Foam sub box lining affecting tuning?

[Outbacksound 1]

Those infinity's look really cheap to me.

So should I go with the 15's? I kinda like the 12's I have, so the line isn't bad, or should I get 1 Alpine Type R 15? The 4 15's would move more air. But they have a tendency to crack the cone (one of mine allready did- crutchfield replaced it). There are videos on YouTube of those infinity's, and they have great excursion. They look kinda cheap, but the P1's have a bad rap; their not great either.

[ChristianMcKay 1]

How many watts are you sending to them?

[Outbacksound 1]

How many watts are you sending to them?

I would run them off of my current amp, not sure what it puts out- can't find that.  That would only be temporary until I could get something to run 800 rms to the 4 15's, or 1000-1200 rms to the infinity's.  Maybe just two 15's on the amp I have.  Or ~750 rms to the type r.  This amp might be suitable for any of the applications (except for 2 of the 15's).

http://www.crutchfield.com/p_113X1200M/Kenwood-Excelon-X1200M.html?tp=115

Edited October 31, 2009 by Feel The Bass

[Outbacksound 1]

I've been planning boxes and there's no way I'm fitting 4 of those 15's in my car, so it would be between the 4 infinity's or 2 of the Rockfords, both in as big a box as recommended. Sealed for lower bass, and ported for louder bass, am I right? Sealed can go over 3 cu. ft. per sub for the 15's. Are my 4 P1 12's louder than the two 15's will be? I know the infinity's would be louder. I think I'm going to go with them.

[ChristianMcKay 1]

..Wait, did you just say you were going to do a sealed AND ported box?

[Outbacksound 1]

..Wait, did you just say you were going to do a sealed AND ported box?

No... That wouldn't make any sense. How could a box be sealed if it had a port in it? I was talking about which type of box is better for which application. Do sealed boxes play low notes better than a low tuned ported box? Would the 2 of the 15's in 3-3.5 cu. ft. each sealed be louder than the 4 infinity's sealed in 1.25 cu. ft. each?

[KU40 173]

For 98% of the music you'll likely listen to, a ported box will be louder.

[Outbacksound 1]

For 98% of the music you'll likely listen to, a ported box will be louder.

I didn't mean louder, i meant deeper and lower. Would big sealed boxes play lower than smaller ported boxes tuned low?

[bigrank916 72]

..Wait, did you just say you were going to do a sealed AND ported box?

No... That wouldn't make any sense. How could a box be sealed if it had a port in it? I was talking about which type of box is better for which application. Do sealed boxes play low notes better than a low tuned ported box? Would the 2 of the 15's in 3-3.5 cu. ft. each sealed be louder than the 4 infinity's sealed in 1.25 cu. ft. each?

Having sealed is geared more towards SQ. Its not going to be as loud but it will have better sound quality. When you want to go louder, you port the box and go the other way. Ported shoould almost always be louder but always depends on the install of course. So if your definition of playing low notes better is actually louder, then yes with the same afforementioned conditions. In a sealed enclosure, I like a smaller size for output. But its kinda backwards looking to get louder than one another with sealed enclosures. And with a name like Feel The Bass I think you want ported.

Edited October 31, 2009 by bigrank916

[Outbacksound 1]

Having sealed is geared more towards SQ. Its not going to be as loud but it will have better sound quality. When you want to go louder, you port the box and go the other way. Ported shoould almost always be louder but always depends on the install of course. So if your definition of playing low notes better is actually louder, then yes with the same afforementioned conditions. In a sealed enclosure, I like a smaller size for output. But its kinda backwards looking to get louder than one another with sealed enclosures. And with a name like Feel The Bass I think you want ported.

