Seel

iTrader: (5)

I just got my Image Dynamics 10" sub in and I already have a Zenclosure. My question is should I use Poly-fill? I already have some but I'm not sure if it's even needed. What is it's purpose? If I should use some how much? Pack it as much as I can or should I pack it loosely? I know it's a noob question and I did search on this. Anyone have some answers? Thanks in advance..

DHCrocks

polyfill is used to increase volume of an enclousure that is too small. you need to check the drivers recommend space requirement vs. the enclosure size. Be sure to subtract out the driver volume. Typically it's stuffed in about from .5-1.5 lbs per cubic foot. spread it out evenly on the inside of the box. The polyfill slows down air movement within the enclosure and to some extent the result is that the box performs like it's an larger enclosure. it won't be a miracle worker, but if the box is sized a little bit undersized then it will help out.

Seel

iTrader: (5)

I really appreciate the post. It helps explain a lot. The recommended sealed speaker box airspace for the Image Dynmics sub is .4 - .8 The Zenclosure box is approximated @ .75

I'm not sure what the driver volume is but it's 5.5" depth.

Have anymore advice based on this?

StreetOC192

iTrader: (7)

The driver displacement isn't going to be much...maybe .05 cu ft.....It should be listed by Image Dynamics on the spec sheet.

Based on the specs, the box is actually perfect for the sub. I don't think you will benefit by adding any polyfill.

To answer the original question - NO, you do not want to add any polyfill to the box.


***EDIT***
I found your speaker's specs on the ID website. The displacement is in fact .05 cu ft.

Nominal Impedance (IMP) 2/8 ohms
DC Resistance (Re) 1.8/7.2 ohm
Resonant Frequency (Fs) 23.2 Hz
Electrical "Q" (Qes) .387
Mechanical "Q" (Qms) 3.714
Total "Q" (Qts) .350
Equivalent Volume (Vas) 2.43 ft3
One Way Linear (Xmax) 17.0 mm
Cone Area (Sd) 350 cm2
Sensitivity (Spl) 86.5db
RMS Power Handling (Pwr) 50 to 400
Speaker Displacement .05 ft3

Seel

iTrader: (5)

I appreciate the post.

I actually ended up adding just a little bit of the poly-fill to the sides and back of the box. Very little, just as a buffer between the sub and the box. I think it sounds really good.

What might I look for (listen for) if I added too much poly-fill???

jadaniya

iTrader: (22)

doubt you'd be able to tell unless you listened to two different set ups back to back (one with and one without). but in most cases the manufacturers specs will sound the best. b/c i dont think theres any way to measure how much volume the polyfill is supposed to imitate I'd say just take i out and it'd probably sound better.

Takhteh

iTrader: (18)

here's a related question/comment bc I am using some of this stuff in my current install, too:

do we absolutely have to make sure the polyfill does not touch the sub(s), etc.. bc I am throwing some in, but not gluing any of it down and I don't want the stuff to ignite!

16psibrick

iTrader: (10)

i make a habbit of putting a little bit of poly fill in all my subboxes, since i neverbuild a box to be really really large as i try to conserve overall space...

it helps a little but more or less just the habbit.

if you hav a .75 cubfeet of airspace for a single image 10, regardless if its the ID, IDQ, you will be fine without polyfill, if you hvae an idmax, you can add a little bit..

honestly, as long as the box is overall corrrect for hte sub, polyfill wont be a dramatic difference

b

Takhteh

iTrader: (18)

how about the "heat" factor? any problems if you just leave the stuff rolling around in there?

StreetOC192

iTrader: (7)

In the 15+ years I've been involved in car audio, I've never heard of polyfill igniting or melting or anything due to heat. The only thing I've ever heard of remotely close was 'back in the day' some guys would use fiberglass insulation instead of polyester fill and the glass fibers would get into the motor structure of the sub and cease the motor structure. This is nothing to worry about with polyester fill thought because the strands are very long and they are plastic, not glass.

The best method that I have found for polyfill is to glue/staple 1-4" to the sides/back/front/top/bottom of the box. I THINK (not 100% sure, can't remember) 4" on all sides of a 1 cubic foot box will make the sub see an additional .25 cubic foot.......you can do the math from there.

StreetOC192

iTrader: (7)

Typically, when the box is a little oversized for the sub, the driver may sound a little boomier. Chances are as stated above, that you won't hear a difference unless you have a side-by-side comparison, and even then you may not even hear it. Subs in sealed enclosures are a LOT more forgiving than in ported enclosures. You could be as much as 20% larger and you most likely won't hear a difference.

Of course if you have a 10" sub in a 3 cubic foot sealed enclosure, it will sound like absolute POO!

Takhteh

iTrader: (18)

ahhh.. that would explain the great feedback you always bring us, haha.. thanks StreetOC.

dkmesa350z

iTrader: (41)

I like to put polyfil in all my sealed enclosures. I only really noticed a difference when I used it in my .4 cubic foot 10" enclosure in my 300zx. Like others have said, it just 'tricks' the driver into thinking there is a little more airspace in the enclosure. Right now I have an ID 10 OEM version in a .80 cuft Zenclosure with no polyfil and it sounds awesome. With more than .6 cubes, you probably won't benefit from using polyfil for an ID10

Seel

iTrader: (5)

A lot of good information here. Thanks to all that posted

DrPhantum

Another n00b question..

So, would this be a good idea to observe in order to use my factory Blose sub location behind the driver's seat to house a "real" sub? Just stuff some polyfill in there? Maybe some dynamat for good measure? Let me know. Thanks

DHCrocks

I have a G not a Z so I'm not sure but from other factory subs I've seen the the enclosure is typically not rigid enough to support a high power sub. There is just too much flex in the walls and poly fill will not help in that respect. They are usually made of plastic and can not withstand the internal pressures that builds up. If you're going to throw a real sub in there I'd suggest you layer the interior with fiberglass to reinforce the structure.

DrPhantum

When I had the panel off and I was looking in there, it seemed to me that it was all metal from the body. Since I have the convertible, the structure from the top mechanism made up most of the enclosure. I don't think there was much plastic, but there was foam (or carpeting or that fiber stuff that looks like fiberglass) lining the metal. Does that help?

DHCrocks

what about the front face where the sub mounts is that metal too. Check to see if you can see any gaps in the metal where they meet. It would be a good idea to go over all the joints with caulking to ensure you don't get any air leakage. I would also rip all the insulation stuff out and line the entire cavity with sound dampening material, this will take out any resonance of the metal. if it's a simple shape you can use a sheet type material like V-max from Cascade. if it's complex and has a lot of bends and stuff then a liquid damper like VB-1 from cascade. I prefer to spray the VB-1 because it can get into every nook and crany that a sheet type wouldn't be able to. if you go this route use 2-3 coats.

StreetOC192

iTrader: (7)

No, as stated, Polyfill is used to make a smaller enclosure perform like a larger enclosure. The bose sub cubby is large enough for almost ay 10" sub, the problem is that it is not a sealed environment.