Bazookajoe254

I've got two 10"s in the back and I'm thinkin about putting a third. Just because.

I have a 400W Jenson amp, 2 channels, in the back, also. To put the third in I would just splice the 3rd into one of the other subs, but I'm wondering if that is going to give one of my subs 200W of power and the others 100W each?

cub and Matt

Becareful! Jensen are not high end products. 3 10 inch subs are going to be difficult to wire in. Not impossible though. What are the impedances? Single voice coil/dual voice coil? Can maybe give you a wiring diagram if I know those answers.

cdoyle

You're not really going to see any increase anyways.
If you're subs are bridged, and if your amp can handle the load of all 3 subs (what type of subs are these?) dont' forget you'll need to make a new box too.

You'll have around 133 watts per sub. so most likely it will sound worse then it did with 2.

cub and Matt

OK I have to slightly disagree. I am going to generalize a bit so as to not have to type a book here.There are several ways of increasing spl (sound pressure level)The two most common are
1:Increasing the amount of power measured in watts you are pumping through your current speakers.

2:Increasing the amount of speakers using the given amount of power you are using.

The rule of thumb behind these two rules is for every time you double the speakers you get a 3db increase in volume with the same total power. Or double the power to a single speaker to get the same 3 db increase.

With that being said, please forgive me omitting increases in sensitivity (efficiency),dropping impedance power gains etc... Again I am generalizing.

So,with a hypothetical amp producing 300 watts peak, with 1 speaker you get 120db with the volume turned all the way up. With two speakers and same amp you would get 123db. With 4 speakers 126db and so on. So what I am trying to say in this incredibly long and drawn out boring post is that 3 subs plays louder than 2 subs with the same total power. And before I get abused here, yes the box plays a role. An incorrect box will ruin all your efforts. Also I way over simplified. But again I hate to type so if you want the actual logarithm that is used, look it up.

Jim85IROC

iTrader: (2)

Adding subs does provide additional output provided the power output stays the same, but if you have to series-wire all of the subs to keep the amp happy, it'll make less power and your output will decrease.

If you want louder stuff, forget about adding another sub and buy a better amp. That Jensen doesn't make any real power.

cub and Matt

I will find you the information explaining in more detail what I wrote. You do actually get more volume (DB) with the same total power when you increase speakers. Yes you get less power per speaker but since you do have to double the power for every 3db increase, the loss of even a 100 watts to a pair of speakers is going to be overcome by adding the extra woofer. I also agree that the Jensen is a waste of space.
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I need to find my old Autosound 2000 papers. They were an incredible source of info. I am a packrat so I know i still have them.

Bill/T/D/Y

try this site http://www.the12volt.com/caraudio/wo...igurations.asp for calculations ect and this for more http://www.the12volt.com/caraudio/boxcalcs.asp
And yet another for info ect.
http://www.diysubwoofers.org/ enjoy the tech.

cub and Matt

Thanks Bill! I did not have all of these websites saved. Most of what I vomit out on these forums is from memory and I like to have the ability to reference as much as possible.

Jim85IROC

iTrader: (2)

I'm well aware of what you just wrote. What I'm trying to illustrate is that with the current configuration, he will NOT make the same power after adding that 3rd sub.

Let's say that right now you've got 2 8 ohm subs, parallel wired for a single 4 ohm load from the amp's perspective. Since that amp can't push anything below 4 ohms without killing itself, adding a 3rd identical sub will now give you 3 8 ohm subs, which when wired in parallel will give you 2.66 ohms... too low for that amp to handle, which means you'll have to series-wire the subs, which will give you 24 ohms, which means your amp will make no power.

If he's got DVC subs with each coil at 4 ohms, then he could parallel/series wire them to achieve a 12 ohm load, but that will still significantly reduce the output of the amp and cause an overall loss of SPL.

Spend the money on a better amp.

cub and Matt

Ahhh yes, I see what you were meaning now. I reread what I wrote and did not make it clear about maintaining the same system impedance with the total power. AND I agree totally that he should save the money for a better amp.

Bill/T/D/Y

Glad ta help C&M always glad ta help out.Personaly I'm not to worried about OPTIMUM potential just what sounds ok to me and not blow my stuff up in the process.If i do np either just order the parts and break out the solderin tools.(big hot stick)But I do research the heck outta everything i do b4 i do it if possiable so i avoid blowin my stuff up.And as a habbit i tend to save fav info/sites addresses on **** for further referance.Was thinkin at 1 time of balancing the 2 petras and the infinity off the same amp but decided against.Thought was 1 big butt sub then off a mono amp.But the math put it at about either 12 ohms or 1.8 so decided against.

Bazookajoe254

Thanks for all the replies.

About the Jenson...Both the subs and the amp were given to me from a guy who
1. Was getting a bigger amp so he gave me his old one. It's a 500W, I wrote 400 in the first post...
2. He knew someone trying to get rid of some subs that he had no room for so he told him and his friend gave them to me for free. They're 350W Pioneers.

So, I know they aren't particularly the best things available, but for free

I've still got the stock 6x9s in there. I had some that I bought on Ebay and about 3 weeks later the insides of them fell apart...somewhat literally. Come to find out they were from a spanish company, started with an M, like Mitsu or something. Went on their website and nothing was in English. Bad mistake.

But yeah, I'm just gonna wait and get some new 6x9s, maybe Christmas

Thanks for all the advice

Jim85IROC

iTrader: (2)

why not upgrade your front speakers instead? Most of your sound comes from in front of you, so that's where the biggest portion of your investment should go.

cub and Matt

I understand the 6X9 choice with only 4X6's up front,You have to sink some significant money just to get spots to add front speakers. I know what Jim is saying though. Having that front soundstage is so important, unless you are just going for loud good sounding music. Are you going to compete? If so, plan on investing in some kickpanels to add some speakers up front.

Gallileo60

cub and mat,
You are 100 percent correct....Power is not all its made out to be.....3 speakers will definately give an increase in SPL with the same amount of power..(Providing everything else is correct) Increasing power will NOT always give you an increase in SPL...Cones can only travel so far, and all the power in the world will not change that...In this case tho, the amp is not capable of handling the load of 3 subs......Tom

Joker1232

u shouldnt splice wires togther to make subs run...check out amp specs and see what it will run at different ohms. So depending on this you will wire them parellel or in series based on ur amp's specs, # of voice coils. Go to Fosgates website, they have wiring diagrams that can explain all this....

Jim85IROC

iTrader: (2)

I think we already did explain it multiple times.