Wiring AMP/Speakers Question

[hobbesateclavin]

I have an Alpine MRP-T220 2 channel amp that I want to connect to a Bazooka RS804DV 8" Dual Voice Coil Subwoofer and want to know the best way to wire it to maximize it's power.

I'd like to run it so that I get 70 watts x 2 at 2 ohms - so how do I wire it to do that?

Bazooka Subwoofer Tube Specs:
8" dual voice coil woofer
frequency response 39-1,500 Hz
handles 200 watts RMS (each coil)
sensitivity 102 dB

Alpine Amp Specs:
50 watts RMS x 2 at 4 ohms
70 watts RMS x 2 at 2 ohms
140 watts RMS x 1 bridged output at 4 ohms
stereo or bridged mono output
4-ohm stable in bridged mode
MOSFET power supply

[GScivic7]

I guess you could wire the sub for 2 ohms and connect it to just one channel. One the sub itself run a wire from + to + and - to - then leads off of that to just one channel on the amp, and don't bridge the channels. That amp and sub don't really match up that well....

[hobbesateclavin]

Originally Posted by GScivic7

I guess you could wire the sub for 2 ohms and connect it to just one channel. One the sub itself run a wire from + to + and - to - then leads off of that to just one channel on the amp, and don't bridge the channels. That amp and sub don't really match up that well....

Well I'm not looking to pound the pavement with it, just add some low end bump. But I know I should move up to a higher wattage amp to really take advantage of what the sub is capable of.

[hobbesateclavin]

Originally Posted by GScivic7

I guess you could wire the sub for 2 ohms and connect it to just one channel. One the sub itself run a wire from + to + and - to - then leads off of that to just one channel on the amp, and don't bridge the channels. That amp and sub don't really match up that well....

Why not bridge the two channels on the amp?

[b16a3sol]

from the website you posted:

"Dual Voice Coils: The woofer has two 4 ohm voice coils, and each coil can handle up to 200 watts RMS (400 watts peak). Each voice coil has its own set of input terminals. Gold-plated bridge plates (jumpers) are included to connect the two sets of terminals together for connection to a mono or bridged amplifier. When the bridge plates are installed, the voice coils are wired in parallel with each other, so the woofer presents a 2 ohm mono load. With the bridge plates installed, the Bazooka may be connected to a mono, or bridged, amplifier capable of delivering up to 400 watts RMS. When the bridge plates are removed, each coil may be connected to a different amplifier channel, and each channel will see a 4 ohm load. With the bridge plates removed, each set of terminals can be connected to a stereo amplifier capable of delivering up to 200 watts RMS per channel."

"Warning Note: If you will be using an amplifier that cannot handle a 2 ohm mono load, the bridge plates should be removed, and each set of terminals should be connected to a separate channel on a stereo amplifier. Connecting this subwoofer, with the bridge plates installed, to a mono, or bridged, amplifier that is not 2 ohm stable will result in amplifier damage."

[hobbesateclavin]

Originally Posted by GScivic7

I guess you could wire the sub for 2 ohms and connect it to just one channel. One the sub itself run a wire from + to + and - to - then leads off of that to just one channel on the amp, and don't bridge the channels. That amp and sub don't really match up that well....

If I connect them that way would this amp be a better choice? Alpine MRD-M300?

[Icantgetno]

Without a doubt you want the mono amp for that application, the first amp you linked does not list a 2 ohm stability in a bridged wiring scheme, typicaly if it aint listed and you do it you are likely to get a cloud in your car that stinks of fryed amplifyer. Besides, a Mono amp usualy has more tunability specificly for sub frequencys due to the fact that it is intended for subwoofer use. Get the monoblock run the sub parralell and you will be glad you did.
"Set the cut-off point for the subsonic filter from 15-50 Hz (in 5 Hz steps) and use the digital parametric EQ (which allows you to control the width of the equalization curve, as well as the center point) to improve overall sound."
this was copyed from the page you linked, this is a great feature with a smaller sub as it will cut the lower frequencys from being amplified therefor not wasting the power on freqs your sub wont reproduce.

[hobbesateclavin]

Originally Posted by GScivic7
I guess you could wire the sub for 2 ohms and connect it to just one channel. One the sub itself run a wire from + to + and - to - then leads off of that to just one channel on the amp, and don't bridge the channels. That amp and sub don't really match up that well....

Originally Posted by hobbesateclavin

If I connect them that way would this amp be a better choice? Alpine MRD-M300?

So I got the Alpine Mono Amp listed above and I connected the Bazooka dual voice coils in parellel to the amp.

Am I running a 2 ohm load now?
How much wattage is each voice coil getting then?

[Icantgetno]

Yes you are now running 2 ohms if you have it wired properly (someone mentioned bridging plates... good idea). It has been a while since I studyed the theoretical aspects of the wiring so im not positive but since an electrical charge seeks the path of less resistance then they should be getting an equal amount, once again just a guess but i would assume half. How does it sound?

[b16a3sol]

if you use the alpine mrd-m300, and wire the sub to make a 2ohm impedance, then you are putting 300w. still a little low for that sub, but its much better than what you had before.

[Icantgetno]

Dont forget to mount that tube tight... lotsa people just lay them in the trunk and loose a lot of sound quality. A firmly mounted sub ALWAYS sounds better.

[hobbesateclavin]

Originally Posted by Icantgetno

Yes you are now running 2 ohms if you have it wired properly (someone mentioned bridging plates... good idea). It has been a while since I studyed the theoretical aspects of the wiring so im not positive but since an electrical charge seeks the path of less resistance then they should be getting an equal amount, once again just a guess but i would assume half. How does it sound?

It sounds pretty good for an 8" tube. Way better than the kenwood that I had before (8" dual voice coil as well, but was self-amplified - only 60 watts RMS per voice coil)

I bought the Bazooka used so I didn't get any bridge plates with it. Know where I can get one(s)?

Right now I am just connecting the two channels with line of 16G speaker wire. For this amps power should I be running 14G speaker wire? I only have 10G power/ground running from battery to amp so I know that I could be getting a bit more punch if I upgrade the wires, but I don't really want to run 8G power/ground under the carpet again. Will going to 14G speaker wire from amp to sub make much diffference given the 10Gpower to the amp?

[Icantgetno]

Not realy but a 4G power and ground probably would. I assume contacting bazooka would get you the plates.