What I'm working with:2 pioneer shallow mount subwoofers 10"The recommended enclosure space is .35 cubic feet to .7 cubic feet1 custom box (separate compartments) ported with a ~4" port (each compartment)Each compartment is .37 cubic feet, within the recommended enclosure size, and it's shaped like a general shoe box, nothing special.
I'm wondering if it would be a good idea to put Poly-Fil in there, since it's to the lower end of the box sizes suggested. also, would a grill over the port hurt? so the Poly-Fil doesn't coming flying out. it would be over the inside of the port, so it would not be seen.
The subwoofers are running a 250 RMS, if that should be a part of the desicion making.
Thanks!-TD
Have you already ported the box? If not, hold your horses. I'm looking at THIS PIONEER and, according to the info on the page, your box is much too small to use with a port. If you are dying to try it out, i suggest you use a smaller diameter. Probably best if you just go sealed and use a bit of poly-fil.
If you have the TS-SW2501S4 subs J Ro linked to, then he/she is correct, your specs are all wrong for a ported box. You mistakenly looked at the sealed box specs for the box volume specs. If going ported then you would need an enclosure no smaller than .5cu/ft (.6cu/ft is ideal) and the port should be 3" diameter x 11.5" long (if using a .6 or .7 cu/ft box). Your .37cu/ft box is actually a bit smaller than the ideal sealed box specs (which is .45 cu/ft), so the Poly-fil would help if you where to go that route. However, if you went with a sealed box then your amp is a bit on the small side with only pushing out 250RMS, each of those subs can handle 300RMS, so you'd be under powering them big time and could end up blowing them by causing them to clip. If you somehow end up going with a ported setup then that amp may work alright, since subs can't handle as much power when in a ported enclosure. Hope this helped.
Weigel21:However, if you went with a sealed box then your amp is a bit on the small side with only pushing out 250RMS, each of those subs can handle 300RMS, so you'd be under powering them big time and could end up blowing them by causing them to clip.
Simply underpowering subs will not cause your amp to clip the output signal, but jacking up the gain to get more output from a small amp (or big amp) will. As long as you properly adjust the amp/HU settings, you will not send a clipped signal to your subs, regardless of the amp's power. (Whether or not your subs can take the power you try to feed them is a whole other story.)
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Ninja1283: Weigel21:However, if you went with a sealed box then your amp is a bit on the small side with only pushing out 250RMS, each of those subs can handle 300RMS, so you'd be under powering them big time and could end up blowing them by causing them to clip. Simply underpowering subs will not cause your amp to clip the output signal, but jacking up the gain to get more output from a small amp (or big amp) will. As long as you properly adjust the amp/HU settings, you will not send a clipped signal to your subs, regardless of the amp's power. (Whether or not your subs can take the power you try to feed them is a whole other story.)
Really? I had an Infinity amp that put out 97x2RMS and when I sold it the guy wanted me to prove that it worked, so I wired ii bridged and then each separate channel to one of my 350RMS subs (only thing I had to would handle the power at the time) Bridged worked fine, but when testing each channel separate the clipping light kept blinking. 125RMS into at 300RMS sub I'm sure isn't as bad as 97RMS into a 350RMS sub, but I'd think clipping would happen nonetheless, right? When I did this I had the gain on the minimal level since I didn't want to mess with setting it since it was only for testing.
Sorry for jacking your thread, please forgive.
^No big deal man haha
Oh and I'm running 250RMS to each sub! lolsorry I wasn't clear about that...
Anyway, that is my correct subwoofer, and according to pioneer, a ported box volume is .35-.7 cubic feet, same as a sealed box, however vented, and bandpass boxes require much more space.
And plus with Poly-Fil, I should be able to make my subwoofer box equate to about ~.44-.5 cubic feet applied correctly.
Do you guys still think port is not the way to go?-TD
TwistedDreams: Anyway, that is my correct subwoofer, and according to pioneer, a ported box volume is .35-.7 cubic feet, same as a sealed box, however vented, and bandpass boxes require much more space.
Ported or vented means the same thing. A port is just a convenient way of venting a box.
TwistedDreams: And plus with Poly-Fil, I should be able to make my subwoofer box equate to about ~.44-.5 cubic feet applied correctly.
The problem with putting a port in that little box isn't just the small size of the box, it's the large size of the port. When you calculate your enclosure, you have to subtract the displacement of the port as well, if it's inside the box. The port is treated as a solid object when calculating net volume. You have to deduct the displacement of the subwoofer as well, but i couldn't find a spec for your model. An average 10 takes up about .025 ft. The port Pioneer suggests (3" x 11.5) would take up .064 ft. Let's do the math... actually i'll let LEAP do it.
Your net volume would be .28 ft. If you filled the box with poly-fil, it would be just over .3 ft. The suggested port would tune the box to 67hz. That's not gonna sound good at all. Skip the port.
There is a diagram for building a ported enclosure on the box if you look here.
