Subwoofer Hookup Advice

Hi all,

I'm looking for some advice on the hookup of subwoofers.....

I want to hook up 2x 10" 4Ohm Dual voice coil subs to a 2 channel amplifier.  My head unit has L+R Subwoofer Pre outs...what would be the best way to hook this all up? 

Amp is a Phoenix Gold Ti600.2, subs are Boston Acoustics G510 4Ohm Dual Voice Coils and the head unit is an Alpine CDA-7998.

Also, when amp specs mention max power is at 2Ohm load, is that 2Ohm's per channel, or overall for the amp?

Any help much appreciated.

Cheers

http://photos.yahoo.com/hotvwnz

Yes, you are correct...run the RCA's into the amp imputs.  You then have the choice of running the subs one to a channel, or wiring the subs together (shown here) and bridging to the amp's bridged terminals.  The load on the amp and the power the subs get will be the same either way.  You just connect the best way for your setup:  e.g. the subs are in two separate enclosures, use the stereo hookup.  If they are sharing the same enclosure, you'll have less wiring by using the bridged method.

The only benefit you would have by using a mono amp would be less power needed from the car as it would be a more efficient amp.  But a two channel amp will work just fine for what you have and would have better specs, too.

The amp is rated at a minimum stereo load of 2 ohms, and 4 ohms bridged.  If you were going to hook one sub to each channel, the wiring for each sub would look like this:

You'll notice the difference in wiring of the voice coils in the two illustrations.  Decide how you are going to hook up to the amp, then wire the voice coils of the subs as needed.

Thanks stevdart, that is awesome info!

So are there any pro's/cons of running stereo subs over mono?  I plan on having two enclosures, so will need to go for the 2nd method...

Even though you will have two enclosures, it can still be wired in either method. I would still use method one myself, quite sure Stevdart would as well.

Thanks guys,

My amp is rated at the following;

150Wx 2 @ 4Ohm Stereo. 300W x 2 @ 2Ohm Stereo. 600W x 1 @ 4Ohms Bridged.

Rated Minimum Speaker Loads are Bridged = 2Ohms or Stereo = 1 Ohm. How do I know if this is stable or not?

So, for method one wiring, the 2 subs "present" a 4 Ohm load to the amp, and when running bridged at 4Ohms, the amp can generate 600W x 1 (so each sub will see 300W)...is this correct?   Forbidden, what are your reasons for choosing method one wiring (bridged) over method 2 (stereo subs).

Poetic got a little mixed up on the impedance of your subs.  You said they are DVC 4 ohm, which means that each voice coil is 4 ohm.  The illustrations are correct.  Now, look at the specs for the amp that you posted:  300W X 2 @ 2 ohm stereo.  That is what you get if each sub is wired as in figure 2 and each take a channel.  600W X 1 @ 4 ohm bridged:  that is the minimum ohm load the amp can take.  It is the same output, as you can see, as the output rating at 2 ohm stereo.  1 X 600 = 2 X 300.  Poetic, again, is under the impression that the act of bridging increases power from the amp...that is an old fable.  The amp ratings alone are proof, but Ohm's Law is better proof.  (There's your bash, poetic!) 

nzbug, your statement   "Rated Minimum Speaker Loads are Bridged = 2Ohms or Stereo = 1 Ohm.  How do I know if this is stable or not?"  is incorrect.  The minimum rating is exactly what you posted in last post.  2 ohm stereo or 4 ohm bridged.  You can't go to a lower ohm load than that.  With your equipment, you won't.

Your last statement is correct.  And when Rob speaks...I listen, and learn.  Let me see if I get this right, from reading the hundreds of posts that I have on the subject of mono vs. stereo with subs, particularly those from Rob: 

It's not the difference in power, which there isn't any.  And it's not a matter of what wiring looks best.  It's the impact you ultimately get when both subs are fed exactly the same signal, at exactly the same power.  While wiring in stereo will net you the same power to each, the signals will be different and the amp output will (most likely) be somewhat different from channel 1 to channel 2.  Even when both channels are set as precisely as possible with a meter when you're setting it up, a slight change can occur somewhere down the line. 

Wiring main speakers in stereo is necessary, of course, but not subwoofers.  You don't benefit from stereo separation when the frequencies are that low.  So, bridging the amp gives you the best and easiest power to two subs, separate enclosures or not. 

The subs will perform with more authority.

So Rob...did I get it?

Thanks again stevdart for clearing that up for me! 

Your thoughts, (and Robs) is great advice, and explains everything I wanted to know.....now all I have to do is wire it up ;)

Cheers guys...very much appreciated...

Mark

Stevdart, you missed a couple of things, one being more important than the other. This is the box. While in this case he may be using two separate boxes, quite a few boxes are designed as a coupled chamber design, for those that do not know what this means, it means two subs or more sharing the same enclosure. Thus it is viewed as a mono box and should be fed with a mono signal. A second thought just came to me, and that is most of the amplifiers used for subs are mono by design anyhow. (not in this case though) The wiring method may be more suited to the amp, than the subs. In this case his choice of amp and subs and box made the determining factor for me. Lastly, you use a little less speaker wire when wiring in method 1.

nzbug, as far as the wiring of the actual subs go, it may be easier than you think. More and more subs these days have multiple input terminals on them on the + and 1 inputs to each coil. This is done solely for ease of wiring in series or parallel circuits. Some of the drivers have spring loaded terminals where it is easy to insert a couple of wires into them. Look at the terminals to figure out what kind you have.