# 1 DVC sub 2 amps?



## Badmunky (Mar 9, 2009)

Ok so my friend and I where talking and he suggested that I use the 2 amps I have to power 1 of the 12" subs that I have.

So here are the specs for every thing.

12" sub. Kicker Comp RV. 2006 model.
Dual 2 ohm VC. 400 watts RMS power total. (200 watts per coil.)

2 amps.
50 x 2 @ 4-ohms
100 x 2 @ 2-ohms
200 x 1 @ 4-ohms (Was going to do one amp like this.)
300 x 1 @ 2 ohms. (2 amps like this)

He said that I could put 600 watts to the sub this way instead of the 200 watts I was going to feed it. 

But I have never put 2 amps on 1 sub before. Is this even worth trying?
Will I even notice any real change in how the sub performs over just the 1 amp? 
Only down side I see right now is I will now need another amp to power my front stage as I was going to use one of the amps I have now for that.

Thanks.


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## 89grand (Nov 23, 2006)

Badmunky said:


> Ok so my friend and I where talking and he suggested that I use the 2 amps I have to power 1 of the 12" subs that I have.
> 
> So here are the specs for every thing.
> 
> ...


You can use two amps to power 1 DVC sub.

It's hard to say how much you'd gain by using two amps at 600 watts vs 1 at 200. You wouldn't gain anything if you don't need more than 200 watts to power the sub for your system. Plus that Kicker sub may be rated to handle 400 watts but that doesn't mean it continues to get louder as more power is applied. It may reach it's maximum output at 250 watts or 300 maybe 150 watts, unless it was tested who knows really.

Beware of anyone saying you'll get 4.5db's louder because that isn't a given at the power level you are talking about.


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## SubNit (Nov 5, 2008)

~600 watts is pushing it for that sub. However you should notice a gain in output coming from 200 to 600, that's just a given

I take it you have 2 of the exact same amps?


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## Badmunky (Mar 9, 2009)

^Yes two of the same amp.
I was running 1 amp on each sub as I also have 2 if the 12" subs but I needed trunk space.

I'm looking to run just one of the 12"s.

I may need to just buy a bigger Mono block amp.

I did some looking and did not find an amp that would push 500 watts RMS @ 4-ohms that would not only fit under my seat but was not to expensive.

I like the PDX1.600. Its the right size to go under the seat and has more power then I need but is way more then I can spend.

Later.


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## 89grand (Nov 23, 2006)

What about this amp? They are small and no too expensive.

STL1.600D - Soundstream 600W RMS Mono Block D Class Stealth Power Amplifier

You can probably find it cheaper on ebay too.


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## Badmunky (Mar 9, 2009)

^ That's not a bad price for 400 watts RMS @ 4-ohms.

Any one used that amp?


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## Oliver (Jun 25, 2007)

MRP-M1000 - Alpine 1000 Watt Mono Subwoofer Amplifier


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## Badmunky (Mar 9, 2009)

^ That amps is not only out of my price rang. But is to big for where I need to put it.

Thanks thou.


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## br85 (May 2, 2008)

Be extra careful to gain match properly (i.e. make sure both amps are pushing exactly the same power with a given input). Turning both gain knobs to the same apparent position will NOT suffice.


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## Badmunky (Mar 9, 2009)

br85 said:


> Be extra careful to gain match properly (i.e. make sure both amps are pushing exactly the same power with a given input). Turning both gain knobs to the same apparent position will NOT suffice.


THAT is the kind of info I was looking for when I posted this in the first place.

How would I even go about making sure of that?

FYI I'm just interested at this point and am not going to do it.


Thanks.


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## Oliver (Jun 25, 2007)

Badmunky said:


> Ok so my friend and I where talking and he suggested that I use the 2 amps I have to power 1 of the 12" subs that I have.
> 
> So here are the specs for every thing.
> 
> ...


This is a great way to go into debt 

As you learn from your mistakes....


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## Badmunky (Mar 9, 2009)

a$$hole said:


> This is a great way to go into debt
> 
> As you learn from your mistakes....


Not only dose your post not make any sens to me.

But it is of no help ether.

I asked the question to prevent from making a mistake in the first place.
And I have no intention of spending any money any time soon on my cars audio system. I may however spend some money in July for my birth day.

This was just me trying to get an answer on a topic that a friend suggested and I know nothing about!

If you had read the last post I made you would know that I have intentions of actually power my sub with the 2 amps I have.

Was just an idea I wanted some info on.

Later.


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## rockinridgeline (Feb 2, 2009)

I agree with the comment about gain matching. If you don't gain match the amps exactly you get a situation where there is different signal being applied to each voice coil. You want the exact same signal. This is one of those deals where in theory it sounds like it will work but actual application may be tough to pull off. It would take someone with the correct equipment and knowledge to make it work.


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## pagustin (Mar 1, 2009)

Not that I have done this myself but I think you would ideally want an oscilloscope to measure the output of each amp so that the are set exactly the same. This is the only way I can think of right now to match properly.

