gtabmx

Hi, I recently bought two Kenwood KFC-W3012's that I plan to put in a 4th order bandpass enclosure that I will build. I have this constant feeling that two 12" subs is a little overdoing it so i wanted to know exactly what the difference two 12" subs would be over a single 12".

Aslso, I have a 800 Watts RMS amp to power the parallel combination of these subs. I bought 4 6x8 40W RMS each Pioneer speakers and another amp to power them. I am not changing the head unit and i am not "rattle-proofing" my car... yet.

So, should i return 1 sub or keep em both? I paid $85 per sub tax in, if that changes anything.

Thanks,
Mike

Lord Huggington

iTrader: (1)

+3dB is twice as loud.

To achieve +3dB you either need to double the cone area or power, so doing both gets you +6dB.

With the same general tuning in a ported box, 2 12's on 750W will be the same loudness as a 12" on 1500W. However, 2 12's have more cone area and will be louder below port tune.

A single 12" in a 4th order BP on 800W is quite a bit of bass and is great for daily if it easily covers 30-40hz before rolling off each way.

gtabmx

Thanks for the info and advice! Actually, each KFC-W3012 is 400 Watts RMS, so one sub will be 400W RMS while the two will be 800W RMS. I've heard that two subs gets you +3dB, double the power gets you +3dB, and building a good enclosure gets you +3dB. So really, in my case, I am gaining 9dB, which is double the perceived loudness.

Basically

Pros: double the perceived loudness
I can tune each enclosure to a certain frequency to get a wider response (40Hz and 60Hz)
It looks beastly.

Cons: It takes a lot of room since I could use the second subs trunk space for both amps.
I need to keep the 2 farad cap I bought for $65.
Costs a little more for extra sub and materials.

I am torn

-Mike

Sinemeup

More is better, but lose the cap

Menace

iTrader: (-1)

bass gets deeper and u gain about 1-2 db per speaker give or take. depends on how much power you have and how u wire them all.

CrazyKenKid

iTrader: (7)

3db's but only in theory lol most of the time it varies from 1-2.5 db pending on the setup and box and what not!

jalat

iTrader: (6)

Those were the very first subwoofers I ever bought. Ditch the 4th order design and go with a straight forward ported enclosure. 1.8 per woofer @ 36-40hz

gtabmx

Thanks for the feedback everyone.

As for the 2 farad cap, why should I get rid of it? If I power the subs to their peak RMS 800W as well as the 40W x 4 for the speakers. that's almost 1kW, which I think requires at least 1 farad. Can someone give me a good enough technical explanation for why the cap is useless/ I would love to get back my $65 and spend it on upgrading my sub amp to 800W instead of the 500W its being powered to now.

I have used the program WinISD and the EBP of the subs are 28.8 and, usually, under 50, its strongly recommended to go with sealed or 4th order. I simulated both setups and the 4th order gives a better response from 40Hz to 60Hz, although it drops off faster after 100Hz.

Perhaps I should seal one and 4th order the other? Or port one and badpass the other?

Thanks,
Mike

AAAAAAA

iTrader: (7)

Actually 3db isn't twice as loud, but it is perceptibly louder though.

veeman

iTrader: (3)

Human percieved 2x loudness is closer to 10dB. Frequency response intensity uses +/- 3dB as a reasonable deviation in output that would be detectable to humans, as 3 dB is considered an amount of change less than which is not easy to detect, more than 3 db is perceptible by most. Obviously, to each person it may be somewhat different depending on their hearing and auditory system, but generally 10dB is considered 2x as loud to the human ear. Go to this link and check it out...it's simple and will clear things up.

http://trace.wisc.edu/docs/2004-About-dB/