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Discussion Starter #1
I am trying to wire a pair of 8" 4ohm woofers that have dual voice cones to a 2 channel zapco amp. After visiting many forums and seeing the wiring diagram from the rockford fosgate link below, I still have questions.

Rockford Fosgate® - Woofer WiringWizard

From that diagram, it would appear that option 2 where it maintains 4 ohms is how I should proceed. But my question is that since my amp is 2 channel, how does this effect wiring regarding the second channel?

Also, I wondered if I can have my system drop down to 2 ohms to get more power out of the amp?

Finally, does bridging my amp to mono work better than using the 2 channel amp in stereo?

Any suggestions or diagrams for how I should hook up the amp and speakers would be much appreciated.

Thanks,
 

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My answer would depend on whether or not your subs will share a common airspace or have separate channels. Your amplifier will make the same amount of power bridged into 4 ohm mono as it will in 2 ohm stereo. If your amp is stable into 2 ohms stereo/4 ohms mono, this is the configuration at which it will make the most power. Some amps (often called high current amps) are stable into lower impedances. all amplifiers make the most power at the lowest impedance they are stable at, although they often run hotter and draw much more current.

In all liklihood your amp is among the 90% of amps that make the most power at 2 ohms stereo 4 ohms mono. Your dual 4 ohm voice coil subs can be wire either with the coils in series for an 8 ohm load or in parallel for a 2 ohm load. If you wire the subs coils in parallel you could use your amplifier in 2 ohms stereo. This would give you the ability to keep stereo bass, but since the subs are typically mounted in the rear (and mounted together) and 99% of bass is in mono, this really isn't much of an advantage. And, if your subs share a common airspace you could experience cancellation if you do encounter stereo bass. So if you want to bridge your amp to 4 ohms mono, you can then wire those 2 subs with their 2 ohm loads in series to get a single 4 ohm load, or you could wire each subs coils in series to obtain an 8 ohm load for each sub and then wire the subs in parallel to get the same 4 ohm load. Typically it is easier to wire the voice coils in series and the subs in parallel. I would therefore recommend you go ahead and wire them in this configuration to your amp bridged into a single 4 ohm load..
 

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Discussion Starter #3
My answer would depend on whether or not your subs will share a common airspace or have separate channels. Your amplifier will make the same amount of power bridged into 4 ohm mono as it will in 2 ohm stereo. If your amp is stable into 2 ohms stereo/4 ohms mono, this is the configuration at which it will make the most power. Some amps (often called high current amps) are stable into lower impedances. all amplifiers make the most power at the lowest impedance they are stable at, although they often run hotter and draw much more current.

In all liklihood your amp is among the 90% of amps that make the most power at 2 ohms stereo 4 ohms mono. Your dual 4 ohm voice coil subs can be wire either with the coils in series for an 8 ohm load or in parallel for a 2 ohm load. If you wire the subs coils in parallel you could use your amplifier in 2 ohms stereo. This would give you the ability to keep stereo bass, but since the subs are typically mounted in the rear (and mounted together) and 99% of bass is in mono, this really isn't much of an advantage. And, if your subs share a common airspace you could experience cancellation if you do encounter stereo bass. So if you want to bridge your amp to 4 ohms mono, you can then wire those 2 subs with their 2 ohm loads in series to get a single 4 ohm load, or you could wire each subs coils in series to obtain an 8 ohm load for each sub and then wire the subs in parallel to get the same 4 ohm load. Typically it is easier to wire the voice coils in series and the subs in parallel. I would therefore recommend you go ahead and wire them in this configuration to your amp bridged into a single 4 ohm load..
YES the woofers will be in the same box sharing the same airspace. Also, my amp can run 2ohm stable so that is not a problem.

What I want is the best sounding bass (SQ), not loudest bass (SQL) from the setup. To give more info, the speakers are Image Dynamics ID8V.3 4 ohm driven by Zapco 350.2 (2 channel amp).

So are you recommending running the subs in parallel and amp bridged into single 4 ohm load?
 

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I would do it that way too. any left right differences would be summed.
 

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My answer would depend on whether or not your subs will share a common airspace or have separate channels. Your amplifier will make the same amount of power bridged into 4 ohm mono as it will in 2 ohm stereo. If your amp is stable into 2 ohms stereo/4 ohms mono, this is the configuration at which it will make the most power. Some amps (often called high current amps) are stable into lower impedances. all amplifiers make the most power at the lowest impedance they are stable at, although they often run hotter and draw much more current.

In all liklihood your amp is among the 90% of amps that make the most power at 2 ohms stereo 4 ohms mono. Your dual 4 ohm voice coil subs can be wire either with the coils in series for an 8 ohm load or in parallel for a 2 ohm load. If you wire the subs coils in parallel you could use your amplifier in 2 ohms stereo. This would give you the ability to keep stereo bass, but since the subs are typically mounted in the rear (and mounted together) and 99% of bass is in mono, this really isn't much of an advantage. And, if your subs share a common airspace you could experience cancellation if you do encounter stereo bass. So if you want to bridge your amp to 4 ohms mono, you can then wire those 2 subs with their 2 ohm loads in series to get a single 4 ohm load, or you could wire each subs coils in series to obtain an 8 ohm load for each sub and then wire the subs in parallel to get the same 4 ohm load. Typically it is easier to wire the voice coils in series and the subs in parallel. I would therefore recommend you go ahead and wire them in this configuration to your amp bridged into a single 4 ohm load..
This is the best, detailed, well structured, description of this process that I have ever read.
Well done.

