Box volume too big??

[Colbyjack 0]

So I had a box design done by someone that seems to be a reputable designer around the car audio forums, and I have a couple of questions about it.

I have a FI BTL N2 12" D2 running on a SAZ-1500, 250amp alt, 0 ga wire throughout including big 3 and additional grounds throughout the engine compartment, XS Power d975 in the back, Optima yellow top up front.

The design he gave me has a net volume of 4 cubes. Is that too big for that one sub? I told him I wanted a daily ground pounder that can kill some lows. Well it does destroy the low notes, but it seems to be pretty weak with the majority of rap/hip-hop songs, and doesn't sound real strong on rock or metal. I know the specs call for 1.7-2.5 cubes on FI's cut sheets, but I was wanting some input on the situation. I know that too much volume can cause excessive excursion and damage the sub. By my calculations the box seems to be tuned right around 35hz.

[ricksi30 923]

Even with that little power 4 cubes seems a bit large. I've never modeled the 12 so I'm not speaking from expeirience.

Edited October 15, 2011 by ricksi30

[snyderd758 0]

So I had a box design done by someone that seems to be a reputable designer around the car audio forums, and I have a couple of questions about it.

I have a FI BTL N2 12" D2 running on a SAZ-1500, 250amp alt, 0 ga wire throughout including big 3 and additional grounds throughout the engine compartment, XS Power d975 in the back, Optima yellow top up front.

The design he gave me has a net volume of 4 cubes. Is that too big for that one sub? I told him I wanted a daily ground pounder that can kill some lows. Well it does destroy the low notes, but it seems to be pretty weak with the majority of rap/hip-hop songs, and doesn't sound real strong on rock or metal. I know the specs call for 1.7-2.5 cubes on FI's cut sheets, but I was wanting some input on the situation. I know that too much volume can cause excessive excursion and damage the sub. By my calculations the box seems to be tuned right around 35hz.

yeah thats to big. I would add enough bracing to bring it down to 2.5 cubes.

[Colbyjack 0]

Ok, that's what I was thinking too. I sent him an email asking why he designed it so big, so I'm curious to see what he says. Guess it's low volume bangin for me for a bit.

[ricksi30 923]

So I had a box design done by someone that seems to be a reputable designer around the car audio forums, and I have a couple of questions about it.

I have a FI BTL N2 12" D2 running on a SAZ-1500, 250amp alt, 0 ga wire throughout including big 3 and additional grounds throughout the engine compartment, XS Power d975 in the back, Optima yellow top up front.

The design he gave me has a net volume of 4 cubes. Is that too big for that one sub? I told him I wanted a daily ground pounder that can kill some lows. Well it does destroy the low notes, but it seems to be pretty weak with the majority of rap/hip-hop songs, and doesn't sound real strong on rock or metal. I know the specs call for 1.7-2.5 cubes on FI's cut sheets, but I was wanting some input on the situation. I know that too much volume can cause excessive excursion and damage the sub. By my calculations the box seems to be tuned right around 35hz.

yeah thats to big. I would add enough bracing to bring it down to 2.5 cubes.

Don't do this without changing the design. If you just add bracing you will change the tuning.

[shizzzon 461]

the designer clearly must have chosen that size based on what you requested!

You said yourself you wanted some killer lows... that's the whole reason why this person\company chose such a size.

[Hzd Skizzy 27]

He could have mis-read or misunderstood and thought 2 12"s?

[Freshh 11]

IMO- order a 15" recone, and cut that hole in the box a little bit bigger to make room

[Hzd Skizzy 27]

IMO- order a 15" recone, and cut that hole in the box a little bit bigger to make room

I think he said it was a design. Can be re-worked.

[Colbyjack 0]

He could have mis-read or misunderstood and thought 2 12"s?

Well I had originally contacted him with the design involving two SA-12's, but then I found the FI at a good price and I wanted to try it out. I told him about the change in drivers and he acknowledged it. And the design only had one cutout for a sub in the pdf pics, so he knew I was using only one sub.

[Colbyjack 0]

IMO- order a 15" recone, and cut that hole in the box a little bit bigger to make room

I think he said it was a design. Can be re-worked.

Yeah, but I already built the box. Don't get me wrong, I have no problem building another one, building boxes is fun to me. Its just gonna be whether or not I can get a response out of him...

[Colbyjack 0]

IMO- order a 15" recone, and cut that hole in the box a little bit bigger to make room

I like where your heads at!

But I'm not real familiar with the recone process. Can you put a 15" recone on a 12" motor and basket? Wouldn't that be a 12" motor running a 15" cone? Does that turn out decent?

[Colbyjack 0]

the designer clearly must have chosen that size based on what you requested!

You said yourself you wanted some killer lows... that's the whole reason why this person\company chose such a size.

Right, but wont that sub still hit some strong lows in a box that's closer to FI's recommended specs? I mean it's 1.5 cubes bigger than their high end recommendation for that sub.

[shizzzon 461]

when you say killer lows.. that to me would indicate an excessive amount, therefore, larger box.

Keeping the box within specs has greater potential to not lose the 40-60hz area in music like what you are experiencing.

But many people who want crazy lows only want the lows...mainly because they are decaf fanatics.

[Hzd Skizzy 27]

IMO- order a 15" recone, and cut that hole in the box a little bit bigger to make room

I like where your heads at!

But I'm not real familiar with the recone process. Can you put a 15" recone on a 12" motor and basket? Wouldn't that be a 12" motor running a 15" cone? Does that turn out decent?

You would just send it in to get reconed to a 15" you'd have to pay a tad extra to get a new basket for the recone.

[Colbyjack 0]

when you say killer lows.. that to me would indicate an excessive amount, therefore, larger box.

Keeping the box within specs has greater potential to not lose the 40-60hz area in music like what you are experiencing.

But many people who want crazy lows only want the lows...mainly because they are decaf fanatics.

Maybe I was a little over zealous when I was telling him I wanted it to slam the lows...

[RAM_Designs 25]

yeah thats to big. I would add enough bracing to bring it down to 2.5 cubes.

That would considerably raise the tuning going from 4ft^3 to 2.5ft^3 and not adjusting the port any.

[Colbyjack 0]

IMO- order a 15" recone, and cut that hole in the box a little bit bigger to make room

I like where your heads at!

But I'm not real familiar with the recone process. Can you put a 15" recone on a 12" motor and basket? Wouldn't that be a 12" motor running a 15" cone? Does that turn out decent?

You would just send it in to get reconed to a 15" you'd have to pay a tad extra to get a new basket for the recone.

$31 for the basket, for a total of $171 not including shipping.

[Colbyjack 0]

yeah thats to big. I would add enough bracing to bring it down to 2.5 cubes.

That would considerably raise the tuning going from 4ft^3 to 2.5ft^3 and not adjusting the port any.

Yeah I think I'm just better off putting that box to the side for time being. I've never run a 15" before, so reconing the FI is actually a pretty good idea. I did also pick up a 12" Nightshade V2 last week, so I'll probably just run that in the mean time until I can get the FI reconed. Ram, any tips I should keep in mind when designing a daily ground pounder for the Nightshade?