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Car Audio for Ritz - Choosing right sub

Marantz offers at HiFiMART.com


New Member
Feb 5, 2013
Hi Guys,

Im going nuts in understanding the concept of choosing the right sub and amp. Pls help. I have a Maruti Ritz and I intend to upgrade the audio system. I have a Kenwood KDC-U7046BT HU with 3 preouts

Here is my requirement.

1. Amplifier
I have zeroed in on JBL GT-X646 4 Ch amp, so that i can power a pair of component speakers and a sub woofer [ by bridging two of its channels ]

Description :800 Watt 4-channel
Output Power(RMS,<1% THD + N; 2 ohms) :4 x 100W
Output Power(RMS,<1% THD + N; 4 ohms) :4 x 65W
Signal to noise (@ 1W) :85dBA

2. Component
Infinity - PR6500CS

RMS Power Range (Watts) 5-80
Peak Power Handling (Watts) 320
Impedance (Ohms) 3

Ch 1 and 2 of the amp will go to each pair of component crossovers [ which is inturn wired to tweeter and woofer ]. Power wise I guess this would be ok, since the channel output of amp [ 65W ] is within the RMS power range of the component. Right?
But i see a difference in impedance. 3ohm for the comp and 4 ohms in amp. Is it going to fry either of these? I'm not getting it right. Do I need to match the impedance?

3. Sub woofer
Boot space is a constraint in Ritz. I am afraid I may not be able to fit in a 12" in the boot. Also, I am not looking for a thump that i can hear a mile away. If the subs can clearly produce the lows within the confines of the car, that would suffice. Two of the 12" that i had thought of are...

a. JBL - GTX 1150W
b. JBL - CS1215B

These subs almost have the same RMS power [275W ] @ 4 ohms. Then again i have a confusion in terms of what happens to the amp impedance if i were to bridge the channels and feed the o/p to one of these subs. Will anyone of them fry [ sub or the amp ] ? Or would the o/p of amp be too low to power the sub ?

Also , since space is of constraint, i thought i would go for a 8" sub and i have kind of zeroed in on this.

Polk Audio - DB840 SVC
Impedance - 4ohms
RMS - 180W

So if i were to bridge the amp and power this sub, will it suffice?

Oh yeah another questions...Since its an 8" sub, how would it be if I dont put them in an enclosure.. rather stick it to the rear tray in the middle [ where my rear speakers are currently fixed]

I have gone nuts reading abt the subu-amp matching the whole day.

Any help would be much appreciated.

Thank you