Bret
PPI-ART COLLECTOR
 

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Yes... DVC subs prevent extra wiring complexity especially for the novice. How I would wire your system is as follows: Take a short (1 foot) piece of 2 conductor speaker wire and separate the wire down the middle so that you have 2 1 foot pieces with one conductor each. Looking at one of your DVC subs, you will see 2 terminals, each have a positive terminal and a negative terminal. Run a piece of your wire from the POSITIVE terminal on one coil to the NEGATIVE terminal on the other coil. Wire both subs like this. This will wire the coils in series, so that each subwoofer presents an 8 ohm load. When you run the wires to the amplifier, connect the 2 conductor speaker wire to the unused positive and negative terminals of each sub. If you run separate wire from each subwoofer to the amplifier, you would run both positive conductors to the bridged mono positive terminal on the amplifier, and both negatives to the negative terminal. This is parallel wiring. If you are using only one speaker wire from the amp to the box, you may Y the wires together at any point along the way including inside the box.
 

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Discussion Starter #7
Yes... DVC subs prevent extra wiring complexity especially for the novice. How I would wire your system is as follows: Take a short (1 foot) piece of 2 conductor speaker wire and separate the wire down the middle so that you have 2 1 foot pieces with one conductor each. Looking at one of your DVC subs, you will see 2 terminals, each have a positive terminal and a negative terminal. Run a piece of your wire from the POSITIVE terminal on one coil to the NEGATIVE terminal on the other coil. Wire both subs like this. This will wire the coils in series, so that each subwoofer presents an 8 ohm load. When you run the wires to the amplifier, connect the 2 conductor speaker wire to the unused positive and negative terminals of each sub. If you run separate wire from each subwoofer to the amplifier, you would run both positive conductors to the bridged mono positive terminal on the amplifier, and both negatives to the negative terminal. This is parallel wiring. If you are using only one speaker wire from the amp to the box, you may Y the wires together at any point along the way including inside the box.
Wow, that was an awesome explanation. Im sure that this will be helpful for many more to come. I was confused as to whether to run in paralled or series, and the answer is both (Speakers in Series / Amp in Paralled).

The last questions I had is with this setup is if I wire following your instructions what will be my ohm load? Im guessing 4 ohm.
 

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if the DVCs are 4ohm each coil, then yes 4 ohms.

1) each sub has (2) 4ohm coils.
2) run each sub series to 8ohms
3) run the sub to your amplifier in parallel to 4 ohms.

the actual formula is: 1 / (1/R1 + 1/R2)
 

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if the DVCs are 4ohm each coil, then yes 4 ohms.

1) each sub has (2) 4ohm coils.
2) run each sub series to 8ohms
3) run both subs to your amplifier in parallel to 4 ohms.

the actual formula is: 1 / (1/R1 + 1/R2)

1 / (1/8 + 1/8) = 4
 

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if the DVCs are 4ohm each coil, then yes 4 ohms.

1) each sub has (2) 4ohm coils.
2) run each sub series to 8ohms
3) run both subs to your amplifier in parallel to 4 ohms.

the actual formula is: 1 / (1/R1 + 1/R2)

1 / (1/8 + 1/8) = 4
You just had to bring math into it didn't you. :mean:

Bret
PPI-ART COLLECTOR
 

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You just had to bring math into it didn't you. :mean:

Bret
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lol, well I AM a math major. :D

always nice to know where these miracle numbers we come up with come from :p
 

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lol, well I AM a math major. :D

always nice to know where these miracle numbers we come up with come from :p
True.
I think I would have probably not disliked it so much if so much of it wasn't demanded during my college years pursuing aerospace engineering.
I started to finally lose my desire for anymore of it once I got to differential equations and abstract applications.
Fortunately, that was as far as I had to go.

But I loved, Loved, LOVED physics.

Bret
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True.
I think I would have probably not disliked it so much if so much of it wasn't demanded during my college years pursuing aerospace engineering.
I started to finally lose my desire for anymore of it once I got to differential equations and abstract applications.
Fortunately, that was as far as I had to go.

But I loved, Loved, LOVED physics.

Bret
PPI-ART COLLECTOR
really? interesting..............calculus is definitely challenging. I found multivariable calc harder than differential equations though.
 

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really? interesting..............calculus is definitely challenging. I found multivariable calc harder than differential equations though.
That's how it goes sometimes.
I remember trigonometry coming to me better than college algebra.

Most of the time, it came down to having a really great teacher to get the concept across.

Bret
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That's how it goes sometimes.
I remember trigonometry coming to me better than college algebra.

Most of the time, it came down to having a really great teacher to get the concept across.

Bret
PPI-ART COLLECTOR
see trig was not all that hard, but it pissed me off that what you had to take 34 steps to do in trig you could accomplish with 5 in calc, lol

complettely agree. teacher made all the world of difference
 

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see trig was not all that hard, but it pissed me off that what you had to take 34 steps to do in trig you could accomplish with 5 in calc, lol

complettely agree. teacher made all the world of difference
Forgot about that.
I remember the teacher stating, "Ok, forget about all that you learned in Trig because here's how you really solve these."

WTF?!?!?

Bret
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Discussion Starter #17
I love how this thread has evolved into a discussion about math.

Stereo wiring and math, two subjects in which I know very little.
I did pass Calculus in College but cannot remember a single thing. Sometimes when its a requirement, you learn just enough to satisfy it. That and being just above the curve. :)
 

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Forgot about that.
I remember the teacher stating, "Ok, forget about all that you learned in Trig because here's how you really solve these."

WTF?!?!?

Bret
PPI-ART COLLECTOR
EXACTLY! 2 years down the drain! lol

I love how this thread has evolved into a discussion about math.

Stereo wiring and math, two subjects in which I know very little.
I did pass Calculus in College but cannot remember a single thing. Sometimes when its a requirement, you learn just enough to satisfy it. That and being just above the curve.
he he, it happens, lol

you would be amazed at how much math goes into audio, lol.
 
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