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Morning everybody. I have a older 12 Type R in my Ram and am running a Fox Accoustics single vented under seat box at approximately 700w rms Specs are 1.85cf tuned at 34 hz (link below). I have never really liked the way it sounded although it would get impressively loud to me but always sounded off. I was playing around with a signal generator yesterday with the seat up and noticed a ton of port noise right around 40hz. Right now I really don't have the funds to change out the box but was curious what would happen if I sealed off the port as far as the woofer. Looking at the subs manual it recommends for sealed .65 gross to 1.25 gross with .90 being optimal. Given I would be at double the optimal size would I be in danger of damaging the woofer, I understand I would loose power handling and would reduce accordingly but would sound quality be diminished greatly by such a large size?

All that being said this is not a knock on the Fox box, it is built very well and their customer service has been great.

 

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My personal opinion is to try it. I wouldn't worry too much about damaging the sub unless you are the type to really crank it up. You could also try putting something inside the box to take up displacement (anything solid and non-resonant will work). In fact that would be a tremendously interesting experiment. Most of us are always fighting for enough box. So, block off the port (surely this could be done in a temporary fashion anyway ? ) and then listen/test. Reduce the volume of the box, listen/test.

I never really understand when people worry about blowing out a sub woofer, maybe I just don't turn things up really loud anymore, but ti sure seems you'd hear the distortion and flapping of a sub that is being driven beyond compliance. Those Type R's are pretty tough anyway.
 

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Morning everybody. I have a older 12 Type R in my Ram and am running a Fox Accoustics single vented under seat box at approximately 700w rms Specs are 1.85cf tuned at 34 hz (link below). I have never really liked the way it sounded although it would get impressively loud to me but always sounded off. I was playing around with a signal generator yesterday with the seat up and noticed a ton of port noise right around 40hz. Right now I really don't have the funds to change out the box but was curious what would happen if I sealed off the port as far as the woofer. Looking at the subs manual it recommends for sealed .65 gross to 1.25 gross with .90 being optimal. Given I would be at double the optimal size would I be in danger of damaging the woofer, I understand I would loose power handling and would reduce accordingly but would sound quality be diminished greatly by such a large size?

All that being said this is not a knock on the Fox box, it is built very well and their customer service has been great.

I agree with preston^ on all counts, unless you're a moron (which I seriously doubt) this should be a rather safe experiment. I have historically run larger than optimal sealed boxes and have never hurt a subwoofer because of it, although I have melted a few Kicker voice coils from running too much power.
 

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What happens when you run a larger sealed box is the woofer can hit its excursion limits on less power because there is less air resistance on the back of the cone with the larger volume of air within the box. You just have to be easier on the power. The good thing with a larger box though is you usually get more low end bass with less power compared to a smaller sealed box. You will also get about 3 to 4 db less SPL with a sealed box vs a ported box, so just keep that in mind. That means you will want to turn up the power to make up for the reduced output.
 

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I think it's important to clarify what JCsAudio said ... the ported box will have more output but the frequency response will tend to be very peaked at the tuning frequency, and will fall off sharply below that frequency. A sealed box will tend to have a flatter frequency response and fall off slowly below Fs. Unless the ported box is tuned very low, you will typically get a better SQ response from a sealed box (assuming the box size is sufficient).
That being said, if you can tune the box to 20Hz ... winner winner chicken dinner :cool:
 

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You’ll enjoy the way it sounds sealed!

I have one that I use a .90 sealed box for and it sounds great with well controlled low end. I’m only running 200 watts and it’s adequate - although I have an early generation (still with HAMR) and I believe RMS power handling is only 350 watts.

-Eric


Sent from my iPhone using Tapatalk
 

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Wouldn’t the port noise be worst at the tuning frequency?

I’ve got the exact same box waiting for me to find a day to install it, I’m still looking for the right driver, using an old RE-RE12 as a start. The port always looked a little too small and too short for 34hz to my eye, but if it’s a noisy 40hz tuned box then everything makes more sense..

