ohms question (1 Viewer)

[MikeHeath]

Hi all,

Can somebody help me understand ohms and how they work in respect to speakers/amps. Have a 4 ohm subwoofer and a 8 ohm amplifier. What is the pro's/con's to hooking this up? Can I hook it up. Will it damage anything? Sorry I am new to this home theatre and I am trying to learn as I go.

Thanks for any help.

 

[Michael R Price]

I don't think there is any such thing as an "8 ohm" amplifier. If an amplifier is not rated to drive certain loads (such as 4 ohms or less) that means it probably can't achieve maximum power, or could overheat or be damaged attempting to deliver high output for a long time.

There is little danger in hooking a 4 ohm load to such an amplifier- go ahead, it'll work fine. I once accidentally connected a 4 ohm speaker to a pretty weak amp and bridged it, making the speaker effectively 2 ohms... and I played it pretty loud with no problem. You're just seeing an indication that the amp is not very strong.

 

[Scott Sabin]

Most amps can take a 4 Ohm load, although you really shouldn't push your luck if your amp is truly expecting a 6 or 8 Ohm load.

Ohms are a measure of electrical resistance. The higher the number, the more resistance to drawing current. Current draw from an amp produces heat and it is the limiting factor for how powerful an amp goes. Most amps put out X watts at 8 Ohms, 2X at 4 Ohms, and that's simply due to the fact that a 4 Ohm load draws twice the current as an 8 Ohm load. AVRs generally have a setting allowing you to setup your receiver for 8 Ohm speakers, or 4 OHms. Not all, but many of them do.