2 Conductor wiring tower speakers

[Laptom]

Hi guys,
I asked before, but I didn't get a satisfied anwser (most likely the anwser were correct, but I really didn't get it :o ).

Our original CC tower speakers set are connected via a 2 wire conductor harness to a Clarion APX280 2 channel amp.
Because the four speakers are setup in parallel in setups of 2 the amplifier sees on each channel 2ohm and therefore.

So originally you'll get around 18V to the speakers (P= (U^2) /2 -> U= sqrt(P*R)=160*2=18V). This is quite easy to follow for me.

But now I want to put a Clarion 480 four channel amp to these four speakers with a 2 wire conductor harness... I heard from mikeski that you will need to bridge the 4 channels to 2 channels and to serilize the speakers. So the speakers will get to 8ohm. The bridged channel will be double the Voltage to around 36V. But how I now calculate is that the power will still be 160W to the speakers... I hope that something I do is wrong, but I really could use somebody's help with this. MikeSki?!

Thanks, Tom

[DanielC]

RE: 2 Conductor wiring tower speakers

Is it possible to change your speakers from 4 ohm speakers, to 8 ohm speakers?
By using 8 ohm speakers, you could parallel them, and the amp would see a four ohm resistance.
You might also consider a higher power amp that will work into a 2 ohm resistance.

[Laptom]

RE: 2 Conductor wiring tower speakers

Hi Daniel,
I wish I could find a solution that the amp would see 4ohm with 2 speakers.. but I find it strange that with a serial setup and 480 amp I still have the same power to the speakers as with a parallel setup and 280 amp. It should be possible to get more power to the tower speakers without changing the wiring harness.

If not, I will propably look for a good 2ohm stable 2ch amp;
Or install new wires in the tower;
Or both.

I'm using the standard 2007 setup at the moment.

[DanielC]

I am sure you are familiar with ohm's law, E=I*R, and Watts law, P=I*E.
E=volts I=amps R=resistance P-watts
I am putting this here, because I am sure you understand the electrical laws, but somebody else reading this thread may not.
I know you can combine the two laws, using square roots, and squaring some numbers, but I find it easier, especially in my head to do an ohms equation first, and then do a power equation.
When you hook up two 4 ohm speakers in parallel, the total resistance of the pair of speakers is 2 ohms.
When you hook up two 4 ohm speakers in series, the total resistance of the pair of speakers is 8 ohms.

Lets say for example, your amp is capable of putting out 8 volts into 8 ohms, and is also stable into a 2 ohm load, meaning it is still capable of producing 8 volts, into that 2 ohm load without destroying itself.
8 volts into 2 ohms will allow 4 amps to flow. This is a parallel connection.
E=R*I
8 volts times 4 amps = 32 watts in the speakers.
P=E*I

8 volts into 8 ohms will allow 1 amp to flow. This is a series connection.
E=R*I
8 volts times 1 amp = 8 watts of power
P=E*I

Notice how changing from a parallel setup in my example, to a series setup cut the power to 1/4 of what it was with the parallel setup.
Notice also in my example, going to a Parallel setup increased the current by a factor of four. Plan your wire gauge accordingly. The amp will also be able to control the speaker cone easier with a larger wire size

[EarmarkMarine]

Laptom,

Don’t sweat the technical details.

Your 4-channel amplifier (480) bridged into 2-channels and driving an 8-ohm load will be, for all practical purposes, the equivalent of a 2-channel amplifier (280) run stereo and driving a 2-ohm load. However, the 480 does have substantially more heat sink and more power supply.

A 10 or 15 percent power differential is negligible since it will require that you double your power to achieve a 3dB increase in acoustic output.

Any scenario that you’ve explored thus far is acceptable except that you don’t want to bridge your particular amplifier into a 2-ohm load. Bridging has the effect of halving the actual speaker load.

Formulas never pan out exactly as the applied science does because it doesn’t consider all variables. Disregarding the amplifiers output section, the power supply of your amp is the true limiting factor and it has a maximum capacity regardless of the load. Seldom, despite theory, does an amplifier truly double its power into half the load.

So your current plan is sound. Series the speakers up top. Run two conductors per side (existing). Bridge the four-channel amplifier into an 8-ohm load (effectively 4-ohms).

And, if you ever decide to upgrade your tower harness it is a painless procedure given you already have an existing harness as a pull.

David
www.earmarkmarine.com

[Laptom]

Hi Earmark and DanielC,

Thanks for clarifying this! I'll do the following this winter then. Get the second 480 out of the package and install the towerspeakers bridged onto it. The 280 will be for the sub and the 2 free channels from the first 480 will be wired to the bow speakers.

Now looking for a small second sub for in the back of the boat and that should be sufficient for us. Not looking for a NVS/Wetsound quality of sound, but with a minimal investment and time the system should be inproved a bit...

Thanks again!