Allright, I am going to go ported.  I was trying to do a sealed box for ease of fabrication, but I have a low tuned ported box now, and I love the sound, but I need more of it.  I ended up ordering 4 Infinity 1252W 12's a few hours ago.  They'll move more, they have lower frequency response, and they'll handle more power than my 4 RF P1 12's.  I think i'm going to build a vented box so that I don't have to order ports.  So where does the box volume end and the port area begin?  Should I design the box area and add the port length to that, or include the port area with the box volume?  They need to be in 2 cu. ft., and I want to tune them really low; as low as possible.  The lowest frequency these subs say they can reproduce is 23 Hz.  Can I tune the box to, say, 20 Hz?  I know it won't be very loud, but it should have great sound quality, and play low notes better than if it were tuned to ~32 Hz, right? Or should I tune around 32-33 Hz to still get low end and be fairly loud as well? I don't have a subsonic filter, so should I not play the subs loud until I can get an amp w/ one built in to prevent loss of control below the tuning frequency?  I've been looking at this amp to power these.

http://www.crutchfield.com/p_113X1200M/Kenwood-Excelon-X1200M.html?tp=115&tab=review#tab

It seems like a good amp, fan cooled, 1200 RMS at 2 ohms, perfect for four DVC 4 ohm subs on a mono amp, CEA blah blah, filters, etc.

Edited November 1, 2009 by Feel The Bass

[KU40 173]

For 98% of the music you'll likely listen to, a ported box will be louder.

I didn't mean louder, i meant deeper and lower. Would big sealed boxes play lower than smaller ported boxes tuned low?

Ported boxes are generally louder above 25 hz if you tune reasonably, while sealed can handle those lower notes better because they don't unload. However, very little music actually has any notes below 25 hz. Hence my comment that 98% of music will be louder in a ported box. If you're going to be listening to big pipe organ music, maybe you would like sealed. Otherwise, you'll probably want ported.

[Outbacksound 1]

Ported boxes are generally louder above 25 hz if you tune reasonably, while sealed can handle those lower notes better because they don't unload. However, very little music actually has any notes below 25 hz. Hence my comment that 98% of music will be louder in a ported box. If you're going to be listening to big pipe organ music, maybe you would like sealed. Otherwise, you'll probably want ported.

Hahaha... Yeah i'm pickin up what your puttin down... I know now that ported is the way to go. Do you know if you include the port area in the overall box volume for a vented box, or if the port area is separate from a main volume?

[crosspug 2]

You have gross volume which includes the port volume and driver displacement.

Then NETT volume which does not include port volume or driver displacement. This is usually what is published.

Jono

[bigrank916 72]

Try using this to get an idea of what size and tuning the slot ported box will be. Its not exact but its works quite well.

http://www.reaudio.com/speaker_box/LPort_Box_Calc.html

[Outbacksound 1]

I've been planning ported and vented boxes, and I could get one to fit, but it would cost me 3-4 times as much as a sealed box would. So my question is: is it ok to build a sealed enclosure larger than recommended, or not? Would a larger sealed box produce a lower sound, or should I build the box to specs and maybe stuff with polyfill? Or will polyfill negatively affect the output if the box is allready the proper size? Is polyfill just for boxes smaller than recommended? Or can you build a box larger than rec. and stuff to have the sub "see" an even larger enclosure?

Edited November 3, 2009 by Feel The Bass

[///M5 2,833]

How would a ported box cost you 4x as much? I can see needing an extra $20 piece of mdf but not 4x.

[KU40 173]

I've been planning ported and vented boxes, and I could get one to fit, but it would cost me 3-4 times as much as a sealed box would. So my question is: is it ok to build a sealed enclosure larger than recommended, or not? Would a larger sealed box produce a lower sound, or should I build the box to specs and maybe stuff with polyfill? Or will polyfill negatively affect the output if the box is allready the proper size? Is polyfill just for boxes smaller than recommended? Or can you build a box larger than rec. and stuff to have the sub "see" an even larger enclosure?

The first question is, why do you want to build a sealed enclosure larger than recommended?

[jcarter1885 995]

I've been planning ported and vented boxes, and I could get one to fit, but it would cost me 3-4 times as much as a sealed box would. So my question is: is it ok to build a sealed enclosure larger than recommended, or not? Would a larger sealed box produce a lower sound, or should I build the box to specs and maybe stuff with polyfill? Or will polyfill negatively affect the output if the box is allready the proper size? Is polyfill just for boxes smaller than recommended? Or can you build a box larger than rec. and stuff to have the sub "see" an even larger enclosure?

If your gonna build a sealed box bigger than recommended then you should just go ported. A ported box shouldnt even cost you more than $10 - $20 in wood if that over the price of a sealed box.

