BigPerm

I know, but Fi has an option on their subs that allows you to change the impedance in the future. Do they build their AA Mayhems the same, universal or permanent impedance? I'm 90% sure they machine the motors to accept D1 and D2 impedance, we'll let Nick chime in. Ok, I appreciate it. I already called both numbers for AA and went through their extensions - the voicemails were full, too. I also sent an email. Basically, I just want to change an 18" D2 to a D1 and still have the power handling. I'm not trying to bother anyone or clutter the forum with simple questions.

I know, but Fi has an option on their subs that allows you to change the impedance in the future. Do they build their AA Mayhems the same, universal or permanent impedance?

Can the Mayhems be re-coned, preferably by Fi, to change the impedance? If so, is there a comparable re-cone available that would maintain the stock Mayhem power handling of 2500 rms? Thanks.

Makes sense. They're all drawing off of the same alt in some way or another. Either way, the batts will all be in the same general area of the car. I thought I could get out of buying an isolator. Thanks.

I'm planning to upgrade my electrical. My battery is in the back of the car (Magnum). Couldn't I just run new wire from the alt to a pair of separate batteries? Rather than wire all three together? I'd be running a pair of 105 AH marine deep cycle batts, dry cells, separate from a regular dry cell car battery. I've never seen it done, although i'm sure it has been. Thanks.

I knew I was doing something wrong. For future searches, I found some other info that basically said the opening that allows the sound "out" must be as large as, or larger than the SD of the sub. Thanks for the responses.

If you're building a downfire enclosure, how do you calculate the distance from the floor? I've searched and haven't found a definitive answer. All i've found is calculations for woofer sag and "just do 3"-4" from the floor." Half the radius, or plus 5% of Xmax... What? Help please! Thank you.

I want to buy another 18" SSD, but I need to have my current sub reconed to a dual 1 ohm. The sub I have now is an 18" SSD dual 2 ohm with the flatwind coil. Can I either send it, or drop it off (I live close) to Fi and have them do it for me? Thank you.

My bad, check it again.

Alright. But what formula did you use to get that length? Is there a good online calculator where you can plug in the variables and will be acurate or am i better off using my graphing calculator with the formula that i've been using? Well BKOLFO4 seems to believe in it. Maybe this is true when one wall of the port is actually a wall of the box? I mean if JL has it on their site i would think it has some truth to it. I mean if you don't take it into acount it'll only throw off your tuning by about .5 hz. So maybe that why people say it is BS. Well i'm going to see if i can get the top of that box off without damaging it too much and take the port out and cut it to length. So this should make it move more air throughout the port? Thanks A good calculator is a free download called Winisd Pro Alpha. http://www.linearteam.dk/default.aspx?download=winisd I only use it to get a port length though. You have to lay out your box and calculate everything else like sub/port/bracing displacement. It was explained to me that subtracting or adding port length for "end correction" doesn't make any difference because you're also subtracting or adding to your internal volume by changing the overall volume of the port. Check your PM

32.625" long = 31hZ for your box. I've been told by a reputable builder (Woodlawn Cabinetry) that end correction is BS. Maybe it is, maybe it isn't. I don't bother with it.