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Mighty Noid said:
Nope... it would be either a single 2 ohm load or a single 8 ohm load.
Okay.

What would the load be with a 6 ohm speaker and a 4 ohm speaker?
 

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Speakers in Parallel
Zt = (Za x Zb) / (Za + Zb)


Zt = (Za x Zb) / (Za + Zb)
Zt = (4 x 4) / (4 + 4)
Zt = 16 / 8
Zt = 2 ohms

Speakers in Series
Zt = Za + Zb


Zt = Za + Zb
Zt = 4 + 4
Zt = 8 ohms
 

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The rating as you've spec'd it is at DC, which is not where speakers actually operate. To truly know the impedance presented to the amplifier, you need to specify the whole characteristics of the speakers. Putting two dissimilar speakers in serial can create a situation where one gets damaged and the other isn't working hard enough (in an extreme case).

Putting them in parallel can also create a situation where one is working harder than the other.

If you want good advice, you need to give as much detail as possible on model numbers and specifications, as well as what amplifier you hope to drive them with and how you want to use them.

If it was easier, there'd be no reason to have so many different ones!
 

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You could get kinda close by running them in parallel and putting a 1 ohm resistor in front of them...
I say kinda close because the voice coils respond to the transient frequencies differently than the resistor will.
 

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Mighty Noid said:
well it depends how you wire up the two speakers together...

either series or parallel....

not sure if you are trying to test me on what I know or not... :)
I wasn't testing your knowledge, just needed an answer to my situation.

I have a 4 ohm amp in my JVC headunit. I have 3 1/2" speakers in the dash @ 4 ohms and I have mids in the doors at 6 ohms. They are currently wired in series, because that's the way I had the 2 ohm OEM speakers wired after I changed the HU. Just wondered what ohms I have now in series and what I would have in parallel?

P.S.
Had the mids for another project, but never used them.
 

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BigBoy said:
I wasn't testing your knowledge, just needed an answer to my situation.

I have a 4 ohm amp in my JVC headunit. I have 3 1/2" speakers in the dash @ 4 ohms and I have mids in the doors at 6 ohms. They are currently wired in series, because that's the way I had the 2 ohm OEM speakers wired after I changed the HU. Just wondered what ohms I have now in series and what I would have in parallel?

P.S.
Had the mids for another project, but never used them.

In series they are at 10 ohms, in parallel they would be at 2.4 ohms. Keep them in series.

Rob
 

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robbyho said:

In series they are at 10 ohms, in parallel they would be at 2.4 ohms. Keep them in series.

Rob
Thanks.

Still a work in progress.
 

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well.. Mids & Highs should almost always be wired in parallel... Usually the speakers themselvs have frequency filters built in so they only play in the range they are designed to play... this will cause your speakers to "fight" and it may sound really goofy.. (tinny highs, and muted voices, with those speakers that you mentioned).

Setting them up in parallel won't cause the full 2.6 ohm load... as they are putting resistance on different parts of the frequency range.

You are probably safe hooking the speakers is parallel.

To do this right, you should find yourself 2 Passive Crossovers... and properly get the things wired together. This will sound the best, make the most noise, and also be the easiest on your head unit.
 

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It's always good to have a second opinion. Thanks.
 

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lafrad said:
well.. Mids & Highs should almost always be wired in parallel... Usually the speakers themselvs have frequency filters built in so they only play in the range they are designed to play... this will cause your speakers to "fight" and it may sound really goofy.. (tinny highs, and muted voices, with those speakers that you mentioned).

Setting them up in parallel won't cause the full 2.6 ohm load... as they are putting resistance on different parts of the frequency range.

You are probably safe hooking the speakers is parallel.

To do this right, you should find yourself 2 Passive Crossovers... and properly get the things wired together. This will sound the best, make the most noise, and also be the easiest on your head unit.
That is absolutely correct! I designed and built 3 passive crossovers two days ago, yet I forgot to mention this.

If they are in parallel with a passive crossover designed to seperate them at 500 hz, the head unit will see 6 ohms below 500 hz and 4 ohms at 500 hz and up.

Send me a pm if you want me to design you some passives for them. The parts will only cost $10 or so, and if you can solder, it is easy.

Rob
 

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Even speakers rated at X ohms aren't at various frequencies.

One thing not even mentioned here is polarity. Make sure you've got them figured out as to which way they drive, or you may be cancelling out sound.

I agree, wire them in parallel. Listen for distortion at high levels, if you hear it, back off on the amp. Distortion kills speakers.
 
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