4 ohm/8 ohm

[wooly]

First time posting here. Alot of good info to be had.

I have a HK AVR140 along with older, now out of business, Audiosphere Research Profiles (4 ohm) with I think sound great along with 4 ohm surrounds.

It seems that most receiver/amplifiers are designed to work best with 8 ohm speakers. So why are 4 ohm speakers even made? What is the advantage and disadvantages of them?

 

[billnchristy]

4ohm being lower resistance usually allows an amp to make more power...ohms law and all.

I think a lot of times maybe that perfect driver just isnt available in a higher resistance and the speaker ends up being under 8ohm.

 

[markw]

"allow" and "force" can have dissimilar meanings here.

4ohm being lower resistance usually allows an amp to make more power...ohms law and all.

...and, by that token, you could say it forces the amp to work a lot harder. That's why some manufacturers advise against using them.

That's kinda like saying that by loading your car's trunk with bricks it allows it to use more of it's limited, available power.

 

[agarwalro]

Donno why but I have noticed that the impedance goes down as the speaker size increases.

Tweeter (16-32 ohms)
Mid (8-16 ohms)
Woofer (4-8 ohms)
Sub-woofer (2-4 ohms)

Also series and or parallel combinations of the speakers effects the total. Eg. Axiom M60 is 8 ohms while the M80 is 4 ohms. If you look closely, M80 has double the speaker combination of the M60. Its basically like having 2x M60's in parallel.

 

[billnchristy]

Of course there are tradeoffs to everything.

If you want to make more power you will make more heat and need beefier components.