Good luck!
 

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I think it's important to clarify what JCsAudio said ... the ported box will have more output but the frequency response will tend to be very peaked at the tuning frequency, and will fall off sharply below that frequency. A sealed box will tend to have a flatter frequency response and fall off slowly below Fs. Unless the ported box is tuned very low, you will typically get a better SQ response from a sealed box (assuming the box size is sufficient).
That being said, if you can tune the box to 20Hz ... winner winner chicken dinner :cool:
how much difference would one see at a 20hz tuning vs a sealed box? I ask because I have a Type R 12 laying around and want to decide what to do with it. A few months back I had someone tell me it modeled very well in a 4th order of 0.90 sealed, 1.00 ported tuned to 50hz. As the OP, I would be open to ideas on any enclosure that will maximize the performance.
 

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Pretty significant I would say ... just need to find room for the 5.6 cuft box /shrug (could do a much smaller box at the expense of output below 30hz, but that's not really what we're going for is it)
275680
 

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Pretty significant I would say ... just need to find room for the 5.6 cuft box /shrug (could do a much smaller box at the expense of output below 30hz, but that's not really what we're going for is it)
View attachment 275680
would you be willing to model the 4th order I mentioned? I would like to see where it stacks up. I personally cant give up close to 6 cubes for a single 12 even though you said it could go a bit smaller.
 

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It could be a lot smaller, and still have more output than the sealed box. I don't see the point in 4th order enclosures for a car, and a low tuned ported box is a lot simpler to build. WinISD is freaking out on my computer, but I'm sure even 2 cubic feet would have noticeably more output, and play lower than a sealed box. You were shooting for 1 cubic foot, but how much could you stretch that?
 

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Acutally he was shooting for 1.9 cubic (.9 sealed and 1 ported) ... the problem with trying to tune down at 20Hz in a undersized box is that the ports get stupid long. In the 5.6 cu I went with a pair of 4" round ports and ended up with 27" ports ... in a 1.9 cu box those same 4" ports end up 86" long! Helps explain folded slot ports lol. Using a 1x11 slot port in the 1.9 cu box you would need it 36" long
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It could be a lot smaller, and still have more output than the sealed box. I don't see the point in 4th order enclosures for a car, and a low tuned ported box is a lot simpler to build. WinISD is freaking out on my computer, but I'm sure even 2 cubic feet would have noticeably more output, and play lower than a sealed box. You were shooting for 1 cubic foot, but how much could you stretch that?
Could you explain more about why you dont like 4ths in cars? I have had pretty good success with them over the years in both sedans and hatchbacks. I will also say the 4th orders I used had closer ratios like 1:1 and higher tuning. I have typically been a sealed box user and asked the designers to model close to the sealed but try and get more gain. It seemed to work, but I could have been barking up the wrong tree
 

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Acutally he was shooting for 1.9 cubic (.9 sealed and 1 ported) ... the problem with trying to tune down at 20Hz in a undersized box is that the ports get stupid long. In the 5.6 cu I went with a pair of 4" round ports and ended up with 27" ports ... in a 1.9 cu box those same 4" ports end up 86" long! Helps explain folded slot ports lol. Using a 1x11 slot port in the 1.9 cu box you would need it 36" long
View attachment 275681
Yes, I was asking if someone could model a 4th order with a sealed section of .90 and ported section of 1.00. I was told the port tuning should be 50hz and that would provide very good bandwidth. The person that provided the info didnt have a graph so I would love if someone could model that for me with the type R 12
 

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Pretty significant I would say ... just need to find room for the 5.6 cuft box /shrug (could do a much smaller box at the expense of output below 30hz, but that's not really what we're going for is it)
View attachment 275680
Sorry for all the questions. Looking at the graph using 5.6 cubes and super low tuning, I started to wonder how large the ave sedan trunk is? Would the type R have the potential to run IB to mimic this or are the specs just not good for IB?
 
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