Speaker wiring for low impedance

[Sguirrelfeather]

Due to poor planning on my part, and the need for some of the subs to work on a different amp, I need to hook up my speakers in a different way than I am used to, and I would like to know two things: If I am doing this right and if it will negatively affect anything in my system.

So, I have a FSD FZ2600D amp which is stable down to 1 Ohm. I have four dual voice coil speakers, each rated at 4 Ohms. If I wire three of the speakers in series, I will have three impedances of 8 Ohms. If I wire the fourth in parallel it will be at 2 Ohms. Now then, if I wire the speakers, with those impedances, in parallel, I would have a "seen" impedance, by the amp, of 1.1429 Ohms. Is that correct?

And once you've got the math all worked out, will having three speakers in series and one in parallel, with the group of them all in parallel mess anything up?? I'm trying to get it as close to 1 Ohm as possible without going below that.

Thanks in advance!

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[dubstepper1000]

You can do this, however, the speaker with the least about of impedance will have power than the others, making it much more louder than the other three. What you could do at your own risk is wire them all in parallel with each other, resulting in a final impedance of 0.5 ohms. The amp will be able to operate at this impedance but it won't be "stable" which just means that if you allow it to, it will push more power than it is made to push. As long as you are careful with how high you tune your gain knob, it shouldn't be a problem. Otherwise the speakers will not be balanced.

 

[Sguirrelfeather]

Anyone else? I've got some advanced education with electronics, but audio drivers were not included in that. lol See, to me it seems that it does not matter because the voice coil is still 4 Ohms, no matter what you do. Changing the way they are wired only changed how the amplifier sees the load....but the load within the voice coil is still the same. At least this is how it would work in the field I was educated in. Is this not the case for audio?

 

[paulmarsh1222]

 

[paulmarsh1222]

Also what dubstepper said is correct but remember this is at your own risk. You can either do the 2 ohm configuration like the diagram above or the .5 ohm. Most people won't recommend that option but it's up to you. You just have to be careful as not to fry the amp. When you post questions like this you should give us the model of your sub also so we know exactly what you're working with.

 

[adulbrich 5,000+ posts]

DO NOT DO IT.

The drivers won't see equal power....

Wire up higher, like to 2 ohms

 

[paulmarsh1222]

DO NOT DO IT.
The drivers won't see equal power....

Wire up higher, like to 2 ohms

Definitely your best option in this case. Always match your amp to your subs needs and you won't run into these problems.

 

[sherrod833 10+ year member]

Pick up another 2600 and strap them at 2 ohms.

 

[Sguirrelfeather]

Or I suppose I could just pick up new subs, which would be cheaper than another FZ2600. lol Well, sorta cheaper. I only have two subs hooked up to it right now. The other two were a future thought. So, since I currently have two HDS208's w/dual 4 Ohm voice coils, and PLAN on getting two HDS210's, I should probably just get the 210's in 2 Ohm, and get two more 208's at 2 Ohm as well? This way I could wire the two 208's in the tline to .5 Ohm, wire the other two 210's in another box to .5, and then wire those in series to get 1 Ohm? Would that be suitable?

 

[adulbrich 5,000+ posts]

Or I suppose I could just pick up new subs, which would be cheaper than another FZ2600. lol Well, sorta cheaper. I only have two subs hooked up to it right now. The other two were a future thought. So, since I currently have two HDS208's w/dual 4 Ohm voice coils, and PLAN on getting two HDS210's, I should probably just get the 210's in 2 Ohm, and get two more 208's at 2 Ohm as well? This way I could wire the two 208's in the tline to .5 Ohm, wire the other two 210's in another box to .5, and then wire those in series to get 1 Ohm? Would that be suitable?

No no no no no no no.....

Don't use different sized subs in your car. Running different subs together is super ghetto. Why would you add two 10's when you already have 8's???