Sorry if this doesn't make sense I've been up for 11 hours with 3 hours sleep. Work is fun!

P


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## 89grand (Nov 23, 2006)

It wouldn't hurt the sub if the signals going to each coil weren't exactly the same. The speaker wouldn't care. You can use a stereo l/r signal to run a DVC speaker and you won't have the same exact signal going to each coil.

I never recommend using a multi meter to set gains, but you could use one in this case with a test tone and get them both pretty close. Pretty close is good enough.


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## rockinridgeline (Feb 2, 2009)

I agree that it would not hurt the sub. However, it wouldn't be best for sound quality to have two different signals. You have two voice coils attached to the same former. Each voice coil needs to get the same information for the best sound quality. A speaker translates an electrical input into mechanical motion which creates a sound wave. Ulimately what we all want is an exact mechanical representation of the signal coming in, which will produce a soundwave to match the electrical wave. If you have two different amplitudes hitting the voice coil, you get something in between on the output. If I am wrong, somebody correct me. I've been wrong before....just ask my wife!


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## 89grand (Nov 23, 2006)

That's not true, that the output will be the average between the two signals on the two coils, if that were the case, using only one coil would give you only half the output in regards to the input power you gave it. Besides we're not talking about gross differences here even setting it by the gain markings on the amp.

Sound quality also would not suffer one bit. They are just two coils connected to the same cone. It's no big deal. DC subs only exist to give you impedance options to best match the amp you are using.


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## rockinridgeline (Feb 2, 2009)

So are you saying that the gain on the second amp can be half of the first amp and there will be no difference in SQ? What if it is 1/4 the output?

I think your logic is faulty. If the difference between the signal to the two coils doesn't matter (you said it wouldn't change SQ one bit), then why bother hooking up the second voice coil to the second amp? What do you gain?

If what you are saying is true, then hooking up the second amp makes no difference other than the negative fact that it is sucking power from your electrical system.


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## rockinridgeline (Feb 2, 2009)

Let me clarify. I am not saying that two amps will sound the same. The extra power applied to the 2nd voice coil should create more force on the woofer cone due to the attraction and repulsion to the magnet assy.

I am just attacking the logic that there is no difference if the amps are not gain matched. Theoretically I think there must be a difference, but I am not sure how that would relate to the audible performance of the woofer.


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## 89grand (Nov 23, 2006)

rockinridgeline said:


> So are you saying that the gain on the second amp can be half of the first amp and there will be no difference in SQ? What if it is 1/4 the output?
> 
> I think your logic is faulty. If the difference between the signal to the two coils doesn't matter (you said it wouldn't change SQ one bit), then why bother hooking up the second voice coil to the second amp? What do you gain?
> 
> If what you are saying is true, then hooking up the second amp makes no difference other than the negative fact that it is sucking power from your electrical system.


Yes, even if the gain on the second amp was 1/4 of the first amp it would not effect SQ at all. Let me ask you, what would it do to the sound quality, add distortion or what? I don't understand your sound quality argument here, it has no effect on it nor should it. Output wise probably, but sound quality wise, no.

Like I said, DVC subs only exist to give you impedance options, that's it, well other than increasing the subs power handling because there are two coils, but that's just by default, not necessarily that it was designed with two coils specifically for that. There are gains to using both coils, but SQ is not one of them. Let's say you have a D4 sub, if you have an amp that does 300 watts @4 ohms, and 500 @ 2 ohms, you would get more power out of the amp and to the speaker using both coils in parallel although efficiency goes down on DVC subs compared to an identical single coil sub so I'm not sure how much of an output gain you actually get. You can wire the coils in series or parallel to match your amp or by using series and parallel wiring for multiple subs.

You can use just one coil if you want to, but it can effect the T/S perimeters so you need to know what effect using just one coil has when designing the enclosure.


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## rockinridgeline (Feb 2, 2009)

So output and SQ are independent of each other? Unrelated? Crap, I wish I hadn't spent all of that money on those big stinking amps. 


I don't think so. You are basically saying that having two different amplitude signals applied to the voice coils that reside in the same magnetic field is no different than having two signals that are the same. You say that there might be an amplitude difference, but somehow that is not related to sound quality. How is amplitude unrelated? Maybe we are hung up on terms? When I say SQ, I mean amplitude (or output) as one of the characteristics. Are we agreeing on that?

I think saying that the T/S parameters change if you only use one coil, but that only using one coil doesn't effect sound quality is also a contradiction.


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## 89grand (Nov 23, 2006)

rockinridgeline said:


> So output and SQ are independent of each other? Unrelated? Crap, I wish I hadn't spent all of that money on those big stinking amps.
> 
> 
> I don't think so. You are basically saying that having two different amplitude signals applied to the voice coils that reside in the same magnetic field is no different than having two signals that are the same. You say that there might be an amplitude difference, but somehow that is not related to sound quality. How is amplitude unrelated? Maybe we are hung up on terms? When I say SQ, I mean amplitude (or output) as one of the characteristics. Are we agreeing on that?
> ...


