketching up some ideas of a tline lmao. I had just watched marks new video and wondered how humungous the box would be. I came out with a 16x14.25in port area, 147.5in long line, thats 12 feet 3.5 inches lol. Came out with a cool ass idea but it was HUGE 17.5 tall, 4ft 0.75in wide, 4ft 5.25in deep, with individual halfwidth ports that merge into one fullwidth port at the center and subs mounted inverted. 

Anyways the subs are TWO Hybrid audio technologies Clarus C15SW dual 4ohm subs. They will each have their own individual amp, wired up to run at 8ohm. The amps will be two LP 4.1HVS.

ill include owner manual pics of the specs for each. Im just wondering what my ideal net volume would need to be for these, thanks guys. 

 

[06RTCharger]

Anyone know how much volume i would need in order do go ported instead of sealed/ or IB? Or maybe if someone has a link giving the formula used to determine air space needed based on specs of the sub and power. 

[DLHgn]

I can play with some models if you want. 

[Joe X]

Here's what modeling shows (in-car response) for a 4 net @28Hz box with 60 square inches of port area, that's for both drivers, this is good to drivers rated power:

 

 

Subsonic filter should be set to about 20Hz.

 

 

[DLHgn]

So I have an enclosure here that has pretty decent extension into the low 20's and is flat from 25 and up. It's f3 is at 21Hz. It never reaches Xmax and has a max port velocity of 22.7 m/s at 3000w (assuming 1500 per sub RMS).

The only problem is that it is huge. 9ft3 net volume with 112in2 of port area and 40in long port. Such a big box for 2 15's makes me a bit nervous but the sim says that they will only get to ~21mm of one way excursion at 3000w and the one way xmax is 23.5. The drivers also seem to like a bigger box anyways.

I tried the recommended specs from the manufacturer and the results were less than impressive. It only gained about 2dB at about 40Hz but lost about 5db at 23Hz. At ~32Hz the recommended enclosure drops below the huge box. 

[DLHgn]

Again, that box is ridiculously large but you get the sub-bass response you're looking for at the expense of SPL. There may be problems i'm not foreseeing so I would wait for some more experienced enclosure designers to chime in if you do like these specs. 

[06RTCharger]

1 hour ago, Joe X said:

Here's what modeling shows (in-car response) for a 4 net @28Hz box with 60 square inches of port area, that's for both drivers, this is good to drivers rated power:

 

 

Subsonic filter should be set to about 20Hz.

 

 

Thank you Joe, ill play with some dimensions in the trunk and see what kind of plan i can come up with. Thanks

[06RTCharger]

1 hour ago, DLHgn said:

So I have an enclosure here that has pretty decent extension into the low 20's and is flat from 25 and up. It's f3 is at 21Hz. It never reaches Xmax and has a max port velocity of 22.7 m/s at 3000w (assuming 1500 per sub RMS).

The only problem is that it is huge. 9ft3 net volume with 112in2 of port area and 40in long port. Such a big box for 2 15's makes me a bit nervous but the sim says that they will only get to ~21mm of one way excursion at 3000w and the one way xmax is 23.5. The drivers also seem to like a bigger box anyways.

I tried the recommended specs from the manufacturer and the results were less than impressive. It only gained about 2dB at about 40Hz but lost about 5db at 23Hz. At ~32Hz the recommended enclosure drops below the huge box. 

Dayum lol 9cubes net!? Just for fun ill try to see if i can draw up some plans close to that. Thanks for taking the time bro, much appreciated. 

I also figured the recommended box specs where just a general purpose box that works safely for the sub and not really maxing out performance.

[06RTCharger]

1 hour ago, DLHgn said:

So I have an enclosure here that has pretty decent extension into the low 20's and is flat from 25 and up. It's f3 is at 21Hz. It never reaches Xmax and has a max port velocity of 22.7 m/s at 3000w (assuming 1500 per sub RMS).

The only problem is that it is huge. 9ft3 net volume with 112in2 of port area and 40in long port. Such a big box for 2 15's makes me a bit nervous but the sim says that they will only get to ~21mm of one way excursion at 3000w and the one way xmax is 23.5. The drivers also seem to like a bigger box anyways.

I tried the recommended specs from the manufacturer and the results were less than impressive. It only gained about 2dB at about 40Hz but lost about 5db at 23Hz. At ~32Hz the recommended enclosure drops below the huge box. 

Noobie question, but when u said 9cubes net, does that include the port in it? Or its 9cubes then also the huge port? 

[DLHgn]

29 minutes ago, 06RTCharger said:

Noobie question, but when u said 9cubes net, does that include the port in it? Or its 9cubes then also the huge port? 

Net is the total airspace that the sub can "see". So that doesn't include the port, bracing, sub displacement or any other misc. items. Gross volume would be the total size of the box including port and all that.