Box for SR124-DVC confusion

Vital

About to order SR124-DVC, doing research on size of the sealed enclosure for it.
Polk lists recommended size - 1.20 cu.ft. but after reading thru lots of threds on this forum all of them state it's better to go with more space then recommended per Polk AND a few people saying that sub sounds muddy when in 1.20cu.ft. box
Some people say 1.50, some even 1.75 box.

So which one is it???
I'm doing a stealth sealed fiberglass box which will take a lot of time to make unlike square mdf box, would really like to know exactly what i'm supposed to work with instead of spending 2 more weeks making it bigger.

and just to clarify - 1.20 cu ft box - that's INCLUDED the sub itleft, right??

catch22atplay

That's free space internal. You must add the sub to your dimension. So if you want 1.20cu ft. the internal volume needs to be 1.34cu ft as the sub takes up 0.14cu ft. And Vital you can trick the sub into thinking it's in a bigger box by using poly fiber fill. In fact it's usually a good idea to use it as it helps to lower speaker panel resonance. I've tried not using it and using it and prefer using it. I just buy the cheap stuff at our craft store.

Vital

you can trick the sub into thinking it's in a bigger box by using poly fiber fill.

exactly how far can i get away with it??? I'm looking to get as much of my truck space s possible so smaller enclosure with same results as bigger (recommended) would help but what exact numbers are we talking about here??

if you want 1.20cu ft. the internal volume

Not that i want it to be 1.20 but it's what recommended per Polk for this particular sub. In the matter of fact i's like it to be less to save space but 1.20 just seems a bit too much when comparing to other 12 subs specs.
With that said - i'd never sacrifice SQ and risk damaging SR sub because i chose to have more space in my trunk. I'll make this box as big as needed but i'm not sure how big/small it actually needs to be. Per Polk it used to be .80something some time ago, now it's 1.20, per users on this forum it needs to be 1.5 and even 1.75.... so which one is it???? Why are there so many different specs for the same type box on the same sub????

arun1963

IIRC Mac ran his SR 124 in a 1.25 cuft box. I think thats a fair reference point for sq. Adding poly fill to the box can give you the effect of a 10% bigger box (approx).

Not an expert on boxes but I'd take a 3/4" mdf box over a FG. I'd go with a FG enclosure for a mid bass driver but a sub.....just my opinion and I could be wrong here.

catch22atplay

Vital you are comparing what the manufactures suggested box sizes are without actually running the numbers. Most all list the smallest size possible. None of which is optimal. Like my JLAudio sub i built to what JL instructions listed. It sounded like garbage and i ended up building a bigger box and stuffing it with fiber fill after calling JL and talking to their engineer who suggested a bigger size. Sound quality improved quite a bit after doing this. BTW 1.5cu ft is about average for a 12" sub ignoring what manufacturers list.

A box using fiber fill is considered max stuffed using 16oz per cu ft.

There are so many different sizes because listeners have different listening tastes. It's like ported vs sealed. If you want max power handling you use a smaller box. If you want a lower Q and a flatter frequency response you use a bigger box.

I know what i listen to. I listen to just about everything. I'm also extremely picky. So i need a box that can play everything good. My box will end up being 1.57cu ft. It will sacrifice some SPL due to cone excursion limits because of this bigger size. So it wouldn't be what i'd suggest to everyone. It's specific just for me.

If i was recommending a box size and SQ was a priority and space was also a secondary concern i'd say use 1.25cu ft and stuff it with 24oz fiber fill. You really can't go wrong with that. If SQ wasn't the priority then as small as 1.0cu ft would be fine. Although i'd never build one that small, not even for someone else. Better to switch to 10" subs imo.

catch22atplay

Guess i can't add well today. Make that 20oz of fiber fill for a 1.25cu ft box. Adding more won't hurt it. It just doesn't help either.

Vital

My box will end up being 1.57cu ft

before the sub?? (so it's 1.57 - 0.14 sub , right??)

Also - polyfill i found i about 2 inches deep while space i have available allows me to have the back of my sub about 2-3 inches away from the back of the enclosure. Does poly have to be right in the back of the sub or i can get away with having it on the sides of it??

catch22atplay

It's 1.57+0.14=1.71 however i don't suggest building it this size. I'm shooting for a bit more output at lower frequencies and i mean 16hz and below. Organ pedal notes can hit that low. Some classical recordings can hit that low. But for rock or rap or most music it's not really needed. And i'll only gain 1-2db at that freq compared to a 1.25cu ft box. And i also prefer the sound of a low Q sub which this size accomplishes. I know some people wouldn't like the sound. If i was limited in size and knew i could only fit 1.25cu ft and if i filled it with 20oz of fiber fill i'd be perfectly fine with that. But my rear seats are coming out. So i got a bit extra space. I was at one time thinking of using a 1.68cu ft box. But i never added in the fiber fill. 1.57cu ft with fiber fill works out better then 1.68cu ft without fiber fill. I've yet to build it. So i can only speculate based on software.

Poly fill should cover all panels as best you can. That includes the rear panel. Just do the best you can without hindering the subs movement. It doesn't have to be perfect.

Ordered a P99RS today so i'm stoked. Now have to sell this Z110BT that's still in the box.

Vital

Ordered my SR124-DVC last night, Per UPS it's gonna arrive on monday. Can't wait to start this proccess.
BTW here's what i'll be doing. I have the same car, will build in in the same location but taller instead of wider.

Any tips and suggestions are welcomed