[Impious 1,476]

I've been planning ported and vented boxes, and I could get one to fit, but it would cost me 3-4 times as much as a sealed box would. So my question is: is it ok to build a sealed enclosure larger than recommended, or not? Would a larger sealed box produce a lower sound, or should I build the box to specs and maybe stuff with polyfill? Or will polyfill negatively affect the output if the box is allready the proper size? Is polyfill just for boxes smaller than recommended? Or can you build a box larger than rec. and stuff to have the sub "see" an even larger enclosure?

Yes, you could build a sealed enclosure larger than "recommended"....especially since there is such a broad range of what manufacturers "recommend" and their reasons for "recommending" that enclosure.

Depends on what you are referring to by "produce a lower sound". A larger enclosure will typically have a higher F3 but a less steep rolloff thereafter compared to a smaller enclosure.

There's no hard-n-fast rules on polyfill. It's one of those things you can just play with.

Why would a ported enclosure be 4x the cost?

[Outbacksound 1]

Well, I really wasn't thinking when I said it would be 4x as much. Another sheet of 3/4" MDF would cost me another $30. I was looking at buying precision ports, which plus the extra MDF would only be $90 more than the $65 I need for a sealed box. . I've come up with a vented plan, but putting the box together would be incredibly difficult. I designed it to have the sides with the ports recessed, because an edge to grab onto helps with removal and installation. I also feel my design is very structurally sound, because I want to use a dato blade to cut 3/4" wide by 1/8"-1/4" deep grooves in a cross in the middle of the baffle board, the bottom, and a few vertical grooves in the sides to hold the center dividing pieces as well as the sides in place (along with glue and screws). The reason I was looking at a sealed box was because the small size would be better. Would the bass hit harder with a sealed box? Like bass that makes it hard to breathe and that you feel in your chest? My ported box only makes loud bass, but not chest constricting. The major problems with building a vented box are that I won't be able to change the tuning, and I read that vented boxes suffer from port noise (which is why I was looking at precision ports). Not going for those anymore though, now it's down to vented or sealed, and I would really only want to do sealed if it would make the throat collapsing, hard hitting bass (which I heard and felt with a friends old infinity's in a sealed box, and the low bass was better than any I've heard, ever).

Edited November 3, 2009 by Feel The Bass

[KU40 173]

You have a number of misconceptions in there. Ported boxes only suffer from port noise if there is too little port area. There would be no problems with that if you make the port big enough.

Ported boxes will be louder than sealed, especially in the lows of most music. What was the size of your old ported box and what was it tuned to? You can change the tune of your ported box, you just have to make the port longer or shorter.

Having the port recessed is ok as long as you account for that extra depth in the port length. So if you recess the port 3/4", you have to realize that that 3/4" counts towards the port length. If you don't account for it your actual tuning frequency will be a little lower than you think. It won't be a huge deal, however, and you probably wouldn't notice the difference. Just thought I'd point it out for thoroughness's sake.

[Outbacksound 1]

Allright, but you can't change the length of a slot port once the box has been assembled. I don't really need to change the tuning- I'm fairly sure I want it tuned anywhere from 29-ish Hz to 33 Hz. So how big should the slot be? In the RE website's slot box calculator, it suggests a 1.5" tall by (I forget how long). So if there is enough area in the port, there won't be any noise? Should I make the vent wider than 1.5"? The width would be 15" I think. My old (well, current) box is 1.805 cu. ft. and is tuned to 29 Hz. I love that the lows are (almost) overpronounced, and I didn't get that until I tuned it that low. I love the sound, I just want it louder. But this would be a complex box, and I've heard some very nice sealed box setups, and if a sealed box makes it hard to breathe or think, that's what I want. That's probably from a properly tuned and built ported box, though, isn't it?

[topgun 262]

Allright, but you can't change the length of a slot port once the box has been assembled.

Yes, you can. You just have to design it to do that from the beginning. It is quite easy to accomplish that with removable ports.

[Outbacksound 1]

Yes, you can. You just have to design it to do that from the beginning. It is quite easy to accomplish that with removable ports.

That was why I was going to use ports instead of a vent. But if I use mdf to make a vent, it will be glued in place, and that's it forever. A sealed box will be easy and quick, but I don't think it's going to be the sound I want.

[KU40 173]

Ports are the same as vents. Interchangeable words. If you want to say round port or PVC port, that's understandably different than a slot port.