The issue I have with ported enclosures is that if you don't make the them to exact specs they sounds like complete crap (IMO). For instance, the specific enclosure shown to build on the back of your package won't work for your install and so you have to alter the dimensions. Then if you don't get it right you've got a sub that sounds like crap because it's tuned at 117Hz (random tuning frequency). I've only heard a couple ported enclosures that sounded good and believe me, they sounded good. Unfortunately , I've heard countless ported setups that sounded horrible because people didn't know what they were doing. If you truly know what you're doing or have a program that can design a ported enclosure to the correct specs yet fit in the space you have, then by all means go for it. However, if you are just winging it, which is how it sounds, then do yourself a favor and stick with a sealed enclosure, they're much easier to build to correct specs. As for poly-fill, I don't really know just how much is needed to trick a box into performing like an X cu ft enclosure. All I know is they say to only use 1- 1.5 pounds per cubic foot, with a box no bigger than .3 cu ft you could only get .3 -.45 lbs of poly-fil in the enclosure and I honestly haven't a clue what that'd do for you. I'm going to wager that J Ro calculated it correctly. And if he/she did, you'd likely be very disappointed with the results.
Oh, and sorry for the misunderstanding, 250RMS to a 300RMS sub is fine, especially if said sub where in a ported box.
Alright, sounds like I'm sticking to a sealed box. I thought that if you'd slap a port in a box, it'd raise the volume a little and clear up the sound.
Still new to the whole box building thing.
Thanks for all your help everyone, I appriciate it!-TD
The volume of an enclosure is the empty space inside it, anything taking up space inside takes away from that ie; the rear of the sub and any port tubs. Also, ported enclosures are for LOUD deeper bass (if tuned right), not clarity. For getting the cleanest sounding, most accurate bass you can you'd want to go with a sealed enclosure anyways. The bass is tight and punchy, not that loud and slightly muddied bass. Also, if you are after clean bass then you'll want to do as much as you can to stop your vehicle from rattling when the bass hits. While it may sound good inside the car, if you listen from outside you can easily hear the trunk, body panels, and license plate vibrating. These vibrations can cancel out some of the notes you want the sub to create and will likely cause the audible bass to sound somewhat muddy.
*Edit*
The displacement of the sub is 0.088 cu ft / 2.49 liters, it is in the owners manual I linked to earlier on page 4.
See I thought about that when I was building the **** box, but at a local car audio place they said you don't need to worry about it!
And the box sits in the back of a regular cab, with two layers of dynomat, and three layers of dyno foam, if you laydown in the bed you can't hear anything. :)I'm pretty happy how well that stuff works!
This box was more or less a test, so now I know what to fix next time on my new box. Thanks again for all the input.-TD
Weigel21: The displacement of the sub is 0.088 cu ft / 2.49 liters, it is in the owners manual I linked to earlier on page 4.
Thanks for putting in that link. I never would have thought the displacement of a shallow mount sub would be so great. That's a lot of space! For example, a JL 10w6v2 is a much more powerful sub, with an enormous motor, yet it displaces less than this Pioneer(.068)
J Ro is short for Jason Roland. I'm a dude. Enough with all the he/she stuff already!
^that's intersting, because the W6's do have massive motors. I wonder they are more or less the some motor size, except the pioneer just basically squished, and the W6 extened for better heat disipation?
Anyway, the box I have now has two .37 (without sub) cubic feet seperate compartmens, but I'm so low on room, would it hurt to get rid of the cross brace and make it one compartment? especially because the pioneer sub box suggested for this is shaped really long.
What's the advantages/disadvantages to having two seperate identical compartments, instead of one symetrical compartment?-TD
Well I could be wrong, but one benifit is that you don't have the subs fiighting each other. When a speaker vibrates it compresses the air inside the enclosure it's in, which if you have two, then they may cause each other to distort some or cancel out the others frequencies. This I believe is very true if you were to use the two subs with a 2 channel amp and seperate signals instead of a mono signal, then the two subs create different waves in the box which could distort the bass or cancel it out. However, the same thing may be true even if a mono signal is used. I honestly am not 100% sure, this just seems correct in my head.
The post above has got it pretty well covered. If you have two identical subs receiving an identical signal, they will both operate in perfect unison to generate a uniform sound wave that is twice as strong. Trouble is, we live in the real world. No 2 subs are exactly alike. Even the same model of a sub breaks in a bit different for each user. If they share the same air space, one of them will eventually have a surround that is less compliant than the other, and one sub will start pushing the other sub, instead of moving air. That's cancellation in a nutshell. Another downside to using a common chamber is if one sub were to fail or become disconnected, the other sub would suddenly be under greater mechanical stress, and possibly fail(blow).
The single advantage to using a common chamber is you can use a single vent for both subs. All the other downsides still apply, but the building of the box is less complicated. In a sealed application, i can't think of any benefit of a common chamber. That slight bit of additional airspace will not overcome the drawbacks of cancellation between the 2 subs. Pop them suckers in and get to rockin!