Can I connect a 100W 3ohm center speaker to an amp rated at 100W 8ohm for the center channel?

Question

I have a Sony STR-DB795 receiver amp rated at 7 x 100W, 8ohms. I am looking at a variety of center speakers and one I like (cosmetically) is a Sony model rated at 100W, 3 ohms. Can I run this speaker from my rec/amp safely or will there be problems?

Answer 1

No you can't. The resistance is very important in speaker setups. If you mismatch you will either blow the speaker or the amp. You need to match resistances always. This is basic electronic theory, but you probably don't want to hear it.

Just thought I would respond to the other answers. First you need to always match the resistance. Wattage makes no difference. Second in general there are only two ohm options, 4 ohm or 8ohm. In general when you buy speakers separately they are 8ohm. When you buy a home theater in a box they are 4 ohms. If you mix the impedance you will usually blow the speaker or the amp. I will spare you the circuit theory behind this.

Answer 2

3 ohms is a very unusual value for a speaker impedance, especially a center speaker. The problem you have is that this speaker will draw more current from the amp than it is designed for, and that can cause overheating and failure of the amp output stages. However, the power drawn by a center speaker is very low even at loud volumes. That is because the center speaker carries only voices and does not handle low frequencies. It is the low frequencies that place the highest power demand on an amplifier. Therefore it is extremely unlikely you will damage your amp. Two or three watts from your center speaker will sound very loud, and will match 50 to 100 watts from the bass below 50Hz. However, 3 ohms is such a low impedance, it could possibly affect the performance of your amp as far as distortion and frequency range is concerned, so it is better to get a speaker 6 ohms or higher.

NOTE: With tube or FET output stage amplifiers impedance matching is important. You find these amps only in very high end audio system and their cost runs to the thousands. Amps for ordinary people use transistor output stages which will drive a wide range of impedances. These amps output more power into low impedance speakers. There is a lot of confusion between maximum power and operating power, and as long as you are running your amp well below maximum power, there will be no problem no matter what your speaker impedance is. As I said above, it is only very low frequencies that demand anything close to maximum power from an amp.

Answer 3

This is not a good idea as that it will draw too much
from the amplifier and will overheat it which may
cause permanent damage to the amp as well
as the speaker. I suggest that either you
find a mono amp that will drive this
center channel, or even better,
get an 8-Ohm CC speaker.

If you can find a matching center speaker to go with the rest
of your surround speaker system, this will give you the best
balance in your system. If there is not a specific center chan-
nel offered with your speakers, stick with the same brand if
possible to get a similarly voice matched center channel.

H a p p y
H o m e
T h e a t e r i n g !

Answer 4

I'm not saying you're wrong, but are you sure about 3-ohm impedance? Most Sony home speakers are run-of-the-mill 8-ohms.

You will damage the amplifier. With impedance it is best when matched (8ohm Amp > 8ohm speaker). The impedance of the speaker can be higher, not lower, than the impedance of the amp (You could use a 16ohm speaker although you would not get maximum power transfer).

Answer 5

Could add padding impedances in the form of power resistors to make up the required value. It will not be as efficent as running the required impedance/power rated speaker however.

Answer 6

no you should get a speaker the same wattage as the receiver. otherwise the speaker or the receiver could blow up (not literally).