another sx 15 question

[stanford1621]

I have 6 sx 15's that are going into an extended cab silveado they will be powered by 3 orion 2500d's

I would like to tune to about 32-30 hz

this is strictly for a daily driver system so I would like a some what flat response (nice sounding) the term loud sound quality was meant for me

I have been told everything from 3 cf to 6 cf per sub

Depending on the electrical requirements to run 3 2500d's I migh just go with 4 sx's, either way each sub will have it's own chamber

I think I can scrounge up 30 cf max behind the seat.

any ideas? or suggestions, any advantages to one chamber vs each sub having it's own?

[Robert]

Are you going sealed or ported. It seems sealed, but Im not too sure. Also, using the Orion 2500's, your loosing 700 watts per amp. It should still get loud (also if you have the standard dvc 2 coils).

Also, do you have any electrical upgrades planned? I dont know of any stock electrical system that will handle a single 2500 watt amp for long let alone three.

[stanford1621]

what do you mean losing 700 watts per amp?

ported (tunes to 30-32 hz)

I will go as far as adding a single 250-300 amp alternator and spend upto $600 on batteries.

If that won't run 3 2500d's then I will just use 2 2500d's and 4 sx's

what about 6 sx 15's run on 2 2500d's 3 a piece, that would be about 1.3 ohms?

[Resonant18]

what he's saying is that if you use the two sx's per amp it will be at 2 ohm instead of 1 ohm like that amp likes so you will be losing power. If you want to run 6 of them I would get different amps that put out power at 2 ohm.

[Robert]

what do you mean losing 700 watts per amp?

ported (tunes to 30-32 hz)

I will go as far as adding a single 250-300 amp alternator and spend upto $600 on batteries.

If that won't run 3 2500d's then I will just use 2 2500d's and 4 sx's

what about 6 sx 15's run on 2 2500d's 3 a piece, that would be about 1.3 ohms?

Orions are 2400 watts at 1 ohm. Dual Sx 15's (assuming dvc 2) series parrallel are 2 ohms nominal. Orions put out iirc 1700 watts rms at 2 ohms. Six Orion 1200d's (one per sub) or three Viper 2500's would be a better match to gain the most power. BUT, this is not to sway you from the big Orions. You'd still be getting over 5k watts and thats an insane amount of power for a daily driver!

About the box, looking at ISd and BBpro, RE's recommend box looks good. 3.5 cubes per sub (21 cubes total) tuned to 32hz's. As for the port, Im not sure how big it should be. Im looking at 700 sq inches but thats an extremely long port length. Maybe call up RE and see what they say about port area (unless someone else chimes in here).

any ideas? or suggestions, any advantages to one chamber vs each sub having it's own?

Single chamber is nice for ported for two main reasons. Smaller box size and easier port dimensions. Seperate chambers are great for bracing but not really needed. As long as all the amps are gain matched, there shouldnt be any problems (Orions are nice because they have a gain sync feature built in).

[95Honda]

Welcome to the forum!

I have a few thoughts on this. First is your electrical system. Each 2500D at full tilt will pull in excess of 200 amps. If you have 3 of them, you can be looking at a potential of 600 amps of current draw..... This will tax a single 250 amp alternator for listening periods at any extended amount of time, and that isn't even assuming the load the rest of your truck and system will be putting on the alt. I would be wary of even running a set of 2500Ds on a single 250 alt.... The battery(s) will help with storage, but they won't supply any additional power, they just store whatever your alt puts out.... If it was up to me, I would leave the stock electrical system intact to run the truck and all of your source components, and then add dual 250s or one 400+ amp alt to run the 3 2500Ds on thier own, with a battery under the hood and one for each amp..... I know that sounds like a lot of work, but you are wasting your money on the amps if you don't do this...

As for the box, 6 SX 15's would absolutley hammer in a 30ft3 wall... Ported at around 30Hz and you would be golden.... Just remeber when designing your box, if you make it a little bigger your efficiency will go up and if you tune a little lower your response cureve will flatten out in the critical 30-60Hz range.....

I wouldn't woory too much about getting the lowest ohm load possible to the amps, especially for a daily driver. You will still get enough power out of those amps to kill yourself with those subs even if you run them at 2x your minimum impedance. It ia always a good feeling or piece of mind knowing that you aren't taxing the amps everytime you turn it up...

A little thought on sound quality....

