isobaric = meh.

[TaylorFade 10+ year member]

I know that nobody does Isobaric builds anymore, but I've always wanted to try one and since I have decided to go with 10's, I have e8's that I am gonna try some different designs with. The iso was up first because it's the smallest box and I could do it with the scrap wood I have laying around.

As far as the sound... it actually sounded pretty good, but holy port noise. 2" was as big as I could go without having to go external. Really solid lows but not exactly an SPL box. Tried it firing through my pass and it didnt' work. Corner loading sounded the best. Love the fact that the box is so small, but I just need more. Now I know why no one does iso's anymore. Don't know if it's normal but there was a lot of "chuffing" from the inverted sub. It also might have sounded a little better if I took more than half an hour to build it and actually used sealant instead of duct tape, even though there wasn't any air leaks.

Anyway, (2) Sundown e8's in .3cf and tuned to 32hz...

Up next, t-line tube... if I can figure out how to fit 8ft of tube in the trunk.

Click to read more...

 

[Tone415 10+ year member]

ummm am i seeing what i think im seeing?!

and why are u trying to get that 8ft tube in the trunnk?

 

[spltuscon 10+ year member]

Isobarics work fine, but if the subs have any mechanical noise then you'll hear it. Also critical is where the subs face each other, it has to be totally airtight and lined up 100%.

A 2" port will never be adequate for a subwoofer so that certainly doesn't help.

Also, the output is only going to be equal to a single sub so with 8's it's not exactly gonna hurt your ears...

I've only used it once personally on a pair of twelves and the SQ was quite good and the box size small, but a single sealed twelve just doesn't have the output I like, so I only kept it in a few days.

 

[TaylorFade 10+ year member]

T-line with the e8's fs of 34.9 = 8ft of line. Obviously I will have to put some 90's in there or fold it with a box, but I have that pvc laying around so...

Yeah, the ouput is -3db of one, but with twice the power of one I figured it might even out. Like you said, the SQ was quite good, but the output wasn't overwhelming. Maybe I'm just used to my ported DD 10 though. I will say that the subs weren't exactly frog's *** tight, but I didn't want to ruin the gasket by nutting them down. I may try a 3" aero external and tighten the subs up tomorrow to see if that cleans it up.

 

[spltuscon 10+ year member]

That would help for sure. Two of them in a t-line will be more impressive though.

 

[mmouse57 10+ year member]

I run 4 jl audio w3 10s in a iso ported setup in my scion now and it sounds unbel.hits every note 2 would but its so tight and acurate its sick

porting the box left the box for 4 as big as for 2 reg even though half the space but the sound payoff and handling make it all worthwhile

 

[Rich B 5,000+ posts]

I love isobarics, but I've only used subs made for sealed enclosures.

 

[ButtaMax 10+ year member]

Im so loving the duct tape!

 

[spltuscon 10+ year member]

Your T-line doesn't actually need to be 8ft long...you can use fiberglass insulation or pillow stuffing to fill the line and make the effective length longer. A 6ft line stuffed properly will have good extension and is much easier to fit.

 

[energizedsbs 10+ year member]

I really cant tell from the pics but are the subs together face to face? You need a ring in between them.

 

[TaylorFade 10+ year member]

One is mounted inside the box on the under side of the baffle.

 

[Jroo 10+ year member]

if you are using a ported woofer in a isobaric box, is the port length and tuning the same? Is the change basically that the box size is cut in half or do you have to redesign the port length and change the tuning? I understand iso for a sealed box, but didnt know how it worked for a ported. Also I saw a guy with a isobaric 6th order bandpass. Again, would the port be the same for the same woofer by itself in a 6th order?

 

[mmouse57 10+ year member]

if 1 speaker needs 1.2cf wth 4in port 6in long for 34hz

2 speakers would be .6cf with a 4in port like12+in long

so you cna see how the boxes can become hard ot desgin you basicaly end up with a ported box for 2 '4 in iso config' that is the same size as a box for all 4 reg style so spac e with iso ported shuldbe as big an issue as sealed

going iso ported should be looked at for the sound and imaging you gain

 

[Jroo 10+ year member]

so you have to double the port length for iso

 

[spltuscon 10+ year member]

The port is still based on the airspace of the box itself, so its not doubled, but it will be long considering how small the chamber will be. Just use a box calculator to figure length like normal.