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How Would I Be Able To Get The Most Power Out Of My Amp?

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Old 10-25-2004, 05:58 AM
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How Would I Be Able To Get The Most Power Out Of My Amp?

Here's my problem, seems like the amp that I bought isn't powerful enough to power my 2 12" RF subs, but seems to work pretty good with one sub, its plenty power for me with one sub. Here's the info of the amp below and and below that, will be the info on the subs. How would I be able to power my one sub as much as possible with the amp, how would I connect to the speaker the amplifer terminals? Is this even possible? Thanks, I would really appreciate it!

Kenwood KAC-749S Amp
- 4, 3, or 2 Channels of Amplification

- Ground Isolation Circuit

- Power MOSFET Switching Power Supply

- Stereo, Left + Right, Mono, or Tri-Mode Operation

- Bridged Power Output at 14.4V (1kHz, 0.8% THD): 120 Watts x 2

- Maximum Output Power (Bridged): 450 Watts

- Power Output at 2 Ohms, at 14.4V (1kHz, 0.8% THD): 60 Watts x 4

- Power Output at 4 Ohms, at 14.4V (20Hz-20kHz, 0.08% THD): 40 Watts x 4

- Input Selector: AB/A (Independent)

- Quiet Turn-On

- RCA Audio Inputs: Gold-Plated

- Speaker Connectors: Gold-Plated, Screw-Type

- Speaker Level Input Terminals

- Speaker Relay Protection

- 2-Ohm Stable

- Black Powder-Coated Top Cover: with Sandblast Finish

- Copper EE-Core Power Transformer

- Noise Supression Filter: Large Toroidal

- Power Indicator

- Power Input Terminals: Gold-Plated, Large Screw-Type

- Secondary Capacitors: 2

Rockford Fosgate RFP4412 Subwoofer Specs:
Brand Rockford Fosgate
Enclosure Non-Enclosed
Estimated Price $50 to $100
Function Subwoofer
Manufacturer Part Number rfp4412
Nominal Power Handling 200 - 250 W • 150 - 200 W
Surround Material Foam
Type Component
UPC 080687306169 • 780687306137
Woofer Material Poly / Plastic
Key Features
Function Subwoofer
Nominal Power Handling 200 Watt
Size 12"
Miscellaneous
MPN rfp4412
Product ID 20607229
Mounting
Top Mounting Depth 5.75 In.
Power
Power Handling 400W (Peak), 200W (RMS)
Technical Features
Frequency Respond 28 Hz - 400 Hz
Impedance 4 ohm
Peak Power Handling 400 Watt
Sensitivity 88 dB
Old 10-25-2004, 06:05 AM
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wrong thread but what the hell
Power Handling 400W (Peak), 200W (RMS)

you need at least 400WRMS 600-700 W peak to power 2 12" subs
Always go off the RMS rating the peak rating is just BS and sales jargon to make the unit sound more powerful than it is
I'd personlly recomend using what you got with one sub.


Originally Posted by Vato Loco
Here's my problem, seems like the amp that I bought isn't powerful enough to power my 2 12" RF subs, but seems to work pretty good with one sub, its plenty power for me with one sub. Here's the info of the amp below and and below that, will be the info on the subs. How
would I be able to power my one sub as much as possible with the amp, how would I connect to the speaker the amplifer terminals? Is this even possible? Thanks, I would really appreciate it!

Kenwood KAC-749S Amp
- 4, 3, or 2 Channels of Amplification

- Ground Isolation Circuit

- Power MOSFET Switching Power Supply

- Stereo, Left + Right, Mono, or Tri-Mode Operation

- Bridged Power Output at 14.4V (1kHz, 0.8% THD): 120 Watts x 2

- Maximum Output Power (Bridged): 450 Watts

- Power Output at 2 Ohms, at 14.4V (1kHz, 0.8% THD): 60 Watts x 4

- Power Output at 4 Ohms, at 14.4V (20Hz-20kHz, 0.08% THD): 40 Watts x 4

- Input Selector: AB/A (Independent)

