Using Crossover to change impedence

[mr_ruready 10+ year member]

Can you use a crossover to change the impedence load presented to an amp?

I.E.- Can I use a crossover to provide a 2-ohm load to an amp using a single 4-ohm VC sub?

If possible, what design would I use?

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[squeak9798 5,000+ posts]

No.

You could use a resistor in parallel with the sub to present a different impedance to the amplifier (4ohm resistor in parallel with the 4ohm voice coil for a final 2ohm load)....but that's a worthless fix, since even though the amplifier would be outputting it's 2ohm power, half of that power would be wasted as heat by the resistor...leaving the subwoofer to only receive the same amount of power as it would have been if wired directly to the amplifier at 4ohms.

There was an older product produced by Veritas and Stinger called the Accumatch....but they are pretty hard to find, and even then there are mixed reviews about them. I guess they went pop pretty easily, and most people were very unhappy with the performance of their speakers when having the Accumatch connected.

So, overall....you're just screwed //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif Which is why having DVC subwoofers comes in handy.....

 

[jrz126 10+ year member]

I think its possible to do that, but any extra power that is put out by the amp will just go into the crossover and be burned up as heat.

It would be the same thing as wiring a 4 ohm resistor in parallel with the speaker, sure the amp will be putting out more power, but it wont be going into the speaker.

 

[mr_ruready 10+ year member]

Thanks Squeak,

I just read PAC's Passive Crossovers made easy. I see that adding a 4-ohm coil would give me the 2-ohm load, but with a 6db (75%) loss of power.

 

[JimJ 5,000+ posts]

You can't do it with simple inductors and capacitors, but there are products out there that use autotransformers to shift the impedance load.

http://www.google.com/search?hl=en&lr=&safe=off&q=Zero+autotransformer+paul+speltz

That's an example of a (very pricey) one //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[ramos 5,000+ posts]

Edumacate me my brothers //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif Isn't doing this pointless as squeak said. Meaning the sub will see the same power regardless. Any extra power will be turned into heat in the resistors. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif