sub for use with not a ton of power?

[NOMAD]

I am looking to run a 10" or even two 8" (to keep size + complexity down) off some lower powered amps I have.

Option 1 = 4 channel runs two fronts @ 65RMS x 2 and one rear sub at 130rms

Option 2 = One amp for 2x35rms and one for 220 RMS sub. It seems like a lot of work to run two amps just for that.

Option 3 = Two smaller 8" subs off of 2x75RMS?

Option 4 = 4 x 65RMS with no sub. Using BMW premium components.

Anything do-able? I'm trying to put together a budget system with the amps I have.

[StereoInstaller1]

The larger the woofer, the higher the efficiency, in general.

Single 10 is easier too, because the 8s would need to be DVC to load the amp properly, but a SVC 4 ohm 10 is not that tough to find.

[NOMAD]

Thanks, does it matter the rating on the sub? A local has a svc 10 with 200rms and 88 sensitivity rating. Would 130 or so be too little power to make it sound good?
I'm looking to amp front BMW speakers and the sub in the rear. Rear speakers off the headunit just for kicks.

Not quite sure how the fronts will sound since with just HU they are really quiet compared to the rears.

[StereoInstaller1]

I think you might have your amp specs wrong.

If it makes 65WPC @ 4 ohms/channel, it makes 260 RMS at 4 ohms mono, per pair of channel...so you would have 65X2 + 260 for bass.

My wife's car is rocking a system just like that. Stock Premiums in front with aftermarket crossovers off of half of a small Alpine 4 channel, a pair of stock PS rears off the deck (variable separate front and rear high pass thank god) and (of course) a single 12 in a V2 box. The car sounds better than 99% of the cars out there, and better than the pricetag would make you believe...

[NOMAD]

I listen at moderate levels BTW

OK, my 4 channel amp is a panasonic cy-pa4003U
specs

So obviously I don't know what I'm talking about but I'm glad you do. I hope this means my car will sound good if i can hook it up right.

What's a V2 box? That is your specialty box right? I don't think i can afford that just yet but would a regular box to a good enough job for starters?

So here's a question: Why do the front speakers sound so quiet compared to the rears? Location? Lack of any type of rear enclosure? Need lots of power to sound good?

So my shopping list is: crossovers for the fronts, 10 or 12 svc sub with 250 or over rms rating and a sealed box.

[NOMAD]

Oh yeah, here's what a local guy in my car club is selling:

12" Alpine Type E SWE-1242 (750w Peak, 250w RMS) Impedance: 4 Ohm.

12" Pioneer TS-W300R (600W Peak, 150w RMS) Impedance: 4 Ohm.

10" MTX Thunder 3000 / Thunder 3104 (400W Peak, 200w RMS) Impedance: 4 Ohm.

[StereoInstaller1]

OK.. a few things.

Lets start off with those woofers. The Alpine is $70ish new. If your buddy wants more than $20, fuck it. The Pioneer is $65 at WalMart, again, $20ish or fuck no.

You have no warranty with those woofers, so they are worth nothing.

WalMart sells a Sony for $65 that kicks the shit out of either of those in one of my boxes. Not so hot in a a small sealed box, but it my box, they rail.

Now you have got to keep in mind that the box is a HUGE factor in how the thing sounds. That Alpine is one of the very few woofers I do NOT recommend in my boxes, and not because of my personal grudge against Alpine, but simply because they do not do well in large ported boxes.

I like the sound of large ported boxes IF THEY ARE DONE RIGHT and 99% of the installers in the world are just too fucking lazy to do it right.

So the thing about that is all about efficiency. (So is the front speaker issue, BTW). If you feed 100 watts to a normal box and feed 1 watt to one of my boxes, mine will be louder, cleaner and play lower...in my opinion, better sounding.

Yes, it really is that big of a difference.

All of the published specs do not make sense on that Panansonic amp. My bet is that Panasonic did a typo, and everyone else followed suit. My bet is that you have 35WPC at 4 ohms and 130 mono, which is plenty. Exactly the same power as my wifes car, and her shit rocks. With the windows down you can hear her half a block away easily...because she "never listens loud"...yeah right. Sorry babe, I hear you coming, you just don't know how loud it is!

So yeah...on the whole front/rear thing...consider this: the fronts play at your ankles, the rears reflect off the rear glass and play at your head. Think about the physics involved and it should all make sense.

You need about 2X the power on the front speaker as you have in the rear to balance things out. Deck power is 12 WPC, that amp is 35WPC, so just about perfect if the bass can keep up (which it really wont)

Had they done the stock E30 system more like the E34/E32 hell even the E31 we would have far better sound in our little cars.

One of these days I need to write a book about this shit.

So yeah, hope that helps.

Luke

[NOMAD]

Great info, thanks. I love learning new stuff.
I'll see what the guy is willing to take for the subs (because $20 sounds good to me) or I'll get the MaoMart Sony and I'll save for one of your nice boxes.

So your wife's car does have rear speakers but also has the sub box ported into the car right? i'll be looking over your other threads one more time. I have 318 vinyl rear with the foam that I plan to shave down a little and I've already removed the steel ski panel.

[StereoInstaller1]

No, I switched her over to a V2 box so she has rear speakers again.

I still prefer the "no rear speaker" option, but she often has rear seat passengers and prefers the rear speakers.

I am not gonna be building again for quite some time, unfortunately. I guess that gives you (and some others) time to get ready to make their car (and there wallets) ready.

Luke

[NOMAD]

OK.

From what little I've heard, aren't the ports critical dimensions for proper bass output? Like too long or too short changes the sound?
How does that factor in with this box? I assume they are all calculated out and so that's why it woulds good too.

Now I'm wondering what the heck to use for a box as I'm all paranoid by the supreme-ness of your boxes...

[StereoInstaller1]

So get whatever cheap POS you can to get rockin' right now, then get one of mine later.

It isn't like I can sell any now anyway, I don't have any...

Luke

[NOMAD]

Hey, POS sounds like a plan that's about my speed, ha ha.

Thanks for all the advice. I feel like I monopolized your time though.
I'm thinking I'll pick up whatever 12" I can for cheap. Might as well get a 12 as opposed to a 10 with the same rating huh?

[StereoInstaller1]

Do that Alpine from your buddy in a small sealed box, like a QLogic.

It is a start.

I gather you read a bunch of crap I posted? All nonsense, of course. All the kids at Circuit City know more than me.

dammit I wasted my life!

PS, thanks for the props. Hope your car sounds good.

Luke

[NOMAD]

I hang on every word you say! *bow*
(and, oh yeah, the pics too)
I'll check out Craigslist for some stuff too.

[aintnothang]

Kenwood 12" sub for $38 dollars w/ free shipping.
http://www.6ave.com/shop/Product.aspx?sku=KENKFCW3011
enter coupon:AFLKEN38