- Quiet Turn-On

- RCA Audio Inputs: Gold-Plated

- Speaker Connectors: Gold-Plated, Screw-Type

- Speaker Level Input Terminals

- Speaker Relay Protection

- 2-Ohm Stable

- Black Powder-Coated Top Cover: with Sandblast Finish

- Copper EE-Core Power Transformer

- Noise Supression Filter: Large Toroidal

- Power Indicator

- Power Input Terminals: Gold-Plated, Large Screw-Type

- Secondary Capacitors: 2

Rockford Fosgate RFP4412 Subwoofer Specs:
Brand Rockford Fosgate
Enclosure Non-Enclosed
Estimated Price $50 to $100
Function Subwoofer
Manufacturer Part Number rfp4412
Nominal Power Handling 200 - 250 W • 150 - 200 W
Surround Material Foam
Type Component
UPC 080687306169 • 780687306137
Woofer Material Poly / Plastic
Key Features
Function Subwoofer
Nominal Power Handling 200 Watt
Size 12"
Miscellaneous
MPN rfp4412
Product ID 20607229
Mounting
Top Mounting Depth 5.75 In.
Power
Power Handling 400W (Peak), 200W (RMS)
Technical Features
Frequency Respond 28 Hz - 400 Hz
Impedance 4 ohm
Peak Power Handling 400 Watt
Sensitivity 88 dB
Old 10-25-2004, 06:52 AM
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I've heard something about experimental cold fusion....but other than that if you wire your subs in parallel it will lower the resistance and up the wattage. If you've already done that you're pretty much gonna have to get a new amp.

edit: after reading the specs. wire the subs in parallel so there will be only one connection and then bridge the amp.

Last edited by Praufet; 10-25-2004 at 06:54 AM.
Old 10-25-2004, 07:21 AM
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or get subs that are more easily driven (higher sensitivity number.)
Old 10-25-2004, 12:25 PM
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Are you wireing the subs corectly? I have a very similar 5 chan kenwood amp running 2 10s at 2 ohms and they pound. you might have your subs wired at 8 ohms instead of 2 which would only pull 1/4 the power the amp can put out assuming it it 2 ohm stable like mine. I mihgt also recomend some infinity subs becuse they are some of the most eficent on the market (I am running Kappa series that go for about $100 each online for 12s).
Old 10-25-2004, 02:45 PM
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Originally Posted by Praufet
I've heard something about experimental cold fusion....but other than that if you wire your subs in parallel it will lower the resistance and up the wattage. If you've already done that you're pretty much gonna have to get a new amp.

edit: after reading the specs. wire the subs in parallel so there will be only one connection and then bridge the amp.
Yeah, what he said. Since they are 2-ohm subs you can wire them in parallel.
Old 10-26-2004, 08:55 AM
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good lord....

Sensitivity really means nothing in the mobile subwoofer world. Look at your VAS, mms, cms, and single coil BL to determine just how 'sensitive' it is.

That is a 4 channel amp, so when bridged you can only have 2 channels each putting out 120 watts @ 4 ohms.

How EXACTLY do you have each sub wired up? This information is imperative...

Those are SVC 4ohm subs, so to get the most out of them you will need to bridge the 4 channels down to 2 channels and run each channel to each sub. No paralleling or seriesing necessary...

Running your amp below minimum recommended impeadance will likely kill it...particularly if you dont know what you are doing...
Old 10-27-2004, 10:20 PM
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Originally Posted by LBC994runner
Yeah, what he said. Since they are 2-ohm subs you can wire them in parallel.
My bad ... was thinking about the wrong model numbered sub .. those are 4 ohm subs, so do what yota said
Old 11-02-2004, 02:03 AM
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1 fard capacitor. I have one 400 watt amp pounding 2 12 inch subs. Let me explain. First off your amp is rated at 14 volts. Your factory system is putting out 12 volts. lower input means less output. Simple. Ok at night you will be running headlights, raining? , windshield wipers also use current, cold outside? , heaters will be running or at least defrost plus your computer cell phone charger ect. ect. ect. your amp is fighting for power. Very few amp companies advertising their rating for 12 volts USAcustics is one of the few i know of. Really just get you a 1 farad capcitor if you plan on running an amp and i would bet MOST of the time your lights wont dim when the bass hits.
Old 10-07-2013, 04:03 AM
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Originally Posted by epic37311
1 fard capacitor. I have one 400 watt amp pounding 2 12 inch subs. Let me explain. First off your amp is rated at 14 volts. Your factory system is putting out 12 volts. lower input means less output. Simple. Ok at night you will be running headlights, raining? , windshield wipers also use current, cold outside? , heaters will be running or at least defrost plus your computer cell phone charger ect. ect. ect. your amp is fighting for power. Very few amp companies advertising their rating for 12 volts USAcustics is one of the few i know of. Really just get you a 1 farad capcitor if you plan on running an amp and i would bet MOST of the time your lights wont dim when the bass hits.
You do realize that when a vehicle is running the battery is actually 14.4 - 14.6v... lol.
Old 10-08-2013, 03:20 PM
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Um you do realize this thread is almost 10 years old right? All vehicle electronics is supposed to be able to sustain 16 volts.
Old 10-22-2013, 04:13 PM
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i remember when i first discovered the interwebz, then i was shown how to check post dates ha ha.
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