2 caps - parallel correct?

ok, on my porch soon will be a JBL BP1200.1, 2 - 1 farad caps, some 0 guage wire and an audiobahn ALUM12Q. I just wanna make sure that I have the caps wired right. I know with batteries series ups voltage and parralell ups amperage. so on my caps would series double the amperage and parallel doubles capacity?

I plan to do it like this- 0 guage fused by battery back to on cap pos., then to other cap pos., then to a d- block and then 4 guage from d block to amp. a 0 guage ground from seatbelt bolt under seat to one cap neg., then other cap neg., then to a d block and a 4 guage from ground d block to amp. and the remote lead is going to open a relay and the relay will draw from battery to turn on both caps and all amps/neons.
im using the d blocks instead of drirect from cap to amp because im going ot have another amp powering rear speakers later on and some neons back there that need power.

theres also gonna be some plexiglass in the system. Ill put up some pics when i finish the setup.

hopefully it turns out alright if not great. the diagram for my monster cap shows multiple cap w a power line to the d block, there it separates to smaller lines toward caps +, then from + caps to the amps + terminal.
and of course the - from the caps and amps goes to ground.

yeah, but I dont want one amp on eahc cap, I need 2 caps for one amp. but power to d block then caps pos then amp pos is pretty much parallel, all positives connected, and negs connected so I should be alright. I ordered my wiring today after I figured all I needed.

DAMN!
between the d blocks, fused pwr d block, 0 ga pwr/grnd, 4 guage pwr/grnd, ring terminals, RCA's, 8 ga spkr wire, and shipping I got about 130 bucks in wire.

you wire caps in parallel to increase the total capacitance

yes i feel u on the rest of wiring kit. i remember purchasing i can't recall if it was a 2 or 0 gauge monster cable power wire. it was almost $4 per foot and i wanted atleast 17 feet (better to be safe than sorry), well just for that it came out to almost 70 dollar for that alone!

people who go cheap on accesories and parts is a huge mistake. well cheap is the wrong word, the right one for the sentence would be poor quality. u can though, get good quality for cheap sometimes, but thats a rarerity. holding out on one part of the system can definately affect the rest, for example, a high quality sub to a p.o.s. box, or a very good amp using crappy small power wires or rca's.

well, the crap I got was the caps. they are pyramids but were cheap. evetuallyI might get brand name ones but even on ebay brand name caps were over twice the price for one of the pyramids. and all my wiring was from knukoncepts, my 1/0 was only 2.25 a foot. and my 4 guage was I think .99 a foot.

also about good subs to a crappy box. I had my old audiobahns in a small (.8 per sub) sealed for a couple days. and they werent very loud and didnt hit very deep. so I made a 3.4 ft^3 ported tuned to 37(dont know why 37 just picked a number) I spent a long time on winisd perfecting it ands it sounded REALLY loud, much louder than 2 in small sealed. and hit lots deeper too. now I am going to go sealed but I plan on giving them 2 ft^3 per sub. what else can you do to a sealed box besides calculate the volume. theres no port to tune or anything so I am wondering what you can do.

what kind of caps u got and how much were they? with the subs, if ur going to build a box, make sure u follow the specs from the speaker's speaker box specification, u can't go wrong. the engineers that made these are obviously are engineers for a reason. and once u build this box, u don't need to change anything unless u want deeper bass responce by adding filling into the box. this will make it sound as if it's from a bigger box.

what kind of caps u got and how much were they? with the subs, if ur going to build a box, make sure u follow the specs from the speaker's speaker box specification, u can't go wrong. the engineers that made these are obviously are engineers for a reason. and once u build this box, u don't need to change anything unless u want deeper bass responce by adding filling into the box. this will make it sound as if it's from a bigger box. I beg to differ, Audiobahn generally shrinks the size of their boxes and adds more power in order to get the "small box subwoofer" name. Also you can't possibly believe that 1.5cf - 3cf on a subwoofer box will be able to handle the exact same RMS power...

I beg to differ, Audiobahn generally shrinks the size of their boxes and adds more power in order to get the "small box subwoofer" name. Also you can't possibly believe that 1.5cf - 3cf on a subwoofer box will be able to handle the exact same RMS power...

i never had an audiobahn so i can't say. but just like b4, follow the specs and u can't go wrong.

I have two and I can tell you, WINISD is about the best thing to use to make a box for those, since audiobahn gives you numbers far spread out and says pick one.

I got a 2 ft^3 ported with 1 4" port tuned to 37 and it crosses the -3db@31, the [email protected], and peaks @5.3db@46Hz.

group delay is highest @ 41Hz and is 18ms, @ 25 its down to 12ms and @ 47Hz it is at 14ms and dropping steadily.

I dont know why I loisted the 14ms spec but I remember hearoing that number once so I figure maybe it is important.

does this sound like a decent frequency response?

