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Discussion Starter · #1 ·
I am aware they are old

Kenwood KFC-W3009

# 12" 4-ohm subwoofer

# pearl mica injection-molded polypropylene woofer cone with urethane foam surround

# overlapping ribs on cone surface for improved rigidity and dampened resonance

# extended pole piece and bumped back plate for increased cone excursion

# power range: 35-400 watts RMS (800 watts peak power)

# frequency response: 25-800 Hz


So My amp went out, and well I've been thinking if there was a better way of hooking these things up

Audiobahn A8002t

# 200 watts RMS x 2 at 4 ohms

# 400 watts RMS x 2 at 2 ohms

# 800 watts RMS x 1 at 4 ohms

# stereo or bridged mono output

# Tri-way capable (Tri-Way crossover required)

# MOSFET power supply

# 4-gauge power and ground leads recommended — wiring and hardware not included with amplifier

# high gloss chrome plate finish with blue illumination

# variable crossovers (50-750 Hz, 18 dB/octave high-pass, and 50-120 Hz, 18 dB/octave low-pass)

# subsonic filter (20-50 Hz)

# 18 dB bass boost (switchable on/off)

# preamp outputs

# preamp- and speaker-level inputs

# cooling fan


I had the subs hooked up with each having their own channel.


I've been looking at wiring diagrams at Crutchfield.com

Since the subs work (hooked up an old amp to test), I didn't really feel the need to replace them, they sounded great so, I figured no need to change anything. But, I always felt the subs should have hit much better, so I just always figured it was the amp, but after looking at a few wiring diagrams on crutchfield.com I found maybe it is better to use a single channel with a daisy chan setup at 2 ohms. (I was probably running them at 200 RMS, instead of the 400 RMS at 4 Ohms). I am a beginner with this kind of stuff, but I don't mind reading, and I don't see how my system can be that complicated to warrant a pro setting it up.


If anyone can give their input, that would be great before I buy a new amp.


I am also looking at the head unit (as I guess that went out too lol), Alpine iDA-X305 since I have the iPhone 3gs, but I've seen good and bad reviews will be checking it out in person before buying from store/off web.


Also hello, as this is my first post. Thanks for any comments one may add.
 

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Discussion Starter · #2 ·
I've been looking at the:

Kenwood X1200M


RATED OUTPUT POWER (14.4V):

800W RMS x 1 @ 4Ω

(20Hz-200Hz @ 1%THD)

1200W RMS x 1 @ 2Ω

(100Hz @ 1% THD)


RMS POWER OUTPUT (CEA-2006)

800W RMS x 1

(RMS @ 4Ω, 1% THD+N)

75dBa Signal-To-Noise Ratio


BUILT-IN CROSSOVER CONTROL:

Variable Low-Pass Filter: 50Hz-200Hz (-24dB/oct)

Variable Infrasonic Filter: 15Hz-40Hz (-24dB/oct)


TERMINALS:

Battery: Hex Type (4 AWG)

Ground: Hex Type (4 AWG)

Speaker: Hex Type (8 AWG)


Operating Voltage: 14.4V

Current Consumption: 90A

S/N Ratio: 105dB

Frequency Response: 20Hz-200Hz

Input Sensitivity: 0.2V ~ 5.0V
 

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Why not wire them in series, and bridge the amp if needed? The amp will run cooler, and I would think you would still get the SPL levels you need. Worth trying?
 

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Discussion Starter · #4 ·
So I was looking at the diagram, and it showed in a series that if I run two 12's at 4 Ohms, I should have the amp running at 2 ohms (that is what the crutchfield guide showed)? Whichever is the best method for getting the highest quality sound with the least amount of heat is the best I would assume. I also noticed if I ran that amp at 2 Ohms, that it would push 1200 Watts RMS, and if I ran it in a series, would that distributed the wattage evenly between the two subs? So it would be 600 watts RMS in theory. Since my 12s are 400 watts rms, would that create a strain that may pop'em or something?
 

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No.


Two 4-ohm speakers in SERIES present an 8 ohm load ( actual load varies with frequency, 8 ohms is approximate average load.)


Two 4-ohm speakers in PARALLEL present a 2 ohm load.


Think of it like water flowing through pipes. Parallel is like having two pipes. Series is like putting two pipes together. The longer the pipe, the more pressure you need to push the water through. If you add pipes, more water can flow. In electricity, the more current that flows ( think flow rate in a pipe,) the more heat.


If you delve into the topic even more, you will find heat increases resistance, which increases heat even more. Some amps are stable into 2 ohms, but they are expensive. And I would guess some amps won't last as long.


If it was me, I would hook them in series.
 

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Ah, I missed the fact this was car audio. The guidelines, may well be different. It was obvious from his post, but it was so long, I did not read it closely. Sorry
 
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