There isn't much in the way of SQ once you start breaking the 150db threshold, which a system of this magnitute is most certainly capable of. Don't expect accuracy and balance at full output, your ears will also start to give in... You will be playing in the Big Boy leagues with a set-up like this, be prepared for it. I'm not saying that it won't sound great at low volumes, just remember what you are trying to do here..... 150+db daily driver systems are obnoxious, I've built a few, so have a couple of other guys on here.... Robert has a very good handle on what he is doing, so does Black00. Doc has a daily system that does 145+ without hesitation, ask him what it's like...

I think you did a great job picking out what you want to use. If you see this through and beef up your electrical system to follow suit, you will have a serious daily driver...

Good Luck!

[TalNLnky]

my take... like 95honda said... upwards of 200amps of draw per orion amp. Run 1 amp... dare god i said it.... yes, 1 amp.
1.5ohm load i believe if you do (3) parallel groups of 4coils in series. In other words, you parallel the coils of 2 subs together.... that gives you 3 groups of 2.... run those 3 groups in series. Ohm load of each group will be .5ohm, so add them up, .5+.5+.5 = 1.5ohm

now, this leaves you with 6 15's, you only need about 3 watts to get loud when you have that much cone area. so who cares if you only have around 1800. It'll still get really loud.

95honda has an 8x re8 box... thing has 150w to it and busted a 142-143 on the termlab. You don't need a lot of power, so save the time, and money that you'd spend on 1: amps. 2: electrical system


even with running a single orion 2500, i'd still run at least 2 batteries, 3 or 4 would be better. And of course the alt will need some work, either upgrade to the largest alt you can find, or add a 2nd 200+ amp alt in addition to the stock alt.


have fun, good luck.


EDIT: keep in mind... you could always decide to upgrade the electrical even more and add a 2nd amp down the road.

[starvingf150]

if he does a separate alt. just for the system..could he find an amp that would take 16 or 17v daily? Like the Incriminator or American Bass?

just a thought..if so it could save 150 amps of juice..

good luck..

Ben

[95Honda]

It is nice having your sub amp system on a seperate charging system so that you can raise the voltage without worrying about your car's electrical system.... That is one of the main reasons why I plan on adding a second alt and charging system to my Bronco...

[stanford1621]

I like to have everything planned out and understand it all before I start, is there a website where I can read up on adding seperate charging system?

[TalNLnky]

It is nice having your sub amp system on a seperate charging system so that you can raise the voltage without worrying about your car's electrical system.... That is one of the main reasons why I plan on adding a second alt and charging system to my Bronco...

that would require a 2nd battery... and you lose the ability to use the cars chasis as the common ground... correct? everything would have to be grounded back to the battery or alternator? lil more cable to buy.. thats all.

[Robert]

Thats actually a great question. Arnt most alternator's grounded through their case to the motor? To run a seperate system, the batteries would have to be grounded only to that alternator. They must make something designed for it :?

[MikeS]

"There isn't much in the way of SQ once you start breaking the 150db threshold."

One's ears kinda smash in and distort pretty much by then, even if the SQ was rather good. A guess......

[stanford1621]

well what I mean is in the past I have had loud systems but they were real peaky and I could only show off my system on 1 or 2 songs, I got tired of driving around listening to akon soul survivor or late night tip.

I guess the goal would be to hit 150 db on any frequency between 30 and 60. Is this realistic?

My current system consists of 4 rockford fosgate p2's and a crossfire bmf1000d it is brutal at 35 hz but above 45hz it has nothing.

[TalNLnky]

Thats actually a great question.
it was more of a statement than a question... looking for a lil validation/confirmation, but yeah.... seperate charging systems requires seperate grounds.

[95Honda]

You don't have to have seperate grounds, use the chassis for everything, it doesn't matter. Look at any multiple alt setup and you won't find the grounds isolated..... You couldn't isolate them easy if you wanted to anyway, alt cases are grounded.

[TalNLnky]

You don't have to have seperate grounds, use the chassis for everything, it doesn't matter. Look at any multiple alt setup and you won't find the grounds isolated..... You couldn't isolate them easy if you wanted to anyway, alt cases are grounded.

then that wouldn't be a completely seperate charging system. you'd have to use something to isolate them....

i've never looked at any dual alt system that tried to isolate the two charging systems to the best of my knowledge.