Group delay seems fine, but with the port like that, you're going to suffer some sound quality. at 31hz, its already dropping 3db. That rolloff is pretty early. The biggest concern is the peak at 46hz. 3db gain near that freq is kind of bad (in terms of SQ) already, but you have 5.3db gain right there. Your outcome would be a huge peak in the frequency response (In car response). To our ears, it'll sound very boomy and bass attack wouldn't sound "quick".

If you're going for SPL, 37hz would be nice. But for daily use, shoot around 30-32hz. My personal favorite is 20-28hz because of the very low group delay and exaggerating low-end. :D It's just sick when you have so many subs hitting 20hz with authority. LOL!

ok, so is that why sealed is good for SQ, I put the same sub in 2 ft^3 sealed and it was a perfect smooth curve never jumping above 0db.

so you think I should tune it to about 28Hz, and I dont want any peaks like the one I got. what do you mean when you say "at that frequency"? is a peak elsewhere acceptable?


right now between 38 and 68 its at 3db, and it crosses 0 on its way up at 32, and then at 114 it is back down to 1 and never really gets to 0 its like .08 forever.

im gonna go modify it right now though and se what I can do.

winisd pops up saying 4 ft^3 each sub tuned at 20Hz but no way I got a spare 8 ft^3 in my trunk for boom! lol

well, I got it at 4 ft^3 total with 2 drivers, and 2 3" ports tuned to 26 Hz the gain and group delay look pretty good to me. now mine doesnt tell me vent mach cuz I dont know the Pe. what is that? will only 2 3" ports in a box wiht 2 12's recieving 1200+ watts make alot of port noise?

also I dont have Z or BL.

Z says its measurement is ohms so i figured maybe the resistance of the sub but Re is ohms as well and 5.4 and its advertised as DVC 6 ohm so i figured that was that.

Pe is watts I am guessing cuz the measurement is just W which i think might stand for watts but I will never have the same amount going to the sub and dont even know exactly what I am gonna be giving them so it cant be that. another thing about xmax, this is the excursion limit right, so if audiobahn says +/- 14mm, I entered 28mm total. was I right. I also attatched the gain and GD chart for you to look at.

the only thing I can help you with is, I think that xmax is only one way, so audiobahn is just saying that it has an equal in out max. Just a thought, not quite sure, could look it up but don't feel like it. Audiobahn has a list of terms on their site if you want to look at it.

well, I changed that spec and it didnt change ythe gain plot or the group delay plot at all. I also put 1000 in pe cuz audiobahn says pe is the rated RMS power handling and I have a port mach of .13 and it is green so I think im fine there. z says total resistance but I still dont get it. each coil is 6 ohm so is it 6, 3, or 12???

I couldnt upload them since they were bmp, sop i got a image converter and changed them to jpg but they are too big. anyone else wanna look at them and give me some help tell me and Ill email them to you.

Total resistance, yeah, where is gsteg when you need him, some of those specs bug me, I would say it is probably 3 ohms but I could be wrong.

Don't worry about BL or Z. They do not influence anything on box. What does affect the subwoofer's need for box size is the Qts and Qes. There are other things that take into account, but not necessary too important. Usually I look at the Qts and get a general idea if the sub needs a big box or a small box.

Pe shouldn't matter because thats the thermal rating of the coil; how much power the coil can handle before it goes kaboom.

Z is the impedance, but most likely you'll see changes on the impedance graph.

And yes, thats why some people prefer SQ of a sealed box over a ported box because usually, the ported box is not designed correctly and you have a huge peak, right near the car's resonant frequency. Thats why it's boomy because the resonant of the system combined with the resonant of the car gives off that exaggerating bass, and our ears/brain process that as boomy.

Tuning to 28hz is a great start. Thats what I would do for SQ purposes. Don't worry too much about the graph on WinISD. Thats only an anehoic response, which means nothing in a car. WinISD assumes everything is perfect and you're in an open environment (ex: out in the opening).

The Xmax is not the limiting excursion of the woofer. Xmax can be defined in many definition. Some will use the overhung method or the underhung, depending on what kind of subwoofer it is. Some will say xmax is 70.7% of the rest BL, or peak BL. But it shouldn't affect the box at all.

I think the port you have right now should be ok. Just tune it pretty low and you'll be fine. As far as port noise, I have no idea. I rarely make my ported box with those circular ports, and when I do use them, It's usually for home audio midrange/midbass speakers.

would a rectangle slot port be better?

I am one of the people who isnt doing this all for my enjoyment, some of it is to show off how loud my system is. I am sure though if one high excursion in 3.5ft^3 ported off of 500 watts was loud enough for me, 2 alum12q's in 2ft^3 off of almost 1400 watts should cut it, even tuned lower.

is it 2.0 cubic feet per driver or for both subs?

yeah, total box is about 4.7 ft^3 which when the subs and ports displacements are figured gives them just over 2 ft^3.