Some Box Help?

[natemikegray]

I am currently thinking about upgrading sub's. I currently have the RE Sexv2 12d4's running 1ohm off a single Cadence Ultrashock A7HC. I have been trying to find 15" subs that can handle that sort of power (I have two of the A7HC). I've found many sub's but I think I'm sold on the NVX VCW 152, specifically because of the price.

Anyway I was going to try and get enough room in my trunk for two sub's in a 8ft³ 28hz tuned ported box (if I pull out the spare I should have room). The car is a 1997 Acura CL 2.2L.

These are the TS parameters from the manual.

Qes: 0.458

QTS: 0.440

Fs: 24hz

Vas: 106.40L

SD: 124.7 (it didn't specify, so I just used cm²)

Xmax: 20mm

Rec Port Box: 2.75ft³

Here are my questions.

1) Is the port volume also included in the box volume? So that I know if I'm going to loose space do to port volume.

2) Am I able to build the port out from the box? Its in relation to the question above.

3) Am I going to over excurt and bottom out the sub's if I build my box this big and power it above recommended RMS? From what I've heard, watched and read, these sub's should be able to take ~1200wrms and/or more.

4) How big should my port area be to keep port noise minimal? I don't know anything about calculating this so any help would be necessary.

5 and last) I currently have only stock electrical except for a 2 fared cap. I know I am going to need more juice so here's my question. Can I get away with adding another cap, adding an extra batt, or go all the way and get another or upgraded alt with a batt?

I was hoping to get a cheap battery or maybe another cap (some 5 fared) and just add another stock alt and use that one specifically for my audio.

I know that this is a lot of info but I am green when it comes to car audio and only know what I've read or have done myself.

If there is any other info you need I will be happy to give it to the best of my knowledge.

[ckeeler11]

I am currently thinking about upgrading sub's. I currently have the RE Sexv2 12d4's running 1ohm off a single Cadence Ultrashock A7HC. I have been trying to find 15" subs that can handle that sort of power (I have two of the A7HC). I've found many sub's but I think I'm sold on the NVX VCW 152, specifically because of the price.

Anyway I was going to try and get enough room in my trunk for two sub's in a 8ft³ 28hz tuned ported box (if I pull out the spare I should have room). The car is a 1997 Acura CL 2.2L.

These are the TS parameters from the manual.

Qes: 0.458

QTS: 0.440

Fs: 24hz

Vas: 106.40L

SD: 124.7 (it didn't specify, so I just used cm²)

Xmax: 20mm

Rec Port Box: 2.75ft³

Here are my questions.

1) Is the port volume also included in the box volume? So that I know if I'm going to loose space do to port volume.

No port will need to be added into the size of the box. that is the net size.

2) Am I able to build the port out from the box? Its in relation to the question above.

Yes you can build the port outside the box. just remember to sub tract any port that is on the inside.

3) Am I going to over excurt and bottom out the sub's if I build my box this big and power it above recommended RMS? From what I've heard, watched and read, these sub's should be able to take ~1200wrms and/or more.

Depends on the box and tuning also if you will be using any bass boost or other eq'ing.

4) How big should my port area be to keep port noise minimal? I don't know anything about calculating this so any help would be necessary.

5 and last) I currently have only stock electrical except for a 2 fared cap. I know I am going to need more juice so here's my question. Can I get away with adding another cap, adding an extra batt, or go all the way and get another or upgraded alt with a batt?

I was hoping to get a cheap battery or maybe another cap (some 5 fared) and just add another stock alt and use that one specifically for my audio.

Capacitors do not help anything a second battery will help if you are playing with the car off. Looks like you have a 90 amp alternator on there now. The only way to get more power is a bigger alternator.

I know that this is a lot of info but I am green when it comes to car audio and only know what I've read or have done myself.

If there is any other info you need I will be happy to give it to the best of my knowledge.

[natemikegray]

For the bottoming out question. I said I was going to be using a 8ft³ box tuned to 28hz. No bass boost, other than maybe on my deck. Would these particular sub's bottom out if I did put 1200-1500w into them in that big of a box?

[andru]

you can model your box, sub and power in winisd, it will tell you how much excursion you could expect.

[ckeeler11]

Yes i would worry about them bottoming out in a box twice as big as recommended. On that kind of power and a big box I would look at the soundqubed HDS315 over the NVX.

[ckeeler11]

DP.

[notorious97200]

They recommend 2.75 per sub, and you have an 8 cu ft box.

You don't need 8 cu ft for 2 subs. If it's your total available volume : ok. You'll have to account for port volume, subs volume, and wood thickness. You'll have way less net volume.

At 4 cu ft net per sub, be careful with the power !

28 Hz for tuning : that is looowwww ! I like 32 Hz usually, or between 30-34 Hz. I don't like to lose too much output by tuning too low.

[Joe X]

I don't think you have 8 net in that vehicle but either way NVX work in smaller boxes, if you don't have enough power to blow them at least they will sound peaky as hell.

[natemikegray]

For everyone saying that they work in smaller boxes, I know. Even a 7 cube box would work (3.5 cubes per sub). I'm just trying to get them lows. With the box at 7-8ft³ and it tuned to 28-30hz I should be able to get those higher to mid 20's. Anything smaller and I'd just get what I'm getting with my current 12's.

So, yes my main concern is bottoming out. I don't know where in the winisd calculator that it will tell me expected xmax. I know that you can input the xmax into the parameters but didn't know and know know where expected xmax would be.

I'm just trying to get budget friendly sub's that can handle that sort of power in a big box tuned low without damage. Personally if there was a 15" SVC sub that could take 1200-1400 at 1 ohm I'd get that instead of any DVC sub, if its budget friendly.

Maybe what I need is a couple 18's, but that drops sq out for SPL.

[natemikegray]

Actually, for those who have WinISD, input this sub and the specs for the box. You should see that I'm not losing any higher hz performance.