QuestionQUESTION: I want to know what would be the best amp or amps for my subs. I have 2 10" rockford fosgate subs, model P3D410 and 1 15" rockford fosgate T215D4 all in one box. Will one amp be sufficent to run these 3 subs or will I need more than one? If one can do it, which one should I go with?
ANSWER: Ouch! Unfortunately you don't want to mix subs sizes. Especially in the same box. If you want decent bass without distortion, all subs should be same size/type in their own enclosure withing the dimensions given by the manufacturer. This can be all done in one enclosure if built right. See my site for that info http://spkrbox1.spaces.live.com
If you really want to keep this setup and possibly do more harm than good, you can. Just expect problems (ie. tuning, distortion, equipment replacement, etc.).
The two 10" subs can handle 400 watts RMS each or 800 together.
The 15" has no problem with 1000 watts RMS
So a mono 800 watt RMS @ 2 ohm for the 10"'s and a mono 800-1000 watt RMS @ 2 ohm amps. The 15" is a 4 ohm DVC (Dual Voice Coil) and would be wired for 2 ohm as shown in the following link.
http://i81.photobucket.com/albums/j230/sparky3489/SINGLE-PARALLEL.jpg
This brings up another issue which has nothing to with sub sizes but would require some elctrical upgrades - power management.
The amount of current required to run such a system is too much for a stock alternator to handle.
A second battery is never a good idea as it's an added strain on the alternator to charge two batteries AND supply power for the car. The ONLY time a second battery is useful is if the audio system is to be used with the car off in SPL competitions.
Note: The real power plant of the car is the alternator. The ONLY purpose of the battery is to start the car and run the acceesories with the engine off including the sound system.
Since you would be in the 1600 watt RMS+ range you will need to:
1. Upgrade the alternator to a high output alternator
2. Upgrade to a heavy duty deep cycle battery
3. Upgrade the "Big 3" - that is to replace the power wire between the battery and alternator, the ground from the battery to the chassis and the ground strap from the engine/tranny to the chassis with at least 2 AWG wire.
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QUESTION: Would I still be in the same boat if my 3 subs were all separated from each other but still in the same box?
Answer"This can be all done in one enclosure if built right." This is because the 10's will have their recommended size and the 15" will have a bit bigger enclosure. If you can afford it, look to a custom fiberglass enclosure if you want it for show as well.
You could make a box with the 15" in the center of the two 10"s by simply joinging boxes. Building one solid box with dividers would be quite a task.
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