[95Honda]

It is still a completely seperate charging system, they just utilize a common ground. The ground provides no link between them, it is just a passage for returning current to flow to the perspective load.

Think of it this way....

Airway Heights and Cheney are on two completely seperate power grids, they may even get thier primary power from completely different sources, but they still use the earth as a refence point for 0V. They are completely seperate power systems but both utilize a common ground...

Same way as a car, you will only have one ground in an auto. You can have unlimited isolated power sources, they will just share the ground as a current return path, they will not effect each other in any way. No matter how loaded down one or the other is, it will have no effect on the other.....

[doc]

It is still a completely seperate charging system, they just utilize a common ground. The ground provides no link between them, it is just a passage for returning current to flow to the perspective load.

Think of it this way....

Airway Heights and Cheney are on two completely seperate power grids, they may even get thier primary power from completely different sources, but they still use the earth as a refence point for 0V. They are completely seperate power systems but both utilize a common ground...

Same way as a car, you will only have one ground in an auto. You can have unlimited isolated power sources, they will just share the ground as a current return path, they will not effect each other in any way. No matter how loaded down one or the other is, it will have no effect on the other.....

Great info and great analogy :)

[TalNLnky]

you were talking about having additional setup (alts & bats) for just the stereo... the stock stuff would be for the normal car electronics and such.

here's my problem in understanding/accepting what you are saying mike. And correct me if i go wrong at anypoint here.

Current flows from negative to positive... as in from the bat/alt current will flow over the ground, to the amp.... then back to the alt/bat over the power cable.

if both charging systems use a common ground, how can you keep the current produced by the stock electrical from being used by the aftermarket stereo? Or the 2nd electrical system from being used by the cars electronics? They both source their current from the same ground.

maybe i misread something you said... I like the idea of having the stock electrical do its job, and be uneffected by the stereo AT ALL... however i can only see that being possible by physically not having any common ground (could they share the same power connection tho??? ehhhh not sure on that... power cable would have to go to both charging systems somehow... i dunno)

[95Honda]

I guess where the dissconnect is that you are thinking that since the ground is common, that the current could flow through both systems, or borrow from one another because the ground is common. It doesn't work that way, and this is why.

The alternator (and battery) are going to be your source currents. Lets say we have two identicle sources (two batts, two alts) and a common ground. Now lets say we also have two identical loads, one hooked up to each source. Lets call it system A and system B. Sytem A has the alternator feeding the battery and the battery feeding the load (same in B) When system A's alternator starts producing current, it will flow into the battery (it is connected to it with a wire) and then from the battery to the load. Current passes throught the load and then to ground and returns back to the alternator (current flow is dependant upon if you are using electron movement or hole theory, we'll just assume + to - to make this easier, but it doesn't really matter). So we have a complete circuit with current flowing for system A. And remember, System A's charging cicuit will produce the amount of current needed to drive it's load because that is the only thing in it's COMPLETE circuit. Now system B is operating the exact same way, everything will work the same. They both share a common return path (ground) but that won't effect one and other because the only complete circuits are the one that contain the source and load and interconnecting cable. If system B's load draws more current, it will get it from B's charging system because that is the only thing that is hooked up to it in a complete circuit.

It also may help to thin of it this way. An alternator will supply DC current on a continous basis and a battery will supply it on a short term basis, but they both are supplying power and both are referenced to the ground point of a vehicle. Now, if you have two identical batteries in a car that are both charged and we hook the - side of each to ground, and then on the + side of one we hook up a light (Between the + battery post and ground) and do the same with the other (Remember, just batteries here, nothing else connected like a single alt or anything like that) we have two completely seperate power sources, both utilizing a common ground. Now, lets say that you forget to turn off the light that is connected to battery A for a few days. What happens? Battery goes dead. Does this affect battery B? No. Why? because the complet circuit for battery A only flows throught the lightbuld that is connected to it, not the other SEPERATE circuit. You could simulate this at home with a small metal toy car and two AA batteries and a couple of lights. You have to understand that the current will only flow in a complete circuit. In our dual charging system we spoke about earlier, if the load is discconected from either circuit, current will cease to flow (with the exception of enough to keep the battery at it's float charge level).

That is how it works. No if ands or butts about it.....

Hope this helps...

[TalNLnky]

ok... ok.... i think i got it, seems really simplistic now... hehehe. Thanks mike.