 

[Sguirrelfeather]

Ghetto because you say so? I've seen setups on here with different sized subs in the same vehicle, so it can't be all that ghetto! lol In all honesty, with the new tline with the 208's, it's loud, it sounds good, it puts out some **** loud bass, but it's missing something. It's just not rich and full sounding....if that makes sense. My old box, which is two JBL 10" in a sealed box, can't get the same volume, or hit the same notes, but sounds so much more full and rich by comparison.....but is also lacking. So I hooked em both up and all of the gaps were filled in! The tline is in the back of the Excursion. The sealed box is in between the front seats. I figured I would get the 210's and experiment with box designs to see what gives me that same richness from those.

 

[BoogerMan]

Ghetto because you say so? I've seen setups on here with different sized subs in the same vehicle, so it can't be all that ghetto! lol In all honesty, with the new tline with the 208's, it's loud, it sounds good, it puts out some **** loud bass, but it's missing something. It's just not rich and full sounding....if that makes sense. My old box, which is two JBL 10" in a sealed box, can't get the same volume, or hit the same notes, but sounds so much more full and rich by comparison.....but is also lacking. So I hooked em both up and all of the gaps were filled in! The tline is in the back of the Excursion. The sealed box is in between the front seats. I figured I would get the 210's and experiment with box designs to see what gives me that same richness from those.

Short answer: it causes sound cancellation. If you are referring to the guys that have like 8s or 10s in their door panels, that's a different story. They aren't running different sized subs in their box. They will have all 12s or all 15s or all 18s etc.

Long answer:

If you have two sound sources creating the same sound at the same time/amplitude/etc, there is of course a large change of cancellation. Wave cancellation is when waves of equal energy collide in such a way as you effectively dimish their energy. You can have cancellation without the sound waves being completely cancelled. Some freqs will be diminished, some may even be amplified due to wave reinforcement (same freq/amplitude waves close enough together to reinforce each other, opposite of cancellation).

The bottom line is the result will be an uneven frequency response, and one that likely will be all over the place. An EQ could adjust for it somewhat, but not completely.... and I really dont see the advantage of trying to do it.

You are simply trying to reproduce a bandwidth of frequencies accurately. A sub in a sealed enclosure gives a nice smooth flat response along the entire bandwidth usually, where as a ported box peaks output at a certain point, dropping off drastically below but remaining relatively flat above this freq (why low tuned boxes can have excellent SQ, contrary to what some people believe). So, why add another speaker of another size/brand/whatever that's going to complicate things?

The only real way Ive heard of mixing sub sizes effectively was with a fairly compex xover setup so each sub size played its own frequency band. But you also have to consider how well each sub will perform in its particular bandwidth, how well they will blend together, the transfer function of the vehicle and its huge impact on the sound, etc. Things get very complicated.

From

http://www.caraudio.com/forums/subwoofers/91716-mixing-sub-sizes.html

But hey, if it sounds better to you, then who cares what we say //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif everyone has a preference and opinion.

 

[Sguirrelfeather]

I can see how that could definitely be a possibility. I guess that would all depend on cabin gain, box placement, etc. All I know is that right now, having the two separate boxes, sounds great. I do, however, have them hooked up to different amps, so that may be why. I'll try hooking them all to the same amp and see what happens. It may sound like total crud! Can't hurt to try though. lol

 

[n2audio 5,000+ posts]

Anyone else? I've got some advanced education with electronics, but audio drivers were not included in that. lol See, to me it seems that it does not matter because the voice coil is still 4 Ohms, no matter what you do. Changing the way they are wired only changed how the amplifier sees the load....but the load within the voice coil is still the same. At least this is how it would work in the field I was educated in.

If you have education in electronics you should be capable of basic circuit analysis.

If you have 1.14 ohms and ~2500w at that impedance you have about 53v.

The 2 parallel with 8 parallel with 8 parallel with 8...

Parallel circuit so V is the same through all loads.

I = 53/2 and 53/8 which is 26.7 and 6.7

53 x 26.7 = 1415w through the 2 ohm load. 53 x 6.7 = 355w through the 8 ohm loads.

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The only way I know of to do different sub sizes correctly would be to have them only working in specific frequency ranges like -- big subs 50hz and down. Smaller subs 50-100. Component woofers 100+.

 

[Papermaker85 5,000+ posts]

that last chart is wrong. WTF they thinking?