Output and sound quality have nothing to with each other if they did, your stereo system would sound like **** when the volume was low.

Two signals going to different coils will not effect the sub other than the potential for a decrease in output. Now if you are calling sheer output sound quality, then you have the terms mixed up. They are two separate things completely. But I still maintain that the potential for lost output is not that great when the coils are powered differently or one is not powered at all, and it has no effect on sound quality.

The T/S parameters have nothing to do with SQ or output either, they were designed to make enclosure calculations.


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## squeak9798 (Apr 20, 2005)

89grand said:


> if that were the case, using only one coil would give you only half the output in regards to the input power you gave it.


Well, technically only running a single coil results in a 3db loss in sensitivity (half the Bl), which _is_ half the acoustic power.


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## 89grand (Nov 23, 2006)

squeak9798 said:


> Well, technically only running a single coil results in a 3db loss in sensitivity (half the Bl), which _is_ half the acoustic power.


Yeah, what he was saying was that if one coil received full power and one received half that power the coil with half power would drag the full power coil down by 25%. What I said was if that was the case, running one coil with the other disconnected with result in only 50% of the output which it wouldn't.

I'm not talking about the overall sensitivity of the subwoofer.


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## subwoofery (Nov 9, 2008)

Don't want to jump in and start a fight... but I have read on the Image Dynamics forum (can't seem to find the thread) that not having the same power going to each coil can damage the cone - like coils fighting each other rather than working together... 

Kelvin


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## subwoofery (Nov 9, 2008)

Don't want to jump in and start a fight... but I have read on the Image Dynamics forum (can't seem to find the thread) that not having the same power going to each coil can damage the cone - like coils fighting each other rather than working together... 

Kelvin


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## sqshoestring (Jun 19, 2007)

If the amps were getting the same mono signal, and were in proper working order, and will live at 2 ohms bridged, then they should present the same exact signal to the DVC sub. All an amp does is apply voltage to the coil, then the opposite polarity to drive it the other way. If one amp is applying slightly less voltage that coil will have a little less force on the cone. However it will still be the same signal, just a little less of the same signal. The sub would have slightly less output. It is likely you could pull the RCA on each in turn to match them by ear, or just use a good RMS DMM to check the voltage out of each amp on a test tone.

If one coil has 100% power, any power the other coil gets with the same signal is going to increase output. I'm not sure it would be that linear, but each coil does the same thing. If the small signal is quite small it may not make much difference, ie if you have 100w and 10w because 10 additional w will hardly change SPL. If the second amp was out of phase, then surely it would reduce output. I would guess that the same total wattage from one amp applied to an identical SVC would have about the same output, although as mentioned above SVC are said to be a little more efficient.

The only time you must match power on a DVC is when you are just about to burn it up, and you don't want one coil to toast before the other when you are pushing max SPL out of it. A DVC works just like a tandem bicycle.


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## subwoofery (Nov 9, 2008)

Don't want to jump in and start a fight... but I have read on the Image Dynamics forum (can't seem to find the thread) that not having the same power going to each coil can damage the cone - like coils fighting each other rather than working together... 

Kelvin


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## 89grand (Nov 23, 2006)

subwoofery said:


> Don't want to jump in and start a fight... but I have read on the Image Dynamics forum (can't seem to find the thread) that not having the same power going to each coil can damage the cone - like coils fighting each other rather than working together...
> 
> Kelvin


I would say that is false.


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## subwoofery (Nov 9, 2008)

Shouldn't have said anything lol


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## my6x9s (Apr 15, 2009)

i have done this in the past on the old punch75s to a single 15" back in the day we used a 60hz tone to simulate the ac wave found in most houses in the usa then used a resistive load and or just a sub you have to use as a load. with you voltage meter or dmm attached place it on ac voltage run your test tone 60hz then adjust the volume to a mid point and slowly adjust the gain level to a voltage with the load. press pause on the source unit
rewire your load and rewire up your voltmeter or dmm to the other amp and now continue the 60hz tone and slowly adjust the gain till it is the same as the fist voltage
this is the cheapest way i know to balance the two amps to match the load without a oscilloscope method. and if the signals are delayed it may cause you to get a lil out of phase.. but it worked like a charm for us back in the day and i dont think much has changed other than they make strapable amps that now to do this.


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## my6x9s (Apr 15, 2009)

i have done this in the past on the old punch75s to a single 15" back in the day we used a 60hz tone to simulate the ac wave found in most houses in the usa then used a resistive load and or just a sub you have to use as a load. with you voltage meter or dmm attached place it on ac voltage run your test tone 60hz then adjust the volume to a mid point and slowly adjust the gain level to a voltage with the load. press pause on the source unit
rewire your load and rewire up your voltmeter or dmm to the other amp and now continue the 60hz tone and slowly adjust the gain till it is the same as the fist voltage
this is the cheapest way i know to balance the two amps to match the load without a oscilloscope method. and if the signals are delayed it may cause you to get a lil out of phase.. but it worked like a charm for us back in the day and i dont think much has changed other than they make strapable amps that now to do this.


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