There won't be such a drastic impedance spike in sealed boxes.

I love sealed enclosures.

Again.

I love sealed enclosures.

Again.

if I get the LMT your not going to let me port it are you

for what i can see is that the smaller the box the less impedance and the bigger the box the more impedance.

Depends on the driver, shape of the enclosure, amp, etc etc etc.

i butchered up my box today. i cut off a bunch of port, then put in 2 boxes i made that take up 1ft^3. so now i have a 6ft net box @ 31Hz instead of 6ft @ 23Hz. i ploted the impedance again. here it is. i have a side by side to. it looks like this one is gonna be better as far as making better use of the amp this makes me happy

i did them in diff colors but for some reason my scanner is only doing b&w

u and ur ghetto a$$ graphs lol

The box that im making, 5ft^3 tuned to 28Hz will have 2ohm impedance rise. 14Hx5Wx38.75L my port cutout.

Measure it when your done, BBP6 isn't all that accurate for impedance rise. Amplifier being used makes a difference, and so does box construction.

Measure it when your done, BBP6 isn't all that accurate for impedance rise. Amplifier being used makes a difference, and so does box construction.

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x2 bbp6 wasn't even close on mine

here's a better graph .........

nice work jelly.

nice work jelly.

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thank you, thank you

today i got to drive around and listen.

oh my god! there is such a diferance!

i don't know whether the gain is from my higher response peak, or my lower impedance curve. it's probably equally both of them.......doesn't go quite as low, but who really drives around and listens to 15Hz test tones? well.... i did a couple of times, cause i could.

Well, I agree thats its prolly a combo of the two... if anything.

You basically doubled power in the 40-45hz range. Along with decent gains in the 35-40 range

it would be perfect if it peaked @ 40Hz. i'm getting metered this weekend at a local comp

with the increased size and higher tuning you should gain some, good luck

the chance has presented itself to maybe trade my d4's for a pair of d2's....with my impedance curve do you think it would be ok to run on my 1 ohm stable soundstream? it would be a .5ohm final load...but playing it would barely be dipping below 1 right? the plot would stay the same, being the same drivers, wouldn't it?

i don't believe the curve would be the same. while they are the same type of driver, they do have different t/s parameters and u are starting out with a different nominal impedence. while i do believe they will be similar, i doubt they will be the same.

is there anyway you can test the d2's before trading? that way you can be sure that you don't smoke an amp...

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

i don't believe the curve would be the same. while they are the same type of driver, they do have different t/s parameters and u are starting out with a different nominal impedence. while i do believe they will be similar, i doubt they will be the same.

is there anyway you can test the d2's before trading? that way you can be sure that you don't smoke an amp...

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

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nope

so essentially in a sealed box all things stay the same? as in no rise in Z?

Also, i'm just a bit boggled at how the higher you tune the box the higher the impedence, kinda, but also the easier it is to blow your sub. Your giving the sub less wattage, but its easier to blow. hmmm

i took out one of the .5ft boxes today to get in there and fix my brace...i had a 2x4, screwed down w/ 4 3" screwes, the big heavy duty ones. well when i got in there i had BROKE 3 of the 4 screws! anyways i left the box out to see how it soundes at 6.5ft @ ~29Hz. by ear it hits the lows SOOO much better. i might take the other one out and try my luck w/ 7ft @ ~26Hz either way i'm gonna do another impedance plot to see what happened and i'll be sure to post the graphs when i get done...

so essentially in a sealed box all things stay the same? as in no rise in Z?

Also, i'm just a bit boggled at how the higher you tune the box the higher the impedence, kinda, but also the easier it is to blow your sub. Your giving the sub less wattage, but its easier to blow. hmmm

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a chitload of this has to do with the topography of the motor (flux et al), more of it also has to do the the spec's of the softparts and how the compliance of the suspension works with the box. so, to answer Your question (while not answering - LoL): the imp shifts depends on the install (driver, box, box design, amp).

as far as sealed, no the Z does not stay at the nominal rating. I should have a fiberglassed sealed ready to go here in the next week or so, i'll try to get a map of it for You for example.

-Nick

Sealed = less drastic impedance spike, but the impedance does change.

here is my new graphs... whatcha think???

6ft @ 31 definitely looks the nicest